使用本地广播

Posted 2020-11-26 ccffhh

MainActivity中的代码，要先导入架包

 

 

 

 

package com.example.broadcasttest;

import androidx.appcompat.app.AppCompatActivity;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;
import androidx.localbroadcastmanager.content.LocalBroadcastManager;

public class MainActivity extends AppCompatActivity {

    private IntentFilter intentFilter;

    private LocalReceiver localReceiver;

    private LocalBroadcastManager localBroadcastManager;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        localBroadcastManager=LocalBroadcastManager.getInstance(this);
        Button button=(Button) findViewById(R.id.button);
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent=new Intent("com.example.broadcasttest.LOCAL_BROADCAST");
                localBroadcastManager.sendBroadcast(intent);
                //sendBroadcast(intent);
                //sendOrderedBroadcast(intent,null);
            }
        });
        intentFilter=new IntentFilter();
        intentFilter.addAction("com.example.broadcasttest.LOCAL_BROADCAST");
        localReceiver=new LocalReceiver();
        localBroadcastManager.registerReceiver(localReceiver,intentFilter);
    }

    @Override
    protected void onDestroy(){
        super.onDestroy();
        localBroadcastManager.unregisterReceiver(localReceiver);
        //unregisterReceiver(networkChangeReceiver);
    }

    class LocalReceiver extends BroadcastReceiver{

        @Override
        public void onReceive(Context context,Intent intent){
            Toast.makeText(context,"received local broadcast",Toast.LENGTH_SHORT).show();
        }
    }

    /*class NetworkChangeReceiver extends BroadcastReceiver{
        @Override
        public void onReceive(Context context, Intent intent){
            ConnectivityManager connectionManager=(ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
            NetworkInfo networkInfo=connectionManager.getActiveNetworkInfo();
            if (networkInfo!=null&&networkInfo.isAvailable()){
                Toast.makeText(context,"network is available",Toast.LENGTH_SHORT).show();
            }
            else{
                Toast.makeText(context,"network is unavailable",Toast.LENGTH_SHORT).show();
            }
        }
    }*/
}

首先通过LocalBroadcastManager的getInstance()方法得到了它的一个实例，如何在注册广播接收器的时候调用LocalBroadcastManager的registerReceiver()方法，在发送广播的时候调用LocalBroadcastManager的sendBroadcast()方法。我们在按钮的点击事件里面发出了一条com.example.broadcasttest.LOCAL_BROADCAST广播，然后在LocalReceiver里去接收这条广播。

运行结果如下图