java - requestFocus 在使用 getCurrentFocus 时不改变焦点

Question

我正在制作一个 OTP Activity 并且需要实现删除功能，我有下面的函数应该在 onKey 退格按钮上触发。我的想法是，我可以使用 getCurrentFocus 来了解当前正在填充哪些字段，然后使用 requestFocus 来选择之前的那个，但它似乎不起作用，我有goToNext 的另一个函数工作得很好，所以我很困惑为什么。

 public void goToPrevious() {
    EditText currentFocus = (EditText) getCurrentFocus();


    if (currentFocus == otpOne) {
        return;
    }

    if (currentFocus == otpTwo) {
        otpOne.requestFocus();

        return;
    }

    if (currentFocus == otpThree) {
        otpTwo.requestFocus();

        return;
    }

    if (currentFocus == otpFour) {
        otpThree.requestFocus();

        return;
    }
}

下面是 goToNext 的代码，运行良好。

public void goToNext() {
    EditText currentFocus = (EditText) getCurrentFocus();

    if (currentFocus == otpOne) {
        otpTwo.requestFocus();

        return;
    }

    if (currentFocus == otpTwo) {
        otpThree.requestFocus();

        return;
    }

    if (currentFocus == otpThree) {
        otpFour.requestFocus();

        return;
    }

    if (currentFocus == otpFour) {
        return;
    }
}

我通过实现一个 onKeyListener 来调用 goToPrevious，下面是代码

 @Override
public boolean onKey(View v, int keyCode, KeyEvent event) {
    EditText currentFocus = (EditText) getCurrentFocus();
    Log.i("ENOUGH", "onKey: " + keyCode + " " + event.getAction() + " " + KeyEvent.KEYCODE_DEL);
    switch (event.getKeyCode()) {
        case KeyEvent.KEYCODE_DEL: {
            currentFocus.setText(null);
            goToPrevious();
            return false;
        }
    }
    return false;
}

Answer 1

我必须通过将 getCurrentFocus 的值直接传递到 goToPrevious 来修复它，出于某些非常奇怪的原因 getCurrentFocus 的值在 onKey 处理程序与 goToPrevious 不同，下面是我最终得到的代码。

public void goToNext(EditText currentFocus) {

    if (currentFocus == otpOne) {
        otpTwo.requestFocus();

        return;
    }

    if (currentFocus == otpTwo) {
        otpThree.requestFocus();

        return;
    }

    if (currentFocus == otpThree) {
        otpFour.requestFocus();

        return;
    }

    if (currentFocus == otpFour) {
        return;
    }
}

public void goToPrevious(EditText currentFocus) {

    if (currentFocus == otpOne) {
        return;
    }

    if (currentFocus == otpTwo) {
        otpOne.requestFocus();

        return;
    }

    if (currentFocus == otpThree) {
        otpTwo.requestFocus();

        return;
    }

    if (currentFocus == otpFour) {
        otpThree.requestFocus();

        return;
    }
}


@Override
public boolean onKey(View v, int keyCode, KeyEvent event) {
    Log.i("ENOUGH", "onKey: " + keyCode + " " + event.getAction() + " " + KeyEvent.KEYCODE_DEL);
    if (event.getAction() == KeyEvent.ACTION_DOWN) {
        EditText currentFocus = (EditText) getCurrentFocus();
        switch (event.getKeyCode()) {
            case KeyEvent.KEYCODE_DEL: {
                if (currentFocus.getText().length() > 0) {
                    currentFocus.setText(null);
                } else {
                    goToPrevious(currentFocus);

                    EditText focused = (EditText) getCurrentFocus();
                    focused.setText(null);
                }

                return false;
            }
            case KeyEvent.KEYCODE_FORWARD:
                return true;
            case KeyEvent.KEYCODE_BACK:
                return true;
            case KeyEvent.KEYCODE_ENTER:
                return true;
            default: {
                currentFocus.setText("");
                goToNext(currentFocus);
            }
        }
    }
    return false;
}