http://www.cloudchou.com/android/post-458.html
1.前言
Binder service入门系列：
上一篇介绍了Framework Binder Service，本篇将介绍如何创建应用层的binder service。 实际上在应用层使用binder service时，并没有直接与ServiceManager交互(应用层不能直接使用ServiceManager 类)，一般是在Service子类里覆盖onBind方法，返回新创建的Binder实体对象。应用层使用Activity作为binder service的客户端，在Activity里创建ServiceConnecttion对象，并调用bindService方法绑定service，在ServiceConnection的onServiceConnected方法将接收到的IBinder对象转化为接口对象，然后再通过这个接口对象调用binder service的接口方法。
2.程序构成
程序在应用开发环境下编译。
整个工程可以在github上下载： https://github.com/cloudchou/AndroidBinderTest
本示例使用remote service，声明service时，使用了android:process属性。
3.程序源码构成
源代码结构如下所示：
AndroidManifeset.xml：声明用到的activity，service组件
ICloudManager.aidl： binder service接口
CloudService: 创建binder service，并返回给客户端
TestAc: 测试binder service的客户端
实现应用层 binder service的步骤
- 1) 使用aidl定义binder service接口ICloudManager
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| package com.cloud.test;
interface ICloudManager{
void print(String str) ;
int add(int a, int b);
} |
aidl全称是android interface definition language，用于定义binder service接口，语法与Java的接口非常类似，详情可参考：http://developer.android.com/guide/components/aidl.html
使用eclipse开发时，它会被自动编译成ICloudManager.java，放在gen目录下。生成的ICloudManager.java源码如下所示：
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| //声明接口ICloudManager 继承自IInterface，这里和在Framework使用binder service类似
public interface ICloudManager extends android.os.IInterface {
/**binder service实体类和framework的binder service实体类类似 */
public static abstract class Stub extends android.os.Binder implements com.cloud.test.ICloudManager {
private static final java.lang.String DESCRIPTOR = "com.cloud.test.ICloudManager";
/** Construct the stub at attach it to the interface. */
public Stub() {
this.attachInterface(this, DESCRIPTOR);
}
/**
* Cast an IBinder object into an com.cloud.test.ICloudManager interface, generating a proxy if needed.
*/
public static com.cloud.test.ICloudManager asInterface(android.os.IBinder obj) {
if ((obj == null)) {
return null;
}
android.os.IInterface iin = obj.queryLocalInterface(DESCRIPTOR);
if (((iin != null) && (iin instanceof com.cloud.test.ICloudManager))) {
return ((com.cloud.test.ICloudManager) iin);
}
return new com.cloud.test.ICloudManager.Stub.Proxy(obj);
}
@Override
public android.os.IBinder asBinder() {
return this;
}
@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_print: {
data.enforceInterface(DESCRIPTOR);
java.lang.String _arg0;
_arg0 = data.readString();
this.print(_arg0);
reply.writeNoException();
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;
}
}
return super.onTransact(code, data, reply, flags);
}
//binder service的引用类，或者说是代理，和framework使用binder service类似
private static class Proxy implements com.cloud.test.ICloudManager {
private android.os.IBinder mRemote;
Proxy(android.os.IBinder remote) {
mRemote = remote;
}
@Override
public android.os.IBinder asBinder() {
return mRemote;
}
public java.lang.String getInterfaceDescriptor() {
return DESCRIPTOR;
}
@Override
public void print(java.lang.String str) throws android.os.RemoteException {
android.os.Parcel _data = android.os.Parcel.obtain();
android.os.Parcel _reply = android.os.Parcel.obtain();
try {
_data.writeInterfaceToken(DESCRIPTOR);
_data.writeString(str);
mRemote.transact(Stub.TRANSACTION_print, _data, _reply, 0);
_reply.readException();
} finally {
_reply.recycle();
_data.recycle();
}
}
@Override
public int add(int a, int b) 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(a);
_data.writeInt(b);
mRemote.transact(Stub.TRANSACTION_add, _data, _reply, 0);
_reply.readException();
_result = _reply.readInt();
} finally {
_reply.recycle();
_data.recycle();
}
return _result;
}
}
static final int TRANSACTION_print = (android.os.IBinder.FIRST_CALL_TRANSACTION + 0);
static final int TRANSACTION_add = (android.os.IBinder.FIRST_CALL_TRANSACTION + 1);
}
public void print(java.lang.String str) throws android.os.RemoteException;
public int add(int a, int b) throws android.os.RemoteException;
