編輯:關於android開發
但是:
Binder不支持RPC,只有本地客戶端和服務端基於消息通信,不適用於流不符合POSIX標准客戶端使用服務
進程之間無法進行直接通信,所以通過Binder驅動
客戶端和服務端不需要了解binder協議,所以使用代理和存根
客戶端不想要知道正在使用IPC,也不關心binder和代理,所以,需要管理對象進行抽象
但是客戶端怎樣獲取它想要通信的服務的handle,只需要問問sevicemanager(Context Manager),服務是否已經注冊
最後,我們看下總體的架構
使用aidl實現跨進程的加減法
新建android工程,創建包com.realize.calc.aidl,新建文件ICalcAIDL.aidl,內容如下
package com.realize.calc.aidl; interface ICalcAIDL { int add(int x , int y); int min(int x , int y ); }
package com.realize.lizijun.binder_server; import com.realize.calc.aidl.ICalcAIDL; import android.app.Service; import android.content.Intent; import android.os.IBinder; import android.os.RemoteException; import android.util.Log; public class CalcService extends Service { private static final String TAG = "server"; public void onCreate() { Log.e(TAG, "onCreate"); } public IBinder onBind(Intent t) { Log.e(TAG, "onBind"); return mBinder; } public void onDestroy() { Log.e(TAG, "onDestroy"); super.onDestroy(); } public boolean onUnbind(Intent intent) { Log.e(TAG, "onUnbind"); return super.onUnbind(intent); } public void onRebind(Intent intent) { Log.e(TAG, "onRebind"); super.onRebind(intent); } private final ICalcAIDL.Stub mBinder = new ICalcAIDL.Stub() { @Override public int add(int x, int y) throws RemoteException { return x + y; } @Override public int min(int x, int y) throws RemoteException { return x - y; } }; }
<service android:name="com.realize.lizijun.binder_server.CalcService"> <intent-filter> <action android:name="com.realize.calc.aidl"> <category android:name="android.intent.category.DEFAULT"> </category></action></intent-filter> </service>
新建android工程,創建包com.realize.calc.aidl,新建文件ICalcAIDL.aidl(與服務端是一樣的),內容如下
package com.realize.calc.aidl; interface ICalcAIDL { int add(int x , int y); int min(int x , int y ); }
package com.realize.lizijun.binder_client; import android.app.Activity; import android.content.ComponentName; import android.content.Context; import android.content.Intent; import android.content.ServiceConnection; import android.os.Bundle; import android.os.IBinder; import android.util.Log; import android.view.View; import android.widget.Toast; import com.realize.calc.aidl.ICalcAIDL; public class MainActivity extends Activity { private static final String TAG = "client"; private ICalcAIDL mCalcAidl; private ServiceConnection mServiceConn = new ServiceConnection() { @Override public void onServiceDisconnected(ComponentName name) { Log.e(TAG, "onServiceDisconnected"); mCalcAidl = null; } @Override public void onServiceConnected(ComponentName name, IBinder service) { Log.e(TAG, "onServiceConnected"); mCalcAidl = ICalcAIDL.Stub.asInterface(service); } }; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); } /** * 點擊BindService按鈕時調用 * @param view */ public void bindService(View view) { Intent intent = new Intent(); intent.setAction("com.realize.calc.aidl"); bindService(intent, mServiceConn, Context.BIND_AUTO_CREATE); } /** * 點擊unBindService按鈕時調用 * @param view */ public void unbindService(View view) { unbindService(mServiceConn); } /** * 點擊12+12按鈕時調用 * @param view */ public void addInvoked(View view) throws Exception { if (mCalcAidl != null) { int addRes = mCalcAidl.add(12, 12); Toast.makeText(this, addRes + "", Toast.LENGTH_SHORT).show(); } else { Toast.makeText(this, "服務器被異常殺死,請重新綁定服務端", Toast.LENGTH_SHORT) .show(); } } /** * 點擊50-12按鈕時調用 * @param view */ public void minInvoked(View view) throws Exception { if (mCalcAidl != null) { int addRes = mCalcAidl.min(50, 12); Toast.makeText(this, addRes + "", Toast.LENGTH_SHORT).show(); } else { Toast.makeText(this, "服務器未綁定或被異常殺死,請重新綁定服務端", Toast.LENGTH_SHORT) .show(); } } }
點擊BindService之後,服務端執行了onCreate和onBind的方法, 客戶端執行onServiceConnected方法然後點擊12+12,50-12可以成功的調用服務端的代碼並返回正確的結果再點擊unBindService, Service調用了onUnbind和onDestory然後點擊12+12,50-12,仍然能夠看到正確的結果,說明客戶端與服務端的連接仍然存在我們通過後台,把服務強制停止掉,可以看到調用了onServiceDisconnected方法,此時,再點擊12+12,50-12,就獲取不到結果了
