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Android

Posted by dlpuxdzztg
dlpuxdzztg
8,243 Points

Trouble with 'if' statement.

Hello.

I have tried executing this multiple times, but no matter what I do it still doesn't work. I want a DialogFragment to open when the EditText's fields are blank or null:

if (mNoteTitleEdit.equals(null)) {
                error();
            }

if (mNoteDescriptionEdit.equals(null)) {
                error();
            }

if (mNoteTitleEdit == null) {
                error();
            }

if (mNoteDescriptionEdit == null) {
                error();
            }

These just give me errors:

if (mNoteTitleEdit && mNoteDescriptionEdit.equals(null)) {
                error();
            }

if (mNoteTitleEdit && mNoteDescriptionEdit == null) {
                error();
            }

Full code (if necessary):

public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.fragment_new_note, container, false);

        mNoteTitleEdit = (EditText) view.findViewById(R.id.NoteTitleEdit);
        mNoteDescriptionEdit = (EditText) view.findViewById(R.id.NoteDescriptionEdit);
        mConfirmImageNN = (ImageView) view.findViewById(R.id.ConfirmImageNN);
        mConfirmImageNN.setOnClickListener(this);
        mCancelImageNN = (ImageView) view.findViewById(R.id.CancelImageNN);
        mCancelImageNN.setOnClickListener(this);

        return view;
    }

@Override
    public void onClick(View v) {
        if (v == mConfirmImageNN) {
            String titleText = mNoteTitleEdit.getText().toString();
            String descriptionText = mNoteDescriptionEdit.getText().toString();

            if (titleText.equals(null)) {
                error();
            }

if (descriptionText.equals(null)) {
                error();
            }
        }

        if (v == mCancelImageNN) {
            goBack();
        }
    }

I can't figure out why it gives me an error and why it does nothing with the first two.

Please help!

1 Answer

Seth Kroger
Seth Kroger
56,413 Points
Seth Kroger
Seth Kroger
56,413 Points

If those two member variables, mNoteTitleEdit and mNoteDescriptionEdit, refer to the EditText's themselves they won't be null unless they don't exist on the Activity (or weren't initialized by findViewById() yet) The EditText is the UI widget that takes text input, not the input text itself. If you want the text you would use EditText.getText().toString().

In the last example, mNoteTitleEdit is just an object reference, not a boolean expression which Java requires in an if statement. Some other languages can use that style of syntax for checking null/empty using truthy/falsey values, but Java is more strict in using only true/false.

dlpuxdzztg
dlpuxdzztg
8,243 Points

Thanks, but for some reason, even with .getText().toString(), the code still doesn't execute. I edited the post to include a little more code if it helps.

Seth Kroger
Seth Kroger
56,413 Points
Seth Kroger
Seth Kroger
56,413 Points

You should check equality with an empty string, "", instead of null. Null is if the string doesn't exist, but the string can exist and be empty.

dlpuxdzztg
dlpuxdzztg
8,243 Points

Got it working, thanks!