TextWatcher.afterTextChanged has invalid line after backspace

Question

I use TextWatcher to listen for key input. When the user enters "@", I open the list, and the user must select from the list. After selection, I put the selected text of the element (including the start @) in the edittext, and normal editing continues.

The problem is that when I click backspace, the line that I get after the aftertextchanged event is incorrect and the activity list appears again.

editText.addTextChangedListener(new TextWatcher() { @Override public void onTextChanged(CharSequence s, int start, int before, int count) { } @Override public void beforeTextChanged(CharSequence s, int start, int count, int after) { } @Override public void afterTextChanged(Editable s) { String str = s.toString(); if (str.length() > 0) { if (str.substring(str.length() - 1).equals("@")) { Intent i = new Intent(MessageComposeActivity.this, MembersListActivity.class); startActivityForResult(i, Util.MEMBERS_LIST); } } } }); 

And in onActivityResult:

 @Override protected void onActivityResult(int requestCode, int resultCode, Intent data) { super.onActivityResult(requestCode, resultCode, data); if (requestCode == Util.MEMBERS_LIST) if (resultCode == RESULT_OK) { editText.setText(editText.getText().toString() + data.getExtras().get("screenname") + " "); editText.setSelection(editText.getText().length()); } } 

For instance:

In EditText, I type '@' and the action pops up and I select 'James'. EditText now displays @James. If I click back once or twice, the activity list reappears and the EditText shows @Jam.

PS: AfterTextChanged () is called twice for the backspace (or any key), the second time afterTextChanged () is executed, I get the wrong input line. The first time I execute afterTextChanged (), I get @Jam, and in the second execution I get "@", so an activity list appears.

Question: Why afterTextChanged () is called twice, and why on the second run I get the wrong text?

Thank you very much.

Answer 1

I had the same problem. I do not know what causes an additional false callback with a length of 0 Editable / CharacterSequence.

I was looking for changes to EditText that actually led to empty EditText. In the end, I had to implement a handler to check the length of the EditText after 500 ms. You may need to make your edittext static or final. It should look something like this:

  final Handler handler =new Handler(); final Runnable r = new Runnable(){ @Override public void run() { // String str = editText.getText().toString(); if (str.length() > 0) { if (str.substring(str.length() - 1).equals("@")) { Intent i = new Intent(MessageComposeActivity.this, MembersListActivity.class); startActivityForResult(i, Util.MEMBERS_LIST); } } } } ; editText.addTextChangedListener(new TextWatcher() { @Override public void beforeTextChanged(CharSequence charSequence, int i, int i2, int i3) { } @Override public void onTextChanged(CharSequence charSequence, int i, int i2, int i3) { } @Override public void afterTextChanged(Editable s) { handler.postDelayed(r,500); } });