Android小技巧OnClickListener去重

当View被快速多次点击，onClickListener事件的onClick(View view)会执行多次。

/**
 * A {@linkplain View.OnClickListener click listener} that debounces multiple clicks posted in the
 * same frame. A click on one button disables all buttons for that frame.
 */
public abstract class DebouncingOnClickListener implements View.OnClickListener {
  private static final Runnable ENABLE_AGAIN = () -> enabled = true;
  private static final Handler MAIN = new Handler(Looper.getMainLooper());

  static boolean enabled = true;

  @Override public final void onClick(View v) {
    if (enabled) {
      enabled = false;

      // Post to the main looper directly rather than going through the view.
      // Ensure that ENABLE_AGAIN will be executed, avoid static field {@link #enabled}
      // staying in false state.
      MAIN.post(ENABLE_AGAIN);

      doClick(v);
    }
  }

  public abstract void doClick(View v);
}

来源：butterknife中DebouncingOnClickListener