android中PathMeasure的简单用法

最新推荐文章于 2024-04-06 10:52:42 发布

mockingbirds

最新推荐文章于 2024-04-06 10:52:42 发布

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分类专栏： android 文章标签： android path

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今天根据PathMeasure实现了一个进度条功能，效果如下：
这里写图片描述

话不多说，直接上代码了，这里要感谢徐医生，参照了代码实现

public class PathMeasureView extends View {

    private Path mPath = null;
    private Path mDest = new Path();
    private Paint mPaint = null;
    private PathMeasure mPathMeasure = new PathMeasure();
    private float mLength = 0f;
    private float mFloatPos = 0f;
    private float mStop = 0f;
    private float mStart = 0f;

    public PathMeasureView(Context context, AttributeSet attrs) {
        super(context, attrs);

        mPath = new Path();
        mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
        mPaint.setColor(Color.parseColor("#f90876"));
        mPaint.setStrokeWidth(5);
        mPaint.setStyle(Paint.Style.STROKE);

        // 创建从0 到1的动画
        ValueAnimator valueAnimator = ValueAnimator.ofFloat(0,1);
        valueAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
            @Override
            public void onAnimationUpdate(ValueAnimator animation) {
                mFloatPos = (float) animation.getAnimatedValue();
                // 不断刷新，重新调用onDraw方法
                invalidate();
            }
        });
        valueAnimator.setRepeatCount(ValueAnimator.INFINITE);
        valueAnimator.setDuration(2000);
        valueAnimator.start();
    }

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

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        //获取到当前view的宽和高
        int width = getWidth();
        int height = getHeight();
        // 绘制的图形为圆形
        mPath.addCircle(width/2,height/2,50, Path.Direction.CW);
        // 将mPath和mPathMeasure关联起来
        mPathMeasure.setPath(mPath,true);
        mLength = mPathMeasure.getLength();

        // 每次重新绘制之前将mDest重置
        mDest.reset();
        mDest.lineTo(0,0);

        mStart = (float) (mFloatPos * mLength - ((0.5 - Math.abs(mFloatPos - 0.5)) * mLength));
        mStop = mFloatPos * mLength;

        // 截取mPath中从mStart起点到mStop终点的片段，到mDest里
        mPathMeasure.getSegment(mStart,mStop,mDest,true);
        // 最终绘制的是截取之后的mDest
        canvas.drawPath(mDest,mPaint);
    }
}