按住按钮但在Android Studio上延迟（LongPress）之后显示窗口

Question

I'm doing a calculator app as a college project. I want the "equals" button to (obviously) calculate the result of the operation, but I also want that button to display the history if you keep the button pressed.

I know how to use OnLongClick but am not sure how to implement this.

Answer 1

Just as with OnClickListener you will have to implement OnLongClickListener and override onLongClick() or use an anonymous inner class for example:

equalsButton.setOnLongClickListener(new View.OnLongClickListener() {
   @Override public boolean onLongClick(View v) {
           displayHistory();
       return true;
   }
});

Unlike onClick(), onLongClick returns a boolean. This is to notify the Android OS if the callback has consumed the event or not. A return value of true indicates to the OS that the event can be discarded and does not have to be passed on to other event listeners registered on the same button.