java - 如何在android中发送事件让我们可以选择订阅者？

Question

我有 4 个类(class)都订阅了事件消息。我只想向其中 2 个类发送事件消息。 EventBus 正在向所有 4 个类发送事件。

Answer 1

This use case can be very easily solved using android JPost library.

JPost让您定义可以发送事件的 channel 。 channel 订阅者仅接收消息。您还可以选择需要接收消息的订阅者。

要实现此操作，请按照以下步骤操作:

Step 1: Create a public channel

public static final int publicChannel1 = 1;
.....
try {
    JPost.getBroadcastCenter().createPublicChannel(ChannelIds.publicChannel1);
}catch (AlreadyExistsException e){
    e.printStackTrace();
}

Step 2: Add subscribers to this channel with subscriberIds

    public static final int  SUBSCRIBER_A_ID = 1;
    ....
    try {
        JPost.getBroadcastCenter().addSubscriber(ChannelIds.publicChannel1, subscriberA, SUBSCRIBER_A_ID);
    }catch (Exception e){
        e.printStackTrace();
    }

类似地，使用不同的订阅者 ID 将所有 4 个类添加到此 channel 。

Step 3: Broadcast the Message event to the selected 2 classes.

    try {
        JPost.getBroadcastCenter().broadcastAsync(ChannelIds.publicChannel1, message, SubsciberA.SUBSCRIBER_A_ID, SubsciberB.SUBSCRIBER_B_ID);
    }catch (JPostNotRunningException e){
        e.printStackTrace();
    }

Step 5: Receive events in the subscriber class.

@OnMessage(channelId = ChannelIds.publicChannel1)
private void onMessage(Message msg){
    System.out.println(msg.getMsg());
}

Note: If in Android you need to update the UI then add @OnUiThread to this method

更多详情请参见 -> https://github.com/janishar/JPost