Have you ever thought of making a coding template for yourself to accelerate your android development? As a Computer Science student studying in Universiti Malaya. I have an exam of a course called “WIA2007: Mobile Application Development” (MAD). This course requires us to code an android app within 3 hours. I find that most of the code used in Android development is actually redundant and reusable. Hence I came up with an idea of doing a template myself.
According to my course, I have learnt the concept of navigation, fragment, activity, database, storage and so on. So I am going to break down my template into parts and explain what they does. Before I begin I just want to appreciate if you are able to support me on https://ko-fi.com/szeyusimwhere this is booster to my motivation to create more wonderful product in the future!
Starting from activity, I have create a code template file called CustomNavigatorMainActivity.java. It is a custom main activity java template code for navigation-based android applications. In the code, I have set up navigation component including side navigation drawer, bottom navigation, toolbar as well as overflow menu. Hence saving time for me to code a navigation based app.
Below are the code template for CustomNavigatorMainActivity.java
/** * Created by Sim Sze Yu * GitHub: https://github.com/szeyu/Awsome-Android-Code-Template * * This template is part of the WIA2007 Mobile Application Development Course * Bachelor of Computer Science (Artificial Intelligence) * Universiti Malaya * * Licensed under MIT License * Copyright (c) 2025 Sim Sze Yu * * Custom main activity template for navigation-based Android applications. * Features: * - Navigation component setup * - Drawer and Bottom Navigation integration * - Toolbar with navigation handling * - Overflow menu for additional options * * Usage: * 1. Replace `${PACKAGE_NAME}` with your actual package name * 2. Ensure `nav_graph.xml` and required menu files exist * 3. Add dependencies for Navigation Component and Material Design */
@Override public boolean onOptionsItemSelected(MenuItem item) { int id = item.getItemId(); if (id == R.id.action_settings) { // Handle settings navigation // Option 1: Navigate using NavController // NavigationUtil.navigateTo(activity, R.id.settingsFragment);
// Option 2: Navigate using Intent // NavigationUtil.navigateTo(activity, SettingsActivity.class); return true; } else if (id == R.id.action_about) { // Handle the "About" action (e.g., show a dialog) return true; } return super.onOptionsItemSelected(item); }
Although the abstraction of room database implementation really hide a lot of details to implement the database with SQLite, room database is actually one of the most redundant code that I will ever come across with. I think since that the code is so redundant to code every time, so making it into a code template is a good choice!
DAO
Data Access Object (DAO) interface is used to code CRUD operations and include SQL Queries. So I have implement a template for it called CustomDAO.java
Code template for CustomDAO.java
/** * Created by Sim Sze Yu * GitHub: https://github.com/szeyu/Awsome-Android-Code-Template * * This template is part of the WIA2007 Mobile Application Development Course * Bachelor of Computer Science (Artificial Intelligence) * Universiti Malaya * * Licensed under MIT License * Copyright (c) 2025 Sim Sze Yu * * Room Database DAO (Data Access Object) interface template. * Features: * - Basic CRUD operations * - LiveData support for reactive programming * - Customizable query methods * - Asynchronous database operations * * Usage: * 1. Create your entity class * 2. Extend this DAO interface * 3. Add custom queries as needed */
// Replace ${PACKAGE_NAME} with your package name // Replace ${DAO_NAME} with your DAO interface name // Replace ${MODEL_NAME} with your data model class name // Replace ${TABLE_NAME} with your database table name
@Dao public interface ${DAO_NAME} {
@Insert void insert(${MODEL_NAME} item);
@Update void update(${MODEL_NAME} item);
@Delete void delete(${MODEL_NAME} item);
@Query("SELECT * FROM ${TABLE_NAME}") LiveData<List<${MODEL_NAME}>> getAllItems();
@Query("SELECT * FROM ${TABLE_NAME} WHERE id = :itemId LIMIT 1") LiveData<${MODEL_NAME}> getItemById(int itemId); }
Database
This database code is mostly fixed and use the same code every time. And I call it CustomDatabase.java
Code template for CustomDatabase.java
/** * Created by Sim Sze Yu * GitHub: https://github.com/szeyu/Awsome-Android-Code-Template * * This template is part of the WIA2007 Mobile Application Development Course * Bachelor of Computer Science (Artificial Intelligence) * Universiti Malaya * * Licensed under MIT License * Copyright (c) 2025 Sim Sze Yu * * Room Database singleton template for Android applications. * Features: * - Thread-safe singleton implementation * - Database instance management * - Migration handling * - Fallback to destructive migration * * Usage: * 1. Define your database entities * 2. Add your DAOs * 3. Access using getInstance() method */
// Replace ${PACKAGE_NAME} with your package name // Replace ${DATABASE_NAME} with your database class name // Replace ${MODEL_NAME} with your data model class name // Replace ${DAO_NAME} with your DAO interface name
@Database(entities = {${MODEL_NAME}.class}, version = 1, exportSchema = false) public abstract class ${DATABASE_NAME} extends RoomDatabase {
This repository code are the code that use DAO to interact with RoomDatabase and I call it CustomDatabase.java
Code template for CustomRepository.java
/** * Created by Sim Sze Yu * GitHub: https://github.com/szeyu/Awsome-Android-Code-Template * * This template is part of the WIA2007 Mobile Application Development Course * Bachelor of Computer Science (Artificial Intelligence) * Universiti Malaya * * Licensed under MIT License * Copyright (c) 2025 Sim Sze Yu * * Repository pattern implementation for data operations. * Features: * - Single source of truth principle * - Async operation handling * - LiveData integration * - Clean architecture compliance * * Usage: * 1. Initialize with your DAO * 2. Implement data operations * 3. Use with ViewModel */
// Replace ${PACKAGE_NAME} with your package name // Replace ${REPOSITORY_NAME} with your Repository class name // Replace ${DAO_NAME} with your DAO interface name // Replace ${MODEL_NAME} with your data model class name // Replace ${DATABASE_NAME} with your Room database class name
public class ${REPOSITORY_NAME} {
private final ${DAO_NAME} dao; private final LiveData<List<${MODEL_NAME}>> allItems; private final ExecutorService executorService;
public ${REPOSITORY_NAME}(Application application) { ${DATABASE_NAME} db = ${DATABASE_NAME}.getDatabase(application); dao = db.${DAO_INSTANCE_NAME}(); allItems = dao.getAllItems(); executorService = Executors.newFixedThreadPool(2); }
public LiveData<List<${MODEL_NAME}>> getAllItems() { return allItems; }
public LiveData<List<${MODEL_NAME}>> getItemById(int itemId) { return dao.getItemById(itemId); }
public void insert(${MODEL_NAME} item) { executorService.execute(() -> dao.insert(item)); }
public void update(${MODEL_NAME} item) { executorService.execute(() -> dao.update(item)); }
public void delete(${MODEL_NAME} item) { executorService.execute(() -> dao.delete(item)); } }
Model
This model represent a Room Database Entity Model which already have basic data structure and primary key configuration set up. User can edit the field that needed according to the need.
