IndexOutOfBoundsException setSpan (0 ... 1) ends beyond length 0

Question

I am using this library for material editText with label: https://github.com/rey5137/Material/wiki/Text-Field nice library :)

but...

i am using next code to check are entered symbols correct:

private boolean hasCorrectSymbols(String input){
        String tre = "[A-Za-z0-9\\@\\#\\$\\%\\&\\*\\(\\)\\-\\+\\_\\;\\:\\?\\.\\,\\!]+$";
        if (input.matches(tre)){
            return true;
        }
        return false;
    }

for checking correct symbols I am using textWatcher:

mEditPass.addTextChangedListener(new TextWatcher() {
            @Override
            public void beforeTextChanged(CharSequence s, int start, int count, int after) {}

            @Override
            public void onTextChanged(CharSequence s, int start, int before, int count) {
                if (s.length() == 1 && !loginPassHasCorrectSymbols(s.toString())){
                    mEditPass.getText().clear();
                    String mess = getString(R.string.toast_login_useLatin);
                    showToastMessage(mess);
                } else if (s.length() >1 && !loginPassHasCorrectSymbols(s.toString())) {
                    String mess = getString(R.string.toast_login_useLatin);
                    showToastMessage(mess);
                    String text = s.toString();
                    text = text.substring(0, start);
                    mEditPass.setText(text);
                    mEditPass.setSelection(start);
                }
            }

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

if first symbol is correct and the second one for example is wrong - system will cut last entered (wrong) symbol and set cursor to the last text position, but if the first symbol is prohibited symbol - it will crash with this error:

java.lang.IndexOutOfBoundsException: setSpan (0 ... 1) ends beyond length 0
            at android.text.SpannableStringBuilder.checkRange(SpannableStringBuilder.java:1016)
            at android.text.SpannableStringBuilder.setSpan(SpannableStringBuilder.java:592)
            at android.text.SpannableStringBuilder.setSpan(SpannableStringBuilder.java:588)
            at android.text.method.PasswordTransformationMethod.onTextChanged(PasswordTransformationMethod.java:108)
            at android.text.SpannableStringBuilder.sendTextChanged(SpannableStringBuilder.java:962)
            at android.text.SpannableStringBuilder.replace(SpannableStringBuilder.java:496)
            at android.text.SpannableStringBuilder.replace(SpannableStringBuilder.java:435)
            at android.text.SpannableStringBuilder.replace(SpannableStringBuilder.java:30)
            at android.view.inputmethod.BaseInputConnection.replaceText(BaseInputConnection.java:683)
            at android.view.inputmethod.BaseInputConnection.commitText(BaseInputConnection.java:198)
            at com.android.internal.widget.EditableInputConnection.commitText(EditableInputConnection.java:183)
            at com.android.internal.view.IInputConnectionWrapper.executeMessage(IInputConnectionWrapper.java:279)
            at com.android.internal.view.IInputConnectionWrapper$MyHandler.handleMessage(IInputConnectionWrapper.java:77)
            at android.os.Handler.dispatchMessage(Handler.java:102)
            at android.os.Looper.loop(Looper.java:136)
            at android.app.ActivityThread.main(ActivityThread.java:5097)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:515)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
            at dalvik.system.NativeStart.main(Native Method) 

Any ideas why it happen? And how to fix this??

Answer 1

In this code snippet, you shorten the text displayed in the EditText (so that the last valid position is start-1), but still try to set the selection position to start.

                text = text.substring(0, start);
                mEditPass.setText(text);
                mEditPass.setSelection(start);

[EDITED]

Assuming that your Toast message is prompting the user to fix the error, I think what you actually want to do is to set the selection to the first character in the EditText with a bad symbol. Here is sample code for doing that:

// A reusable Pattern (at the class level) that defines the regex for bad characters.
private static final Pattern ILLEGAL_CHAR_PATTERN = Pattern.compile(
    "[^A-Za-z0-9\\@\\#\\$\\%\\&\\*\\(\\)\\-\\+\\_\\;\\:\\?\\.\\,\\!]"
);

    // Replacement for your listener code.
    mEditPass.addTextChangedListener(new TextWatcher() {
        @Override
        public void beforeTextChanged(CharSequence s, int start, int count, int after) {
        }

        @Override
        public void onTextChanged(CharSequence s, int start, int before, int count) {
            if (s.length() == 0 || count == 0) {
                return;
            }
            Matcher matcher = ILLEGAL_CHAR_PATTERN.matcher(s);
            if (matcher.find()) {
                int firstIllegalPos = matcher.start();
                mEditPass.setSelection(firstIllegalPos);
                String mess = getString(R.string.toast_login_useLatin);
                showToastMessage(mess);
            }
        }

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