Android 自定義手機輸入框

1. 自定義類PhoneTextView

PhoneTextView繼承EditText，在構造函數裏面可以初始化類型，限定長度和輸入類型，並添加TextWatcher監聽器。

public class PhoneTextView extends EditText {

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

    public PhoneTextView(Context context, AttributeSet attrs) {
        super(context, attrs);

        setFilters(new InputFilter[] {new InputFilter.LengthFilter(13)});
        setInputType(InputType.TYPE_CLASS_NUMBER);

        new PhoneTextWatcher(this);
    }

}

2. 自定義TextWatcher

TextWatcher主要用於監聽EditText的文本變化，詳情可見TextWatcher監聽器。

覆蓋onTextChanged()方法，去除空格，並調整光標的位置。

static class PhoneTextWatcher implements TextWatcher {
    private static final char SPACE_CHAR = ' ';

    private EditText mEditText;

    PhoneTextWatcher(EditText editText) {
        this.mEditText = editText;
    }

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

    @Override
    public void onTextChanged(CharSequence s, int start, int before, int count) {
        int selection = start + count;

        char[] array = new char[s.length()];
        int len = 0;
        int space = 0;
        for (int index = 0; index < s.length(); index++) {
            if (s.charAt(index) == SPACE_CHAR) {
                if (index < selection) {
                    ++space;
                }
            } else {
                array[len++] = s.charAt(index);
            }
        }
        setPhoneText(new String(array, 0, len), selection - space);
    }

    @Override
    public void afterTextChanged(Editable s) {
    }
}

setPhoneText()方法,通過isEmptyPlace(int)方法來判斷是否需要添加空格，並調整光標。在設置新的字符時，要先關閉監聽器。

private void setPhoneText(String phoneText, int selection) {
    LogTool.logi("PhoneTextView", phoneText + ", selection = " + selection);
    String text = "";
    int space = 0;
    for (int index = 0; index < phoneText.length(); index++) {
        if (isEmptyPlace(text.length())) {
            text += SPACE_CHAR;
            if (index < selection) {
                ++space;
            }
        }
        text += phoneText.charAt(index);
    }

    mEditText.removeTextChangedListener(this);
    mEditText.setText(text);
    mEditText.setSelection(selection + space);
    mEditText.addTextChangedListener(this);
}

private boolean isEmptyPlace(int index) {
    return 3 == index || 8 == index;
}