Code template for CustomModel.java
/** * Created by Sim Sze Yu * GitHub: https://github.com/szeyu/Awsome-Android-Code-Template * * This template is part of the WIA2007 Mobile Application Development Course * Bachelor of Computer Science (Artificial Intelligence) * Universiti Malaya * * Licensed under MIT License * Copyright (c) 2025 Sim Sze Yu * * Room Entity model template for data structure. * Features: * - Room Entity annotations * - Primary key configuration * - Basic data structure setup * - Common field implementations * * Usage: * 1. Define your entity fields * 2. Add necessary Room annotations * 3. Implement getters and setters */
// Replace ${PACKAGE_NAME} with your package name // Replace ${MODEL_NAME} with your data model class name
@Entity(tableName = "${TABLE_NAME}") public class ${MODEL_NAME} {
@PrimaryKey(autoGenerate = true) private int id;
// Add your fields here private String title; private String content; private String imagePath; private String audioPath; private long timestamp;
// Empty constructor public ${MODEL_NAME}() { }
// Getters and Setters // For each field, create public getter and setter methods
public int getId() { return id; }
public void setId(int id) { this.id = id; }
// Repeat for other fields }
UI
These consist of all the code that user can use to interact with the components of the XML layout. I will help you to speed up your backend setup to link with your frontend development.
Adapter
This is a RecyclerView Adapter template which implement the ViewHolder pattern, click listener interface, data binding and list management methods.
Code template for CustomAdapter.java
/** * Created by Sim Sze Yu * GitHub: https://github.com/szeyu/Awsome-Android-Code-Template * * This template is part of the WIA2007 Mobile Application Development Course * Bachelor of Computer Science (Artificial Intelligence) * Universiti Malaya * * Licensed under MIT License * Copyright (c) 2025 Sim Sze Yu * * CustomAdapter template. */
// Replace ${PACKAGE_NAME} with your package name // Replace ${ADAPTER_NAME} with your Adapter class name // Replace ${VIEW_HOLDER_NAME} with your ViewHolder class name
public class ${ADAPTER_NAME} extends RecyclerView.Adapter<${ADAPTER_NAME}.${VIEW_HOLDER_NAME}> {
public interface OnItemClickListener { void onItemClick(${MODEL_NAME} item); }
public void setOnItemClickListener(OnItemClickListener listener) { this.listener = listener; }
public ${ADAPTER_NAME}(List<${MODEL_NAME}> itemList) { this.itemList = itemList; }
@NonNull @Override public ${VIEW_HOLDER_NAME} onCreateViewHolder(@NonNull ViewGroup parent, int viewType) { View view = LayoutInflater.from(parent.getContext()) .inflate(R.layout.${ITEM_LAYOUT_NAME}, parent, false); return new ${VIEW_HOLDER_NAME}(view); }
@Override public void onBindViewHolder(@NonNull ${VIEW_HOLDER_NAME} holder, int position) { ${MODEL_NAME} item = itemList.get(position); holder.bind(item, listener); }
@Override public int getItemCount() { return itemList != null ? itemList.size() : 0; }
public void setItemList(List<${MODEL_NAME}> newList) { this.itemList.clear(); this.itemList.addAll(newList); notifyDataSetChanged(); }
public static class ${VIEW_HOLDER_NAME} extends RecyclerView.ViewHolder { // Define your view components here private final TextView textViewTitle; private final TextView textViewSubtitle;
public ${VIEW_HOLDER_NAME}(View itemView) { super(itemView); // Initialize your view components textViewTitle = itemView.findViewById(R.id.tv_card_title); textViewSubtitle = itemView.findViewById(R.id.tv_card_subtitle); }
public void bind(final ${MODEL_NAME} item, final OnItemClickListener listener) { // Bind data to your views // Example: textView.setText(item.getTitle()); textViewTitle.setText(item.getTitle()); textViewSubtitle.setText(item.getSubtitle());
These components files are just created for defining the logic of the component quicker. Feel free to contribute more components to my GitHub.
