Android使用binder访问service的方式（一）
2015-11-05 08:34
549 查看
binder机制是贯穿整个android系统的进程间访问机制，经常被用来访问service，我们结合代码看一下binder在访问service的情形下是怎么具体使用的。
service 你可以理解成没有的界面的activity，它是跑在后台的程序，所谓后台是相对于可以被看得到的程序的，后台程序是不能直接交互的程序。
binder主要是用来进程间通信的，但也可用在和本地service通信。
1. 我们先来看一个与本地service通信的例子。
[java] view plaincopyprint?
package com.ckt.wangxin;
import android.app.Service;
import android.content.Intent;
import android.os.Binder;
import android.os.IBinder;
import android.widget.Toast;
/**
* This is a service stub for both LocalBinderClient
* and RemoteBinderClient
* @author Wang Xin
* @email springnap@163.com
*
*/
public class LocalService extends Service {
@Override
public IBinder onBind(Intent intent) {
return new LocalBinder();
}
public void sayHelloWorld(){
Toast.makeText(this.getApplicationContext(), "Hello World Local Service!", Toast.LENGTH_SHORT).show();
}
public class LocalBinder extends Binder {
LocalService getService() {
// Return this instance of LocalService so clients can call public methods
return LocalService.this;
}
}
}
local servcie 的代码如上，在onBinder方法中返回binder，binder包含了service的句柄，客户端得到句柄以后就可以调用servcie的公共方法了，这种调用方式是最常见的。
客户端代码
[java] view plaincopyprint?
package com.ckt.wangxin;
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 com.ckt.wangxin.LocalService.LocalBinder;
public class LocalServiceTestActivity extends Activity {
static final String TAG = "LocalBinderTestActivity";
ServiceConnection mSc;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
mSc = new ServiceConnection(){
@Override
public void onServiceConnected(ComponentName name, IBinder service) {
Log.d(TAG, "service connected");
LocalService ss = ((LocalBinder)service).getService();
ss.sayHelloWorld();
}
@Override
public void onServiceDisconnected(ComponentName name) {
Log.d(TAG, "service disconnected");
}
};
}
@Override
protected void onStart() {
super.onStart();
Log.d(TAG, this.getApplicationContext().getPackageCodePath());
Intent service = new Intent(this.getApplicationContext(),LocalService.class);
this.bindService(service, mSc, Context.BIND_AUTO_CREATE);
}
@Override
protected void onStop() {
super.onStop();
//must unbind the service otherwise the ServiceConnection will be leaked.
<span style="color: rgb(255, 0, 0); ">this.unbindService(mSc);</span>
}
}
需要注意的是在onStop中要解绑定service, 否则会造成内存泄露的问题。
2. 我们再看一下与另外一个进程中的service进行通信的问题（跨进程通信！）。
如何将servcie运行在另外一个进程呢？在manifest 里面配置个属性就行了。
android:process=":remote" , 代表这个service运行在同一个应用程序的不同进程中。
[html] view plaincopyprint?
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.ckt.wangxin"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk android:minSdkVersion="15" />
<application
android:icon="@drawable/ic_launcher"
android:label="@string/app_name" >
<activity
android:name=".LocalServiceTestActivity"
android:label="@string/app_name" >
<!-- <intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter> -->
</activity>
<service android:name=".LocalService"></service>
<!-- android:process=":remote" specify this service run in
another process in the same application. -->
<service android:name=".RemoteService" android:process=":remote"></service>
<activity android:name="RemoteServiceTestActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
客户端可以使用Messenger发送消息到service。
客户端代码：
[java] view plaincopyprint?
package com.ckt.wangxin;
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.Handler;
import android.os.IBinder;
import android.os.Message;
import android.os.Messenger;
import android.os.RemoteException;
import android.util.Log;
import android.widget.Toast;
public class RemoteServiceTestActivity extends Activity {
static final String TAG = "RemoteServiceTestActivity";
ServiceConnection mSc;
public static final int SAY_HELLO_TO_CLIENT = 0;
/**
* Handler of incoming messages from service.
