安卓学习：广播

一、发送与接收广播案例

1、创建安卓案例【SendReceiveBroadcast】

2、编写主布局资源文件

<?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:gravity="center"
    android:orientation="vertical"
    android:padding="20dp"
    tools:context=".MainActivity">

    <EditText
        android:id="@+id/edtMessage"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="@string/input_message"
        android:singleLine="true"
        android:textSize="20sp" />

    <Button
        android:id="@+id/btnSendBroadcast"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:onClick="doSendBroadcast"
        android:text="@string/send_broadcast"
        android:textSize="20sp" />
</LinearLayout>

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3、编写字符串资源文件strings.xml

<resources>
    <string name="app_name">发送与接收广播</string>
    <string name="input_message">请输入要广播的消息</string>
    <string name="send_broadcast">发送广播的消息</string>
</resources>

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4、创建自定义广播接收者

package net.xxr.sendreceivebroadcast;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.util.Log;

/**
 * 功能：自定义广播接收者
 * 作者：小小榕
 * 日期：2020年12月30日
 */
public class CustomReceiver extends BroadcastReceiver {

    private final String TAG = "send_receive_broadcast"; // 标记
    private final String INTENT_ACTION_SEND_MESSAGE = "net.xxr.intent.action.SEND_MESSAGE"; // 广播频道

    @Override
    public void onReceive(Context context, Intent intent) {
        // 按照频道获取广播信息
        if (intent.getAction().equals(INTENT_ACTION_SEND_MESSAGE)) {
            // 获取广播信息
            String message = intent.getStringExtra("message");
            // 输出广播信息
            Log.d(TAG, message);
        }
    }
}


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5、编写主界面类

package net.xxr.sendreceivebroadcast;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Intent;
import android.content.IntentFilter;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;

import net.xxr.sendreceivebroadcast.CustomReceiver;

import java.util.PrimitiveIterator;

public class MainActivity extends AppCompatActivity {
    private final String TAG = "send_receive_broadcast";
    private final String INTENT_SEND_MESSAGE = "net.xxr.intent.action.SEND_MESSAGE";
    private EditText editMessage;
    private int broadcastCount;

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

        editMessage = findViewById(R.id.edtMessage);

        CustomReceiver receiver = new CustomReceiver();
        IntentFilter filter = new IntentFilter();
        filter.addAction(INTENT_SEND_MESSAGE);
        registerReceiver(receiver, filter);


    }
    /**
     * 发布广播
     */
    public void doSendBroadcast(View view) {
        broadcastCount++;
        String message = editMessage.getText().toString();
        Intent intent = new Intent();
        intent.setAction(INTENT_SEND_MESSAGE);
        intent.putExtra("message","第" + broadcastCount + "次广播信息：" + message);
        sendBroadcast(intent);
    }
}
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6、采用动态方式注册广播接收者

• 编写项目清单文件对广播接收者的注册
  

查看运行结果