How can restrict my EditText input to some special character like backslash(/),tild(~) etc by soft keyboard in android programmatically

Question

I am developing an application for keyboard, but i am geting an issue. I want to restrict/block some special character from soft keyboard in EditText in android programmatic

Answer 1

This should work:

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))) { 
                                return ""; 
                        } 
                } 
                return null; 
        } 
}; 

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

Or if you prefer the easy way:

<EditText android:inputType="text" android:digits="0123456789*,qwertzuiopasdfghjklyxcvbnm" />

Answer 2

For those who might be facing issues while adding space please add a blank space with all the alphabets. Below is an example Also you should know that user won't be able to add a new line in this case.

            <EditText
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:inputType="text"
            android:digits="0123456789,a bcdefghijklmnopqrstuvwxyz"
            android:maxLines="1"
            android:singleLine="true" />

Answer 3

You can create regular expression and check it on onTextChanged method

yourEditText.addTextChangedListener(new TextWatcher() {

          public void afterTextChanged(Editable s) {

            // you can call or do what you want with your EditText here
            yourEditText. ... 

          }

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

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

Answer 4

Try this may work for you

public class MainActivity extends Activity {

    private EditText editText;
    private String blockCharacterSet = "~#^|$%&*!";

    private InputFilter filter = new InputFilter() {

        @Override
        public CharSequence filter(CharSequence source, int start, int end, Spanned dest, int dstart, int dend) {

            if (source != null && blockCharacterSet.contains(("" + source))) {
                return "";
            }
            return null;
        }
    };

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        editText = (EditText) findViewById(R.id.editText);
        editText.setFilters(new InputFilter[] { filter });
    }

}