How to filter the input of EditText?

Question

I want to filter the input of an EditText, only digits and letters are allowed, first I use TextWatcher to deal with the last input character, but when you move the cursor or you past some content to the EditText, this method failed, now I want to know is there a way to filter the illegal input and give the user a feedback.

Check out : https://github.com/vekexasia/android-edittext-validator — Haresh Chhelana, May 15 '15 at 12:30

Don Chakkappan · Accepted Answer · 2015-05-15T12:29:22.913

15

Add InputFilter to your EditText & provide a Toast for user . This code snippet will help you.

 InputFilter filter = new InputFilter() {
                public CharSequence filter(CharSequence source, int start, int end,
                        Spanned dest, int dstart, int dend) {
                    for (int i = start; i < end; i++) {
                        if (!Character.isLetterOrDigit(source.charAt(i))) { // Accept only letter & digits ; otherwise just return
                            Toast.makeText(context,"Invalid Input",Toast.LENGTH_SHORT).show();
                            return "";
                        }
                    }
                    return null;
                }

            };

        editText.setFilters(new InputFilter[] { filter });

edited May 15 '15 at 12:29

answered May 15 '15 at 12:19

Don Chakkappan

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Could the 'InputFilter' confilts with the 'TextWatcher', I use `TextWatcher` to control the a button state with the length of the `EditText` at the same time, but with the `InputFilter`, the `InputFilter` doesn't work. – twlkyao May 15 '15 at 13:11
I have used the same code and works fine. Please post your complete code – Don Chakkappan May 15 '15 at 13:14
I have found the problem, the filters were reset somewhere. – twlkyao May 18 '15 at 07:47
@twlkyao It is very happy to see that your problem is solved .Cheers – Don Chakkappan May 18 '15 at 07:49

score 6 · Answer 2 · answered May 15 '15 at 12:21

6

Have you tried the xml way? It will look something like this

<EditText 
  android:id="@+id/editText"
  android:inputType="text" 
  android:digits="0,1,2,3,4,5,6,7,8,9,*,qwertzuiopasdfghjklyxcvbnm" 
  android:hint="Only letters and numbers allowed.."
/>

answered May 15 '15 at 12:21

Bidhan

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This method has no feedback. – twlkyao May 15 '15 at 12:27
There is hint however. What kind of feedback are you looking for? A toast message? – Bidhan May 15 '15 at 12:29
This is awesome. I'm pretty sure if you're entering for example a telephone it's pretty obvious if only numbers and - work or something like that. No feedback needed. – csga5000 Apr 14 '16 at 05:17
2

Commas "," are not necessary. You can write `android:digits="0123456789*qwertzuiopasdfghjklyxcvbnm"` – Rafa0809 Oct 25 '16 at 23:47
i want to use alphabets digits and spaces then what to do? @Rafa0809 – Shashwat Gupta Aug 01 '17 at 10:10
1

@ĜüptåŠhãsĥwæt Try this: android:digits="0123456789abcdefghijklmnopqrstuvwxyz ABCDEFGHIJKLMNOPQRSTUVWXYZ " – Rafa0809 Aug 01 '17 at 11:38
@Rafa0809 I have tried this but it doesn't take spaces – Shashwat Gupta Aug 01 '17 at 13:32
Have you ensured you included the space in the middle of the android:digits? Otherwise the problem is not focused on the android:digits. Take a look at this post: https://stackoverflow.com/questions/26057279/making-an-edittext-field-accept-only-letters-and-white-spaces-in-android – Rafa0809 Aug 02 '17 at 08:48

score 6 · Answer 3 · answered Nov 29 '17 at 12:44

Work on all Android Versions:

public static InputFilter getOnlyCharactersFilter() {
    return getCustomInputFilter(true, false, false);
}

public static InputFilter getCharactersAndDigitsFilter() {
    return getCustomInputFilter(true, true, false);
}

public static InputFilter getCustomInputFilter(final boolean allowCharacters, final boolean allowDigits, final boolean allowSpaceChar) {
    return new InputFilter() {
        @Override
        public CharSequence filter(CharSequence source, int start, int end, Spanned dest, int dstart, int dend) {
            boolean keepOriginal = true;
            StringBuilder sb = new StringBuilder(end - start);
            for (int i = start; i < end; i++) {
                char c = source.charAt(i);
                if (isCharAllowed(c)) {
                    sb.append(c);
                } else {
                    keepOriginal = false;
                }
            }
            if (keepOriginal) {
                return null;
            } else {
                if (source instanceof Spanned) {
                    SpannableString sp = new SpannableString(sb);
                    TextUtils.copySpansFrom((Spanned) source, start, sb.length(), null, sp, 0);
                    return sp;
                } else {
                    return sb;
                }
            }
        }

        private boolean isCharAllowed(char c) {
            if (Character.isLetter(c) && allowCharacters) {
                return true;
            }
            if (Character.isDigit(c) && allowDigits) {
                return true;
            }
            if (Character.isSpaceChar(c) && allowSpaceChar) {
                return true;
            }
            return false;
        }
    };
}

Now you can use this filer like:

 //Accept Characters Only
edit_text.setFilters(new InputFilter[]{getOnlyCharactersFilter()});

//Accept Digits and Characters
edit_text.setFilters(new InputFilter[]{getCharactersAndDigitsFilter()});

//Accept Digits and Characters and SpaceBar
edit_text.setFilters(new InputFilter[]{getCustomInputFilter(true,true,true)});

How to filter the input of EditText?

3 Answers3

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