android - 向 MainActivity 发送广播，然后显示一个 TextView [英] android - Sending a broadcast to MainActivity and then showing a TextView

问题描述

一旦在另一个视图文件中调用方法，我想取消隐藏 TextView.TextView 在 MainActivity 中.

I want to unhide a TextView once a method is called in another View file. The TextView is in MainActivity.

为此，我打算从 View 文件向 MainActivity 发送广播，但没有成功.

For this, I am planning to send a broadcast from the View file to MainActivity, but it didn't work.

我将如何实现这一目标?

How would I achieve this?

推荐答案

第 0 步:定义一个动作:

Step 0 : Define an action :

public static final String ACTION_SHOW_TEXT= "showText";

第 1 步:在 MainActivity 中创建广播接收器:

Step 1 : Create your Broadcast receiver in your MainActivity :

BroadcastReceiver  mReceiver = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            if (myText != null) {
                myText.setVisibility(View.VISIBLE);
            }
        }
    };

第 2 步:在 MainActivity 中添加注册和取消注册事件:

Step 2 : Add the register and unregister events in your MainActivity :

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    setContentView(R.layout.activity_main);
    LocalBroadcastManager.getInstance(this)
            .registerReceiver(mReceiver, new IntentFilter(ACTION_SHOW_TEXT));
}

@Override
protected void onDestroy() {
    super.onDestroy();
    LocalBroadcastManager.getInstance(this).unregisterReceiver(mReceiver);
}

第 3 步:当你想显示你的 TextView 时，从任何地方调用:

Step 3 : Whenever you want to display your TextView, call from anywhere :

Intent i = new Intent(MainActivity.ACTION_SHOW_TEXT);
                        i.putExtra("success", true);
                        LocalBroadcastManager.getInstance(this)
                                .sendBroadcast(i);
}

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