关于一个支付项目用到的，银行卡输入框和显示的TextView。

银行卡输入框，四位一组。

自定义一个BankCardNumEditText继承EditText，代码如下：

public class BankCardNumEditText extends EditText {

public BankCardNumEditText(Context context) {

super(context);

this.addTextChangedListener(new BankCardNumWatcher());

}

public BankCardNumEditText(Context context, AttributeSet attrs) {

super(context, attrs);

this.addTextChangedListener(new BankCardNumWatcher());

}

/**

* 获取真实的text(去掉空格)

*

* @return

*/

public String getTextWithoutSpace() {

String text = super.getText().toString();

if (android.text.TextUtils.isEmpty(text)) {

return "";

} else {

return text.replace(" ", "");

}

}

/**

* 银行卡号输入框格式(每4位有个空格)

*

* @author Administrator

*/

class BankCardNumWatcher implements TextWatcher {

int beforeTextLength = 0;

int onTextLength = 0;

boolean isChanged = false;

int location = 0;// 记录光标的位置

private char[] tempChar;

private StringBuffer buffer = new StringBuffer();

int konggeNumberB = 0;

@Override

public void onTextChanged(CharSequence s, int start, int before,

int count) {

onTextLength = s.length();

buffer.append(s.toString());

if (onTextLength == beforeTextLength || onTextLength <= 3

|| isChanged) {

isChanged = false;

return;

}

isChanged = true;

}

@Override

public void beforeTextChanged(CharSequence s, int start, int count,

int after) {

beforeTextLength = s.length();

if (buffer.length() > 0) {

buffer.delete(0, buffer.length());

}

konggeNumberB = 0;

for (int i = 0; i < s.length(); i++) {

if (s.charAt(i) == ' ') {

konggeNumberB++;

}

}

}

@Override

public void afterTextChanged(Editable s) {

if (isChanged) {

location = getSelectionEnd();

int index = 0;

while (index < buffer.length()) {

if (buffer.charAt(index) == ' ') {

buffer.deleteCharAt(index);

} else {

index++;

}

}

index = 0;

int konggeNumberC = 0;

while (index < buffer.length()) {

if ((index == 4 || index == 9 || index == 14 || index == 19)) {

buffer.insert(index, ' ');

konggeNumberC++;

}

index++;

}

if (konggeNumberC > konggeNumberB) {

location += (konggeNumberC - konggeNumberB);

}

tempChar = new char[buffer.length()];

buffer.getChars(0, buffer.length(), tempChar, 0);

String str = buffer.toString();

if (location > str.length()) {

location = str.length();

} else if (location < 0) {

location = 0;

}

setText(str);

Editable etable = getText();

Selection.setSelection(etable, location);

isChanged = false;

}

}

}

}