main.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" > <Button
android:id="@+id/btnStartActivity"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="启动 activity" />
<Button
android:id="@+id/btnStartService"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="启动service" />
<Button
android:id="@+id/btnStopService"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="停止 service" /> </LinearLayout>
mainActivity.java
package com.sxt.day07_05; import android.os.Bundle;
import android.app.Activity;
import android.content.Intent;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener; public class MainActivity extends Activity implements OnClickListener{ @Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
setListener();
} private void setListener() {
findViewById(R.id.btnStartActivity).setOnClickListener(this);
findViewById(R.id.btnStartService).setOnClickListener(this);
findViewById(R.id.btnStopService).setOnClickListener(this);
} @Override
public void onClick(View v) {
Intent intent=new Intent();
switch (v.getId()) {
case R.id.btnStartActivity:
intent.setAction("com.sxt.day07_05.start_activity");//发送一条广播，被MyReceiver接收到，
break;
case R.id.btnStartService:
intent.setAction("com.sxt.day07_05.start_service");
break;
case R.id.btnStopService:
intent.setAction("com.sxt.day07_05.stop_service");
break;
}
sendBroadcast(intent);//发送广播
}
}
广播接收者：
package com.sxt.day07_05; import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent; public class MyReceiver extends BroadcastReceiver { @Override
public void onReceive(Context context, Intent intent) {//收到广播
String action=intent.getAction();
Intent intent2=null;
if(action.equals("com.sxt.day07_05.start_activity")){
//启动SecondActivity
intent2=new Intent(context, SecondActivity.class);//context是上下文，就是发送广播的Activity
intent2.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);//标志，一个Activity启动另一个Activity不用这个，因为2个Activity处于同一个任务栈，广播接收者没有任务栈，所以必出把SecondActivity启动在一个新的任务栈。因为每个Activity都在任务栈里面。
context.startActivity(intent2);
}else if(action.equals("com.sxt.day07_05.start_service")){
intent2=new Intent(context, MyService.class);
context.startService(intent2);//启动service
}else if(action.equals("com.sxt.day07_05.stop_service")){
intent2=new Intent(context, MyService.class);
context.stopService(intent2);//停止service
}
} }
广播接收者启动的service：
package com.sxt.day07_05; import android.app.Service;
import android.content.Intent;
import android.os.IBinder;
import android.os.SystemClock;
import android.util.Log; public class MyService extends Service {
boolean mLooper=true;//true:循环继续
@Override
public IBinder onBind(Intent intent) {
// TODO Auto-generated method stub
return null;
}
@Override
//service是一个后台进程，onBind，onStartCommand，onDestroy以on开头的方法都是在主线程执行的，所以为了不占用主线程的时间，这些方法里面的代码都要开辟工作线程执行。
public int onStartCommand(Intent intent, int flags, int startId) {
//耗时操作都要在工作线程里面写
//即使这个service停止了，但是这个工作线程仍然不会停，
//在Activity和service写的工作线程，即使Activity和service销毁了，这个工作线程还在执行。
new Thread(){
public void run() {
while(mLooper){
SystemClock.sleep(1000);
Log.i("main","service is loop...");
}
};
}.start();
return super.onStartCommand(intent, flags, startId);
}
@Override
public void onDestroy() {
super.onDestroy();
mLooper=false;//service销毁工作线程不会停止，因此要mLooper=false
}
}
广播接收者启动的Activity：
package com.sxt.day07_05; import android.os.Bundle;
import android.app.Activity;
import android.view.Menu; public class SecondActivity extends Activity { @Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_second);
} @Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.second, menu);
return true;
} } <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".SecondActivity" > <TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="SecondActivity" /> </RelativeLayout>
系统描述文件：
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.sxt.day07_05"
android:versionCode="1"
android:versionName="1.0" > <uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="18" /> <application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name="com.sxt.day07_05.MainActivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity> <receiver android:name="com.sxt.day07_05.MyReceiver" > 一个广播接收者接收3个action,3个字符串，3个频道的广播，
<intent-filter>
<action android:name="com.sxt.day07_05.start_activity" />
<action android:name="com.sxt.day07_05.start_service" />
<action android:name="com.sxt.day07_05.stop_service" />
</intent-filter>
</receiver> <service android:name="com.sxt.day07_05.MyService" /> 声明service <activity 声明activity
android:name="com.sxt.day07_05.SecondActivity"
android:label="@string/title_activity_second" >
</activity>
</application> </manifest>