*/
class IncomingHandler extends Handler {
@Override
public void handleMessage(Message msg) {
switch (msg.what) {
case SAY_HELLO_TO_CLIENT:
Toast.makeText(RemoteServiceTestActivity.this.getApplicationContext(), "Hello World Remote Client!",
Toast.LENGTH_SHORT).show();
break;
default:
super.handleMessage(msg);
}
}
}
Messenger messenger_reciever = new Messenger(new IncomingHandler());
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
mSc = new ServiceConnection(){
@Override
public void onServiceConnected(ComponentName name, IBinder service) {
Log.d(TAG, "service connected");
<span style="color: rgb(204, 0, 0); ">Messenger messenger = new Messenger(service);
Message msg = new Message();
msg.what = RemoteService.MSG_SAY_HELLO;</span>
msg.replyTo = messenger_reciever;
try {
<span style="color: rgb(255, 0, 0); ">messenger.send(msg);</span>
} catch (RemoteException e) {
e.printStackTrace();
}
}
@Override
public void onServiceDisconnected(ComponentName name) {
Log.d(TAG, "service disconnected");
}
};
}
@Override
protected void onStart() {
super.onStart();
Log.d(TAG, this.getApplicationContext().getPackageCodePath());
Intent service = new Intent(this.getApplicationContext(),RemoteService.class);
this.bindService(service, mSc, Context.BIND_AUTO_CREATE);
}
@Override
protected void onStop() {
super.onStop();
//must unbind the service otherwise the ServiceConnection will be leaked.
this.unbindService(mSc);
}
}
获得service端传来的binder，用来构建一个Messenger向service发送消息。
service端代码：
[java] view plaincopyprint?
package com.ckt.wangxin;
import android.app.Service;
import android.content.Intent;
import android.os.Handler;
import android.os.IBinder;
import android.os.Message;
import android.os.Messenger;
import android.os.RemoteException;
import android.widget.Toast;
public class RemoteService extends Service {
public static final int MSG_SAY_HELLO = 0;
@Override
public IBinder onBind(Intent intent) {
<span style="color: rgb(204, 0, 0); "> return messager.getBinder();</span>
}
Handler IncomingHandler = new Handler() {
@Override
public void handleMessage(Message msg) {
if(msg.replyTo != null){
Message msg_client = this.obtainMessage();
msg_client.what = RemoteServiceTestActivity.SAY_HELLO_TO_CLIENT;
try {
((Messenger)msg.replyTo).send(msg_client);
} catch (RemoteException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
switch (msg.what) {
case MSG_SAY_HELLO:
Toast.makeText(RemoteService.this.getApplicationContext(), "Hello World Remote Service!",
Toast.LENGTH_SHORT).show();
break;
default:
super.handleMessage(msg);
}
}
};
Messenger messager = new Messenger (IncomingHandler);
}
构建一个Messenger，包含一个handler，然后将messenger的binder传给客户端，客户端可以通过handler再构造一个messenger与service通信，消息在handler里面被处理。
现在是service端单向响应客户端的消息，同理可以做成双向发送消息，实现双向通信。
service 你可以理解成没有的界面的activity，它是跑在后台的程序，所谓后台是相对于可以被看得到的程序的，后台程序是不能直接交互的程序。
binder主要是用来进程间通信的，但也可用在和本地service通信。
1. 我们先来看一个与本地service通信的例子。
[java] view plaincopyprint?
