Android仿薄荷健康的刻度尺效果

    /**     * 尺圖     */    public class RulerView extends View {        private Context mContext;        private Paint centerLinePaint;        private Paint grayLinePaint;        private Paint txtPaint;        private int space = 20; // 豎線間空隙        private int startValue = 40; // 起始刻度        private int endValue = 100; // 結(jié)束刻度        private int width;        private int height;        private int currentOffset; // 當(dāng)前操作偏移量        private int totalOffset; // 之前操作偏移量        private float downX;        private float lastMoveX;        private int touchSlop;
        public RulerView(Context context) {            this(context, null);        }
        public RulerView(Context context, @Nullable AttributeSet attrs) {            super(context, attrs);            init(context, attrs);        }
        private void init(Context context, AttributeSet attrs) {            mContext = context;            centerLinePaint = new Paint();            centerLinePaint.setAntiAlias(true);            centerLinePaint.setColor(Color.parseColor("#49BA72"));            centerLinePaint.setStrokeWidth(3);
            grayLinePaint = new Paint();            grayLinePaint.setAntiAlias(true);            grayLinePaint.setColor(Color.parseColor("#66666666"));            grayLinePaint.setStrokeWidth(3);
            txtPaint = new Paint();            txtPaint.setAntiAlias(true);            txtPaint.setColor(Color.parseColor("#333333"));            txtPaint.setTextSize(30);
            touchSlop = ViewConfiguration.get(mContext).getScaledTouchSlop();        }    }

    @Override    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {        super.onMeasure(widthMeasureSpec, heightMeasureSpec);        int widthMode = MeasureSpec.getMode(widthMeasureSpec);        if(widthMode == MeasureSpec.EXACTLY){            width = MeasureSpec.getSize(widthMeasureSpec);        }else{            width = mContext.getResources().getDisplayMetrics().widthPixels;        }        int heightMode = MeasureSpec.getMode(heightMeasureSpec);        if(heightMode == MeasureSpec.EXACTLY){            height = MeasureSpec.getSize(heightMeasureSpec);        }else{            height = (int) (mContext.getResources().getDisplayMetrics().density * 60 + 0.5);        }        setMeasuredDimension(width, height);    }

    @Override    protected void onDraw(Canvas canvas) {        super.onDraw(canvas);        for (int i = startValue * 10; i < endValue * 10 + 1; i++) {            int lineHeight = 60;            if(i % 5 == 0){                if(i % 10 == 0){                    lineHeight = 80;                    int x = (i - startValue * 10) * space + currentOffset + totalOffset;                    if(x > 0 || x < width) {                        canvas.drawText(String.valueOf(i / 10), x, lineHeight + 30, txtPaint);                    }                }            }else{                lineHeight = 30;            }            int startX = (i - startValue * 10) * space + currentOffset + totalOffset;            if(startX > 0 || startX < width) {                canvas.drawLine(startX, 0, startX, lineHeight, grayLinePaint);            }        }        canvas.drawLine(width / 2, 0, width / 2, 120, centerLinePaint);    }

index % 10 == 0

index % 5 == 0

    int startX = (i - startValue * 10) * space + currentOffset + totalOffset;    if(startX > 0 || startX < width) {        canvas.drawLine(startX, 0, startX, lineHeight, grayLinePaint);    }

    int x = (i - startValue * 10) * space + currentOffset + totalOffset;    if(x > 0 || x < width) {        canvas.drawText(String.valueOf(i / 10), x, lineHeight + 30, txtPaint);    }

    @Override    public boolean onTouchEvent(MotionEvent event) {        int action = event.getAction();        switch (action){            case MotionEvent.ACTION_DOWN:                downX = event.getX();                break;            case MotionEvent.ACTION_MOVE:                float moveX = event.getX();                currentOffset = (int) (moveX - downX);                invalidate();                break;            case MotionEvent.ACTION_UP:            case MotionEvent.ACTION_CANCEL:                currentOffset = 0;                totalOffset += event.getX() - downX;                if(totalOffset > width / 2){                    totalOffset = width / 2;                }else if(totalOffset < width / 2 - (endValue - startValue) * space * 10){                    totalOffset = width / 2 - (endValue - startValue) * space * 10;                }                if(totalOffset % space != 0){                    totalOffset -= totalOffset % space;                }                invalidate();                break;        }        return true;    }

currentOffset = 0;