Monday, 10 June 2013

Setting MaxLength of EditText at run time Andriod


Some times we have to set max length of edit text By Code Or
we can use xml  tag as
android:maxLength="5" 

If we want to limit the character input in an EditText , EditText in XML layout gives us android:maxLength to do this. But in java codes you might wonder why there isn't any setMaxLength(int length) function. The reason behind this is that when you want to restrict the EditText to accept certain value, you have to filter them and this would be invoked by setFilters. To make our EditText to have a fixed size we can use the following code.


                  int maxLength = 5;
                  InputFilter[] FilterArray = new InputFilter[1];
                  FilterArray[0] = new InputFilter.LengthFilter(maxLength);

                  nameTxt.setFilters(FilterArray);



Here is one good example I found on stack over flow by

For anyone else wondering how to achieve this, here is my extended EditText class EditTextNumeric.
.setMaxLength(int) - sets maximum number of digits
.setMaxValue(int) - limit maximum integer value
.setMin(int) - limit minimum integer value
.getValue() - get integer value

import android.content.Context;
import android.text.InputFilter;
import android.text.InputType;
import android.widget.EditText;

public class EditTextNumeric extends EditText {
    protected int max_value = Integer.MAX_VALUE;
    protected int min_value = Integer.MIN_VALUE;

    // constructor
    public EditTextNumeric(Context context) {
        super(context);
        this.setInputType(InputType.TYPE_CLASS_NUMBER);
    }

    // checks whether the limits are set and corrects them if not within limits
    @Override
    protected void onTextChanged(CharSequence text, int start, int before, int after) {
        if (max_value != Integer.MAX_VALUE) {
            try {
                if (Integer.parseInt(this.getText().toString()) > max_value) {
                    // change value and keep cursor position
                    int selection = this.getSelectionStart();
                    this.setText(String.valueOf(max_value));
                    if (selection >= this.getText().toString().length()) {
                        selection = this.getText().toString().length();
                    }
                    this.setSelection(selection);
                }
            } catch (NumberFormatException exception) {
                super.onTextChanged(text, start, before, after);
            }
        }
        if (min_value != Integer.MIN_VALUE) {
            try {
                if (Integer.parseInt(this.getText().toString()) < min_value) {
                    // change value and keep cursor position
                    int selection = this.getSelectionStart();
                    this.setText(String.valueOf(min_value));
                    if (selection >= this.getText().toString().length()) {
                        selection = this.getText().toString().length();
                    }
                    this.setSelection(selection);
                }
            } catch (NumberFormatException exception) {
                super.onTextChanged(text, start, before, after);
            }
        }
        super.onTextChanged(text, start, before, after);
    }

    // set the max number of digits the user can enter
    public void setMaxLength(int length) {
        InputFilter[] FilterArray = new InputFilter[1];
        FilterArray[0] = new InputFilter.LengthFilter(8);
        this.setFilters(FilterArray);
    }

    // set the maximum integer value the user can enter.
    // if exeeded, input value will become equal to the set limit
    public void setMaxValue(int value) {
        max_value = value;
    }
    // set the minimum integer value the user can enter.
    // if entered value is inferior, input value will become equal to the set limit
    public void setMinValue(int value) {
        min_value = value;
    }

    // returns integer value or 0 if errorous value
    public int getValue() {
        try {
            return Integer.parseInt(this.getText().toString());
        } catch (NumberFormatException exception) {
            return 0;
        }
    }
}
Example usage:
final EditTextNumeric input = new EditTextNumeric(this);
input.setMaxLength(5);
input.setMaxValue(total_pages);
input.setMinValue(1);
All other methods and attributes that apply to EditText, of course work too.