App crashes when I press "continue" button (transitioning between activities)

Question

I am creating an app where you log in and then access a database of files unique to each user account. I have a continue button linking the "LoginActivity" and "MainActivity" activities together. The code that I have in the LoginActivity file is this:

@Override
    public void onClick(View v) {
        switch (v.getId()) {
            case R.id.email_create_account_button:
                createAccount(mEdtEmail.getText().toString(), mEdtPassword.getText().toString());
                break;
            case R.id.email_sign_in_button:
                signIn(mEdtEmail.getText().toString(), mEdtPassword.getText().toString());
                break;
            case R.id.sign_out_button:
                signOut();
                break;
            case R.id.continue_button:
                Button btn = (Button)findViewById(R.id.continue_button);
                startActivity(new Intent(LoginActivity.this, MainActivity.class));
                break;
        }
    }

and on the MainActivity side I have this:

@Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        upload_button = findViewById(R.id.upload_button);
        showall_button = findViewById(R.id.showall_button);
        progressBar = findViewById(R.id.progressBar);
        imageView = findViewById(R.id.imageView);

        progressBar.setVisibility(View.INVISIBLE);

        imageView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent galleryIntent = new Intent();
                galleryIntent.setAction(Intent.ACTION_GET_CONTENT);
                galleryIntent.setType("image/*");
                startActivityForResult(galleryIntent , 2);
            }
        });

What is wrong with my code? I can't seem to figure it out. Please let me know if you need more code from my project. Thanks!

Do you get an Exception thrown? An error message? If so, please include a copy. — Old Dog Programmer, Aug 29 '22 at 23:56
@James Because of the phone emulator in android studio, "com.example.auth keeps stopping" is the emulator message when it crashes. — Morgan, Aug 30 '22 at 00:29
why your `continue_button` clicked twice? you already inside the method `onClick` and then you trigger again `setOnClickListener` ? — Ticherhaz FreePalestine, Aug 30 '22 at 01:33
@TicherhazFreePalestine I corrected that, but the button still doesn't work. Thanks for catching that though! — Morgan, Aug 30 '22 at 01:48
@Morgan Did you fixed the part where you are reassigning onClick after clicking continue button? If yes, then paste your edited code of that part. — Ahsan Ullah Rasel, Aug 30 '22 at 02:20
If the app crashes, there is a stack trace. Please look that up on logcat, and add it to your question. Please respond using @AlexMamo — Alex Mamo, Aug 30 '22 at 05:01
When an app crashes, it writes an error message and stack trace to its logcat. Please find those, and add them to your question by clicking the `edit` link under it. Also see https://stackoverflow.com/questions/23353173/unfortunately-myapp-has-stopped-how-can-i-solve-this and https://stackoverflow.com/questions/3988788/what-is-a-stack-trace-and-how-can-i-use-it-to-debug-my-application-errors — Frank van Puffelen, Aug 30 '22 at 07:00
@AlexMamo java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.auth/com.example.auth.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.ImageView.setOnClickListener(android.view.View$OnClickListener)' on a null object reference — Morgan, Aug 30 '22 at 21:31

score 0 · Answer 1 · answered Aug 30 '22 at 00:34

0

You should initialize your buttons and after that, set onclicklistener to them. For the complete explanation visit Android App Crashes on Button Click

answered Aug 30 '22 at 00:34

Dorrin Samadian

68
13

They're all initialized and have onclicklistener set. All the other buttons work, just not the continue button. – Morgan Aug 30 '22 at 00:51

score 0 · Accepted Answer · answered Aug 31 '22 at 04:43

0

According to your logcat, it seems that, you are referencing an resource ID which doesn't exists on your XML (activity_main.xml) file.
Check whether the ID imageView exists or not. It might not present in your layout file or it may have different name. Make the ID name same both in activity_main.xml side and MainActivity side.

answered Aug 31 '22 at 04:43

Ahsan Ullah Rasel

606
6
14

1

Thank you! activity_main.xml had "imageView2" from a previous edit and I forgot to change it over. Works now. – Morgan Aug 31 '22 at 19:33

App crashes when I press "continue" button (transitioning between activities)

2 Answers2