发送自定义广播：跨进程通信、发送有序广播、发送标准广播、本地广播

发送标准广播

1.新建一个广播接收器MyBroadcastReceiver

package com.example.broadcasttest;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.widget.Toast;

public class MyBroadcastReceiver extends BroadcastReceiver {

    @Override
    public void onReceive(Context context, Intent intent) {
        // TODO: This method is called when the BroadcastReceiver is receiving
        // an Intent broadcast.
        //throw new UnsupportedOperationException("Not yet implemented");
        Toast.makeText(context,"my broadcast",Toast.LENGTH_LONG).show();
    }
}

2.在AndroidMainfest.xml中修改广播接收器

让MyBroadcastReceiver接收一条值为com.example.broadcast.MY_BROADCAST的广播。

3.定义一个按钮，用于点击发送广播

4.修改MainActivity

构建Intent对象，把要发送的光播的值传入。
调用Context的sendBroadcast()将广播发送出去。

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

5.运行程序

跨进程通信

6.新建一个项目BroadcastTest2

7.新建广播接收器AnotherBroadcastReceiver

package com.example.broadcasttest2;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.widget.Toast;

public class AnotherBroadcastReceiver extends BroadcastReceiver {

    @Override
    public void onReceive(Context context, Intent intent) {
        // TODO: This method is called when the BroadcastReceiver is receiving
        // an Intent broadcast.
        //throw new UnsupportedOperationException("Not yet implemented");
        Toast.makeText(context,"received in another broadcast",Toast.LENGTH_LONG).show();
    }
}

8.在AndroidMainfest.xml中对新广播接收器进行修改

Another同样接收com.example.broadcast.MY_BROADCAST。

发送有序广播

1.修改sendBroadcast()方法

sendOrderBroadcast()方法接收两个参数，一个参数仍是Intent，一个参数是一个域权限相关的字符串，直接传入null即可。

 Button button = (Button)findViewById(R.id.button);
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent intent = new Intent("com.example.broadcast.MY_BROADCAST");
                //发送标准广播
                //sendBroadcast(intent);
                //发送有序广播
                sendOrderedBroadcast(intent,null);
            }
        });

2.设置优先级

android:priority给广播接收器设置优先级，优先级比较高的广播接收器就可以先收到广播。

3.选择是否允许广播继续传递

修改MyBroadcastReceiver中的代码

public class MyBroadcastReceiver extends BroadcastReceiver {

    @Override
    public void onReceive(Context context, Intent intent) {
        // TODO: This method is called when the BroadcastReceiver is receiving
        // an Intent broadcast.
        //throw new UnsupportedOperationException("Not yet implemented");
        Toast.makeText(context,"my broadcast",Toast.LENGTH_LONG).show();
        //截断广播消息
        abortBroadcast();
    }
}

重新运行程序，点击Send Broad按钮，只有MyBroadcastReceiver中的信息都弹出。

本地广播机制

使用该机制发出的广播只能在应用程序的内部进行传递，而且广播接收器也只接收来自本应用程序的广播。

本地广播无法通过静态注册的方式来接收

修改MainActivity中的代码
先是通过LocalBroadcastManager的getInstance()方法得到它的一个实例，注册广播接收器时调用LocalBroadcastManager的registerReceiver()方法；发送广播时调用LocalBroadcastManager的sendBroadcast()方法；取消注册广播接收器调用LocalBroadcastManager的unregisterReceiver()方法。

public class MainActivity extends AppCompatActivity {

    private IntentFilter intentFilter;
    private LocalBroadcastManager localBroadcastManager;
    private LocalReceiver localReceiver;
    //private NetworkReceiver networkReceiver;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
//发送本地广播
        localBroadcastManager = LocalBroadcastManager.getInstance(this);//获取实例
        Button button = (Button)findViewById(R.id.button);
        intentFilter = new IntentFilter();
        intentFilter.addAction("com.example.broadcasttest.LOCAL_BROADCAST");
        localReceiver = new LocalReceiver();
        localBroadcastManager.registerReceiver(localReceiver,intentFilter);//注册本地广播接收器
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent intent = new Intent("com.example.broadcasttest.LOCAL_BROADCAST");
                localBroadcastManager.sendBroadcast(intent);//发送本地广播
            }
        });
    }



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

运行程序