}
|
由此可见应用层使用binder service实际上和framework使用binder service是非常类似的，只是在应用层使用binder service时，只需编写aidl，开发工具可帮我们自动编译生成java源码文件，该源文件里包含接口，binder service实体类(抽象类，接口方法还未实现)，binder service引用类的源码。
- 2) 实现Service
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| public class CloudService extends Service {
private final static String TAG = CloudService.class.getSimpleName();
//实现binder service实体类
class CloudMananger extends ICloudManager.Stub {
@Override
public void print(String str) throws RemoteException {
Log.d(TAG, "[ThreadId " + Thread.currentThread().getId()
+ "] [ProcessId" + Process.myPid()
+ "]CloudService receive client print msg request: "
+ str);
}
@Override
public int add(int a, int b) throws RemoteException {
Log.d(TAG, "[ThreadId " + Thread.currentThread().getId()
+ "] [ProcessId" + Process.myPid()
+ "[CloudService receive client add request : ");
return a + b;
}
}
@Override
public void onCreate() {
super.onCreate();
Log.d(TAG, "[ThreadId " + Thread.currentThread().getId()
+ "] [ProcessId" + Process.myPid() + "] onCreate");
}
//定义binder service实体类对象
private CloudMananger manager = new CloudMananger();
//覆盖onBind方法，返回binder service实体类对象
@Override
public IBinder onBind(Intent intent) {
Log.d(TAG, "[ThreadId " + Thread.currentThread().getId()
+ "] [ProcessId" + Process.myPid() + "] onBind");
return manager;
}
}
|
- 3) 实现Client
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| public class TestAc extends Activity {
private static final String TAG = TestAc.class.getSimpleName();
private ICloudManager manager = null;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Log.d(TAG, "[ThreadId " + Thread.currentThread().getId()
+ "] [ProcessId" + Process.myPid() + "] onCreate");
findViewById(R.id.btn_print).setOnClickListener(
new View.OnClickListener() {
@Override
public void onClick(View v) {
try {
Log.d(TAG, "=========== Client call "
+"CloudService print function");
//调用print方法
manager.print("Hello world");
} catch (RemoteException e) {
e.printStackTrace();
}
}
});
findViewById(R.id.btn_add).setOnClickListener(
new View.OnClickListener() {
@Override
public void onClick(View v) {
try {
Log.d(TAG, "======Client call "
+"CloudService add function");
int a = manager.add(3, 2);
Log.d(TAG, "======Client add function reuslt : " + a);
} catch (RemoteException e) {
e.printStackTrace();
}
}
});
}
@Override
protected void onStart() {
super.onStart();
//绑定 remote service
Intent intent = new Intent(this, CloudService.class);
bindService(intent, connection, BIND_AUTO_CREATE);
}
@Override
protected void onStop() {
super.onStop();
unbindService(connection);
}
//和remote service绑定时用的ServiceConnection对象
private ServiceConnection connection = new ServiceConnection() {
@Override
public void onServiceDisconnected(ComponentName name) {
Log.d(TAG, "[ThreadId " + Thread.currentThread().getId()
+ "] [ProcessId" + Process.myPid()
+ "] onServiceDisconnected");
}
@Override
public void onServiceConnected(ComponentName name, IBinder service)
{
Log.d(TAG, "[ThreadId " + Thread.currentThread().getId()
+ "] [ProcessId" + Process.myPid()
+ "] onServiceConnected");
//将IBinder对象转为ICloudManager接口对象，实际上是创建了一个代理对象
manager = ICloudManager.Stub.asInterface(service);
findViewById(R.id.btn_print).setEnabled(true);
findViewById(R.id.btn_add).setEnabled(true);
}
};
}
|
- 4) AndroidManifest.xml，声明程序组件Activity和Service
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| <manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.cloud.test"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="15"
android:targetSdkVersion="15" />
<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity android:name=".TestAc" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER"/>
</intent-filter>
</activity>
<!—remote service-->
<service
android:name=".CloudService"
android:enabled="true"
android:process=":remote" />
</application>
</manifest> |
4.测试
- 运行apk程序：
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