android 49 广播接收者中启动其他组件

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>