Android本地绑定

Question

为什么我们在这里使用getService方法？

public class LocalBinder extends Binder { 
    LocalService getService() { 
     return LocalService.this; 
    } 
} 

Answer 1

• 的BoundService作为客户端 - 服务器架构的服务器。（你可能知道这部分）。
• 服务器始终将某些服务导出到客户端。该服务可能是一种公共方法（如“public void reverse（String）”）。
• getService（）函数用于返回LocalService的实例，以便客户端可以通过该实例访问该BoundService的公共方法。

下面是从Android官方文档

'公共类本地服务延伸服务的一个范例程序{// 粘结剂提供给客户端 私人最终的IBinder mBinder =新LocalBinder（）; //随机数发生器 private final mGenerator = new Random（）;

/** 
* Class used for the client Binder. Because we know this service always 
* runs in the same process as its clients, we don't need to deal with IPC. 
*/ 
public class LocalBinder extends Binder { 
    LocalService getService() { 
     // Return this instance of LocalService so clients can call public methods 
     return LocalService.this; 
    } 
} 

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

/** method for clients */ 
public int getRandomNumber() { 
    return mGenerator.nextInt(100); 
} 

} `

`公共类BindingActivity延伸活动{ 本地服务MSERVICE; boolean mBound = false;

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

@Override 
protected void onStart() { 
    super.onStart(); 
    // Bind to LocalService 
    Intent intent = new Intent(this, LocalService.class); 
    bindService(intent, mConnection, Context.BIND_AUTO_CREATE); 
} 

@Override 
protected void onStop() { 
    super.onStop(); 
    // Unbind from the service 
    if (mBound) { 
     unbindService(mConnection); 
     mBound = false; 
    } 
} 

/** Called when a button is clicked (the button in the layout file attaches to 
    * this method with the android:onClick attribute) */ 
public void onButtonClick(View v) { 
    if (mBound) { 
     // Call a method from the LocalService. 
     // However, if this call were something that might hang, then this request should 
     // occur in a separate thread to avoid slowing down the activity performance. 
     int num = mService.getRandomNumber(); 
     Toast.makeText(this, "number: " + num, Toast.LENGTH_SHORT).show(); 
    } 
} 

/** Defines callbacks for service binding, passed to bindService() */ 
private ServiceConnection mConnection = new ServiceConnection() { 

    @Override 
    public void onServiceConnected(ComponentName className, 
      IBinder service) { 
     // We've bound to LocalService, cast the IBinder and get LocalService instance 
     LocalBinder binder = (LocalBinder) service; 
     mService = binder.getService(); 
     mBound = true; 
    } 

    @Override 
    public void onServiceDisconnected(ComponentName arg0) { 
     mBound = false; 
    } 
}; 

}`

让我们看起来更接近。

服务器部分。

公共类LocalService是将某些功能导出（或给予）客户端活动或服务的服务。客户端导入（或使用）funtcionality。

public int getRandomNumber() { return mGenerator.nextInt(100); }

上面的代码是实际的功能或服务的服务器导出。

客户端部分。

LocalBinder binder = (LocalBinder) service; mService = binder.getService(); mBound = true;

这里binder.getService（）被用于获取LocalBinder类的运行（或电流）实例（或对象）。

然后，

int num = mService.getRandomNumber(); Toast.makeText(this, "number: " +num,Toast.LENGTH_SHORT).show();

mService.getRandomNumber（）被用于访问公共方法。