android之广播(二)

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>