如何在编辑格式类似于美国货币的 EditText 字段时重新定位光标 - Android

Question

我正在按照美国货币格式格式化编辑文本字段，在字段中键入数字时，假设“12345678”看起来像“12,345,678”。为此，我使用了 TextWatcher 和 afterTextChanged(...) 方法，我将输入的文本格式化为：

@Override
    public void afterTextChanged(Editable editable) {
        String str = editable.toString();
        String number = str.replaceAll("[,]", "");
        if (number.equals(previousNumber) || number.isEmpty()) {
            return;
        }
        previousNumber = number;

        DecimalFormat formatter = new DecimalFormat("#,###.##", new DecimalFormatSymbols(Locale.US));

        String formattedString = formatter.format(number);
        editText.setText(formattedString);
    }

此外，我正在使用 onSelectionChanged(...) 回调方法，例如：

 @Override
protected void onSelectionChanged(int selStart, int selEnd) {
    this.setSelection(selStart);
}

但是这里 'selStart' 不是 return 数字的实际长度，因为它不包括每种货币中“,”的数量。例如：对于“12,345,678”，它 returns 算作 8 而不是 10。这就是为什么我无法将光标放在字段末尾的原因。

以下是我使用的自定义EditText代码：

public class CurrencyEditText extends AppCompatEditText {
private static final int MAX_LENGTH = 16;
private static final int MAX_DECIMAL_DIGIT = 2;
private static String prefix = "";
private CurrencyTextWatcher currencyTextWatcher = new CurrencyTextWatcher(this, prefix);

public CurrencyEditText(Context context) {
    this(context, null);
}

public CurrencyEditText(Context context, AttributeSet attrs) {
    this(context, attrs, android.support.v7.appcompat.R.attr.editTextStyle);
}

public CurrencyEditText(Context context, AttributeSet attrs, int defStyleAttr) {
    super(context, attrs, defStyleAttr);
    this.setInputType(InputType.TYPE_CLASS_NUMBER | InputType.TYPE_NUMBER_FLAG_DECIMAL);
}

@Override
protected void onFocusChanged(boolean focused, int direction, Rect previouslyFocusedRect) {
    super.onFocusChanged(focused, direction, previouslyFocusedRect);
    if (focused) {
        this.addTextChangedListener(currencyTextWatcher);
    } else {
        this.removeTextChangedListener(currencyTextWatcher);
    }
    handleCaseCurrencyEmpty(focused);
}

private void handleCaseCurrencyEmpty(boolean focused) {
    if (!focused) {
        if (getText().toString().equals(prefix)) {
            setText("");
        }
    }
}

private static class CurrencyTextWatcher implements TextWatcher {
    private final EditText editText;
    DecimalFormat formatter;
    private String previousNumber;
    private String prefix;
    Context mContext;

    CurrencyTextWatcher(EditText editText, String prefix) {
        this.editText = editText;
        this.prefix = prefix;
        formatter = new DecimalFormat("#,###.##", new DecimalFormatSymbols(Locale.US));
    }

    @Override
    public void beforeTextChanged(CharSequence s, int start, int count, int after) {
    }

    @Override
    public void onTextChanged(CharSequence s, int start, int before, int count) {
    }

    @Override
    public void afterTextChanged(Editable editable) {
        String str = editable.toString();
        String number = str.replaceAll("[,]", "");
        if (number.equals(previousNumber) || number.isEmpty()) {
            return;
        }
        previousNumber = number;

        String formattedString = prefix + formatNumber(number);
        editText.removeTextChangedListener(this);
        editText.setText(formattedString);
        //handleSelection();
        editText.addTextChangedListener(this);
    }

    private String formatNumber(String number) {
        if (number.contains(".")) {
            return formatDecimal(number);
        }
        return formatInteger(number);
    }

    private String formatInteger(String str) {
        BigDecimal parsed = new BigDecimal(str);
        return formatter.format(parsed);
    }

    private String formatDecimal(String str) {
        if (str.equals(".")) {
            return "0.";
        }
        BigDecimal parsed = new BigDecimal(str);
        DecimalFormat formatter = new DecimalFormat("#,##0." + getDecimalPattern(str),
                new DecimalFormatSymbols(Locale.US));
        formatter.setRoundingMode(RoundingMode.DOWN);
        return formatter.format(parsed);
    }

    private String getDecimalPattern(String str) {
        int decimalCount = str.length() - str.indexOf(".") - 1;
        StringBuilder decimalPattern = new StringBuilder();
        for (int i = 0; i < decimalCount && i < MAX_DECIMAL_DIGIT; i++) {
            decimalPattern.append("0");
        }
        return decimalPattern.toString();
    }

    /*private void handleSelection() {
        if (editText.getText().length() <= MAX_LENGTH) {
            editText.setSelection(editText.getText().length());
        }
    }*/
}

@Override
protected void onSelectionChanged(int selStart, int selEnd) {
    this.setSelection(selStart);
}

}

我不想使用 this.setSelection(lengthOfTheEnteredText)，因为它会在您编辑字段时产生问题！ onSelectionChanged(...) 不考虑“,”的计数的原因可能是什么？

Answer 1

在对这个问题进行更多探索之后，我找到了解决方案。我在哪里计算光标位置。我已经从我的代码中删除了 onSelectionChanged(...) 方法，我正在处理 afterTextChanged(...) 方法中的选择。在以下代码中，我对 afterTextChanged(...) 进行了更改：

@Override
    public void afterTextChanged(Editable editable) {

        String str = editable.toString();
        String number = str.replaceAll("[,]", "");
        if (number.equals(previousNumber) || number.isEmpty()) {
            return;
        }
        previousNumber = number;

        int startText, endText;
        startText = editText.getText().length();

        int selectionStart = editText.getSelectionStart();

        String formattedString = prefix + formatNumber(number);
        editText.removeTextChangedListener(this);
        editText.setText(formattedString);
        endText = editText.getText().length();

        int selection = (selectionStart + (endText - startText));
        editText.setSelection(selection);

        editText.addTextChangedListener(this);
    }

如何在编辑格式类似于美国货币的 EditText 字段时重新定位光标 - Android

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