Set as wallpaper programmatically in android

public class MainActivity extends AppCompatActivity

{

int hasPermissionSetAsWallpaper; // for set wallpaper permission.

    final private int REQUEST_CODE_ASK_PERMISSIONS_SETASWALLPAPER = 201;  // for external storage permission

@Override

    protected void onCreate(Bundle savedInstanceState) {

........

if (Build.VERSION.SDK_INT >= 23)

        {

            hasPermissionReadExtSt = ContextCompat.checkSelfPermission(MainActivity.this, Manifest.permission.READ_EXTERNAL_STORAGE);

            // READ_EXTERNAL_STORAGE izni var mı diye bak, yoksa gir.

            if (hasPermissionReadExtSt != PackageManager.PERMISSION_GRANTED)

            {

                // shouldShowRequestPermissionRationale() method'u kullanıcı never ask'ı seçm,ş mi diye bakar.

                if (shouldShowRequestPermissionRationale(Manifest.permission.READ_EXTERNAL_STORAGE)) {

                    // getErrorDialog() method'u kullanıcıdan tekrar izin vermesini ister.

                    getErrorDialog("You need to allow Read External Storage permission." +

                            "\nIf you disable this permission, You will not able to add attachment.", MainActivity.this, false).show();

                }

                else {

                    requestPermissions(new String[]{Manifest.permission.READ_EXTERNAL_STORAGE}, REQUEST_CODE_ASK_PERMISSIONS_EXTERNAL_STORAGE);

                }

            }

            hasPermissionSetAsWallpaper = ContextCompat.checkSelfPermission(MainActivity.this, Manifest.permission.SET_WALLPAPER);

            // SET_WALLPAPER izni var mı diye bak, yoksa gir.

            if (hasPermissionSetAsWallpaper != PackageManager.PERMISSION_GRANTED)

            {

                // shouldShowRequestPermissionRationale() method'u kullanıcı never ask'ı seçmiş mi diye bakar.

                if (shouldShowRequestPermissionRationale(Manifest.permission.SET_WALLPAPER)) {

                    // getErrorDialog() method'u kullanıcıdan tekrar izin vermesini ister.

                    getErrorDialog("You need to allow permission to be able to set an image as wallpaper" +

                            "\nIf you disable this permission, You cannot your drawings as wallpaper", MainActivity.this,).show();

                }

                else {

                    requestPermissions(new String[]{Manifest.permission.SET_WALLPAPER}, REQUEST_CODE_ASK_PERMISSIONS_SETASWALLPAPER);

                }

            }

        }

...........

}

public AlertDialog.Builder getErrorDialog(String message, Context context, final boolean isFromsetwallpaper) {

        

            final AlertDialog.Builder alertDialog = new AlertDialog.Builder(context);

            alertDialog.setTitle(getString(R.string.app_name)).setMessage(message);

            alertDialog.setPositiveButton("Ok", new DialogInterface.OnClickListener() {

                @Override

                public void onClick(DialogInterface dialog, int which)

                {

                    dialog.dismiss();

                    if (Build.VERSION.SDK_INT >= 23) {

                        requestPermissions(new String[]{Manifest.permission.SET_WALLPAPER},

                                REQUEST_CODE_ASK_PERMISSIONS_SETASWALLPAPER);

                    }

                }

            });

            return alertDialog;

        

    }

   public void setAsWallpaper(Context mContext, String imageName, int version){

    WallpaperManager myWallpaperManager = WallpaperManager.getInstance(mContext);
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N && !myWallpaperManager.isSetWallpaperAllowed()) // api>24 ise ve izin yoksa    {
        myDialog.dismiss();
        final AlertDialog.Builder alertDialog = new AlertDialog.Builder(mContext);
        alertDialog.setTitle("HATA!").setMessage("Wallpaper degistirme iznini vermediginiz icin bu ozelligi kullanamiyorsunuz.");
        alertDialog.setPositiveButton("Ok", new DialogInterface.OnClickListener() {
            @Override            public void onClick(DialogInterface dialog, int which)
            {
                //do nothing.            }
        });
        return;
    }

