Android app stops when trying to change activity

Question

In my app, there is a registration button which is supposed to open an activity named "registrationActivity" I tried this:

In XML file:

<Button
    android:id="@+id/btnRegister"
    android:onClick="startRegister"
/>

In Java file:

public void startRegister(View view)
    {
        Intent intent = new Intent(LoginActivity.this, RegistrationActivity.class);
        startActivity(intent);
    }

but every time I click the register button, the app keeps stopping.

Edit 1: error from logcat:

Runtime: FATAL EXCEPTION: main Process: com.test.stork, PID: 5152

java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.test.stork/com.test.stork.RegistrationActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'android.view.Window$Callback android.view.Window.getCallback()' on a null object reference

Edit 2: I found the problem in the registrationActivity itself and now it works. Thanks so much everyone.

Post the stack trace from logcat. It will tell you why you're crashing. Which is more likely to be in the new activity than the old one. — Gabe Sechan, Aug 30 '18 at 13:53
Edit your question to include the full Activity, your layout and manifest. See [mcve] for more information — OneCricketeer, Aug 30 '18 at 14:06
Possible duplicate of [Attempt to invoke virtual method 'android.view.Window$Callback android.view.Window.getCallback()' on a null object reference](https://stackoverflow.com/questions/36666091/attempt-to-invoke-virtual-method-android-view-windowcallback-android-view-wind) — dilix, Aug 30 '18 at 14:08

score 0 · Answer 1 · answered Aug 30 '18 at 14:01

0

Like Bruno mentioned in the comments, you need to declare the RegistrationActivity in your manifest file like :

<activity
    android:name="yourPackage.RegistrationActivity"/>

under the application object.

answered Aug 30 '18 at 14:01

Bubu

1,533
14
14

score 0 · Answer 2 · answered Aug 30 '18 at 14:08

The issue is in your Registration Activity onCreate or onResume method. Post your Registration xml. Basically it is failing to do something with a null object in your startup. Set a break point in your onCreate of your RegisterActivity and see which item is null and you will be good.

Android app stops when trying to change activity

2 Answers2