gistfile1.txt

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.RectF;
import android.util.AttributeSet;
import android.view.View;

import java.util.ArrayList;
import java.util.List;

public class PieChartView extends View {
    public static class Data {
        public final float value;
        public final int colour;

        public Data(float value, int colour) {
            this.value = value;
            this.colour = colour;
        }
    }

    private final List<Data> dataPoints = new ArrayList<>();
    private RectF bounds;
    private Paint paint = new Paint();

    public PieChartView(Context context) {
        this(context, null, 0);
    }

    public PieChartView(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
    }

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

        float strokeWidth = 2.0f;
        if (attrs != null) {
            TypedArray attributes = context.obtainStyledAttributes(attrs, R.styleable.PieChartView);
            strokeWidth = attributes.getFloat(R.styleable.PieChartView_strokeThickness, strokeWidth);
            attributes.recycle();
        }

        paint.setStrokeWidth(strokeWidth);
        paint.setStyle(Paint.Style.STROKE);
        paint.setAntiAlias(true);

        if (isInEditMode()) {
            addData(new Data(10, 0xffff0000));
            addData(new Data(20, 0xff00ff00));
            addData(new Data(30, 0xff0088ff));
        }
    }

    public void addData(Data data) {
        dataPoints.add(data);
        postInvalidate();
    }

    private float determineTotalData() {
        float total = 0;
        for (Data dataPoint : dataPoints) {
            total += dataPoint.value;
        }
        return total;
    }

    @Override
    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
        super.onSizeChanged(w, h, oldw, oldh);
        bounds = new RectF(paint.getStrokeWidth(), paint.getStrokeWidth(), w - paint.getStrokeWidth() * 2, h - paint.getStrokeWidth() * 2);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        float lastStartAngle = -90;
        float totalData = determineTotalData();
        for (Data dataPoint : dataPoints) {
            float sweep = (dataPoint.value / totalData) * 360;
            paint.setColor(dataPoint.colour);
            canvas.drawArc(bounds, lastStartAngle, sweep, false, paint);
            lastStartAngle += sweep;
        }
    }
}

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <declare-styleable name="PieChartView">
        <attr name="strokeThickness" format="float"/>
    </declare-styleable>
</resources>

<.......PieChartView
        android:id="@+id/piechartview"
        app:strokeThickness="6.0"
        android:layout_width="100dp"
        android:layout_height="100dp"/>