Can't extend main class with anything but Activity - android

Hi
I am trying to extend my main entry point with a superclass (so I don't have to override onCreateOptionsMenu in each activity i got for example) but for some reason it seems I am not allowed to do this with the class I got set as my main entry point for my application in android.
For example: MainClass extends Activity works fine but MainClass extends mySuperClass where mySuperClass extends Activity does not work - anyone got any idea if I am doing something wrong or if this is an android specific issue?
Thanks for any help or input!


All Android Activity classes MUST extend an Activity base class. Your superclass definition must be missing something: post the class definition.

Related

what does getConfirmationTts() in voice interaction do

the clip of the code written for using voice interaction which is used in another Java file I have already tried importing android.app.VoiceInteractor but its not working

You may have imported all necessary classes in your code. As your snippet you forgot to extend that, But you are already extending AppCompatActivity so that you can't extend another class in the same Activity. What you need to do is create another class inside MyVoiceActivity and extend VoiceInteractor.ConfirmationRequest in that class.
Your Activity will look something like this
public class MyVoiceActivity extends AppCompatActivity{
class Confirm extends VoiceInteractor.ConfirmationRequest {
//All method you wanted goes here
}
}

Android Class Diagram UML

I'm trying to create a class diagram for an android project.
I want my classes represent the activities, services and interfaces that I will implement.
There are several questions about it on the web, but I couldn't find a definitive answer.
I know that there aren't specific rules for Android and UML, but I have some doubts.
How can I represent the relationship between an Activity and a AsyncTask ?
How can I indicate that an Activity has an intent to another Activity ?
Maybe if someone has an example, will really help.

Maybe something like this?
MyBackgroundTask IS A AsyncTask
MyActivity IS A Activity
MyActivity HAS ONE MyBackgroundTask
You can use a dependency to show that there is an relationship between the AnActivity class and the AnotherActivity class:
In this case, it means that the AnActivity class requires the AnotherActivity class for its specification or implementation. Also, use notes to make it clear.
Update:
Another example:
MainActivity IS A FragmentActivity
MainActivity HAS SOME fragments. The fragments are of type String.

Android: Want to call main activity's class function in service class

Here I have a main class that extends activity and having a function say abc(). Now I want to call it in my services class. But I am unable to do that plz some one help as I found error : "Source not found"..

Maybe some of the related Topics/Questions have already solved your problem, e.g.
In Android: How to Call Function of Activity from a Service?
Call a Method in the main activity from a custom view
How to call An activity class from a service class

How to use multilevel inheritance in android

I am making an app in which i have to run an activity in background until the app is running.each activity related to this app is using first activity.how can it possible?
can i use the inheritance for this?
can anyone tell me any example of multilevel interitance in android?

You can create a BaseActivity class that extends Activity and all other Activities will extend this BaseActivity. Then what ever happened in all other activities (like resume and pause) will also effect the actions of BaseActivity.
If you have to accomplish background task you better to see android service

You are already extending the Activity class in a base class, and again you are extending this base class in other class. This is itself an example of multilevel inheritance. I am posting an example that may be relevant for your question:
public class basecls extends Activity{
/*The base class*/
}
public class secondcls extends basecls{
/* basecls extended by secondcls */
}
You can extend the secondcls in another class, and the new class will inherit all super classes such that you can use the methods of its super classes.

Your main activity is already using inheritance, since it extends the Activity class.

Android - abstract class that extends activity or TabActivity

I have created an abstract class which extends the Activity Class.
I want to extend it in an activity which extends TabActivity Class, how can I achieve that?
Get the TabActivity and abstract class Functionality at the same time.
I do realize that multiple inheritance is not possible in Java, but can I avoid extending TabActivity Class and still use getTabHost()?
10x :)

I don't think you can achieve this with this design. If your abstract class extending SomeOtherActivityClass and new Class need to extended SomeotherActivityClass (through inheritence) and TabActivityClass, that may confuse dalvik to choose which activity at runtime and it doesn't make sense. You may need to reconsider your design.

yes sure, you can use. By using following snippet:
TabHost host=(TabHost)findViewById(id of tabhost);

It's better way to create another class that extends Application class. Or use singleton pattern and create class with all functionality that you're need.

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