android 格式化输入控制

Article from : http://horribile.blogspot.com/2011/11/formatting-edittext-input-with-regular.html

It will be the short article. Now we will format text in EditText with regular expressions.

The simple class will extend Input Filter:

 public class PartialRegexInputFilter implements InputFilter {

     private Pattern mPattern;

     public PartialRegexInputFilter(String pattern){
       mPattern = Pattern.compile(pattern);
     }

     @Override
     public CharSequence filter(CharSequence source,
             int sourceStart, int sourceEnd,
             Spanned destination, int destinationStart,
             int destinationEnd)
     {
         String textToCheck = destination.subSequence(0, destinationStart).
             toString() + source.subSequence(sourceStart, sourceEnd) +
             destination.subSequence(
             destinationEnd, destination.length()).toString();

         Matcher matcher = mPattern.matcher(textToCheck);

         // Entered text does not match the pattern
         if(!matcher.matches()){

             // It does not match partially too
              if(!matcher.hitEnd()){
                  return "";
              }

         }

         return null;
     }

 }

The trick is that if the input text does not match the pattern it can match it partially.
If so we will allow the text pasting.

And finally formatting a phone number:

 final String regex = "\\(\\d{3}\\)\\d{3}\\-\\d{2}\\-\\d{2}";

 txt.setFilters(
     new InputFilter[] {
         new PartialRegexInputFilter(regex)
     }
 );

 txt.addTextChangedListener(
     new TextWatcher(){

             @Override
             public void afterTextChanged(Editable s) {
                 String value  = s.toString();
                 if(value.matches(regex))
                     txt.setTextColor(Color.BLACK);
                 else
                     txt.setTextColor(Color.RED);
             }

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

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

          }
 );

We have: