devbox
我家自动化
这个屌丝很懒，什么也没留下！
关注作者
热门标签
热门文章
当前位置:   article > 正文

深入浅出 Android Service（4）_public void throws android.os.remoteexception;

作者：我家自动化 | 2024-03-15 23:19:05

赞

踩

public void throws android.os.remoteexception;
       在android平台中，一个进程通常不能访问其他进程中的内存区域的。但是，我们可以使用IDL语言来把对象伪装成操作系统能理解的简单形式，以便伪装成对象跨越边界访问。
       如果想在应用程序中调用其他进程中的Service，则需要用到AIDL，AIDL(android接口描述语言)是一种IDL语言，它可以生成一段代码，可以使在一个android设备上运行的两个进程使用内部通信进程进行交互。如果你需要在一个进程中(例如:在一个Activity中)访问另一个进程中(例如:一个Service)某个对象的方法,你就可以使用AIDL来生成这样的代码来伪装传递各种参数。
 

使用AIDL的方法如下：
1.首先要编写一个IMusicService.aidl的服务接口，ADT会根据这个接口文件帮我们自动生成一个 Stub类，这个类继承了Binder类，同时继承了IMusicService这个接口，还可以看到其中包含了一个Proxy代理类，以实现远程代理，访问不同的进程。(aidl和Stub类如下所示)。 
  1. /**
  2.  * IMusicService.aidl
  3.  * com.androidtest.service.mediaplayer
  4.  *
  5.  * Function： TODO 
  6.  *
  7.  *   ver     date      		author
  8.  * ──────────────────────────────────
  9.  *   		 2011-5-19 		Leon
  10.  *
  11.  * Copyright (c) 2011, TNT All Rights Reserved.
  12. */
  13.  
  14. package com.zuiniuwang.service;
  15. /**
  16.  * ClassName:IMusicService
  17.  * Function: TODO ADD FUNCTION
  18.  * Reason:	 TODO ADD REASON
  19.  *
  20.  * @author   Leon
  21.  * @version  
  22.  * @since    Ver 1.1
  23.  * @Date	 2011-5-19
  24.  */
  25.  
  26.  
  27. interface IMusicService{
  28. 	void play();
  29. 	void pause();
  30. 	void stop();
  31. }
2. 生成的Stub类如下，我们暂不做详细讲解，后面的课程中我们会尝试自己来写一个类似的类，完成不同进程的访问。 

  1. /*
  2.  * This file is auto-generated.  DO NOT MODIFY.
  3.  * Original file: E:\\myworkspace\\musicservice4\\src\\com\\zuiniuwang\\service\\IMusicService.aidl
  4.  */
  5. package com.zuiniuwang.service;
  6. /**
  7.  * ClassName:IMusicService
  8.  * Function: TODO ADD FUNCTION
  9.  * Reason:	 TODO ADD REASON
  10.  *
  11.  * @author   Leon
  12.  * @version  
  13.  * @since    Ver 1.1
  14.  * @Date	 2011-5-19
  15.  */
  16. public interface IMusicService extends android.os.IInterface
  17. {
  18. /** Local-side IPC implementation stub class. */
  19. public static abstract class Stub extends android.os.Binder implements com.zuiniuwang.service.IMusicService
  20. {
  21. private static final java.lang.String DESCRIPTOR = "com.zuiniuwang.service.IMusicService";
  22. /** Construct the stub at attach it to the interface. */
  23. public Stub()
  24. {
  25. this.attachInterface(this, DESCRIPTOR);
  26. }
  27. /**
  28.  * Cast an IBinder object into an com.zuiniuwang.service.IMusicService interface,
  29.  * generating a proxy if needed.
  30.  */
  31. public static com.zuiniuwang.service.IMusicService asInterface(android.os.IBinder obj)
  32. {
  33. if ((obj==null)) {
  34. return null;
  35. }
  36. android.os.IInterface iin = (android.os.IInterface)obj.queryLocalInterface(DESCRIPTOR);
  37. if (((iin!=null)&&(iin instanceof com.zuiniuwang.service.IMusicService))) {
  38. return ((com.zuiniuwang.service.IMusicService)iin);
  39. }
  40. return new com.zuiniuwang.service.IMusicService.Stub.Proxy(obj);
  41. }
  42. public android.os.IBinder asBinder()
  43. {
  44. return this;
  45. }
  46. @Override public boolean onTransact(int code, android.os.Parcel data, android.os.Parcel reply, int flags) throws android.os.RemoteException
  47. {
  48. switch (code)
  49. {
  50. case INTERFACE_TRANSACTION:
  51. {
  52. reply.writeString(DESCRIPTOR);
  53. return true;
  54. }
  55. case TRANSACTION_play:
  56. {
  57. data.enforceInterface(DESCRIPTOR);
  58. this.play();
  59. reply.writeNoException();
  60. return true;
  61. }
  62. case TRANSACTION_pause:
  63. {
  64. data.enforceInterface(DESCRIPTOR);
  65. this.pause();
  66. reply.writeNoException();
  67. return true;
  68. }
  69. case TRANSACTION_stop:
  70. {
  71. data.enforceInterface(DESCRIPTOR);
  72. this.stop();
  73. reply.writeNoException();
  74. return true;
  75. }
  76. }
  77. return super.onTransact(code, data, reply, flags);
  78. }
  79. private static class Proxy implements com.zuiniuwang.service.IMusicService
  80. {
  81. private android.os.IBinder mRemote;
  82. Proxy(android.os.IBinder remote)
  83. {
  84. mRemote = remote;
  85. }
  86. public android.os.IBinder asBinder()
  87. {
  88. return mRemote;
  89. }
  90. public java.lang.String getInterfaceDescriptor()
  91. {
  92. return DESCRIPTOR;
  93. }
  94. public void play() throws android.os.RemoteException
  95. {
  96. android.os.Parcel _data = android.os.Parcel.obtain();
  97. android.os.Parcel _reply = android.os.Parcel.obtain();
  98. try {
  99. _data.writeInterfaceToken(DESCRIPTOR);
  100. mRemote.transact(Stub.TRANSACTION_play, _data, _reply, 0);
  101. _reply.readException();
  102. }
  103. finally {
  104. _reply.recycle();
  105. _data.recycle();
  106. }
  107. }
  108. public void pause() throws android.os.RemoteException
  109. {
  110. android.os.Parcel _data = android.os.Parcel.obtain();
  111. android.os.Parcel _reply = android.os.Parcel.obtain();
  112. try {
  113. _data.writeInterfaceToken(DESCRIPTOR);
  114. mRemote.transact(Stub.TRANSACTION_pause, _data, _reply, 0);
  115. _reply.readException();
  116. }
  117. finally {
  118. _reply.recycle();
  119. _data.recycle();
  120. }
  121. }
  122. public void stop() throws android.os.RemoteException
  123. {
  124. android.os.Parcel _data = android.os.Parcel.obtain();
  125. android.os.Parcel _reply = android.os.Parcel.obtain();
  126. try {
  127. _data.writeInterfaceToken(DESCRIPTOR);
  128. mRemote.transact(Stub.TRANSACTION_stop, _data, _reply, 0);
  129. _reply.readException();
  130. }
  131. finally {
  132. _reply.recycle();
  133. _data.recycle();
  134. }
  135. }
  136. }
  137. static final int TRANSACTION_play = (android.os.IBinder.FIRST_CALL_TRANSACTION + 0);
  138. static final int TRANSACTION_pause = (android.os.IBinder.FIRST_CALL_TRANSACTION + 1);
  139. static final int TRANSACTION_stop = (android.os.IBinder.FIRST_CALL_TRANSACTION + 2);
  140. }
  141. public void play() throws android.os.RemoteException;
  142. public void pause() throws android.os.RemoteException;
  143. public void stop() throws android.os.RemoteException;
  144. }

