Android广播的使用（自定义广播和本地广播）

Posted 2021-02-06 (?ω?)

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