CustomInfoButton.java implement custom image button with Material Design integration and click handling. CustomFormControls.java consist of a collection of form control component logic including radio, checkbox, switch, autocomplete text view, spinner dropdown and button
Code template for CustomFormControls.java
/** * Created by Sim Sze Yu * GitHub: https://github.com/szeyu/Awsome-Android-Code-Template * * This template is part of the WIA2007 Mobile Application Development Course * Bachelor of Computer Science (Artificial Intelligence) * Universiti Malaya * * Licensed under MIT License * Copyright (c) 2025 Sim Sze Yu * * Custom form controls activity implementing various interactive UI components. * Features: * - RadioGroup with multiple radio buttons * - Checkbox group with multiple selections * - Switch component for toggling options * - AutoCompleteTextView with sample data * - Spinner dropdown with predefined options * - Button to submit selections * * Usage: * 1. Inflate the layout `activity_custom_form_controls.xml` * 2. Call `setupRadio()`, `setupCheckbox()`, etc., in `onCreate()` * 3. Handle user interactions using event listeners */
/** * Created by Sim Sze Yu * GitHub: https://github.com/szeyu/Awsome-Android-Code-Template * * This template is part of the WIA2007 Mobile Application Development Course * Bachelor of Computer Science (Artificial Intelligence) * Universiti Malaya * * Licensed under MIT License * Copyright (c) 2025 Sim Sze Yu * * Custom ImageButton implementation for information display. * Features: * - Material Design integration * - Built-in click handling * - Customizable appearance * - Easy integration with activities and fragments * * Usage: * 1. Add to your layout XML * 2. Customize appearance through attributes * 3. Set click listener for actions */
public class InfoButton extends AppCompatImageButton implements View.OnClickListener {
public InfoButton(Context context) { super(context); init(); }
public InfoButton(Context context, AttributeSet attrs) { super(context, attrs); init(); }
public InfoButton(Context context, AttributeSet attrs, int defStyleAttr) { super(context, attrs, defStyleAttr); init(); }
private void init() { // Set up the button (e.g., set image resource) setImageResource(R.drawable.baseline_info_24); // Replace with your actual drawable setOnClickListener(this); }
@Override public void onClick(View v) { // Handle the click event, e.g., show a dialog or toast // You can also define an interface to communicate back to the activity } }
Fragment
I have made 2 important and commonly used Fragment which are CustomListFragment.java and CustomEditModelFragment.java.
CustomListFragment is a fragment template that displays a list of items using RecycleView, ViewModel and NavigationUtil. It support different layout managers and item click navigation.
CustomEditFragment is a fragment template that allow for editing a specific model entity by ID. It integrates ViewModel for data binding and form validation, using NavigationUtil for navigation
Code template for CustomListFragment.java
/** * Created by Sim Sze Yu * GitHub: https://github.com/szeyu/Awsome-Android-Code-Template * * This template is part of the WIA2007 Mobile Application Development Course * Bachelor of Computer Science (Artificial Intelligence) * Universiti Malaya * * Licensed under MIT License * Copyright (c) 2025 Sim Sze Yu * * CustomListFragment Template. * Features: * - Displays a list of ${MODEL_NAME} items using RecyclerView, a ViewModel, and NavigationUtil. * - Offers options for different LayoutManagers. * - Handles item clicks to navigate to another fragment. * * Usage: * 1. Replace placeholders with your specific names: * - ${PACKAGE_NAME}: Your package name (e.g., com.multimediajournalapp.peoplemory.ui.fragments) * - ${FRAGMENT_NAME}: The name of this fragment (e.g., PeopleListFragment) * - ${MODEL_NAME}: Your model class name (e.g., Person) * - ${ADAPTER_NAME}: Your adapter class name (e.g., PersonAdapter) * - ${VIEW_MODEL_CLASS}: Your ViewModel class name (e.g., PersonViewModel) * - ${LAYOUT_RESOURCE}: The layout resource (e.g., R.layout.fragment_people_list) * - ${RECYCLER_VIEW_ID}: The RecyclerView id (e.g., R.id.recycler_view_people) * - ${NAVIGATION_ACTION_ID}: Navigation action id (e.g., R.id.action_peopleListFragment_to_editPersonFragment) * - ${ITEM_ID_KEY}: The key for the item's id in the bundle (e.g., "personId") * 2. Uncomment the LayoutManager option that you want. */
public ${FRAGMENT_NAME}() { // Required empty public constructor }
@Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { // Inflate the layout for this fragment return inflater.inflate(${LAYOUT_RESOURCE}, container, false); }
@Override public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) { if (view == null) { throw new NullPointerException("Fragment view is null, check " + ${LAYOUT_RESOURCE} + " layout."); }
RecyclerView recyclerView = view.findViewById(${RECYCLER_VIEW_ID}); if (recyclerView == null) { throw new NullPointerException("RecyclerView with ID " + ${RECYCLER_VIEW_ID} + " not found in the inflated layout"); }
// Set LayoutManager (Required) // Uncomment one of the options below:
// For a default vertical list: // recyclerView.setLayoutManager(new LinearLayoutManager(requireContext()));
// For a grid layout with 2 columns: // recyclerView.setLayoutManager(new GridLayoutManager(requireContext(), 2));
// For a staggered grid layout with 2 columns: recyclerView.setLayoutManager(new StaggeredGridLayoutManager(2, StaggeredGridLayoutManager.VERTICAL));
// Initialize adapter, set item click listener, and assign adapter to RecyclerView adapter = new ${ADAPTER_NAME}(); adapter.setOnItemClickListener(item -> { // Create a bundle to pass the selected ${MODEL_NAME}'s ID Bundle args = new Bundle(); args.putInt("${ITEM_ID_KEY}", item.getId()); NavigationUtil.navigateTo(${FRAGMENT_NAME}.this, ${NAVIGATION_ACTION_ID}, args); }); recyclerView.setAdapter(adapter);
// Initialize ViewModel viewModel = new ViewModelProvider(this).get(${VIEW_MODEL_CLASS}.class);
// Observe the LiveData and update RecyclerView when data changes viewModel.getAllItems().observe(getViewLifecycleOwner(), (List<${MODEL_NAME}> ${MODEL_NAME_LOWER}) -> { adapter.setItemList(${MODEL_NAME_LOWER}); }); } }
Code template for CustomEditModelFragment.java
