显示其他文件中的文本，没有mainActivity

Question

Is there a way to write to the screen from another file other than the mainActivity file? I can write the the screen in my mainActivity as follows.

MainActivity.java

TextView myTextViewTime= (TextView)findViewById(R.id.connected);
myTextViewTime.setText("Hello");

but I can't do this from say a file called hell.java

  String msg = "hello";
  public void  message_recieve(String msg){
      TextView myTextViewTime= (TextView)findViewById(R.id.connected);
      myTextViewTime.setText("Hello");
   }

Answer 1

You can do so if you pass the other class a context of your activity. You can also for communication to occur on the UIThread with the setting of text via a

runOnUiThread(new Runnable() {
                            @Override
                            public void run() {
                               myTextViewTime.setText("Hello");
                            }
                     });