[Medium] Butterknife's DebouncingOnClickListener as abstract class

DebouncingOnClickListener.java

public abstract class DebouncingOnClickListener implements View.OnClickListener {
  static boolean enabled = true;

  private static final Runnable ENABLE_AGAIN = new Runnable() {
    @Override 
    public void run() {
      enabled = true;
    }
  };
  
  public abstract void doClick(View v);

  @Override
  public final void onClick(View v) {
    if (enabled) {
      enabled = false;
      v.post(ENABLE_AGAIN);
      doClick(v);
    }
  }
}