/** * Created by Sim Sze Yu * GitHub: https://github.com/szeyu/Awsome-Android-Code-Template * * This template is part of the WIA2007 Mobile Application Development Course * Bachelor of Computer Science (Artificial Intelligence) * Universiti Malaya * * Licensed under MIT License * Copyright (c) 2025 Sim Sze Yu * * A fully customizable fragment for editing a model. * * Features: * - Supports dynamic model (`${MODEL_NAME}`) * - Allows updating and deleting entities * - Uses ViewModel for data binding * - Supports NavigationUtil for smooth transitions * * Usage: * 1. Replace `${MODEL_NAME}` with your model class (e.g., `Person`, `Task`) * 2. Define necessary attributes (name, description, etc.) * 3. Ensure the corresponding ViewModel (`${MODEL_NAME}ViewModel`) exists */
public class CustomEditModelFragment extends Fragment {
private ${MODEL_NAME}ViewModel viewModel; private int modelId; // ID passed as an argument
@Override public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { // Inflate your layout for editing a model return inflater.inflate(R.layout.fragment_edit_${MODEL_NAME}.toLowerCase(), container, false); }
// Fetch and display existing ${MODEL_NAME} data viewModel.getItemById(modelId).observe(getViewLifecycleOwner(), model -> { if (model != null) { etName.setText(model.getName()); etDescription.setText(model.getDescription()); } });
// Handle Save button click btnSave.setOnClickListener(v -> { String name = etName.getText().toString().trim(); String description = etDescription.getText().toString().trim();
if (TextUtils.isEmpty(name)) { Toast.makeText(getContext(), "Name cannot be empty", Toast.LENGTH_SHORT).show(); return; }
// Update model object ${MODEL_NAME} updatedModel = new ${MODEL_NAME}(name, description); updatedModel.setId(modelId); viewModel.update(updatedModel);
// Navigate back NavigationUtil.navigateBack(this); }); } }
Navigation
I have implemented 2 main navigation part which will exist in mobile app which are the bottom navigation and side menu. Those template are designed with Mateiral Design and using NavigationUtil for seamless navigation.
Code template for BottomNavigation.java
/** * Created by Sim Sze Yu * GitHub: https://github.com/szeyu/Awsome-Android-Code-Template * * This template is part of the WIA2007 Mobile Application Development Course * Bachelor of Computer Science (Artificial Intelligence) * Universiti Malaya * * Licensed under MIT License * Copyright (c) 2025 Sim Sze Yu * * Material Design bottom navigation implementation. * Features: * - Pre-configured navigation listener * - Easy integration with fragments using NavigationUtil * - Customizable menu items * - Supports both fragment-based and intent-based navigation * * Usage: * 1. Include bottom_nav_menu.xml in your resources * 2. Initialize in your activity * 3. Uncomment either fragment-based or intent-based navigation */
/** * Created by Sim Sze Yu * GitHub: https://github.com/szeyu/Awsome-Android-Code-Template * * This template is part of the WIA2007 Mobile Application Development Course * Bachelor of Computer Science (Artificial Intelligence) * Universiti Malaya * * Licensed under MIT License * Copyright (c) 2025 Sim Sze Yu * * Navigation drawer implementation using Material Design. * Features: * - Material Design NavigationView * - Drawer layout configuration * - Menu item handling with NavigationUtil * - Supports both fragment-based and intent-based navigation * * Usage: * 1. Include the side menu in your activity layout * 2. Setup menu items in res/menu * 3. Uncomment either fragment-based or intent-based navigation */
// Replace ${PACKAGE_NAME} with your actual package name // Replace ${VIEW_HOLDER_NAME} with the name of your ViewHolder class // Replace ${ITEM_LAYOUT_NAME} with the layout resource ID for your item view
public class ${VIEW_HOLDER_NAME} extends RecyclerView.ViewHolder {
// Define your view components here private final TextView textViewTitle; private final TextView textViewSubtitle;
public ${VIEW_HOLDER_NAME}(@NonNull View itemView) { super(itemView); // Initialize your view components textViewTitle = itemView.findViewById(R.id.tv_card_title); textViewSubtitle = itemView.findViewById(R.id.tv_card_subtitle); }
/** * Bind data to the views. * * @param item The data item to bind */ public void bind(${MODEL_NAME} item) { // Set data to your views textViewTitle.setText(item.getTitle()); textViewSubtitle.setText(item.getSubtitle()); } }
ViewModel
I have implement a view model for repository integration for Entity View Model so far. It have CRUD operations for lifecyle-aware data handling too.
Code template for CustomEntityViewModel.java
/** * Created by Sim Sze Yu * GitHub: https://github.com/szeyu/Awsome-Android-Code-Template * * This template is part of the WIA2007 Mobile Application Development Course * Bachelor of Computer Science (Artificial Intelligence) * Universiti Malaya * * Licensed under MIT License * Copyright (c) 2025 Sim Sze Yu * * AndroidViewModel implementation for MVVM architecture. * Features: * - LiveData management * - Repository integration * - Configuration change handling * - Clean architecture compliance * * Usage: * 1. Initialize with repository * 2. Implement data operations * 3. Observe LiveData in UI */
// Replace ${PACKAGE_NAME} with your package name // Replace ${ENTITY_VIEW_MODEL_NAME} with your EntityViewModel class name // Replace ${MODEL_NAME} with your data model class name // Replace ${REPOSITORY_NAME} with your repository class name
public class ${ENTITY_VIEW_MODEL_NAME} extends AndroidViewModel {
private final ${REPOSITORY_NAME} repository; private final LiveData<List<${MODEL_NAME}>> allItems;
public ${ENTITY_VIEW_MODEL_NAME}(@NonNull Application application) { super(application); repository = new ${REPOSITORY_NAME}(application); allItems = repository.getAllItems(); }
public LiveData<List<${MODEL_NAME}>> getAllItems() { return allItems; }
public LiveData<${MODEL_NAME}> getItemById(int itemId) { return repository.getItemById(itemId); }
public void insert(${MODEL_NAME} item) { repository.insert(item); }
public void update(${MODEL_NAME} item) { repository.update(item); }
public void delete(${MODEL_NAME} item) { repository.delete(item); } }
Util
These utilities are so important that I have created so much utilities to help me to speed up the backend development. There are indeed too many redundant code and packaging them up into a Class is definitely the best idea.
