Service代码示例

时间：2022-06-30 05:26:46
 package com.homily.training.service;

 import android.app.Service;

 import android.content.Intent;

 import android.os.Binder;

 import android.os.IBinder;

 import android.support.annotation.Nullable;

 import android.util.Log;

 import com.homily.training.test.service.ICallbackResult;

 /**

  * Created by Rubert on 2016/7/6.

  */

 public class BindService extends Service{

     private final static String TAG = BindService.class.getSimpleName();

     private MBinder mMBinder;

     private ICallbackResult mICallbackResult;

     private boolean unBindTarget = false;

     @Nullable

     @Override

     public IBinder onBind(Intent intent) {

         Log.i(TAG, "============onBind==================");

         return mMBinder;

     }

     @Override

     public void onCreate() {

         super.onCreate();

         Log.i(TAG, "============onCreate==================");

         mMBinder = new MBinder();

     }

     @Override

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

         Log.i(TAG, "============onStartCommand==================");

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

     }

     @Override

     public void onDestroy() {

         unBindTarget = true;

         super.onDestroy();

         Log.i(TAG, "============onDestroy==================");

     }

     @Override

     public boolean onUnbind(Intent intent) {

         Log.i(TAG, "============onUnbind==================");

         unBindTarget = true;//该处代码需要这么写是因为，Service中开启了线程。如果该Service直接onUnbind了，但是线程没有停止，并且如果再次bind该Service时，程序会再次重新实例化一个线程，并之前的线程也会一直运行下去，除非该app销毁。

         return super.onUnbind(intent);

     }

     public class MBinder extends Binder {

         public void start(){

             Log.i(TAG, "============MBinder-start==================");

             new Thread(new Runnable() {

                 @Override

                 public void run() {

                     while (true) {

                         if(unBindTarget) {

                             break;

                         }

                         Log.i(TAG, Thread.currentThread().getName() + "============MBinder-start-run==================");

                         mICallbackResult.OnBackResult(null);

                         try {

                             Thread.currentThread().sleep(5000);

                         } catch (InterruptedException e) {

                             e.printStackTrace();

                         }

                     }

                 }

             }).start();

         }

         public void bind(ICallbackResult result) {

             mICallbackResult = result;

         }

     }

 }
 package com.homily.training.service;

 import android.app.Service;

 import android.content.Intent;

 import android.os.IBinder;

 import android.support.annotation.Nullable;

 import android.util.Log;

 /**

  * Created by Rubert on 2016/7/6.

  */

 public class StartService extends Service{

     private final static String TAG = StartService.class.getSimpleName();

     @Nullable

     @Override

     public IBinder onBind(Intent intent) {

         Log.i(TAG, "============onBind==================");

         return null;

     }

     @Override

     public void onCreate() {

         super.onCreate();

         Log.i(TAG, "============onCreate==================");

     }

     @Override

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

         Log.i(TAG, "============onStartCommand==================");

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

     }

     @Override

     public void onDestroy() {

         super.onDestroy();

         Log.i(TAG, "============onDestroy==================");

     }

     @Override

     public boolean onUnbind(Intent intent) {

         Log.i(TAG, "============onUnbind==================");

         return super.onUnbind(intent);

     }

 }
 package com.homily.training.test.service;

 import android.app.Activity;

 import android.content.ComponentName;

 import android.content.Context;

 import android.content.Intent;

 import android.content.ServiceConnection;

 import android.os.Binder;

 import android.os.Bundle;

 import android.os.IBinder;

 import android.util.Log;

 import android.view.View;

 import android.widget.Button;

 import com.homily.training.R;

 import com.homily.training.service.BindService;

 import com.homily.training.service.StartService;

 /**

  * Created by Rubert on 2016/7/6.

  * 主要验证startService 启动后再次启动；以及bindService绑定后，解绑再次绑定的情况。

  */

 public class ServiceMainAct extends Activity implements View.OnClickListener{

     private final static String TAG = ServiceMainAct.class.getSimpleName();

     Button startServiceBtn;

     Button closeServiceBtn;

     Button bindServiceBtn;

     Button unbindServiceBtn;

     BindService.MBinder mMBinder;

     boolean IsBinder = false;

