Your null pointer exception seems to be on this line: because intent.getExtras() returns null when the intent doesn’t have any extras. You have to realize that this piece of code: doesn’t start the activity you wrote in Main.java, it will attempt to start an activity called ToClass and if that doesn’t exist, your app crashes. … Read more
The problem My Android automated tests are unreliable, because the tested activities are sometimes running and are sometimes paused. The cause If my android device (a Samsung Galaxy S2) has its Lock Screen on, all activities are immediately put in Pause mode. How can I programmatically disable the Lock Screen while my tests are running? … Read more
mFragmentFavorite in your code is a FragmentActivity which is not the same thing as a Fragment. That’s why you’re getting the type mismatch. Also, you should never call new on an Activity as that is not the proper way to start one. If you want to start a new instance of mFragmentFavorite, you can do so via an Intent. From a Fragment: From an Activity If you … Read more
Add the below to your manifest:
In XML, xmlns declares a Namespace. In fact, when you do: Instead of calling android:id, the xml will use http://schemas.android.com/apk/res/android:id to be unique. Generally this page doesn’t exist (it’s a URI, not a URL), but sometimes it is a URL that explains the used namespace. The namespace has pretty much the same uses as the package name in … Read more
You can do it programatically: Or you can do it via your AndroidManifest.xml file: Edit: If you are using AppCompatActivity then you need to add new theme and then use it. Thanks to https://stackoverflow.com/a/25365193/1646479
Usually you restore your state in onCreate(). It is possible to restore it in onRestoreInstanceState() as well, but not very common. (onRestoreInstanceState() is called after onStart(), whereas onCreate() is called before onStart(). Use the put methods to store values in onSaveInstanceState(): And restore the values in onCreate():
android.intent.action.MAIN means that this activity is the entry point of the application, i.e. when you launch the application, this activity is created. From the docs Also,from here Activity Action Start as a main entry point, does not expect to receive data. android.intent.category.DEFAULT is mainly used for implicit intents. If your activity wishes to be started by an implicit intent … Read more
One option could be letting your custom class implement the Serializable interface and then you can pass object instances in the intent extra using the putExtra(Serializable..) variant of the Intent#putExtra() method. Pseudocode: Note: Make sure each nested class of your main custom class has implemented Serializable interface to avoid any serialization exceptions. For example:
If the new activity not in the same packet with MainActivity(you call from here?), try declare on manifest and in the caller Hope this helps!