Edittext cursor resetting to left after Android Data Binding update

EditText Cursor Resetting to Left After Android Data Binding Update

Android Data Binding is a powerful tool for simplifying UI development by connecting UI elements directly to data sources. However, one common issue that developers face is the EditText cursor resetting to the left after a Data Binding update.

Understanding the Issue

This problem occurs because the default behavior of Data Binding is to completely replace the contents of the EditText when the bound data changes. This replacement process causes the cursor to jump back to the beginning of the text.

Solutions

Here are several approaches to prevent the EditText cursor from resetting after Data Binding updates:

1. Using the `android:textCursorDrawable` Attribute

By setting the `android:textCursorDrawable` attribute to a custom drawable, we can override the default cursor behavior. This custom drawable can be designed to maintain the cursor’s position even after the text is replaced.

<EditText
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:textCursorDrawable="@drawable/custom_cursor"
    android:text="@{viewModel.editTextValue}" />

2. Maintaining the Cursor Position Manually

We can use an `OnTextChangedListener` to track the cursor’s position before and after the Data Binding update. This listener can then programmatically reset the cursor to the previous position after the update.

<EditText
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:text="@{viewModel.editTextValue}"
    android:onTextChanged="@{(s, start, before, count) -> viewModel.onTextChanged(s, start, before, count)}" />

// In your ViewModel
public void onTextChanged(CharSequence s, int start, int before, int count) {
    previousCursorPosition = start;
}

// In your ViewModel
public void updateEditTextValue() {
    editTextValue = newText;
    // After updating the bound data, reset the cursor
    editText.setSelection(previousCursorPosition);
}

3. Using `android:editable=”false”`

If the EditText is for display purposes and user input is not required, setting `android:editable=”false”` will prevent the cursor from appearing altogether. This might be a viable solution if you only need to display text and avoid any cursor-related issues.

<EditText
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:editable="false"
    android:text="@{viewModel.editTextValue}" />

Comparison of Solutions

Conclusion

The EditText cursor resetting after Data Binding update is a common issue that can be addressed using a combination of techniques. By choosing the appropriate solution based on your specific requirements, you can ensure smooth data binding updates while maintaining the desired cursor behavior.