    try {
        DrawingView.drawSavedThings(mContext,imageName,version);
        File fileImage = new File(Environment.getExternalStoragePublicDirectory(DIRECTORY_PICTURES).toString() + File.separator + "MandalaApp"   + File.separator + imageName + ".jpeg");
        BitmapFactory.Options bmOptions = new BitmapFactory.Options();
        Bitmap bitmapAsWallpaper = BitmapFactory.decodeFile(fileImage.getAbsolutePath(),bmOptions);
        int[] arr = MainActivity.getDeviceDimens((AppCompatActivity) mContext);
        bitmapAsWallpaper = Bitmap.createScaledBitmap(bitmapAsWallpaper,arr[0],arr[1],true);

        myWallpaperManager.setBitmap(bitmapAsWallpaper);
        bitmapAsWallpaper.recycle();

    } catch (IOException e)
    {
        e.printStackTrace();
    }
}

}

also add permission to manifestx.ml for older android versions:

<uses-permission android:name="android.permission.SET_WALLPAPER"/>

Abstract Factory Pattern nedir, nasıl kullanılır, örnek

https://www.tutorialspoint.com/design_pattern/abstract_factory_pattern.htm
Abstract Factory pattern aslında factory'lerin factory'sidir. Hatırlayalım, Factory pattern'da bir factory shape'leri üretiyordu. Abstract Factory pattern'da ise shape'leri, color'ları üreten factory'leri üreten bir factory vardır.

- Aşağıda Shape ve Color diye 2 tane interface tanımlayacağız.
- Sonra bu interface'leri implement eden concrete class'lar tanımlayacağız (Circle, Rectangle, Square, - Red, Blue, Green class'larını tanımlayacağız).
- Sonra AbstractFactory isimli bir abstract class tanımlayacağız.
- Sonra AbstractFactory isimli abstract class'ı implement eden ShapeFactory ve ColorFactory isimli concrete class'ları tanımlayacağız. Bu class'lar, yukarıdaki Circle, Rectangle, Square, - Red, Blue, Green concrete class'larından birini return eder.
- FactoryProducer class'ını tanımlarız. Bu class, uygun factory class'ını return eder : ShapeFactory veya ColorFactory.
- AbstractFactoryPatternDemo class'ını implement ederiz. Bu class'da FactoryProducer class'ının static method'u olan getFactory() method'unu çağırarak bir factory elde ederiz. Sonra bu factory'nin getShape() method'Unu çağırarak bir shape object elde ederiz:

      //get shape factory
      AbstractFactory shapeFactory = FactoryProducer.getFactory("SHAPE");

      //get an object of Shape Circle
      Shape shape1 = shapeFactory.getShape("CIRCLE");

      //call draw method of Shape Circle
      shape1.draw();

Aşağıdaki uml'de görülen kodu yazacağız birazdan. Bu kodda abstract factory pattern design'ı kullanılmıştır.

Step 1

Create an interface for Shapes.

Shape.java

public interface Shape {
   void draw();
}

Step 2

Create concrete classes implementing the same interface.

Rectangle.java

public class Rectangle implements Shape {

   @Override
   public void draw() {
      System.out.println("Inside Rectangle::draw() method.");
   }
}

Square.java

public class Square implements Shape {

   @Override
   public void draw() {
      System.out.println("Inside Square::draw() method.");
   }
}

Circle.java

public class Circle implements Shape {

   @Override
   public void draw() {
      System.out.println("Inside Circle::draw() method.");
   }
}

Step 3

Create an interface for Colors.

Color.java

public interface Color {
   void fill();
}

Step4

Create concrete classes implementing the same interface.

Red.java

public class Red implements Color {

   @Override
   public void fill() {
      System.out.println("Inside Red::fill() method.");
   }
}

Green.java

public class Green implements Color {

   @Override
   public void fill() {
      System.out.println("Inside Green::fill() method.");
   }
}

Blue.java

public class Blue implements Color {

   @Override
   public void fill() {
      System.out.println("Inside Blue::fill() method.");
   }
}

Step 5

Create an Abstract class to get factories for Color and Shape Objects.