There are Navigation Util and Storage Util. Navigation Util will handle the navigation between fragment or activity either using intent or navigation graph. Then the storage utils are so many and I will then let user choose which one to use according to their suitability in their project.
To avoid confusion, I have added the sample usage of these util classes in the comment section of the code.
Code template for AppStorageUtil.java
/** * Created by Sim Sze Yu * GitHub: https://github.com/szeyu/Awsome-Android-Code-Template * * This template is part of the WIA2007 Mobile Application Development Course * Bachelor of Computer Science (Artificial Intelligence) * Universiti Malaya * * Licensed under MIT License * Copyright (c) 2025 Sim Sze Yu * * A modular utility class for app-specific storage using internal storage. * Features: * - Singleton pattern for easy access. * - Methods to save and read text data to/from a file. * - File deletion support. * * Usage: * 1. Retrieve an instance via AppStorageUtil.getInstance(context); * 2. Use saveToFile() to write data and readFromFile() to retrieve data. * * Sample Usage * // requireContext() gets Fragment’s context * // 'this' refers to the Activity context * * // Save data to internal storage * AppStorageUtil.saveToFile(context, "config.json", "{ 'theme': 'dark' }"); * * // Read data from internal storage * String configData = AppStorageUtil.readFromFile(context, "config.json"); * * // Delete a file * AppStorageUtil.deleteFile(context, "config.json"); * * // Check if file exists * boolean exists = AppStorageUtil.fileExists(context, "config.json"); */ public class AppStorageUtil { private static AppStorageUtil instance; private Context context;
public static synchronized AppStorageUtil getInstance(Context context) { if (instance == null) { instance = new AppStorageUtil(context); } return instance; }
// Save text data to a file. public boolean saveToFile(String fileName, String data) { try (FileOutputStream fos = context.openFileOutput(fileName, Context.MODE_PRIVATE)) { fos.write(data.getBytes()); fos.flush(); return true; } catch (IOException e) { e.printStackTrace(); return false; } }
// Read text data from a file. public String readFromFile(String fileName) { try (FileInputStream fis = context.openFileInput(fileName); InputStreamReader isr = new InputStreamReader(fis); BufferedReader br = new BufferedReader(isr)) {
// Delete a file. public boolean deleteFile(String fileName) { return context.deleteFile(fileName); } }
Code template for DiskCacheUtil.java
/** * Created by Sim Sze Yu * GitHub: https://github.com/szeyu/Awsome-Android-Code-Template * * This template is part of the WIA2007 Mobile Application Development Course * Bachelor of Computer Science (Artificial Intelligence) * Universiti Malaya * * Licensed under MIT License * Copyright (c) 2025 Sim Sze Yu * * A persistent disk cache using DiskLruCache. * Features: * - Stores data on disk for long-term caching. * - Automatic eviction when full. * * Usage: * 1. Initialize using DiskCacheUtil.getInstance(context); * 2. Use put() and get() for cache operations. * * Sample Usage * // requireContext() gets Fragment’s context * // 'this' refers to the Activity context * * // Save data to disk cache * DiskCacheUtil.put(context, "user_profile", "{ 'name': 'John', 'age': 25 }"); * * // Retrieve data from disk cache * String userProfile = DiskCacheUtil.get(context, "user_profile"); * * // Check if cache entry exists * boolean exists = DiskCacheUtil.contains(context, "user_profile"); * * // Remove specific cache entry * DiskCacheUtil.remove(context, "user_profile"); * * // Clear entire disk cache * DiskCacheUtil.clearAll(context); */ public class DiskCacheUtil { private static final int APP_VERSION = 1; private static final int VALUE_COUNT = 1; private static final long MAX_SIZE = 10 * 1024 * 1024; // 10MB cache size
public void clear() throws IOException { diskCache.delete(); } }
Code template for HybridCacheUtil.java
/** * Created by Sim Sze Yu * GitHub: https://github.com/szeyu/Awsome-Android-Code-Template * * This template is part of the WIA2007 Mobile Application Development Course * Bachelor of Computer Science (Artificial Intelligence) * Universiti Malaya * * Licensed under MIT License * Copyright (c) 2025 Sim Sze Yu * * A hybrid caching system using LruCache (memory) and DiskLruCache (disk). * Features: * - Uses memory cache for fast access. * - Falls back to disk cache if memory cache misses. * - Evicts old data automatically when full. * * Usage: * 1. Initialize using HybridCacheUtil.getInstance(context, maxSize); * 2. Use put(), get(), and remove() to manage cache. * * Sample Usage * // requireContext() gets Fragment’s context * // 'this' refers to the Activity context * * // Store data in hybrid cache (tries memory first, then disk) * HybridCacheUtil.put(context, "session_token", "abcdef123456"); * * // Retrieve data (first tries memory, then falls back to disk) * String token = HybridCacheUtil.get(context, "session_token"); * * // Remove an entry from hybrid cache * HybridCacheUtil.remove(context, "session_token"); * * // Clear entire hybrid cache * HybridCacheUtil.clearAll(context); */ public class HybridCacheUtil { private static HybridCacheUtil instance; private MemoryCacheUtil memoryCache; private DiskCacheUtil diskCache;
private HybridCacheUtil(Context context, int memorySize) throws IOException { memoryCache = new MemoryCacheUtil(memorySize); diskCache = DiskCacheUtil.getInstance(context); }
public static synchronized HybridCacheUtil getInstance(Context context, int memorySize) throws IOException { if (instance == null) { instance = new HybridCacheUtil(context, memorySize); } return instance; }