3. 在Activity中得到Binder的方式，是通过Stub类的IMusicService.Stub.asInterface(binder)方法（这一点和以前不同）。相应的代码如下： 
  1. /**
  2.  * RemoteMusicPlayerActivity.java
  3.  * com.androidtest.activity.musicplayer
  4.  *
  5.  * Function： TODO 
  6.  *
  7.  *   ver     date      		author
  8.  * ──────────────────────────────────
  9.  *   		 2011-5-20 		Leon
  10.  *
  11.  * Copyright (c) 2011, TNT All Rights Reserved.
  12.  */
  13.  
  14. package com.zuiniuwang.playeractivity;
  15.  
  16.  
  17.  
  18. import android.app.Activity;
  19. import android.content.ComponentName;
  20. import android.content.Context;
  21. import android.content.Intent;
  22. import android.content.ServiceConnection;
  23. import android.os.Bundle;
  24. import android.os.IBinder;
  25. import android.util.Log;
  26. import android.view.View;
  27. import android.view.View.OnClickListener;
  28. import android.widget.Button;
  29.  
  30. import com.zuiniuwang.R;
  31. import com.zuiniuwang.service.IMusicService;
  32.  
  33. /**
  34.  * ClassName:RemoteMusicPlayerActivity Function: TODO ADD FUNCTION Reason: TODO
  35.  * ADD REASON
  36.  * 
  37.  * @author Leon
  38.  * @version
  39.  * @since Ver 1.1
  40.  * @Date 2011-5-20
  41.  */
  42. public class RemoteMusicPlayerActivity extends Activity implements
  43. 		OnClickListener { 
  44.  
  45. 	private static final String TAG = RemoteMusicPlayerActivity.class
  46. 			.getSimpleName();
  47.  
  48. 	private Button playButton, pauseButton, stopButton, closeActivityButton,
  49. 			exitActivityButton;
  50.  
  51. 	private IMusicService musicServiceInterface;
  52.  
  53. 	@Override
  54. 	protected void onCreate(Bundle savedInstanceState) {
  55.  
  56. 		// TODO Auto-generated method stub
  57. 		super.onCreate(savedInstanceState);
  58. 		this.setContentView(R.layout.music_player_layout);
  59. 		findViews();
  60. 		bindViews();
  61. 		connection();
  62. 	}
  63.  
  64. 	private void findViews() {
  65. 		playButton = (Button) this.findViewById(R.id.play);
  66. 		pauseButton = (Button) this.findViewById(R.id.pause);
  67. 		stopButton = (Button) this.findViewById(R.id.stop);
  68. 		closeActivityButton = (Button) this.findViewById(R.id.close);
  69. 		exitActivityButton = (Button) this.findViewById(R.id.exit);
  70. 	}
  71.  
  72. 	private void bindViews() {
  73. 		playButton.setOnClickListener(this);
  74. 		pauseButton.setOnClickListener(this);
  75. 		stopButton.setOnClickListener(this);
  76. 		closeActivityButton.setOnClickListener(this);
  77. 		exitActivityButton.setOnClickListener(this);
  78. 	}
  79.  
  80. 	private void connection() {
  81. 		Intent intent = new Intent(
  82. 				"com.androidtest.service.mediaplayer.RemoteMusicService");
  83. 		this.startService(intent);
  84. 		this.bindService(intent, myServiceConnection, Context.BIND_AUTO_CREATE);
  85.  
  86. 	}
  87.  
  88. 	private ServiceConnection myServiceConnection = new ServiceConnection() {
  89.  
  90. 		@Override
  91. 		public void onServiceConnected(ComponentName name, IBinder binder) {
  92. 			musicServiceInterface = IMusicService.Stub.asInterface(binder);
  93. 			Log.d(TAG, " onServiceConnected");
  94. 		}
  95.  
  96. 		@Override
  97. 		public void onServiceDisconnected(ComponentName name) {
  98. 			musicServiceInterface = null;
  99. 			Log.d(TAG, " onServiceDisconnected");
  100. 		}
  101.  
  102. 	};
  103.  
  104. 	@Override
  105. 	public void onClick(View view) {
  106.  
  107. 		// TODO Auto-generated method stub
  108. 		try {
  109. 			switch (view.getId()) {
  110. 			case R.id.play:
  111. 				Log.d(TAG, "play.......");
  112. 				musicServiceInterface.play();
  113. 				break;
  114. 			case R.id.pause:
  115. 				Log.d(TAG, "pause.......");
  116. 				musicServiceInterface.pause();
  117. 				break;
  118. 			case R.id.stop:
  119. 				Log.d(TAG, "stop.......");
  120. 				musicServiceInterface.stop();
  121. 				break;
  122. 			case R.id.close:
  123. 				//Activity退出之前要解除绑定，不然会报错
  124. 				this.unbindService(myServiceConnection);
  125. 				Log.d(TAG, "close.......");
  126. 				this.finish();
  127. 				break;
  128. 			case R.id.exit:
  129. 				Log.d(TAG, "exit.......");
  130. 				this.unbindService(myServiceConnection);
  131. 				this.stopService(new Intent("com.androidtest.service.mediaplayer.RemoteMusicService"));
  132. 				this.finish();
  133.  
  134. 			}
  135.  
  136. 		} catch (Exception e) {
  137. 			e.printStackTrace();
  138. 		}
  139.  
  140. 	}
  141.  
  142. }

4. 最后在此Service注册的时候我们需要指定它是在一个不同的进程中运行的，本例子指定的是remote进程。注意 process参数。 
  1.        <!-- 注册Service -->
  2. 		<service android:enabled="true"
  3. 			android:name=".service.RemoteMusicService"  android:process=":remote">
  4. 			<intent-filter>
  5. 				<action android:name="com.androidtest.service.mediaplayer.RemoteMusicService" />
  6. 			</intent-filter>
  7. 		</service>

本节的源代码可在此下载：http://download.csdn.net/detail/internetman/3967828  
有问题可以发表评论或者微博私信我。

声明：本文内容由网友自发贡献，不代表【wpsshop博客】立场，版权归原作者所有，本站不承担相应法律责任。如您发现有侵权的内容，请联系我们。转载请注明出处：https://www.wpsshop.cn/w/我家自动化/article/detail/245336
推荐阅读
相关标签

Copyright © 2003-2013 www.wpsshop.cn 版权所有，并保留所有权利。

  

闽ICP备14008679号