鸿蒙开发中，有没有简易广播的实现？

Question

鸿蒙开发中，有没有简易广播的实现？

Answer 1

在鸿蒙开发中，可以通过以下步骤实现简易广播：
首先创建一个广播接收器，然后注册广播接收器，在合适的时机发送广播。以下是一个简单的示例代码：

import featureAbility from '@ohos.ability.featureAbility';

// 定义广播接收器
const receiver = {
  onReceive(context, intent) {
    // 处理接收到广播的逻辑
    console.log('Received broadcast: ' intent.action);
  }
};

// 注册广播接收器
featureAbility.registerReceiver('your_broadcast_action', receiver);

// 发送广播
featureAbility.sendBroadcast({
  action: 'your_broadcast_action'
});

Answer 2

1. 创建最简化的 BroadcastManager 类，用于注册、发送和接收广播消息。

   import java.util.ArrayList;
   import java.util.List;
   
   public class BroadcastManager {
   
    // 定义一个接口用于广播回调
    public interface BroadcastReceiver {
        void onReceive(String message);
    }
   
    // 存储所有注册的广播接收器
    private static List<BroadcastReceiver> receivers = new ArrayList<>();
   
    // 注册广播接收器
    public static void registerReceiver(BroadcastReceiver receiver) {
        receivers.add(receiver);
    }
   
    // 发送广播消息给所有注册的接收器
    public static void sendBroadcast(String message) {
        for (BroadcastReceiver receiver : receivers) {
            receiver.onReceive(message);
        }
    }
   }
   

2. 接下来，在 AbilitySlice 中使用 BroadcastManager。

   import ohos.aafwk.ability.AbilitySlice;
   import ohos.aafwk.content.Intent;
   import ohos.agp.components.Button;
   import ohos.agp.components.Text;
   
   public class MainAbilitySlice extends AbilitySlice {
   
    @Override
    public void onStart(Intent intent) {
        super.onStart(intent);
        setUIContent(ResourceTable.Layout_ability_main);
   
        Text messageText = (Text) findComponentById(ResourceTable.Id_message_text);
        Button sendButton = (Button) findComponentById(ResourceTable.Id_send_button);
   
        // 注册广播接收器
        BroadcastManager.registerReceiver(message -> messageText.setText(message));
   
        // 点击按钮时发送广播
        sendButton.setClickedListener(component -> 
            BroadcastManager.sendBroadcast("Broadcast received!"));
    }
   }
   

3. 简化的布局文件（XML）。

   <!-- ability_main.xml -->
   <DirectionalLayout
    xmlns:ohos="http://schemas.huawei.com/res/ohos"
    ohos:width="match_parent"
    ohos:height="match_parent"
    ohos:orientation="vertical"
    ohos:alignment="center">
   
    <Text
        ohos:id="$+id:message_text"
        ohos:width="wrap_content"
        ohos:height="wrap_content"
        ohos:text="Waiting for Broadcast..." />
   
    <Button
        ohos:id="$+id:send_button"
        ohos:width="wrap_content"
        ohos:height="wrap_content"
        ohos:text="Send Broadcast"
        ohos:margin_top="20vp" />
   </DirectionalLayout>