Android广播的使用（自定义广播和本地广播）

1》自定义广播

//定义接收器
public class MyBroadcastReceiver extends BroadcastReceiver {
    @Override
    public void onReceive(Context context, Intent intent) {
 Toast.makeText(context,"接收我的广播",Toast.LENGTH_LONG).show();
 }
}

·//注册事件
    <receiver
        android:name=".MyBroadcastReceiver"//类名
 android:enabled="true"
 android:exported="true">
 <intent-filter>
 <action android:name="com.example.broadcasttext.MY_BROADCAST"/>广播名称
 </intent-filter>
 </receiver>

//定义按钮发送广播

Button button=(Button)findViewById(R.id.b1);
button.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View view) {
        Intent intent=new Intent("com.example.broadcasttext.MY_BROADCAST");
 sendBroadcast(intent);
 }
});
　　

广播在另外的程序上进行接收，默认的发送方式是标准广播，若想发送有序广播，需要一点点修改

MainActivity.java

button.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View view) {
        Intent intent=new Intent("com.example.broadcasttext.MY_BROADCAST");
 sendBroadcast(intent);
 sendOrderedBroadcast(intent,null);
 }
});

加入这一行代码后广播的接收就有了顺序

注册时候可以设置接收广播的优先级

<receiver
    android:name=".MyBroadcastReceiver"
 android:enabled="true"
 android:exported="true">
 <intent-filter android:priority="100">
 <action android:name="com.example.broadcasttext.MY_BROADCAST"/>
 </intent-filter>
</receiver>

优先接收到广播后就可以判断是否继续发送广播

public class MyBroadcastReceiver extends BroadcastReceiver {
    @Override
    public void onReceive(Context context, Intent intent) {
        Toast.makeText(context,"接收我的广播",Toast.LENGTH_LONG).show();
 abortBroadcast();
 }
}

abortBroadcast();可以截断广播

2》本地广播

上述例子中发送的广播可以被其他程序所接受，这对安全造成了威胁，所以安卓引入了一套本地广播的体制

　　MainActivity.java

package com.example.guangbo;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.location.LocationManager;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.net.NetworkRequest;
import android.support.v4.content.LocalBroadcastManager;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;

import java.nio.channels.NetworkChannel;

public class MainActivity extends AppCompatActivity {
 private IntentFilter intentFilter;
 private NetworkChangeReceiver networkChangeReceiver;
 //本地广播
 private LocalReceiver localReceiver;
 private LocalBroadcastManager localBroadcastManager;
 @Override
 protected void onCreate(Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 setContentView(R.layout.activity_main);
 //本地广播
 localBroadcastManager= LocalBroadcastManager.getInstance(this);

 intentFilter=new IntentFilter();
 intentFilter.addAction("android.net.conn.CONNECTIVITY_CHANGE");
 networkChangeReceiver=new NetworkChangeReceiver();
 registerReceiver(networkChangeReceiver,intentFilter);
 Button button=(Button)findViewById(R.id.b1);
 button.setOnClickListener(new View.OnClickListener() {
 @Override
 public void onClick(View view) {
 //本地广播
 Intent intent=new Intent("com.example.broadcasttext.LOCAL_BROADCAST");
 localBroadcastManager.sendBroadcast(intent);

 }
 });
 //动态注册本地广播
 intentFilter=new IntentFilter();
 intentFilter.addAction("com.example.broadcasttext.LOCAL_BROADCAST");
 localReceiver=new LocalReceiver();
 localBroadcastManager.registerReceiver(localReceiver,intentFilter);
 }

 @Override
 protected void onDestroy() {
 super.onDestroy();
 //本地广播
 localBroadcastManager.unregisterReceiver(localReceiver);
 }
 class NetworkChangeReceiver extends BroadcastReceiver{
 @Override
 public void onReceive(Context context, Intent intent) {
 ConnectivityManager connectivityManager=(ConnectivityManager)getSystemService(Context.CONNECTIVITY_SERVICE);
 NetworkInfo networkInfo=connectivityManager.getActiveNetworkInfo();
 if(networkInfo!=null&&networkInfo.isAvailable()){
 Toast.makeText(context,"网络可用",Toast.LENGTH_SHORT).show();
 }else{
 Toast.makeText(context,"网络不可用",Toast.LENGTH_SHORT).show();
 }


 }
 }
 class LocalReceiver extends BroadcastReceiver{
 @Override
 public void onReceive(Context context, Intent intent) {

 Toast.makeText(context,"接收本地广播",Toast.LENGTH_SHORT).show();



 }
 }
}

啊本地广播主要是通过LocalBriadcaseManager来进行管理