AbstractFactory.java

public abstract class AbstractFactory {
   abstract Color getColor(String color);
   abstract Shape getShape(String shape) ;
}

Step 6

Create Factory classes extending AbstractFactory to generate object of concrete class based on given information.

ShapeFactory.java

public class ShapeFactory extends AbstractFactory {
 
   @Override
   public Shape getShape(String shapeType){
   
      if(shapeType == null){
         return null;
      }  
      
      if(shapeType.equalsIgnoreCase("CIRCLE")){
         return new Circle();
         
      }else if(shapeType.equalsIgnoreCase("RECTANGLE")){
         return new Rectangle();
         
      }else if(shapeType.equalsIgnoreCase("SQUARE")){
         return new Square();
      }
      
      return null;
   }
   
   @Override
   Color getColor(String color) {
      return null;
   }
}

ColorFactory.java

public class ColorFactory extends AbstractFactory {
 
   @Override
   public Shape getShape(String shapeType){
      return null;
   }
   
   @Override
   Color getColor(String color) {
   
      if(color == null){
         return null;
      }  
      
      if(color.equalsIgnoreCase("RED")){
         return new Red();
         
      }else if(color.equalsIgnoreCase("GREEN")){
         return new Green();
         
      }else if(color.equalsIgnoreCase("BLUE")){
         return new Blue();
      }
      
      return null;
   }
}

Step 7

Create a Factory generator/producer class to get factories by passing an information such as Shape or Color

FactoryProducer.java

public class FactoryProducer {
   public static AbstractFactory getFactory(String choice){
   
      if(choice.equalsIgnoreCase("SHAPE")){
         return new ShapeFactory();
         
      }else if(choice.equalsIgnoreCase("COLOR")){
         return new ColorFactory();
      }
      
      return null;
   }
}

Step 8

Use the FactoryProducer to get AbstractFactory in order to get factories of concrete classes by passing an information such as type.

AbstractFactoryPatternDemo.java

public class AbstractFactoryPatternDemo {
   public static void main(String[] args) {

      //get shape factory
      AbstractFactory shapeFactory = FactoryProducer.getFactory("SHAPE");

      //get an object of Shape Circle
      Shape shape1 = shapeFactory.getShape("CIRCLE");

      //call draw method of Shape Circle
      shape1.draw();

      //get an object of Shape Rectangle
      Shape shape2 = shapeFactory.getShape("RECTANGLE");

      //call draw method of Shape Rectangle
      shape2.draw();
      
      //get an object of Shape Square 
      Shape shape3 = shapeFactory.getShape("SQUARE");

      //call draw method of Shape Square
      shape3.draw();

      //get color factory
      AbstractFactory colorFactory = FactoryProducer.getFactory("COLOR");

      //get an object of Color Red
      Color color1 = colorFactory.getColor("RED");

      //call fill method of Red
      color1.fill();

      //get an object of Color Green
      Color color2 = colorFactory.getColor("Green");

      //call fill method of Green
      color2.fill();

      //get an object of Color Blue
      Color color3 = colorFactory.getColor("BLUE");

      //call fill method of Color Blue
      color3.fill();
   }
}

Step 9

Verify the output.

Inside Circle::draw() method.
Inside Rectangle::draw() method.
Inside Square::draw() method.
Inside Red::fill() method.
Inside Green::fill() method.
Inside Blue::fill() method.

Factory Pattern nedir, nasıl kullanılır, örnek

https://www.tutorialspoint.com/design_pattern/factory_pattern.htm
Örnek :
- Shape isimli bir interface yaratılır.
- Bu interface'i implement eden Rectangle, Circle ve Square isimli 3 tane concrete class yaratalım.
- ShapeFactory isimli bir class tanımlanır. Bu class'da getInstance isimli bir method tanımlanır. Bu method aldığı argument'e göre 3 farklı concrete class'dan birini return edebilir.
- main() method'unu içeren FactoryPatternDemo isimli bir class tanımlanır. main() method'unda, ShapeFactory class'ından bir object yaratılır, bu object kullanılarak yukarıdaki 3 concrete class'ın object'lerden biri elde edilebilir.