package com.ckt.wangxin;
import android.app.Service;
import android.content.Intent;
import android.os.Binder;
import android.os.IBinder;
import android.widget.Toast;
/**
* This is a service stub for both LocalBinderClient
* and RemoteBinderClient
* @author Wang Xin
* @email springnap@163.com
*
*/
public class LocalService extends Service {
@Override
public IBinder onBind(Intent intent) {
return new LocalBinder();
}
public void sayHelloWorld(){
Toast.makeText(this.getApplicationContext(), "Hello World Local Service!", Toast.LENGTH_SHORT).show();
}
public class LocalBinder extends Binder {
LocalService getService() {
// Return this instance of LocalService so clients can call public methods
return LocalService.this;
}
}
}
package com.ckt.wangxin;
import android.app.Service;
import android.content.Intent;
import android.os.Binder;
import android.os.IBinder;
import android.widget.Toast;
/**
* This is a service stub for both LocalBinderClient
* and RemoteBinderClient
* @author Wang Xin
* @email springnap@163.com
*
*/
public class LocalService extends Service {
@Override
public IBinder onBind(Intent intent) {
return new LocalBinder();
}
public void sayHelloWorld(){
Toast.makeText(this.getApplicationContext(), "Hello World Local Service!", Toast.LENGTH_SHORT).show();
}
public class LocalBinder extends Binder {
LocalService getService() {
// Return this instance of LocalService so clients can call public methods
return LocalService.this;
}
}
}local servcie 的代码如上，在onBinder方法中返回binder，binder包含了service的句柄，客户端得到句柄以后就可以调用servcie的公共方法了，这种调用方式是最常见的。
客户端代码
[java] view plaincopyprint?
package com.ckt.wangxin;
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 com.ckt.wangxin.LocalService.LocalBinder;
public class LocalServiceTestActivity extends Activity {
static final String TAG = "LocalBinderTestActivity";
ServiceConnection mSc;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
mSc = new ServiceConnection(){
@Override
public void onServiceConnected(ComponentName name, IBinder service) {
Log.d(TAG, "service connected");
LocalService ss = ((LocalBinder)service).getService();
ss.sayHelloWorld();
}
@Override
public void onServiceDisconnected(ComponentName name) {
Log.d(TAG, "service disconnected");
}
};
}
@Override
protected void onStart() {
super.onStart();
Log.d(TAG, this.getApplicationContext().getPackageCodePath());
Intent service = new Intent(this.getApplicationContext(),LocalService.class);
this.bindService(service, mSc, Context.BIND_AUTO_CREATE);
}
@Override
protected void onStop() {
super.onStop();
//must unbind the service otherwise the ServiceConnection will be leaked.
<span style="color: rgb(255, 0, 0); ">this.unbindService(mSc);</span>
}
}
package com.ckt.wangxin;
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 com.ckt.wangxin.LocalService.LocalBinder;
public class LocalServiceTestActivity extends Activity {
static final String TAG = "LocalBinderTestActivity";
ServiceConnection mSc;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
mSc = new ServiceConnection(){
@Override
public void onServiceConnected(ComponentName name, IBinder service) {
Log.d(TAG, "service connected");
LocalService ss = ((LocalBinder)service).getService();
ss.sayHelloWorld();
}
@Override
public void onServiceDisconnected(ComponentName name) {
Log.d(TAG, "service disconnected");
}
};
}
@Override
protected void onStart() {
super.onStart();
Log.d(TAG, this.getApplicationContext().getPackageCodePath());
Intent service = new Intent(this.getApplicationContext(),LocalService.class);
this.bindService(service, mSc, Context.BIND_AUTO_CREATE);
}
@Override
protected void onStop() {
super.onStop();
//must unbind the service otherwise the ServiceConnection will be leaked.
<span style="color: rgb(255, 0, 0); ">this.unbindService(mSc);</span>
}
}需要注意的是在onStop中要解绑定service, 否则会造成内存泄露的问题。
2. 我们再看一下与另外一个进程中的service进行通信的问题（跨进程通信！）。
如何将servcie运行在另外一个进程呢？在manifest 里面配置个属性就行了。
android:process=":remote" , 代表这个service运行在同一个应用程序的不同进程中。
[html] view plaincopyprint?
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.ckt.wangxin"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk android:minSdkVersion="15" />
<application
android:icon="@drawable/ic_launcher"
android:label="@string/app_name" >
<activity
android:name=".LocalServiceTestActivity"
android:label="@string/app_name" >
<!-- <intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter> -->
</activity>
<service android:name=".LocalService"></service>
<!-- android:process=":remote" specify this service run in
another process in the same application. -->
<service android:name=".RemoteService" android:process=":remote"></service>
<activity android:name="RemoteServiceTestActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
<?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.ckt.wangxin" android:versionCode="1" android:versionName="1.0" > <uses-sdk android:minSdkVersion="15" /> <application android:icon="@drawable/ic_launcher" android:label="@string/app_name" > <activity android:name=".LocalServiceTestActivity" android:label="@string/app_name" > <!-- <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> --> </activity> <service android:name=".LocalService"></service> <!-- android:process=":remote" specify this service run in another process in the same application. --> <service android:name=".RemoteService" android:process=":remote"></service> <activity android:name="RemoteServiceTestActivity"> <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity> </application> </manifest>
客户端可以使用Messenger发送消息到service。
客户端代码：
[java] view plaincopyprint?
