final EditText editText = (EditText) findViewById(R.id.zsm);
    editText.setOnTouchListener(new OnTouchListener() {

      final int DRAWABLE_LEFT = 0;
      final int DRAWABLE_TOP = 1;
      final int DRAWABLE_RIGHT = 2;
      final int DRAWABLE_BOTTOM = 3;

      @Override
      public boolean onTouch(View v, MotionEvent event) {
        if (event.getX() >= (editText.getRight() - editText
            .getCompoundDrawables()[DRAWABLE_RIGHT].getBounds()
            .width())){
          Toast.makeText(getApplicationContext(), "aaaa", 1000).show();
        }
          return false;
      }
    });

private TextWatcher watcher = new TextWatcher(){

 @Override
 public void afterTextChanged(Editable s) {
 // TODO Auto-generated method stub
 }

 @Override
 public void beforeTextChanged(CharSequence s, int start, int count, int after) {
 // TODO Auto-generated method stub
 }

 @Override
 public void onTextChanged(CharSequence s, int start, int before, int count) {
 Log.d("TAG","[TextWatcher][onTextChanged]"+s);
 }
 
};

EditText et = (EditText)findViewById(R.id.edit);
et.addTextChangedListener(watcher);