Android Canvas 绘图

画图
http://www.2cto.com/kf/201404/296296.html
http://blog.csdn.net/tianjian4592/article/details/44783283
http://blog.csdn.net/wangfayinn/article/details/8685310
http://www.cnblogs.com/tianzhijiexian/p/4298660.html

 

 

实现一个自定义的进度条

public class ArcProgress extends View {
    private Paint paint;
    private RectF rectF = new RectF();
    private float strokeWidth;
    private int progress = 0;
    private int max;
    private float arcAngle;
    private final float default_stroke_width;
    private final int default_max = 100;
    private final float default_arc_angle = 360;

    public ArcProgress(Context context) {
        this(context, null);
    }

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

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

        default_stroke_width = Utils.dp2px(context, 4);

        TypedArray attributes = context.getTheme().obtainStyledAttributes(
                attrs, R.styleable.ArcProgress, defStyleAttr, 0);
        initByAttributes(attributes);
        attributes.recycle();
    }

    protected void initByAttributes(TypedArray attributes) {
        arcAngle = attributes.getDimension(R.styleable.ArcProgress_arc_angle,
                default_arc_angle);
        setMax(attributes.getInt(R.styleable.ArcProgress_arc_max, default_max));
        setProgress(attributes.getInt(R.styleable.ArcProgress_arc_progress, 0));
        strokeWidth = attributes.getDimension(
                R.styleable.ArcProgress_arc_stroke_width, default_stroke_width);
    }

    @Override
    public void invalidate() {
        super.invalidate();
    }

    public int getProgress() {
        return progress;
    }

    public void setProgress(int progress) {
        this.progress = progress;
        if (this.progress > getMax()) {
            this.progress %= getMax();
        }
        invalidate();
    }



    public int getMax() {
        return max;
    }

    public void setMax(int max) {
        if (max > 0) {
            this.max = max;
            invalidate();
        }
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        float startAngle = 90 - arcAngle / 2f;
        float finishedSweepAngle = progress / (float) getMax() * arcAngle;
        float finishedStartAngle = startAngle;

        int width = getMeasuredWidth();

        rectF.set(strokeWidth / 2f, strokeWidth / 2f,
                getMeasuredWidth() - strokeWidth / 2f,
                getMeasuredWidth() - strokeWidth / 2f);

        paint = new Paint();
        paint.setAntiAlias(true);
        paint.setStrokeWidth(strokeWidth);
        paint.setStyle(Paint.Style.STROKE);
        paint.setStrokeCap(Paint.Cap.ROUND);

        Bitmap bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.uu_loading_bg);
        bitmap = Bitmap.createScaledBitmap(bitmap, width, width, false);
        // 可以使用图片座位画笔 注意图片可以设置为平铺 拉伸这些属性
        paint.setShader(new BitmapShader(bitmap, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP));
        // 可以使用变换属性来实现一些效果
        canvas.scale((float) 0.9, (float) 0.9, width / 2, width / 2);
        // 绘制圆弧 等矩形图形
        canvas.drawArc(rectF, startAngle, arcAngle, false, paint);

        bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.uu_loading);
        bitmap = Bitmap.createScaledBitmap(bitmap, width, width, false);
        paint.setShader(new BitmapShader(bitmap, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP));
        canvas.drawArc(rectF, finishedStartAngle, finishedSweepAngle, false, paint);

        // 可以对位图来进行一些变换 效果然后绘制上去
        Bitmap bitmap_loadingpoint = BitmapFactory.decodeResource(getResources(), R.drawable.uu_loadingpoint);
        Matrix matrix = new Matrix();
        matrix.setTranslate(bitmap_loadingpoint.getHeight() / 2, bitmap_loadingpoint.getHeight() / 2);
        matrix.postRotate(finishedSweepAngle + 45, getWidth() / 2, getWidth() / 2);
        canvas.drawBitmap(bitmap_loadingpoint, matrix, null);
    }
}