相关疑难解决方法(0)

我想创建一个EditText接受密码的.我想在输入字符后立即隐藏字符.所以,我用了一个TransformationMethod.我是新手,所以,我尝试了以下代码.

EditText editText = (EditText) findViewById(R.id.editText);
editText.setTransformationMethod(new PasswordTransformationMethod());


private class PasswordTransformationMethod extends Transformation implements TransformationMethod {

    @Override
    public CharSequence getTransformation(CharSequence source, View view) {
        return "/";
    }

    @Override
    public void onFocusChanged(View view, CharSequence source, boolean focused, int direction, Rect previouslyFocusedRect) {
        source = getTransformation(source, view);
    }
}

然而,它抛出,

01-03 10:22:35.750: E/AndroidRuntime(2102): java.lang.IndexOutOfBoundsException

我错过了什么.任何帮助将不胜感激.