/** * Created by Sim Sze Yu * GitHub: https://github.com/szeyu/Awsome-Android-Code-Template * * This template is part of the WIA2007 Mobile Application Development Course * Bachelor of Computer Science (Artificial Intelligence) * Universiti Malaya * * Licensed under MIT License * Copyright (c) 2025 Sim Sze Yu * * A lightweight memory cache using LruCache. * Features: * - Stores objects in memory for fast access. * - Removes least recently used items when full. * * Usage: * 1. Initialize using MemoryCacheUtil.init(maxSize); * 2. Use put(), get(), and remove() for caching. * * Sample Usage * // requireContext() gets Fragment’s context * // 'this' refers to the Activity context * * // Add data to memory cache * MemoryCacheUtil.put("api_response", "{ 'status': 'ok', 'data': [] }"); * * // Retrieve data from memory cache * String response = MemoryCacheUtil.get("api_response"); * * // Check if cache contains key * boolean exists = MemoryCacheUtil.contains("api_response"); * * // Remove a specific entry * MemoryCacheUtil.remove("api_response"); * * // Clear entire memory cache * MemoryCacheUtil.clearAll(); */ public class MemoryCacheUtil { private static MemoryCacheUtil instance; private LruCache<String, Object> memoryCache;
private MemoryCacheUtil(int maxSize) { memoryCache = new LruCache<>(maxSize); }
public static synchronized void init(int maxSize) { if (instance == null) { instance = new MemoryCacheUtil(maxSize); } }
public static MemoryCacheUtil getInstance() { if (instance == null) { throw new IllegalStateException("MemoryCacheUtil not initialized. Call init(maxSize) first."); } return instance; }
public void put(String key, Object value) { memoryCache.put(key, value); }
public Object get(String key) { return memoryCache.get(key); }
public void remove(String key) { memoryCache.remove(key); }
public void clear() { memoryCache.evictAll(); } }
Code template for NavigationUtil.java
/** * Created by Sim Sze Yu * GitHub: https://github.com/szeyu/Awsome-Android-Code-Template * * This template is part of the WIA2007 Mobile Application Development Course * Bachelor of Computer Science (Artificial Intelligence) * Universiti Malaya * * Licensed under MIT License * Copyright (c) 2025 Sim Sze Yu * * Utility class for handling navigation throughout the app. * Features: * - Static navigation methods * - Intent management * - Activity transition handling * - Common navigation patterns * * Usage: * 1. Import this utility class * 2. Call static methods for navigation * 3. Uncomment the navigation option (fragment-based or intent-based) */
public static synchronized void init(Context context) { if (instance == null) { instance = new SharedPrefsUtil(context); } }
public static SharedPrefsUtil getInstance() { if (instance == null) { throw new IllegalStateException("SharedPrefsUtil is not initialized. Call init(context) in your Application class."); } return instance; }
// Save a String value. public void putString(String key, String value) { sharedPreferences.edit().putString(key, value).apply(); }
// Retrieve a String value. public String getString(String key, String defaultValue) { return sharedPreferences.getString(key, defaultValue); }
// Save an integer value. public void putInt(String key, int value) { sharedPreferences.edit().putInt(key, value).apply(); }
// Retrieve an integer value. public int getInt(String key, int defaultValue) { return sharedPreferences.getInt(key, defaultValue); }
// Save a boolean value. public void putBoolean(String key, boolean value) { sharedPreferences.edit().putBoolean(key, value).apply(); }
// Retrieve a boolean value. public boolean getBoolean(String key, boolean defaultValue) { return sharedPreferences.getBoolean(key, defaultValue); }
// Save a long value. public void putLong(String key, long value) { sharedPreferences.edit().putLong(key, value).apply(); }
// Retrieve a long value. public long getLong(String key, long defaultValue) { return sharedPreferences.getLong(key, defaultValue); }
// Save a float value. public void putFloat(String key, float value) { sharedPreferences.edit().putFloat(key, value).apply(); }
// Retrieve a float value. public float getFloat(String key, float defaultValue) { return sharedPreferences.getFloat(key, defaultValue); }
// Save a list of strings. public void putStringList(String key, List<String> list) { String json = gson.toJson(list); sharedPreferences.edit().putString(key, json).apply(); }
// Retrieve a list of strings. public List<String> getStringList(String key) { String json = sharedPreferences.getString(key, null); if (json == null) { return new ArrayList<>(); } Type type = new TypeToken<List<String>>() {}.getType(); return gson.fromJson(json, type); }
// Save a list of integers. public void putIntList(String key, List<Integer> list) { String json = gson.toJson(list); sharedPreferences.edit().putString(key, json).apply(); }
// Retrieve a list of integers. public List<Integer> getIntList(String key) { String json = sharedPreferences.getString(key, null); if (json == null) { return new ArrayList<>(); } Type type = new TypeToken<List<Integer>>() {}.getType(); return gson.fromJson(json, type); }
// Remove a specific key. public void remove(String key) { sharedPreferences.edit().remove(key).apply(); }
// Clear all preferences. public void clear() { sharedPreferences.edit().clear().apply(); } }
Layouts
Now these are the xml templates for layout which is the frontend development. Here come the song APT: “All you gotta do is just..” ok just copy and paste those xml file into the android studio XD😆.
custom_login_layout.xml — Mateiral Design login screen with email and password field.
custom_bottom_nav_layout.xml — Layout for bottom navigation integrated with a fragment container.
custom_side_nav_layout.xml — Layout for a navigation drawer with header and menu items.
custom_card_layout.xml — Material card layout with image, title, and subtitle.
custom_button_layout.xml — Layout showcasing various Material button styles.
custom_toolbar_layout.xml —Custom toolbar layout with title and menu support.
custom_navigator_main_activity.xml — Layout for CustomNavigatorMainActivity, including AppBarLayout with Toolbar, FragmentContainerView, BottomNavigationView, and NavigationView for side menu.
custom_form_controls_layout.xml — Layout for which consists of variety of component for form control.
custom_list_recyler_view_layout.xml — Custom RecyclerView layout with standard spacing and consistent design.
