ドローアブルの概要

private lateinit var constraintLayout: ConstraintLayout

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)

    // Instantiate an ImageView and define its properties
    val i = ImageView(this).apply {
        setImageResource(R.drawable.my_image)
        contentDescription = resources.getString(R.string.my_image_desc)

        // set the ImageView bounds to match the Drawable's dimensions
        adjustViewBounds = true
        layoutParams = ViewGroup.LayoutParams(
                ViewGroup.LayoutParams.WRAP_CONTENT,
                ViewGroup.LayoutParams.WRAP_CONTENT)
    }

    // Create a ConstraintLayout in which to add the ImageView
    constraintLayout = ConstraintLayout(this).apply {

        // Add the ImageView to the layout.
        addView(i)
    }

    // Set the layout as the content view.
    setContentView(constraintLayout)
}

ConstraintLayout constraintLayout;

protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);

  // Create a ConstraintLayout in which to add the ImageView
  constraintLayout = new ConstraintLayout(this);

  // Instantiate an ImageView and define its properties
  ImageView i = new ImageView(this);
  i.setImageResource(R.drawable.my_image);
  i.setContentDescription(getResources().getString(R.string.my_image_desc));

  // set the ImageView bounds to match the Drawable's dimensions
  i.setAdjustViewBounds(true);
  i.setLayoutParams(new ViewGroup.LayoutParams(
          ViewGroup.LayoutParams.WRAP_CONTENT,
          ViewGroup.LayoutParams.WRAP_CONTENT));

  // Add the ImageView to the layout and set the layout as the content view.
  constraintLayout.addView(i);
  setContentView(constraintLayout);
}

val myImage: Drawable = ResourcesCompat.getDrawable(context.resources, R.drawable.my_image, null)

Resources res = context.getResources();
Drawable myImage = ResourcesCompat.getDrawable(res, R.drawable.my_image, null);

val transition= ResourcesCompat.getDrawable(
        context.resources,
        R.drawable.expand_collapse,
        null
) as TransitionDrawable

val image: ImageView = findViewById(R.id.toggle_image)
image.setImageDrawable(transition)

// Description of the initial state that the drawable represents.
image.contentDescription = resources.getString(R.string.collapsed)

// Then you can call the TransitionDrawable object's methods.
transition.startTransition(1000)

// After the transition is complete, change the image's content description
// to reflect the new state.

Resources res = context.getResources();
TransitionDrawable transition =
    (TransitionDrawable) ResourcesCompat.getDrawable(res, R.drawable.expand_collapse, null);

ImageView image = (ImageView) findViewById(R.id.toggle_image);
image.setImageDrawable(transition);

// Description of the initial state that the drawable represents.
image.setContentDescription(getResources().getString(R.string.collapsed));

// Then you can call the TransitionDrawable object's methods.
transition.startTransition(1000);

// After the transition is complete, change the image's content description
// to reflect the new state.

class CustomDrawableView(context: Context) : View(context) {
    private val drawable: ShapeDrawable = run {
        val x = 10
        val y = 10
        val width = 300
        val height = 50
        contentDescription = context.resources.getString(R.string.my_view_desc)

        ShapeDrawable(OvalShape()).apply {
            // If the color isn't set, the shape uses black as the default.
            paint.color = 0xff74AC23.toInt()
            // If the bounds aren't set, the shape can't be drawn.
            setBounds(x, y, x + width, y + height)
        }
    }

    override fun onDraw(canvas: Canvas) {
        drawable.draw(canvas)
    }
}

public class CustomDrawableView extends View {
  private ShapeDrawable drawable;

  public CustomDrawableView(Context context) {
    super(context);

    int x = 10;
    int y = 10;
    int width = 300;
    int height = 50;
    setContentDescription(context.getResources().getString(
            R.string.my_view_desc));

    drawable = new ShapeDrawable(new OvalShape());
    // If the color isn't set, the shape uses black as the default.
    drawable.getPaint().setColor(0xff74AC23);
    // If the bounds aren't set, the shape can't be drawn.
    drawable.setBounds(x, y, x + width, y + height);
  }

  protected void onDraw(Canvas canvas) {
    drawable.draw(canvas);
  }
}

private lateinit var customDrawableView: CustomDrawableView

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    customDrawableView = CustomDrawableView(this)

    setContentView(customDrawableView)
}

CustomDrawableView customDrawableView;

protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  customDrawableView = new CustomDrawableView(this);

  setContentView(customDrawableView);
}

class MyDrawable : Drawable() {
    private val redPaint: Paint = Paint().apply { setARGB(255, 255, 0, 0) }

    override fun draw(canvas: Canvas) {
        // Get the drawable's bounds
        val width: Int = bounds.width()
        val height: Int = bounds.height()
        val radius: Float = Math.min(width, height).toFloat() / 2f

        // Draw a red circle in the center
        canvas.drawCircle((width / 2).toFloat(), (height / 2).toFloat(), radius, redPaint)
    }

    override fun setAlpha(alpha: Int) {
        // This method is required
    }

    override fun setColorFilter(colorFilter: ColorFilter?) {
        // This method is required
    }

    override fun getOpacity(): Int =
        // Must be PixelFormat.UNKNOWN, TRANSLUCENT, TRANSPARENT, or OPAQUE
        PixelFormat.OPAQUE
}

public class MyDrawable extends Drawable {
    private final Paint redPaint;

    public MyDrawable() {
        // Set up color and text size
        redPaint = new Paint();
        redPaint.setARGB(255, 255, 0, 0);
    }

    @Override
    public void draw(Canvas canvas) {
        // Get the drawable's bounds
        int width = getBounds().width();
        int height = getBounds().height();
        float radius = Math.min(width, height) / 2;

        // Draw a red circle in the center
        canvas.drawCircle(width/2, height/2, radius, redPaint);
    }

    @Override
    public void setAlpha(int alpha) {
        // This method is required
    }

    @Override
    public void setColorFilter(ColorFilter colorFilter) {
        // This method is required
    }

    @Override
    public int getOpacity() {
        // Must be PixelFormat.UNKNOWN, TRANSLUCENT, TRANSPARENT, or OPAQUE
        return PixelFormat.OPAQUE;
    }
}

val myDrawing = MyDrawable()
val image: ImageView = findViewById(R.id.imageView)
image.setImageDrawable(myDrawing)
image.contentDescription = resources.getString(R.string.my_image_desc)

MyDrawable mydrawing = new MyDrawable();
ImageView image = findViewById(R.id.imageView);
image.setImageDrawable(mydrawing);
image.setContentDescription(getResources().getString(R.string.my_image_desc));