package com.ckt.wangxin;
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.Handler;
import android.os.IBinder;
import android.os.Message;
import android.os.Messenger;
import android.os.RemoteException;
import android.util.Log;
import android.widget.Toast;
public class RemoteServiceTestActivity extends Activity {
static final String TAG = "RemoteServiceTestActivity";
ServiceConnection mSc;
public static final int SAY_HELLO_TO_CLIENT = 0;
/**
* Handler of incoming messages from service.
*/
class IncomingHandler extends Handler {
@Override
public void handleMessage(Message msg) {
switch (msg.what) {
case SAY_HELLO_TO_CLIENT:
Toast.makeText(RemoteServiceTestActivity.this.getApplicationContext(), "Hello World Remote Client!",
Toast.LENGTH_SHORT).show();
break;
default:
super.handleMessage(msg);
}
}
}
Messenger messenger_reciever = new Messenger(new IncomingHandler());
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
mSc = new ServiceConnection(){
@Override
public void onServiceConnected(ComponentName name, IBinder service) {
Log.d(TAG, "service connected");
<span style="color: rgb(204, 0, 0); ">Messenger messenger = new Messenger(service);
Message msg = new Message();
msg.what = RemoteService.MSG_SAY_HELLO;</span>
msg.replyTo = messenger_reciever;
try {
<span style="color: rgb(255, 0, 0); ">messenger.send(msg);</span>
} catch (RemoteException e) {
e.printStackTrace();
}
}
@Override
public void onServiceDisconnected(ComponentName name) {
Log.d(TAG, "service disconnected");
}
};
}
@Override
protected void onStart() {
super.onStart();
Log.d(TAG, this.getApplicationContext().getPackageCodePath());
Intent service = new Intent(this.getApplicationContext(),RemoteService.class);
this.bindService(service, mSc, Context.BIND_AUTO_CREATE);
}
@Override
protected void onStop() {
super.onStop();
//must unbind the service otherwise the ServiceConnection will be leaked.
this.unbindService(mSc);
}
}
package com.ckt.wangxin;
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.Handler;
import android.os.IBinder;
import android.os.Message;
import android.os.Messenger;
import android.os.RemoteException;
import android.util.Log;
import android.widget.Toast;
public class RemoteServiceTestActivity extends Activity {
static final String TAG = "RemoteServiceTestActivity";
ServiceConnection mSc;
public static final int SAY_HELLO_TO_CLIENT = 0;
/**
* Handler of incoming messages from service.
*/
class IncomingHandler extends Handler {
@Override
public void handleMessage(Message msg) {
switch (msg.what) {
case SAY_HELLO_TO_CLIENT:
Toast.makeText(RemoteServiceTestActivity.this.getApplicationContext(), "Hello World Remote Client!",
Toast.LENGTH_SHORT).show();
break;
default:
super.handleMessage(msg);
}
}
}
Messenger messenger_reciever = new Messenger(new IncomingHandler());
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
mSc = new ServiceConnection(){
@Override
public void onServiceConnected(ComponentName name, IBinder service) {
Log.d(TAG, "service connected");
<span style="color: rgb(204, 0, 0); ">Messenger messenger = new Messenger(service);
Message msg = new Message();
msg.what = RemoteService.MSG_SAY_HELLO;</span>
msg.replyTo = messenger_reciever;
try {
<span style="color: rgb(255, 0, 0); ">messenger.send(msg);</span>
} catch (RemoteException e) {
e.printStackTrace();
}
}
@Override
public void onServiceDisconnected(ComponentName name) {
Log.d(TAG, "service disconnected");
}
};
}
@Override
protected void onStart() {
super.onStart();
Log.d(TAG, this.getApplicationContext().getPackageCodePath());
Intent service = new Intent(this.getApplicationContext(),RemoteService.class);
this.bindService(service, mSc, Context.BIND_AUTO_CREATE);
}
@Override
protected void onStop() {
super.onStop();
//must unbind the service otherwise the ServiceConnection will be leaked.
