一起Talk Android吧(第二百零五回:Android中服务的大结局)

本文深入探讨Android服务的生命周期,详解Service与IntentService的区别及应用场景,通过完整代码示例,帮助读者掌握服务的创建、绑定与通信机制。

各位看官们大家好,上一回中咱们说的是Android中服务生命周期的例子,这一回咱们说的例子是服务的大结局。闲话休提,言归正转。让我们一起Talk Android吧!

看官们,我们在前面章回中介绍了两种服务,并且通过代码演示了如何使用这两种服务。与此同时还介绍了服务的运行状态以及生命周期。本章回是对涉及服务所有章回的总结。还有一点就是给出完成的代码,因为有看官说,代码放到步骤中容易理解,但是断断续续的代码不方便运行,因此我们在本章回中展示所有的代码;

首先说一下代码的结构:Java文件一共三个:

  • MainActivity:用来操作服务;
  • ServiceA:是自定义service子类的文件;
  • IntentServiceA:是自定义IntentService子类的文件;

下面是全部内容:

package com.example.talk8.blogapp06;

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.widget.Button;

public class MainActivity extends AppCompatActivity {
    public  String TAG = "ServiceA";

    private Button mButtonStartService;
    private Button mButtonStopService;
    private Button mButtonBindService;
    private Button mButtonUnBindService;

    private Button mButtonStartIntentService;
    private Button mButtonStopIntentService;
    private Button mButtonBindIntentService;
    private Button mButtonUnBindIntentService;

    private Button mButtonStartIntentServiceByFooAction;

    private ConnectionImpl mConnection;
    private ServiceA.BinderSub mBinderSub;
    private IntentServiceA.IntentServiceBinderSub mIntentServiceBinderSub;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        Log.i(TAG, "Activity onCreate: ThreadID: "+Thread.currentThread().getId());
        Log.i(TAG, "Activity onCreate: ThreadID: "+Thread.currentThread().toString());
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mConnection = new ConnectionImpl();

        //启动,停止,绑定,解除绑定Service的Buttion
        mButtonStartService = (Button)findViewById(R.id.id_start_service);
        mButtonStopService = (Button)findViewById(R.id.id_stop_service);
        mButtonBindService = (Button)findViewById(R.id.id_bind_service);
        mButtonUnBindService = (Button)findViewById(R.id.id_unbind_service);

        //启动,停止,绑定,解除绑定IntentService的Buttion
        mButtonStartIntentService = (Button)findViewById(R.id.id_start_intentservice);
        mButtonStopIntentService = (Button)findViewById(R.id.id_stop_intentservice);
        mButtonBindIntentService = (Button)findViewById(R.id.id_bind_intentservice);
        mButtonUnBindIntentService = (Button)findViewById(R.id.id_unbind_intentservice);

        //通过某种Action:Foo来启动IntentService
        mButtonStartIntentServiceByFooAction = (Button)findViewById(R.id.id_foo_intentservice);
        mButtonStartIntentServiceByFooAction.setOnClickListener(v ->
                IntentServiceA.startActionFoo(this,"Foo Action",null));

        //给操作Service的Button添加事件监听器
        final Intent intent = new Intent(this,ServiceA.class);
        mButtonStartService.setOnClickListener(v -> startService(intent));
        mButtonStopService.setOnClickListener(v -> stopService(intent));
        mButtonBindService.setOnClickListener(v -> bindService(intent,mConnection,this.BIND_AUTO_CREATE));
        mButtonUnBindService.setOnClickListener(v -> unbindService(mConnection));

        //给操作IntentService的Button添加事件监听器
        final Intent intentA = new Intent(this,IntentServiceA.class);
        mButtonStartIntentService.setOnClickListener(v -> startService(intentA));
        mButtonStopIntentService.setOnClickListener(v -> stopService(intentA));
        mButtonBindIntentService.setOnClickListener(v -> bindService(intentA,mConnection,this.BIND_AUTO_CREATE));
        mButtonUnBindIntentService.setOnClickListener(v -> unbindService(mConnection));

