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16.3. Service和Activity通信

16.3.1. Layout

			
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout 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:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <LinearLayout
        android:layout_width="368dp"
        android:layout_height="229dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="8dp"
        android:layout_marginEnd="8dp"
        android:layout_marginBottom="8dp"
        android:orientation="vertical"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.0"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.0">

        <Button
            android:id="@+id/startService"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="Start service" />

        <Button
            android:id="@+id/stopService"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="Stop service" />

        <Button
            android:id="@+id/bindService"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="Bind Service" />

        <Button
            android:id="@+id/unbindService"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="Unbind Service" />

    </LinearLayout>

</android.support.constraint.ConstraintLayout>			
			
			

16.3.2. Service

			
package cn.netkiller.service;

import android.app.Service;
import android.content.Intent;
import android.os.Binder;
import android.os.IBinder;
import android.util.Log;

public class MyService extends Service {

    private MyBinder myBinder = new MyBinder();

    public MyService() {
    }

    @Override
    public void onCreate() {
        super.onCreate();
        Log.d("Service", "onCreate() executed");
        Log.d("Service", "MyService thread id is " + Thread.currentThread().getId());
    }

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {

        Log.d("Service", "onStartCommand() begin");
        new Thread(new Runnable() {
            @Override
            public void run() {
                // 開始執行後台任務
                Log.d("Service", "onStartCommand() executed");
            }
        }).start();

        Log.d("Service", "onStartCommand() end");

        return super.onStartCommand(intent, flags, startId);
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        Log.d("Service", "onDestroy() executed");
    }

    @Override
    public IBinder onBind(Intent intent) {
        return myBinder;
    }

    class MyBinder extends Binder {

        public void startTask() {
            new Thread(new Runnable() {
                @Override
                public void run() {
                    // 執行具體的任務
                    Log.d("Service", "startTask()");
                }
            }).start();
        }

    }
}			
			
			

16.3.3. Activity

			
package cn.netkiller.service;

import android.content.ComponentName;
import android.content.Intent;
import android.content.ServiceConnection;
import android.os.IBinder;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;

public class MainActivity extends AppCompatActivity implements View.OnClickListener {

    private Button startService;
    private Button stopService;
    private Button bindService;
    private Button unbindService;

    private MyService.MyBinder myBinder;

    private ServiceConnection connection = new ServiceConnection() {

        @Override
        public void onServiceDisconnected(ComponentName name) {
        }

        @Override
        public void onServiceConnected(ComponentName name, IBinder service) {
            myBinder = (MyService.MyBinder) service;
            myBinder.startTask();
        }
    };

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        startService = (Button) findViewById(R.id.startService);
        stopService = (Button) findViewById(R.id.stopService);
        startService.setOnClickListener(this);
        stopService.setOnClickListener(this);

        bindService = (Button) findViewById(R.id.bindService);
        unbindService = (Button) findViewById(R.id.unbindService);
        bindService.setOnClickListener(this);
        unbindService.setOnClickListener(this);

        Log.d("Service", "MainActivity thread id is " + Thread.currentThread().getId());

    }

    @Override
    public void onClick(View v) {
        Intent intent;
        switch (v.getId()) {
            case R.id.startService:
                intent = new Intent(this, MyService.class);
                startService(intent);
                break;
            case R.id.stopService:
                intent = new Intent(this, MyService.class);
                stopService(intent);
                break;
            case R.id.bindService:
                Intent bindIntent = new Intent(this, MyService.class);
                bindService(bindIntent, connection, BIND_AUTO_CREATE);
                break;
            case R.id.unbindService:
                unbindService(connection);
                break;
            default:
                break;
        }
    }
}