Step 1

Create an interface.

Shape.java

public interface Shape {
   void draw();
}

Step 2

Create concrete classes implementing the same interface.

Rectangle.java

public class Rectangle implements Shape {

   @Override
   public void draw() {
      System.out.println("Inside Rectangle::draw() method.");
   }
}

Square.java

public class Square implements Shape {

   @Override
   public void draw() {
      System.out.println("Inside Square::draw() method.");
   }
}

Circle.java

public class Circle implements Shape {

   @Override
   public void draw() {
      System.out.println("Inside Circle::draw() method.");
   }
}

Step 3

Create a Factory to generate object of concrete class based on given information.

ShapeFactory.java

public class ShapeFactory {
 
   //use getShape method to get object of type shape 
   public Shape getShape(String shapeType){
      if(shapeType == null){
         return null;
      }  
      if(shapeType.equalsIgnoreCase("CIRCLE")){
         return new Circle();
         
      } else if(shapeType.equalsIgnoreCase("RECTANGLE")){
         return new Rectangle();
         
      } else if(shapeType.equalsIgnoreCase("SQUARE")){
         return new Square();
      }
      
      return null;
   }
}

Step 4

Use the Factory to get object of concrete class by passing an information such as type.

FactoryPatternDemo.java

public class FactoryPatternDemo {

   public static void main(String[] args) {
      ShapeFactory shapeFactory = new ShapeFactory();

      //get an object of Circle and call its draw method.
      Shape shape1 = shapeFactory.getShape("CIRCLE");

      //call draw method of Circle
      shape1.draw();

      //get an object of Rectangle and call its draw method.
      Shape shape2 = shapeFactory.getShape("RECTANGLE");

      //call draw method of Rectangle
      shape2.draw();

      //get an object of Square and call its draw method.
      Shape shape3 = shapeFactory.getShape("SQUARE");

      //call draw method of circle
      shape3.draw();
   }
}

Step 5

Verify the output.

Inside Circle::draw() method.
Inside Rectangle::draw() method.
Inside Square::draw() method.

Neden Factory Pattern kullanalım? Bu pattern'a hangi durumlarda ihtiyaç duyarız ?

Factory pattern'ını kullanarak, bir class'ın implementation'ını bu class'ın client'larından gizlemiş oluruz. Yukarıdaki örneği düşünürsek   Shape, Rectangle, Circle, Square, ShapeFactory class'larını ben yazdım diyelim. Bu class'ları kullanacak olan iş arkadaşım Ahmet ise main() method'unu içeren  FactoryPatternDemo() class'ını geliştirecek. Ahmet benim class'larımı nasıl implement ettiğimi ben ona kodları vermediğim müddetçe göremeyecektir, zaten görmesine de gerek yoktur, Ahmet sadece bilmesi gerekenleri class'ımın draw() isimli bir method içerdiğini ne işe yaradığını bilecektir, draw() method'Unun implementation'ını bilmeyecektir. Ahmet'İn tek yapması geren aşağıdaki gibi bir object yaratmak ve bu object'in method'unu çağırmak olacaktır.

      Shape shape1 = shapeFactory.getShape("CIRCLE");

      //call draw method of Circle
      shape1.draw();

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Şu linkten alıntıdır : https://softwareengineering.stackexchange.com/questions/253254/why-should-i-use-a-factory-class-instead-of-direct-object-construction

Factory classes are often implemented because they allow the project to follow the SOLID principles more closely. In particular, the interface segregation and dependency inversion principles.

Factories and interfaces allow for a lot more long term flexibility. It allows for a more decoupled - and therefore more testable - design.

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