上面創建ICalcAIDL.aidl之後,在gen目錄下回生成文件ICalcAIDL.java, 該文件實現了客戶端和服務端的代理(proxy)和存根(stub)
服務端代碼中調用ICalcAIDL.Stub
private final ICalcAIDL.Stub mBinder = new ICalcAIDL.Stub() { @Override public int add(int x, int y) throws RemoteException { return x + y; } @Override public int min(int x, int y) throws RemoteException { return x - y; } };
public static abstract class Stub extends android.os.Binder implements com.realize.calc.aidl.ICalcAIDL
@Override public boolean onTransact(int code, android.os.Parcel data, android.os.Parcel reply, int flags) throws android.os.RemoteException { switch (code) { case INTERFACE_TRANSACTION: { reply.writeString(DESCRIPTOR); return true; } case TRANSACTION_add: { data.enforceInterface(DESCRIPTOR); int _arg0; _arg0 = data.readInt(); int _arg1; _arg1 = data.readInt(); int _result = this.add(_arg0, _arg1); reply.writeNoException(); reply.writeInt(_result); return true; } case TRANSACTION_min: { data.enforceInterface(DESCRIPTOR); int _arg0; _arg0 = data.readInt(); int _arg1; _arg1 = data.readInt(); int _result = this.min(_arg0, _arg1); reply.writeNoException(); reply.writeInt(_result); return true; } } return super.onTransact(code, data, reply, flags); } 服務端會根據客戶端發送來的消息執行onTransact方法,該方法有四個參數 code 是一個整形的唯一標識,用於區分執行哪個方法 data 客戶端傳遞過來的參數 reply 服務器返回的值 flags 標明是否有返回值,0為有(雙向),1為沒有(單向)
客戶端代碼中,調用了ICalcAIDL.Stub.asInterface
private ServiceConnection mServiceConn = new ServiceConnection() { @Override public void onServiceDisconnected(ComponentName name) { Log.e(TAG, "onServiceDisconnected"); mCalcAidl = null; } @Override public void onServiceConnected(ComponentName name, IBinder service) { Log.e(TAG, "onServiceConnected"); mCalcAidl = ICalcAIDL.Stub.asInterface(service); } };
public static com.realize.calc.aidl.ICalcAIDL asInterface(android.os.IBinder obj) { if ((obj==null)) { return null; } android.os.IInterface iin = obj.queryLocalInterface(DESCRIPTOR); if (((iin!=null)&&(iin instanceof com.realize.calc.aidl.ICalcAIDL))) { return ((com.realize.calc.aidl.ICalcAIDL)iin); } return new com.realize.calc.aidl.ICalcAIDL.Stub.Proxy(obj); }
@Override public int add(int x, int y) throws android.os.RemoteException { android.os.Parcel _data = android.os.Parcel.obtain(); android.os.Parcel _reply = android.os.Parcel.obtain(); int _result; try { _data.writeInterfaceToken(DESCRIPTOR); _data.writeInt(x); _data.writeInt(y); mRemote.transact(Stub.TRANSACTION_add, _data, _reply, 0); _reply.readException(); _result = _reply.readInt(); } finally { _reply.recycle(); _data.recycle(); } return _result; } 聲明了兩個android.os.Parcel對象,_data用於傳遞數據,_replay用於接收返回的數據 最後調用transact方法,與服務端進行通信
怎樣不通過AIDL文件,實現跨進程通信呢,從上面的分析中,我們可以知道,不通過AIDL文件,實現跨進程通信,那麼實際上,就是要實現自動生成的AIDL文件中的接口功能, 下面我們實現跨進程的乘除調用
創建工程,實現CalcService.java,代碼如下
package com.realize.lizijun.noaidl_binder_server; import android.app.Service; import android.content.Intent; import android.os.Binder; import android.os.IBinder; import android.os.Parcel; import android.os.RemoteException; import android.util.Log; public class CalcService extends Service { private static final String DESCRIPTOR = "CalcService"; private static final String TAG = "server"; public void onCreate() { Log.e(TAG, "onCreate"); } @Override public int onStartCommand(Intent intent, int flags, int startId) { Log.e(TAG, "onStartCommand"); return super.onStartCommand(intent, flags, startId); } public IBinder onBind(Intent t) { Log.e(TAG, "onBind"); return mBinder; } public void onDestroy() { Log.e(TAG, "onDestroy"); super.onDestroy(); } public boolean onUnbind(Intent intent) { Log.e(TAG, "onUnbind"); return super.onUnbind(intent); } public void onRebind(Intent