Building Android UIs with Custom Views

Basic implementation

Our basic implementation will be quite straightforward. Let's start by creating the class and its constructor:

public class Chart extends View {    private Paint linePaint;    public Chart(Context context, AttributeSet attrs) {        super(context, attrs);        linePaint = new Paint();        linePaint.setAntiAlias(true);        linePaint.setColor(0xffffffff);        linePaint.setStrokeWidth(8.f);        linePaint.setStyle(Paint.Style.STROKE);    }}

We've initialized a Paint object on our constructor, but this time we've set the style to Paint.Style.STROKE as we're only interested in drawing lines. Let's now add a method so whoever is using the custom view can set the data to render:

private float[] dataPoints;private float minValue;private float maxValue;private float ...