如果您仍在搜索，我在最后一天遇到了这个问题，发现使用TextWatcher是最好的（仍然不是很好）的选择。我必须对信用卡号码的数字进行分组。
someEditText.addTextChagedListener(new TextWatcher()
{
//According to the developer guide, one shall only edit the EditText's
//content in this function.
@Override
public void afterTextChanged(Editable text)
{
//You somehow need to access the EditText to remove this listener
//for the time of the changes made here. This is one way, but you
//can create a proper TextWatcher class and pass the EditText to
//its constructor, or have the EditText as a member of the class
//this code is running in (in the last case, you simply have to
//delete this line).
EditText someEditText = (EditText) findViewById(R.id.someEditText);
//Remove listener to prevent further call due to the changes we're
//about to make (TextWatcher is recursive, this function will be
//called again for every change you make, and in my experience,
//replace generates multiple ones, so a flag is not enough.
someEditText.removeTextChangedListener(this);
//Replace text with processed the processed string.
//FormatText is a function that takes a CharSequence (yes, you can
//pass the Editable directly), processes it the way you want, then
//returns the result as a String.
text.replace(0, text.length(), FormatText(text));
//Place the listener back
someEditText.addTextChangedListener(this);
}
@Override
public void beforeTextChaged(CharSequence s, int start, int count, int after)
{
}
@Override
public void onTextChanged(CharSequence s, int start, int before, int count)
{
}
});
我的信用卡号格式化函数如下所示：
String FormatText(CharSequence text)
{
StringBuilder formatted = new StringBuilder();
int count = 0;
for (int i = 0; i < text.length(); ++i)
{
if (Character.isDigit(text.charAt(i)))
{
//You have to be careful here, only add extra characters before a
//user-typed character, otherwise the user won't be able to delete
//with backspace, since you put the extra character back immediately.
//However, this way, my solution would put a space at the start of
//the string that I don't want, hence the > check.
if (count % 4 == 0 && count > 0)
formatted.append(' ');
formatted.append(text.charAt(i));
++count;
}
}
return formatted.toString();
}
您可能还需要注意其他问题，因为此解决方案实际上会在每次进行更改时重写 EditText 的内容。例如，您应该避免处理您自己插入的字符（这是 isDigit 检查的另一个原因）。