android on Text Change Listener

In Android, you can use a TextWatcher to listen for changes to the text in a TextView or EditText view.

Here's an example of how you can use a TextWatcher to implement a text change listener:

EditText editText = findViewById(R.id.edit_text);

editText.addTextChangedListener(new TextWatcher() {
  @Override
  public void beforeTextChanged(CharSequence s, int start, int count, int after) {
    // This method is called before the text is changed
  }

  @Override
  public void onTextChanged(CharSequence s, int start, int before, int count) {
    // This method is called when the text is changed
  }

  @Override
  public void afterTextChanged(Editable s) {
    // This method is called after the text is changed
  }
});

In this example, the TextWatcher has three methods: beforeTextChanged, onTextChanged, and afterTextChanged. The beforeTextChanged method is called before the text is changed, the onTextChanged method is called when the text is changed, and the afterTextChanged method is called after the text is changed.

You can use these methods to perform some action whenever the text in the EditText view is changed. For example, you might use the onTextChanged method to update a text field in real-time as the user types.

I hope this helps! Let me know if you have any questions.