intent) { Log.e(TAG, "onRebind"); super.onRebind(intent); } private MyBinder mBinder = new MyBinder(); private class MyBinder extends Binder { @Override protected boolean onTransact(int code, Parcel data, Parcel reply, int flags) throws RemoteException { switch (code) { case 0x110: { Log.e(TAG, "0x110"); data.enforceInterface(DESCRIPTOR); int _arg0; _arg0 = data.readInt(); int _arg1; _arg1 = data.readInt(); int _result = _arg0 * _arg1; reply.writeNoException(); reply.writeInt(_result); return true; } case 0x111: { Log.e(TAG, "0x111"); data.enforceInterface(DESCRIPTOR); int _arg0; _arg0 = data.readInt(); int _arg1; _arg1 = data.readInt(); int _result = _arg0 / _arg1; reply.writeNoException(); reply.writeInt(_result); return true; } } return super.onTransact(code, data, reply, flags); } }; } 自定義了一個Binder子類,然後復寫了其onTransact方法
<service android:name="com.realize.lizijun.noaidl_binder_server.CalcService"> <intent-filter> <action android:name="com.realize.noaidl.calc"> <category android:name="android.intent.category.DEFAULT"> </category></action></intent-filter> </service>
創建工程,其主activity內容如下所示:
package com.realize.lizijun.noaidl_binder_client; import android.app.Activity; import android.content.ComponentName; import android.content.Context; import android.content.Intent; import android.content.ServiceConnection; import android.os.Bundle; import android.os.IBinder; import android.os.RemoteException; import android.util.Log; import android.view.View; import android.widget.Toast; public class MainActivity extends Activity { private static final String TAG = "client"; private IBinder mPlusBinder = null; private ServiceConnection mServiceConnPlus = new ServiceConnection() { // 只有當servie異常退出時,系統才會調用onServiceDisconnected() @Override public void onServiceDisconnected(ComponentName name) { Log.e(TAG, "mServiceConnPlus onServiceDisconnected"); mPlusBinder = null; } @Override public void onServiceConnected(ComponentName name, IBinder service) { Log.e(TAG, " mServiceConnPlus onServiceConnected"); mPlusBinder = service; } }; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); } public void bindService(View view) { Intent intentPlus = new Intent(); intentPlus.setAction("com.realize.noaidl.calc"); boolean result = bindService(intentPlus, mServiceConnPlus, Context.BIND_AUTO_CREATE); Log.e(TAG, result + ""); } public void unbindService(View view) { if (mServiceConnPlus != null) { Log.e(TAG, "unbindService"); unbindService(mServiceConnPlus); //mServiceConnPlus = null; } } public void mulInvoked(View view) { if (mPlusBinder == null) { Toast.makeText(this, "未連接服務端或服務端被異常殺死", Toast.LENGTH_SHORT).show(); } else { android.os.Parcel _data = android.os.Parcel.obtain(); android.os.Parcel _reply = android.os.Parcel.obtain(); int _result = 0; try { _data.writeInterfaceToken("CalcService"); _data.writeInt(50); _data.writeInt(12); mPlusBinder.transact(0x110, _data, _reply, 0); _reply.readException(); _result = _reply.readInt(); Toast.makeText(this, _result + "", Toast.LENGTH_SHORT).show(); } catch (RemoteException e) { e.printStackTrace(); } finally { _reply.recycle(); _data.recycle(); } } } public void divInvoked(View view) { if (mPlusBinder == null) { Toast.makeText(this, "未連接服務端或服務端被異常殺死", Toast.LENGTH_SHORT).show(); } else { android.os.Parcel _data = android.os.Parcel.obtain(); android.os.Parcel _reply = android.os.Parcel.obtain(); int _result = 0; try { _data.writeInterfaceToken("CalcService"); _data.writeInt(36); _data.writeInt(12); mPlusBinder.transact(0x111, _data, _reply, 0); _reply.readException(); _result = _reply.readInt(); Toast.makeText(this, _result + "", Toast.LENGTH_SHORT).show(); } catch (RemoteException e) { e.printStackTrace(); } finally { _reply.recycle(); _data.recycle(); } } } }
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