android本地后台服务示例

在android编写Service入门中介绍了android的两种后台服务，本地和远程的。这里用本地服务做了一个模拟定时后台发短信的技术原型。

启动该示例应用的样子：

选择启动：

启动后，可看到ddms logcat日志：

这是操作：启动、停止和退出应用，显示的调试日志信息。模拟后台服务每5秒钟发送一次短信信息。

主要代码，后台服务SmsService：

package com.easymorse;

import android.app.Service;

import android.content.Intent;

import android.os.Binder;

import android.os.IBinder;

import android.util.Log;

public class SmsService extends Service {

private boolean started;

private boolean threadDisable;

private ServiceBinder serviceBinder = new ServiceBinder();

public class ServiceBinder extends Binder implements ISmsService {

@Override

public boolean isStarted() {

return started;

}

@Override

public void start() {

started=true;

Log.d(“sms.service”, “sms service started.”);

}

@Override

public void stop() {

started=false;

Log.d(“sms.service”, “sms service stopped.”);

}

@Override

public IBinder onBind(Intent intent) {

return serviceBinder;

}

@Override

public void onCreate() {

super.onCreate();

Thread thread = new Thread() {

@Override

public void run() {

while (!threadDisable) {

try {

if (started) {

Log.d(“sms.service”, “send a sms message.”);

}

Thread.sleep(1000 * 5);

} catch (InterruptedException e) {

}

};

thread.start();

Log.d(“sms.service”, “sms service created.”);

}

@Override

public void onDestroy() {

super.onDestroy();

threadDisable = true;

Log.d(“sms.service”, “sms service shutdown.”);

}

前台的Actvity代码，SmsServiceOptions：

package com.easymorse;

import android.app.TabActivity;

import android.content.ComponentName;

import android.content.Intent;

import android.content.ServiceConnection;

import android.os.Bundle;

import android.os.IBinder;

import android.util.Log;

import android.widget.RadioGroup;

import android.widget.TabHost;

import android.widget.RadioGroup.OnCheckedChangeListener;

public class SmsServiceOptions extends TabActivity {

private RadioGroup radioGroup;

private ISmsService smsService; private ServiceConnection serviceConnection = new ServiceConnection() {

@Override

public void onServiceConnected(ComponentName name, IBinder service) {

smsService = (ISmsService) service;

if (smsService.isStarted()) {

radioGroup.check(R.id.radioButtonStart);

} else {

radioGroup.check(R.id.radioButtonStop);

}

radioGroup

.setOnCheckedChangeListener(new OnCheckedChangeListener() {

@Override

public void onCheckedChanged(RadioGroup group,

int checkedId) {

if (checkedId == R.id.radioButtonStart) {

Log.d(“sms.service”, “starting service…”);

smsService.start();

} else {

Log.d(“sms.service”, “stopping service…”);

smsService.stop();

}

});

}

@Override

public void onServiceDisconnected(ComponentName name) {

smsService = null;

}

};

/** Called when the activity is first created. */

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

this.setTitle(“短信服务器”);

this.bindService(new Intent(“com.easymorse.SmsService”),

this.serviceConnection, BIND_AUTO_CREATE);

TabHost tabHost = this.getTabHost();

tabHost.setup();

TabHost.TabSpec spec = tabHost.newTabSpec(“服务选项”);

spec.setContent(R.id.Option01);

spec.setIndicator(“服务选项”);

tabHost.addTab(spec);

spec = tabHost.newTabSpec(“服务状态”);

spec.setContent(R.id.Option02);

spec.setIndicator(“服务状态”);

tabHost.addTab(spec);

radioGroup = (RadioGroup) this.findViewById(R.id.radioGroup01);

}

@Override

protected void onDestroy() {

super.onDestroy();

this.unbindService(serviceConnection);

}

另外，不要忘记在配置文件中增加对service的声明，见AndroidManafest.xml：

<?xml version=”1.0″ encoding=”utf-8″?>

package=”com.easymorse” android:versionCode=”1″ android:versionName=”1.0″>

源代码见：

http://easymorse.googlecode.com/svn/tags/android.local.service.1.demo/

这个示例的局限性在于，如果Activity退出，则后台服务也一起退出。本地服务是否可以在Activity退出后依然在后台执行，还需要进一步了解android api。我猜测应该是不可以的，本地服务和Activity可能是同一个进程的不同线程关系。

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