【Android】使用 Broadcast 实现进程间通讯

1 Broastcast 简介

        Broadcast（广播）是 Android 中一种广泛运用的在应用程序之间传输信息的机制。使用 Broadcast 能够很方便得实现进程间通讯，一端通过 sendBroadcast(intent) 广播消息，另一端通过 registerReceiver(myReceiver) 注册 BroadcastReceiver（接收器）接收消息。

2 clien_A 代码

        （1）主 Activity

        MainActivity.java

package com.zhyan8.client_A;

import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;

public class MainActivity extends AppCompatActivity {
    private EditText et_msg;
    private Button btn_send;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        init();
    }

    private void init() {
        et_msg = (EditText) findViewById(R.id.et_msg);
        btn_send = (Button) findViewById(R.id.btn_send);
        btn_send.setOnClickListener(cl);
    }

    View.OnClickListener cl = new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            if (v.getId()==R.id.btn_send) {
                String str = et_msg.getText().toString();
                Intent intent = new Intent();
                intent.setAction("com.zhyan8.client_A.MainActivity");
                Bundle bundle = new Bundle();
                bundle.putString("msg_A", "from client_A, msg: " + str);
                intent.putExtras(bundle);
                sendBroadcast(intent);
            }
        }
    };
}

        （2）布局 

        activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:orientation="vertical"
    tools:context="com.zhyan8.client_A.MainActivity">

    <EditText
        android:id="@+id/et_msg"
        android:layout_width="match_parent"
        android:layout_height="100dp"
        android:text=""
        android:background="#ffcc66"/>

    <Button
        android:id="@+id/btn_send"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal"
        android:layout_marginTop="30dp"
        android:textSize="40sp"
        android:text="发送"/>
</LinearLayout>

        界面如下：

3 client_B 代码

        （1）主 Activity

        MainActivity.java

package com.zhyan8.client_B;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {
    private TextView tv_msg;
    private IntentFilter intentFilter;
    private MyReceiver myReceiver;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        init();
    }

    private void init() {
        tv_msg = (TextView) findViewById(R.id.tv_msg);
        intentFilter = new IntentFilter();
        intentFilter.addAction("com.zhyan8.client_A.MainActivity");
        myReceiver = new MyReceiver();
        registerReceiver(myReceiver, intentFilter);
    }

    private class MyReceiver extends BroadcastReceiver {
        @Override
        public void onReceive(Context context, Intent intent) {
            Bundle bundle = intent.getExtras();
            String str = bundle.getString("msg_A");
            tv_msg.setText(str);
        }
    }
}

        （2）布局

         activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:orientation="vertical"
    tools:context="com.zhyan8.client_B.MainActivity">

    <TextView
        android:id="@+id/tv_msg"
        android:layout_width="match_parent"
        android:layout_height="100dp"
        android:background="#ffcc66"/>
</LinearLayout>

        界面如下：

4 效果展示

        在 client_A 端编辑文本【Qwert】，如下：

        点击【发送】按钮后，在client_B端收到消息【from client_A, msg: Qwert】，如下：