android之广播(二)

时间：2022-02-23 18:40:42

广播接受者不仅可以通过清单文件来向系统注册，也可以通过代码来注册。并且有的广播必须通过代码来注册广播接受者。

  • 锁屏和解锁广播
  • 电量改变广播

打开屏幕和关闭屏幕

这里将广播接收者写在服务里面

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

    android:orientation="vertical" android:layout_width="match_parent"

    android:layout_height="match_parent">

    <Button

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:textSize="18sp"

        android:text="开始播放"

        android:onClick="start"/>

    <Button

        android:id="@+id/stop"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:textSize="18sp"

        android:text="停止播放"

        android:onClick="stop"/>

</LinearLayout>

Activity

package xidian.dy.com.chujia;

import android.content.Intent;

import android.os.Bundle;

import android.support.v7.app.AppCompatActivity;

import android.view.View;

public class MainActivity extends AppCompatActivity {

    Intent service;

    @Override

    public void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.main);

        service = new Intent(this, MyService.class);

    }

    public void start(View v){

        startService(service);

    }

    public void stop(View v){

        stopService(service);

    }

}

服务

在服务开启的时候注册广播，在服务销毁的时候销毁广播

package xidian.dy.com.chujia;

import android.app.Service;

import android.content.BroadcastReceiver;

import android.content.Context;

import android.content.Intent;

import android.content.IntentFilter;

import android.os.IBinder;

import android.support.annotation.Nullable;

import android.util.Log;

/**

 * Created by dy on 2016/7/12.

 */

class MyReceiver extends BroadcastReceiver{

    @Override

    public void onReceive(Context context, Intent intent) {

        String action = intent.getAction();

        if(action.equals(Intent.ACTION_SCREEN_OFF))

            Log.i(this.getClass().getName(), "屏幕关闭");

        if(action.equals(Intent.ACTION_SCREEN_ON))

            Log.i(this.getClass().getName(), "屏幕点亮");

    }

}

public class MyService extends Service {

    MyReceiver ms = new MyReceiver();

    @Override

    public void onCreate() {

        super.onCreate();

        IntentFilter filter = new IntentFilter();

        filter.addAction(Intent.ACTION_SCREEN_OFF);

        filter.addAction(Intent.ACTION_SCREEN_ON);

        registerReceiver(ms, filter);

    }

    @Nullable

    @Override

    public IBinder onBind(Intent intent) {

        return null;

    }

    @Override

    public void onDestroy() {

        super.onDestroy();

        unregisterReceiver(ms);

    }

}

清单文件

在清单文件中只需要注册服务即可

<?xml version="1.0" encoding="utf-8"?>

<manifest xmlns:android="http://schemas.android.com/apk/res/android"

package="xidian.dy.com.chujia">

    <application

    android:allowBackup="true"

    android:icon="@mipmap/ic_launcher"

    android:label="@string/app_name"

    android:supportsRtl="true"

    android:theme="@style/AppTheme">

    <activity

        android:name=".MainActivity"

        android:label="主界面">

        <intent-filter>

            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />

        </intent-filter>

    </activity>

    <service android:name=".MyService" />

</application>

</manifest>

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