    }

    class ConnectionImpl implements ServiceConnection {
        @Override
        public void onServiceConnected(ComponentName name, IBinder service) {
            Log.i(TAG, "onServiceConnected: ");
            //使用服务提供的func方法来实现Activity和服务通信
            if(service instanceof ServiceA.BinderSub) {
                mBinderSub = (ServiceA.BinderSub) service;
                mBinderSub.func();
            }else if (service instanceof IntentServiceA.IntentServiceBinderSub) {
                mIntentServiceBinderSub = (IntentServiceA.IntentServiceBinderSub) service;
                mIntentServiceBinderSub.foo();
            }else {
                Log.i(TAG, "onServiceConnected: There is not Binder");
            }
        }

        @Override
        public void onServiceDisconnected(ComponentName name) {
            mBinderSub = null;
            mIntentServiceBinderSub = null;
            Log.i(TAG, "onServiceDisconnected: ");
        }
    }

}
package com.example.talk8.blogapp06;

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

public class ServiceA extends Service {
    private static final String TAG = "ServiceA";
    private BinderSub mBinderSub = new BinderSub();

    public ServiceA() {
    }

    @Override
    public IBinder onBind(Intent intent) {
        // TODO: Return the communication channel to the service.
        Log.i(TAG, "onBind: ");
        if(mBinderSub != null)
            return mBinderSub;
        else
            throw new UnsupportedOperationException("Not yet implemented");
    }

    @Override
    public void onCreate() {
        super.onCreate();
        Log.i(TAG, "onCreate: ThreadID:  "+Thread.currentThread().getId());
        Log.i(TAG, "onCreate: ThreadName:  "+Thread.currentThread().toString());
    }

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        Log.i(TAG, "onStartCommand: ");
        return super.onStartCommand(intent, flags, startId);
    }

    @Override
    public boolean onUnbind(Intent intent) {
        Log.i(TAG, "onUnbind: ");
        return super.onUnbind(intent);
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        Log.i(TAG, "onDestroy: ");
    }


    class BinderSub extends Binder {
        public void func() {
            Log.i(TAG, "func: do something of service.");
        }
    }
}
package com.example.talk8.blogapp06;

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

/**
 * An {@link IntentService} subclass for handling asynchronous task requests in
 * a service on a separate handler thread.
 * <p>
 * TODO: Customize class - update intent actions, extra parameters and static
 * helper methods.
 */
public class IntentServiceA extends IntentService {
    private static final String TAG = "IntentServiceA";
    private IntentServiceBinderSub mBinder = new IntentServiceBinderSub();
    // TODO: Rename actions, choose action names that describe tasks that this
    // IntentService can perform, e.g. ACTION_FETCH_NEW_ITEMS
    private static final String ACTION_FOO = "com.example.talk8.blogapp06.action.FOO";
    private static final String ACTION_BAZ = "com.example.talk8.blogapp06.action.BAZ";

    // TODO: Rename parameters
    private static final String EXTRA_PARAM1 = "com.example.talk8.blogapp06.extra.PARAM1";
    private static final String EXTRA_PARAM2 = "com.example.talk8.blogapp06.extra.PARAM2";

    public IntentServiceA() {
        super("IntentServiceA");
    }

    /**
     * Starts this service to perform action Foo with the given parameters. If
     * the service is already performing a task this action will be queued.
     *
     * @see IntentService
     */
    // TODO: Customize helper method
    public static void startActionFoo(Context context, String param1, String param2) {
        Log.i(TAG, "startActionFoo: ");
        Intent intent = new Intent(context, IntentServiceA.class);
        intent.setAction(ACTION_FOO);
        intent.putExtra(EXTRA_PARAM1, param1);
        intent.putExtra(EXTRA_PARAM2, param2);
        context.startService(intent);
    }

    /**
     * Starts this service to perform action Baz with the given parameters. If
     * the service is already performing a task this action will be queued.
     *
     * @see IntentService
     */
    // TODO: Customize helper method
    public static void startActionBaz(Context context, String param1, String param2) {
        Intent intent = new Intent(context, IntentServiceA.class);
        intent.setAction(ACTION_BAZ);
        intent.putExtra(EXTRA_PARAM1, param1);
        intent.putExtra(EXTRA_PARAM2, param2);
        context.startService(intent);
    }