this.unbindService(mSc);
}
}获得service端传来的binder，用来构建一个Messenger向service发送消息。
service端代码：
[java] view plaincopyprint?
package com.ckt.wangxin;
import android.app.Service;
import android.content.Intent;
import android.os.Handler;
import android.os.IBinder;
import android.os.Message;
import android.os.Messenger;
import android.os.RemoteException;
import android.widget.Toast;
public class RemoteService extends Service {
public static final int MSG_SAY_HELLO = 0;
@Override
public IBinder onBind(Intent intent) {
<span style="color: rgb(204, 0, 0); "> return messager.getBinder();</span>
}
Handler IncomingHandler = new Handler() {
@Override
public void handleMessage(Message msg) {
if(msg.replyTo != null){
Message msg_client = this.obtainMessage();
msg_client.what = RemoteServiceTestActivity.SAY_HELLO_TO_CLIENT;
try {
((Messenger)msg.replyTo).send(msg_client);
} catch (RemoteException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
switch (msg.what) {
case MSG_SAY_HELLO:
Toast.makeText(RemoteService.this.getApplicationContext(), "Hello World Remote Service!",
Toast.LENGTH_SHORT).show();
break;
default:
super.handleMessage(msg);
}
}
};
Messenger messager = new Messenger (IncomingHandler);
}
package com.ckt.wangxin;
import android.app.Service;
import android.content.Intent;
import android.os.Handler;
import android.os.IBinder;
import android.os.Message;
import android.os.Messenger;
import android.os.RemoteException;
import android.widget.Toast;
public class RemoteService extends Service {
public static final int MSG_SAY_HELLO = 0;
@Override
public IBinder onBind(Intent intent) {
<span style="color: rgb(204, 0, 0); "> return messager.getBinder();</span>
}
Handler IncomingHandler = new Handler() {
@Override
public void handleMessage(Message msg) {
if(msg.replyTo != null){
Message msg_client = this.obtainMessage();
msg_client.what = RemoteServiceTestActivity.SAY_HELLO_TO_CLIENT;
try {
((Messenger)msg.replyTo).send(msg_client);
} catch (RemoteException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
switch (msg.what) {
case MSG_SAY_HELLO:
Toast.makeText(RemoteService.this.getApplicationContext(), "Hello World Remote Service!",
Toast.LENGTH_SHORT).show();
break;
default:
super.handleMessage(msg);
}
}
};
Messenger messager = new Messenger (IncomingHandler);
}构建一个Messenger，包含一个handler，然后将messenger的binder传给客户端，客户端可以通过handler再构造一个messenger与service通信，消息在handler里面被处理。
现在是service端单向响应客户端的消息，同理可以做成双向发送消息，实现双向通信。
内容来自用户分享和网络整理，不保证内容的准确性，如有侵权内容，可联系管理员处理 
相关文章推荐
- Android Service GetSystemService
- Android权限学习之请求权限实例
- 极光推送报so文件加载错误
- android串口通信——电子扫描枪
- android串口通信——电子扫描枪
- Android 中布局，如果有些参数不起作用，那么使用相对布局一般都起作用
- Android / iOS 招聘
- Android实现渐色变圆形
- Mac系统下对Android apk进行反编译
- iOS 和 Android 哪个更利于赚钱呢?
- Toast提示框
- Dialog对话框
- 通知栏的提示（notification）
- Android菜单的几种方法
- Android内的动画两种
- Android 四大组件【持续更新中】
- Android 简单几步实现手机号码归属地查询，可监听文本框的变化自动查询
- Android的常用传感器开发教程案例
- MeiTuanRefreshListView高仿美团下拉刷新《IT蓝豹》
- Android之Bundle类(浅谈)