Code template for custom_login_layout.xml
<?xml version="1.0" encoding="utf-8"?> <!-- ~ Created by Sim Sze Yu ~ GitHub: https://github.com/szeyu/Awsome-Android-Code-Template ~ ~ This template is part of the WIA2007 Mobile Application Development Course ~ Bachelor of Computer Science (Artificial Intelligence) ~ Universiti Malaya ~ ~ Licensed under MIT License ~ Copyright (c) 2025 Sim Sze Yu ~ ~ Material Design login layout template. ~ Features: ~ - Material TextInputLayout for fields ~ - Responsive design ~ - Error handling support ~ - Remember me option ~ ~ Usage: ~ 1. Include in your login activity ~ 2. Customize colors and text ~ 3. Add validation logic --> <ScrollView xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto" android:layout_width="match_parent" android:layout_height="match_parent" android:fillViewport="true" android:background="@color/background">
<?xml version="1.0" encoding="utf-8"?> <!-- ~ Created by Sim Sze Yu ~ GitHub: https://github.com/szeyu/Awsome-Android-Code-Template ~ ~ This template is part of the WIA2007 Mobile Application Development Course ~ Bachelor of Computer Science (Artificial Intelligence) ~ Universiti Malaya ~ ~ Licensed under MIT License ~ Copyright (c) 2025 Sim Sze Yu ~ ~ Material Design bottom navigation layout template. ~ Features: ~ - Fixed bottom navigation ~ - Fragment container ~ - Material Design styling ~ - Customizable menu items ~ ~ Usage: ~ 1. Include in your main activity ~ 2. Set up menu resource ~ 3. Configure navigation behavior --> <androidx.coordinatorlayout.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto" android:layout_width="match_parent" android:layout_height="match_parent" android:background="@color/background">
<?xml version="1.0" encoding="utf-8"?> <!-- ~ Created by Sim Sze Yu ~ GitHub: https://github.com/szeyu/Awsome-Android-Code-Template ~ ~ This template is part of the WIA2007 Mobile Application Development Course ~ Bachelor of Computer Science (Artificial Intelligence) ~ Universiti Malaya ~ ~ Licensed under MIT License ~ Copyright (c) 2025 Sim Sze Yu ~ ~ Navigation drawer layout template. ~ Features: ~ - DrawerLayout implementation ~ - Header view support ~ - Menu grouping ~ - Material Design styling ~ ~ Usage: ~ 1. Include in your main activity ~ 2. Set up navigation menu ~ 3. Add header layout if needed --> <androidx.drawerlayout.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto" android:id="@+id/drawer_layout" android:layout_width="match_parent" android:layout_height="match_parent" android:fitsSystemWindows="true">
<!-- Main Content --> <LinearLayout android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical">
<?xml version="1.0" encoding="utf-8"?> <!-- ~ Created by Sim Sze Yu ~ GitHub: https://github.com/szeyu/Awsome-Android-Code-Template ~ ~ This template is part of the WIA2007 Mobile Application Development Course ~ Bachelor of Computer Science (Artificial Intelligence) ~ Universiti Malaya ~ ~ Licensed under MIT License ~ Copyright (c) 2025 Sim Sze Yu ~ ~ Material Design toolbar template. ~ Features: ~ - AppBarLayout integration ~ - Title customization ~ - Menu support ~ - Elevation control ~ ~ Usage: ~ 1. Include in activity layout ~ 2. Set up menu items ~ 3. Configure navigation icon --> <com.google.android.material.appbar.AppBarLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto" android:layout_width="match_parent" android:layout_height="wrap_content" android:background="@color/primary">
Code template for custom_navigator_main_activity.xml
<?xml version="1.0" encoding="utf-8"?> <!-- Created by Sim Sze Yu GitHub: https://github.com/szeyu/Awsome-Android-Code-Template
This template is part of the WIA2007 Mobile Application Development Course Bachelor of Computer Science (Artificial Intelligence) Universiti Malaya
Licensed under MIT License Copyright (c) 2025 Sim Sze Yu
XML layout for CustomNavigatorMainActivity. Features: - AppBarLayout with Toolbar - Fragment container for Navigation Component - Bottom navigation menu - Side navigation drawer --> <androidx.drawerlayout.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto" xmlns:tools="http://schemas.android.com/tools" android:id="@+id/drawer_layout" android:layout_width="match_parent" android:layout_height="match_parent" tools:context=".CustomNavigatorMainActivity">
<?xml version="1.0" encoding="utf-8"?> <!-- ~ Created by Sim Sze Yu ~ GitHub: https://github.com/szeyu/Awsome-Android-Code-Template ~ ~ This template is part of the WIA2007 Mobile Application Development Course ~ Bachelor of Computer Science (Artificial Intelligence) ~ Universiti Malaya ~ ~ Licensed under MIT License ~ Copyright (c) 2025 Sim Sze Yu ~ ~ Custom form controls layout with Material Design styling. ~ Features: ~ - Styled RadioGroup, CheckBox, Switch, AutoCompleteTextView, Spinner ~ - Uses Material Theme colors and dimensions ~ - Consistent spacing and typography -->
Code template for custom_list_recycler_view_layout.xml
<?xml version="1.0" encoding="utf-8"?> <!-- ~ Created by Sim Sze Yu ~ GitHub: https://github.com/szeyu/Awsome-Android-Code-Template ~ ~ This template is part of the WIA2007 Mobile Application Development Course ~ Bachelor of Computer Science (Artificial Intelligence) ~ Universiti Malaya ~ ~ Licensed under MIT License ~ Copyright (c) 2025 Sim Sze Yu ~ ~ Custom RecyclerView layout with standard spacing and consistent design. ~ Features: ~ - RecyclerView with ConstraintLayout ~ - Custom list item using person_card_layout ~ - Standard margin and padding ~ ~ Usage: ~ 1. Place RecyclerView inside layouts ~ 2. Use with custom adapter and `custom_card_layout` for list items ~ 3. Maintain consistent spacing and design across RecyclerView -->
<!-- RecyclerView for displaying list of people --> <androidx.recyclerview.widget.RecyclerView android:id="@+id/recycler_view_people" android:layout_width="0dp" android:layout_height="0dp" app:layout_constraintBottom_toBottomOf="parent" app:layout_constraintEnd_toEndOf="parent" app:layout_constraintStart_toStartOf="parent" app:layout_constraintTop_toTopOf="parent" tools:listitem="@layout/custom_card_layout" />
custom_bottom_nav_menu.xml — Menu resource for bottom navigation items.
