Hello! In this course, we will learn how to create a task management application on Android using Java. Task management apps provide various features necessary for managing and efficiently carrying out daily tasks. Through this course, we will learn about basic UI components, database management, user input handling, and how to implement complete functionality while running the app.
Table of Contents
- 1. Project Setup
- 2. UI Design
- 3. Database Configuration
- 4. Task Addition Functionality Implementation
- 5. Displaying Task List
- 6. Task Deletion and Modification Functions
- 7. App Optimization and Conclusion
- 8. Conclusion
1. Project Setup
Open Android Studio and create a new project. Select the “Empty Activity” template, set the project name and package name, and click the “Finish” button to create the project.
Once the project is created, you can add the necessary dependencies to Gradle to set up the database and UI-related libraries. Here is the code that needs to be added to the build.gradle file:
dependencies {
implementation 'com.android.support:appcompat-v7:28.0.0'
implementation 'androidx.room:room-runtime:2.3.0'
annotationProcessor 'androidx.room:room-compiler:2.3.0'
}2. UI Design
Now let’s design the UI. Open the res/layout/activity_main.xml file and add the following layout:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<EditText
android:id="@+id/taskEditText"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="Enter a new task"/>
<Button
android:id="@+id/addTaskButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Add"/>
<ListView
android:id="@+id/taskListView"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1"/>
</LinearLayout>3. Database Configuration
We set up the Room database to store task data. Create the entity class as follows:
import androidx.room.Entity;
import androidx.room.PrimaryKey;
@Entity
public class Task {
@PrimaryKey(autoGenerate = true)
private int id;
private String description;
public Task(String description) {
this.description = description;
}
// Getter and Setter
public int getId() { return id; }
public void setId(int id) { this.id = id; }
public String getDescription() { return description; }
public void setDescription(String description) { this.description = description; }
}Next, create the DAO interface:
import androidx.room.Dao;
import androidx.room.Insert;
import androidx.room.Query;
import java.util.List;
@Dao
public interface TaskDao {
@Insert
void insert(Task task);
@Query("SELECT * FROM task")
List getAllTasks();
} Finally, create the database class:
import androidx.room.Database;
import androidx.room.Room;
import androidx.room.RoomDatabase;
import android.content.Context;
@Database(entities = {Task.class}, version = 1)
public abstract class AppDatabase extends RoomDatabase {
public abstract TaskDao taskDao();
private static AppDatabase INSTANCE;
public static AppDatabase getDatabase(final Context context) {
if (INSTANCE == null) {
synchronized (AppDatabase.class) {
if (INSTANCE == null) {
INSTANCE = Room.databaseBuilder(context.getApplicationContext(),
AppDatabase.class, "task_database")
.build();
}
}
}
return INSTANCE;
}
}4. Task Addition Functionality Implementation
In the Activity, we connect the UI elements and the database to implement the functionality to add tasks entered by the user. Open the MainActivity.java file and add the following code:
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import androidx.appcompat.app.AppCompatActivity;
public class MainActivity extends AppCompatActivity {
private EditText taskEditText;
private Button addTaskButton;
private AppDatabase db;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
taskEditText = findViewById(R.id.taskEditText);
addTaskButton = findViewById(R.id.addTaskButton);
db = AppDatabase.getDatabase(this);
addTaskButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
String taskDescription = taskEditText.getText().toString();
if (!taskDescription.isEmpty()) {
Task task = new Task(taskDescription);
new Thread(() -> db.taskDao().insert(task)).start();
taskEditText.setText("");
}
}
});
}
}5. Displaying Task List
To display the list of tasks, we will use a ListView and an adapter. First, create a custom adapter class:
import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.TextView;
import java.util.List;
public class TaskAdapter extends ArrayAdapter {
public TaskAdapter(Context context, List tasks) {
super(context, 0, tasks);
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
Task task = getItem(position);
if (convertView == null) {
convertView = LayoutInflater.from(getContext()).inflate(android.R.layout.simple_list_item_1, parent, false);
}
TextView taskTextView = convertView.findViewById(android.R.id.text1);
taskTextView.setText(task.getDescription());
return convertView;
}
} Now set up the ListView in MainActivity.java:
import android.widget.ListView;
import androidx.lifecycle.Observer;
import androidx.lifecycle.ViewModelProvider;
public class MainActivity extends AppCompatActivity {
// ...
private ListView taskListView;
private TaskAdapter taskAdapter;
private List taskList;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// ...
taskListView = findViewById(R.id.taskListView);
taskList = new ArrayList<>();
taskAdapter = new TaskAdapter(this, taskList);
taskListView.setAdapter(taskAdapter);
loadTasks();
}
private void loadTasks() {
new Thread(() -> {
taskList.clear();
taskList.addAll(db.taskDao().getAllTasks());
runOnUiThread(() -> taskAdapter.notifyDataSetChanged());
}).start();
}
} 6. Task Deletion and Modification Functions
Add functionality to delete or modify each task by clicking on it. To add the functionality to delete a task, handle the click event of the ListView:
taskListView.setOnItemClickListener((parent, view, position, id) -> {
Task task = taskList.get(position);
new Thread(() -> {
db.taskDao().delete(task); // Implement the delete method correctly
taskList.remove(position);
runOnUiThread(taskAdapter::notifyDataSetChanged);
}).start();
});The task modification feature can be implemented by adding a separate EditText and a Confirm button.
7. App Optimization and Conclusion
Test the app to fix bugs and find areas for improvement for optimization. Test on various devices to ensure that the layout works properly.
8. Conclusion
Through this course, we learned how to develop a task management app on Android using Java. We integrated the database and user interface components to implement basic CRUD (Create, Read, Update, Delete) functionality. Based on this project, feel free to add more features to create a more complete task management app.