EditText设置点击按钮显示与隐藏密码

private void showOrHidePasswd() {        if (showOrHidePasswd) {            //设置EditText文本为可见的            et_bank_num.setTransformationMethod(HideReturnsTransformationMethod.getInstance());        } else {            //设置EditText文本为隐藏的            et_bank_num.setTransformationMethod(PasswordTransformationMethod.getInstance());        }        showOrHidePasswd = !showOrHidePasswd;        et_bank_num.postInvalidate();        //切换后将EditText光标置于末尾        CharSequence charSequence = et_bank_num.getText();        if (charSequence instanceof Spannable) {            Spannable spanText = (Spannable) charSequence;            Selection.setSelection(spanText, charSequence.length());        }    }