custom_main_nav_menu.xml — Menu resource for the overflow menu in CustomNavigatorMainActivity.
custom_side_nav_menu.xml — Menu resource for navigation drawer items.
Code template for custom_bottom_nav_menu.xml
<?xml version="1.0" encoding="utf-8"?> <!-- ~ Created by Sim Sze Yu ~ GitHub: https://github.com/szeyu/Awsome-Android-Code-Template ~ ~ This template is part of the WIA2007 Mobile Application Development Course ~ Bachelor of Computer Science (Artificial Intelligence) ~ Universiti Malaya ~ ~ Licensed under MIT License ~ Copyright (c) 2025 Sim Sze Yu ~ ~ Bottom navigation menu resource template. ~ Features: ~ - Standard navigation items ~ - Icon and label support ~ - Material Design icons ~ - Item ID configuration ~ ~ Usage: ~ 1. Customize menu items ~ 2. Add icons ~ 3. Set up navigation IDs --> <menu xmlns:android="http://schemas.android.com/apk/res/android"> <item android:id="@+id/nav_home" android:icon="@drawable/baseline_home_24" android:title="Home" />
<?xml version="1.0" encoding="utf-8"?><!-- ~ Created by Sim Sze Yu ~ GitHub: https://github.com/szeyu/Awsome-Android-Code-Template ~ ~ This template is part of the WIA2007 Mobile Application Development Course ~ Bachelor of Computer Science (Artificial Intelligence) ~ Universiti Malaya ~ ~ Licensed under MIT License ~ Copyright (c) 2025 Sim Sze Yu ~ ~ Overflow menu resource template. ~ Features: ~ - Supports action items and overflow menu ~ - Configurable icons and titles ~ - Easy extension for additional actions ~ ~ Usage: ~ 1. Add menu items with appropriate IDs and icons ~ 2. Configure "showAsAction" based on UI needs ~ 3. Implement actions in onOptionsItemSelected() -->
custom_colors.xml — Material Design color system resources.
custom_dimens.xml — Material Design color system resources.
custom_styles.xml — Material component styles and themes.
Code template for custom_colors.xml
<?xml version="1.0" encoding="utf-8"?> <!-- ~ Created by Sim Sze Yu ~ GitHub: https://github.com/szeyu/Awsome-Android-Code-Template ~ ~ This template is part of the WIA2007 Mobile Application Development Course ~ Bachelor of Computer Science (Artificial Intelligence) ~ Universiti Malaya ~ ~ Licensed under MIT License ~ Copyright (c) 2025 Sim Sze Yu ~ ~ Material Design color resource template. ~ Features: ~ - Material Design color system ~ - Primary and secondary colors ~ - Light and dark theme support ~ - Semantic color naming ~ ~ Usage: ~ 1. Use in themes and styles ~ 2. Reference in layouts ~ 3. Maintain consistent branding --> <resources> <!-- Primary Colors --> <color name="primary">#1976D2</color> <color name="primary_dark">#1565C0</color> <color name="primary_light">#42A5F5</color>
<?xml version="1.0" encoding="utf-8"?> <!-- ~ Created by Sim Sze Yu ~ GitHub: https://github.com/szeyu/Awsome-Android-Code-Template ~ ~ This template is part of the WIA2007 Mobile Application Development Course ~ Bachelor of Computer Science (Artificial Intelligence) ~ Universiti Malaya ~ ~ Licensed under MIT License ~ Copyright (c) 2025 Sim Sze Yu ~ ~ Dimension resource template for consistent spacing and sizing. ~ Features: ~ - Standard spacing system ~ - Component dimensions ~ - Text sizes ~ - Common measurements ~ ~ Usage: ~ 1. Reference in layouts ~ 2. Use in styles ~ 3. Maintain consistent spacing --> <resources> <!-- Margins and Padding --> <dimen name="spacing_tiny">4dp</dimen> <dimen name="spacing_small">8dp</dimen> <dimen name="spacing_medium">16dp</dimen> <dimen name="spacing_large">24dp</dimen> <dimen name="spacing_xlarge">32dp</dimen> <dimen name="spacing_xxlarge">48dp</dimen>
<!-- Additional Text Sizes for Headline, Title, and Body --> <dimen name="text_headline">24sp</dimen> <dimen name="text_title">20sp</dimen> <dimen name="text_body">16sp</dimen>
Alright! Now here comes the end of the templates code for my Android Development. I do really hope that these templates are able to help you to accelerate your mobile application development. If you like my project, come and support me on https://ko-fi.com/szeyusim!😍
Doing these templates took me days to edit the template over and over again until it works perfectly and speed up my development time. Although there are things called GPT and DeepSeek alrready but writing your own is cool!
Follow me for more update on Medium, I will write more blogs regarding my personal development on Coding Journey and share the notes with you all!
