An abstract view simplifying the creation of Android widgets by scaling the canvas to the right size (following the device density), translating it following the set padding and by taking into account the view padding in the measurements

AbstractView.java

import android.content.Context;
import android.graphics.Canvas;
import android.util.AttributeSet;
import android.view.View;

public abstract class AbstractView extends View {

    private float mOffsetX;
    private float mOffsetY;

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

    public AbstractView(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public AbstractView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }

    protected float getmOffsetX() {
        return mOffsetX;
    }

    protected float getmOffsetY() {
        return mOffsetY;
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        float screenDensity = getResources().getDisplayMetrics().density;

        int independentWidth = Math.round(screenDensity * calculateDesiredWidth());
        int independentHeight = Math.round(screenDensity * calculateDesiredHeight());

        int desiredWidth = independentWidth + getPaddingLeft() + getPaddingRight();
        int desiredHeight = independentHeight + getPaddingTop() + getPaddingBottom();

        int widthMode = MeasureSpec.getMode(widthMeasureSpec);
        int widthSize = MeasureSpec.getSize(widthMeasureSpec);
        int heightMode = MeasureSpec.getMode(heightMeasureSpec);
        int heightSize = MeasureSpec.getSize(heightMeasureSpec);

        int width;
        int height;

        if (widthMode == MeasureSpec.EXACTLY) {
            width = widthSize;
        } else if (widthMode == MeasureSpec.AT_MOST) {
            width = Math.min(desiredWidth, widthSize);
        } else {
            width = desiredWidth;
        }

        if (heightMode == MeasureSpec.EXACTLY) {
            height = heightSize;
        } else if (heightMode == MeasureSpec.AT_MOST) {
            height = Math.min(desiredHeight, heightSize);
        } else {
            height = desiredHeight;
        }

        mOffsetX = getPaddingLeft() / screenDensity;
        mOffsetY = getPaddingTop() / screenDensity;

        setMeasuredDimension(width, height);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        float screenDensity = getResources().getDisplayMetrics().density;
        canvas.scale(screenDensity, screenDensity);
        canvas.translate(mOffsetX, mOffsetY);
    }

    protected abstract float calculateDesiredWidth();

    protected abstract float calculateDesiredHeight();
}