    @Override
    protected void onHandleIntent(Intent intent) {
        Log.i(TAG, "onHandleIntent: ThreadID: "+Thread.currentThread().getId());
        Log.i(TAG, "onHandleIntent: ThreadName: "+Thread.currentThread().toString());
        if (intent != null) {
            final String action = intent.getAction();
            if (ACTION_FOO.equals(action)) {
                final String param1 = intent.getStringExtra(EXTRA_PARAM1);
                final String param2 = intent.getStringExtra(EXTRA_PARAM2);
                handleActionFoo(param1, param2);
            } else if (ACTION_BAZ.equals(action)) {
                final String param1 = intent.getStringExtra(EXTRA_PARAM1);
                final String param2 = intent.getStringExtra(EXTRA_PARAM2);
                handleActionBaz(param1, param2);
            }
        }
    }

    /**
     * Handle action Foo in the provided background thread with the provided
     * parameters.
     */
    private void handleActionFoo(String param1, String param2) {
        // TODO: Handle action Foo
        if(param1 != null) {
            Log.i(TAG, "handleActionFoo: param1: " + param1);
        }else {
            throw new UnsupportedOperationException("Not yet implemented");
        }
    }

    /**
     * Handle action Baz in the provided background thread with the provided
     * parameters.
     */
    private void handleActionBaz(String param1, String param2) {
        // TODO: Handle action Baz
        throw new UnsupportedOperationException("Not yet implemented");
    }

    @Override
    public void onCreate() {
        super.onCreate();
        Log.i(TAG, "onCreate: ");
        Log.i(TAG, "onCreate: ThreadID: "+Thread.currentThread().getId());
        Log.i(TAG, "onCreate: ThreadName: "+Thread.currentThread().toString());
    }

    @Override
    public IBinder onBind(Intent intent) {
        Log.i(TAG, "onBind: ");
        if (mBinder != null)
            return mBinder;
        else
            return super.onBind(intent);
    }

    @Override
    public int onStartCommand( Intent intent, int flags, int startId) {
        Log.i(TAG, "onStartCommand: ");
        return super.onStartCommand(intent, flags, startId);
    }

    @Override
    public boolean onUnbind(Intent intent) {
        Log.i(TAG, "onUnbind: ");
        return super.onUnbind(intent);
    }

    @Override
    public void onDestroy() {
        Log.i(TAG, "onDestroy: ");
        super.onDestroy();
    }

    class IntentServiceBinderSub extends Binder {
        public void foo() {
            Log.i(TAG, "foo of IntentServiceBinderSub: ");
        }
    }
}

各个Service使用的Binder子类是各自的内部类,位于各自的类文件中;ServiceConnection的实现类在MainActivity中,该文件中还定义各种Button以及为它们设置监听器;

xml布局文件只有一个:activity_main。没有使用复杂的布局,里面只有各种操作服务的Button.下面是全部内容:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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"
    android:orientation="vertical"
    tools:context=".MainActivity">

    <Button
        android:id="@+id/id_start_service"
        android:text="Start Service"
        android:textAllCaps="false"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

    <Button
        android:id="@+id/id_stop_service"
        android:text="Stop Service"
        android:textAllCaps="false"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

    <Button
        android:id="@+id/id_bind_service"
        android:text="Bind Service"
        android:textAllCaps="false"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

    <Button
        android:id="@+id/id_unbind_service"
        android:text="UnBind Service"
        android:textAllCaps="false"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

    <Button
        android:id="@+id/id_start_intentservice"
        android:text="Start IntentService"
        android:textAllCaps="false"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

    <Button
        android:id="@+id/id_stop_intentservice"
        android:text="Stop IntentService"
        android:textAllCaps="false"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

    <Button
        android:id="@+id/id_bind_intentservice"
        android:text="Bind IntentService"
        android:textAllCaps="false"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

    <Button
        android:id="@+id/id_unbind_intentservice"
        android:text="UnBind IntentService"
        android:textAllCaps="false"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

    <Button
        android:id="@+id/id_foo_intentservice"
        android:text="IntentService by foo Action"
        android:textAllCaps="false"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />
</LinearLayout>

看官们,代码虽然列出来了但是建议大家自己动手去实践,特别是生命周期中的回调方法,大家可以结合程序运行时打印出来的log去理解。

各位看官,关于Android中服务大结局的例子咱们就介绍到这里,欲知后面还有什么例子,且听下回分解!

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