Cannot create a default constructor from a class that extends Dialog

Question

I have a class that extends Dialog. When I tried to generate my app, I got a message

Error: This class should provide a default constructor (a public constructor with no arguments)

I have tried public myclass(){}, but it doesn't work. How can I define a default constructor?

Take a look at the API docs, https://developer.android.com/reference/android/app/Dialog.html If you look at direct subclasses, such as AlertDialog, you can see the constructors those subclasses are Implementing. Maybe you are not implementing all the needed constructors? — Dage, Sep 12 '16 at 12:20
@ELITE if i do as you said i have to make this `public myclass(Context context){super(context);}` and i want to make a default constructor — abdelrhman, Sep 12 '16 at 12:27
Did you write your own constructor with parameters? You may have overridden the default constructor. If so you need to add a constructor without parameters. — DerpyNerd, Sep 12 '16 at 13:49

ELITE · Accepted Answer · 2016-09-12T13:10:01.227

2

FIRST WAY

private static Context context;

public static void setContext(Context context_) {
    context = context_;
}

public myclass() {
    super(context);
}

Note : Don't forget to call setContext method before going to call Constructor of this class.

SECOND WAY

1) Create Application class in your project

public class MyApplication extends Application {

    private static Context mContext;

    @Override
    public void onCreate() {
        super.onCreate();
        mContext = getApplicationContext();
    }

    public static Context getContext() {
        return mContext;
    }
}

2) Declare this Application in Manifest like below

<application
    android:name=".MyApplication"
    android:icon="@drawable/icon"
    android:label="@string/app_name" >

3) And class super method in your class like

public myclass() {
    super(MyApplication.getContext());
}

Hope it'll help.

edited Sep 12 '16 at 13:10

answered Sep 12 '16 at 12:24

ELITE

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can't resolve symbol 'context' and i tried to declare it it said cannot reference it before supertype constructor has been called – abdelrhman Sep 12 '16 at 12:35
change the constructor then...like `public myclass(Context context) {`, this will resolve the problem. – ELITE Sep 12 '16 at 12:45
You have to create an Object of this class by passing `Context` to the constructor. – ELITE Sep 12 '16 at 12:45
that will lead us to the begining that i need a default constructor that has no argument – abdelrhman Sep 12 '16 at 12:47
1

ohh, sorry i forgot the main aim...you can achieve that using static `Context` object – ELITE Sep 12 '16 at 12:54
Thank you very much – abdelrhman Sep 12 '16 at 13:00
You can achieve this in better way [here is how](http://stackoverflow.com/questions/21818905/get-application-context-from-non-activity-singleton-class) – ELITE Sep 12 '16 at 13:04
1

honestly I would really avoid keeping static reference to Context – Blackbelt Sep 12 '16 at 13:16

Priyank Patel · Answer 2 · 2016-09-12T12:30:26.510

-1

Try with adding default constructor like below...

public myclass(Context context){ 
  super(context);
}

edited Sep 12 '16 at 12:30

answered Sep 12 '16 at 12:21

Priyank Patel

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you can't have that constructor. – Blackbelt Sep 12 '16 at 12:26
it works but if i do that doesn't that cause any problem during the program running – abdelrhman Sep 12 '16 at 12:32

Cannot create a default constructor from a class that extends Dialog

2 Answers2

FIRST WAY

SECOND WAY