Trying to get a button to load another activity however the is OnClickListner crashing the app

Question

When the register button is clicked the app should load another activity however it just crashes. Tried looking here and here for help but I still couldn't fix it. I also tried removing 'implements View.OnClickListner' and using it how its shown in the examples and it didn't work. Also tried changing the xml file to a LinearLayout and that didn't work either. Thanks in advance!

public class LogInActivity extends AppCompatActivity implements View.OnClickListener {

//user input variables
EditText emailAddressInput;
EditText passwordInput;
Button logInButton;
Button registerButton;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    //set the layout to activity_login.xml
    setContentView(R.layout.activity_login);

    //get user inputs and set to the variables
    emailAddressInput = (EditText)findViewById(R.id.emailAddressInput);
    passwordInput = (EditText)findViewById(R.id.passwordInput);
    logInButton = (Button)findViewById(R.id.logInButton);
    registerButton = (Button)findViewById(R.id.registerButton);

    logInButton.setOnClickListener(this);
    registerButton.setOnClickListener(this);
}

@Override
public void onClick(View view) {
    Intent registerIntent = new Intent (LogInActivity.this,RegisterActivity.class);

    switch (view.getId())
    {
        case R.id.logInButton:
            break;
        case R.id.registerButton:
            startActivity(registerIntent);
            break;
    }
}

}

EDIT: the logcat:

2020-04-04 16:02:10.759 12718-12718/com.example.blooddonorsystem E/AndroidRuntime: FATAL EXCEPTION: main Process: com.example.blooddonorsystem, PID: 12718 java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.blooddonorsystem/com.example.blooddonorsystem.RegisterActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.Spinner.setAdapter(android.widget.SpinnerAdapter)' on a null object reference at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3270) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3409) at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:83) at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135) at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2016) at android.os.Handler.dispatchMessage(Handler.java:107) at android.os.Looper.loop(Looper.java:214) at android.app.ActivityThread.main(ActivityThread.java:7356) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:930) Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.Spinner.setAdapter(android.widget.SpinnerAdapter)' on a null object reference at com.example.blooddonorsystem.RegisterActivity.onCreate(RegisterActivity.java:56) at android.app.Activity.performCreate(Activity.java:7825) at android.app.Activity.performCreate(Activity.java:7814) at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1306) at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3245) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3409) at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:83) at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135) at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2016) at android.os.Handler.dispatchMessage(Handler.java:107) at android.os.Looper.loop(Looper.java:214) at android.app.ActivityThread.main(ActivityThread.java:7356) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:930)

Use Logcat to examine the stack trace associated with your crash: https://stackoverflow.com/questions/23353173/unfortunately-myapp-has-stopped-how-can-i-solve-this — CommonsWare, Apr 04 '20 at 14:59
Try button.setOnClickListener(new View.OnClickListener() {}) — deymbwoi, Apr 04 '20 at 15:02

score 1 · Accepted Answer · answered Apr 04 '20 at 15:05

1

In your RegisterActivity, seems like the Spinner you are setting the adapter to is null. Make sure it has correct value, usually its an ArrayAdapter of String.

answered Apr 04 '20 at 15:05

Mike

1,313
12
21

score 0 · Answer 2 · edited Apr 04 '20 at 17:01

0

The error is not in LoginActivity but in RegisterActivity.There is a null pointer exception in RegisterActivity when you are setting adapter to a spinner.

edited Apr 04 '20 at 17:01

Bhargav Rao

50,140
28
121
140

answered Apr 04 '20 at 15:10

Rahul Verma

1
1

Trying to get a button to load another activity however the is OnClickListner crashing the app

2 Answers2