     @Override

     protected void onCreate(Bundle savedInstanceState) {

         super.onCreate(savedInstanceState);

         setContentView(R.layout.service_layout);

         startServiceBtn = (Button)findViewById(R.id.startService);

         closeServiceBtn = (Button)findViewById(R.id.closeService);

         bindServiceBtn = (Button)findViewById(R.id.binService);

         unbindServiceBtn = (Button)findViewById(R.id.unbinService);

         startServiceBtn.setOnClickListener(this);

         closeServiceBtn.setOnClickListener(this);

         bindServiceBtn.setOnClickListener(this);

         unbindServiceBtn.setOnClickListener(this);

     }

     ServiceConnection mConnection = new ServiceConnection(){

         @Override

         public void onServiceConnected(ComponentName componentName, IBinder iBinder) {

             Log.i(TAG, "=============onServiceConnected==================");

             mMBinder = (BindService.MBinder)iBinder;

             mMBinder.bind(mICallbackResult);

             mMBinder.start();

             IsBinder = true;

         }

         @Override

         public void onServiceDisconnected(ComponentName componentName) {

             Log.i(TAG, "=============onServiceDisconnected==================");

             IsBinder = false;

         }

     };

     ICallbackResult mICallbackResult = new ICallbackResult(){

         @Override

         public void OnBackResult(Object result) {

             Log.i(TAG, "=============result==================");

         }

     };

     @Override

     public void onClick(View view) {

         switch (view.getId()) {

             case R.id.startService:

                 Intent sintent = new Intent(ServiceMainAct.this, StartService.class);

                 startService(sintent);

                 break;

             case R.id.closeService:

                 Intent cintent = new Intent(ServiceMainAct.this, StartService.class);

                 stopService(cintent);

                 break;

             case R.id.binService:

                 Intent service = new Intent(ServiceMainAct.this, BindService.class);

                 bindService(service, mConnection, Context.BIND_AUTO_CREATE);

                 break;

             case R.id.unbinService:

                 if(mConnection != null && IsBinder)

                 unbindService(mConnection);

                 break;

         }

     }

 }
 package com.homily.training.test.service;

 /**

  * Created by Rubert on 2016/7/6.

  */

 public interface ICallbackResult {

     void OnBackResult(Object result);

 }
<application

        android:allowBackup="true"

        android:icon="@mipmap/ic_launcher"

        android:label="@string/app_name"

        android:theme="@style/AppTheme" >

        <service android:name="com.homily.training.service.StartService" />

        <service android:name="com.homily.training.service.BindService" />

<activity android:name=".test.service.ServiceMainAct">

            <intent-filter>

                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />

            </intent-filter>

        </activity>

</application>
 <?xml version="1.0" encoding="utf-8"?>

 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

     android:layout_width="match_parent"

     android:layout_height="match_parent"

     android:orientation="vertical"

     >

     <Button

         android:id="@+id/startService"

         android:layout_width="match_parent"

         android:layout_height="wrap_content"

         android:text="startService"

         />

     <Button

         android:id="@+id/closeService"

         android:layout_width="match_parent"

         android:layout_height="wrap_content"

         android:text="closeService"

         />

     <Button

         android:id="@+id/binService"

         android:layout_width="match_parent"

         android:layout_height="wrap_content"

         android:text="binService"

         />

     <Button

         android:id="@+id/unbinService"

         android:layout_width="match_parent"

         android:layout_height="wrap_content"

         android:text="unbinService"

         />

 </LinearLayout>
Android开发的过程中，每次调用startService(Intent)的时候，都会调用该Service对象的onStartCommand(Intent,int,int)方法，然后在onStartCommand方法中做一些处理。然后我们注意到这个函数有一个int的返回值，这篇文章就是简单地讲讲int返回值的作用。
从Android官方文档中，我们知道onStartCommand有4种返回值：
START_STICKY：如果service进程被kill掉，保留service的状态为开始状态，但不保留递送的intent对象。随后系统会尝试重新创建service，由于服务状态为开始状态，所以创建服务后一定会调用onStartCommand(Intent,int,int)方法。如果在此期间没有任何启动命令被传递到service，那么参数Intent将为null。
START_NOT_STICKY：“非粘性的”。使用这个返回值时，如果在执行完onStartCommand后，服务被异常kill掉，系统不会自动重启该服务。
START_REDELIVER_INTENT：重传Intent。使用这个返回值时，如果在执行完onStartCommand后，服务被异常kill掉，系统会自动重启该服务，并将Intent的值传入。
START_STICKY_COMPATIBILITY：START_STICKY的兼容版本，但不保证服务被kill后一定能重启。

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