title: Android Java, setOnTouchListener delete 1 last character from string every 0.25s
body: <p>I am making calculator on java. I want to make a button, which corresponds to delete the last character.<br>
  If you press on it for 1 second, it starts to delete 1 character every 0.25s form EditText string.<br></p>
  <p>Clear button:</p>
  <pre><code>clear.setOnClickListener(new View.OnClickListener() {
          @Override
          public void onClick(View v) {
              if(operation.length() != 0){
                  String s=operation.getText().toString();
                  s = s.substring(0,operation.length()-1);
                  operation.setText(s);}
          }
      });
  </code></pre>
  <p>Long touch idea:</p>
  <pre><code>clear.setOnTouchListener(new View.OnTouchListener() {
              @Override
              public boolean onTouch(View v, MotionEvent event) {
                  return false;
              }
          });
  </code></pre>