I'm trying to detect a soft keyboard backspace in an empty EditText view. I've searched Stack Overflow and also Google and ~20 similar questions, but
none have a solution for detecting a backspace in an empty EditText.
All of the answers evolve around this blog article https://code.i-harness.com/en/q/4a914a
which specifically notes in the end that this does not detect backspace on an empty EditText view.
Help is much appreciated.
Most reliable solution to detect any event or text change of an EditText is using TextWatcher but if EditText is already empty, you can not detect backspace/delete key event on all devices.
Please keep it in mind that it is not possible and hopefully you or any other will not waste your time.
Hopefully this might help. I tried to use this in my projects.
public class MTextWatcher implements TextWatcher, View.OnKeyListener {
private int prevLen;
public MTextWatcher(int prevLen) {
this.prevLen = prevLen;
}
@Override
public void beforeTextChanged(CharSequence s, int start, int count, int after) {
}
@Override
public void onTextChanged(CharSequence s, int start, int before, int count) {
}
@Override
public void afterTextChanged(Editable s) {
//do something if you need
prevLen = s.toString().length();
}
@Override
public boolean onKey(View v, int keyCode, KeyEvent event) {
if (keyCode == KeyEvent.KEYCODE_DEL && prevLen == 0){
// here you can trap the delete key pressed on empty edit text
}
return false;
}
}
next you can attach this listener with edit text like this
MTextWatcher watcher = new MTextWatcher(edittext.getText().toString().length());
edittext.addTextChangedListener(watcher);
edittext.setOnKeyListener(watcher);
You can detect if edittext is empty or not with this code:
EditText usernameEditText = (EditText) findViewById(R.id.editUsername);
sUsername = usernameEditText.getText().toString();
if (sUsername.matches("")) {
Toast.makeText(this, "You did not enter a username", Toast.LENGTH_SHORT).show();
return;}
