在圆形滑块iOS中，不允许从1％滑动到100％，反之亦然

时间：2014-12-25 17:05:09

标签： ios objective-c xcode uislider

我使用这个类来创建一个圆形滑块，但我有一个问题，如何在用户从1％滑动到100％时不允许，反之亦然？请帮我解决这个问题。提前谢谢。

这是代码：

@interface SLCircularSlider()

@property (nonatomic) CGPoint thumbCenterPoint;

#pragma mark - Init and Setup methods
- (void)setup;

#pragma mark - Thumb management methods
- (BOOL)isPointInThumb:(CGPoint)point;

#pragma mark - Drawing methods
- (CGFloat)sliderRadius;
- (void)drawThumbAtPoint:(CGPoint)sliderButtonCenterPoint inContext:(CGContextRef)context;
- (CGPoint)drawCircularTrack:(float)track atPoint:(CGPoint)point withRadius:(CGFloat)radius inContext:(CGContextRef)context;
- (CGPoint)drawPieTrack:(float)track atPoint:(CGPoint)point withRadius:(CGFloat)radius inContext:(CGContextRef)context;

@end

#pragma mark -
@implementation SLCircularSlider

@synthesize value = _value;
- (void)setValue:(float)value {
    if (value != _value) {
        if (value > self.maximumValue) { value = self.maximumValue; }
        if (value < self.minimumValue) { value = self.minimumValue; }
        _value = value;
        [self setNeedsDisplay];
        if (self.isContinuous) {
            [self sendActionsForControlEvents:UIControlEventValueChanged];
        }
    }
}
@synthesize minimumValue = _minimumValue;
- (void)setMinimumValue:(float)minimumValue {
    if (minimumValue != _minimumValue) {
        _minimumValue = minimumValue;
        if (self.maximumValue < self.minimumValue)  { self.maximumValue = self.minimumValue; }
        if (self.value < self.minimumValue)         { self.value = self.minimumValue; }
    }
}
@synthesize maximumValue = _maximumValue;
- (void)setMaximumValue:(float)maximumValue {
    if (maximumValue != _maximumValue) {
        _maximumValue = maximumValue;
        if (self.minimumValue > self.maximumValue)  { self.minimumValue = self.maximumValue; }
        if (self.value > self.maximumValue)         { self.value = self.maximumValue; }
    }
}

@synthesize minimumTrackTintColor = _minimumTrackTintColor;
- (void)setMinimumTrackTintColor:(UIColor *)minimumTrackTintColor {
    if (![minimumTrackTintColor isEqual:_minimumTrackTintColor]) {
        _minimumTrackTintColor = minimumTrackTintColor;
        [self setNeedsDisplay];
    }
}

@synthesize maximumTrackTintColor = _maximumTrackTintColor;
- (void)setMaximumTrackTintColor:(UIColor *)maximumTrackTintColor {
    if (![maximumTrackTintColor isEqual:_maximumTrackTintColor]) {
        _maximumTrackTintColor = maximumTrackTintColor;
        [self setNeedsDisplay];
    }
}

@synthesize thumbTintColor = _thumbTintColor;
- (void)setThumbTintColor:(UIColor *)thumbTintColor {
    if (![thumbTintColor isEqual:_thumbTintColor]) {
        _thumbTintColor = thumbTintColor;
        [self setNeedsDisplay];
    }
}

@synthesize continuous = _continuous;

@synthesize sliderStyle = _sliderStyle;
- (void)setSliderStyle:(UICircularSliderStyle)sliderStyle {
    if (sliderStyle != _sliderStyle) {
        _sliderStyle = sliderStyle;
        [self setNeedsDisplay];
    }
}

@synthesize thumbCenterPoint = _thumbCenterPoint;

/** @name Init and Setup methods */
#pragma mark - Init and Setup methods
- (id)initWithFrame:(CGRect)frame {
    self = [super initWithFrame:frame];
    if (self) {
        [self setup];
    } 
    return self;
}
- (void)awakeFromNib {
    [self setup];
}

- (void)setup {
    self.value = 0.0;
    self.minimumValue = 0.0;
    self.maximumValue = 1.0;
    /*self.minimumTrackTintColor = [UIColor blueColor];
    self.maximumTrackTintColor = [UIColor whiteColor];
    self.thumbTintColor = [UIColor darkGrayColor];*/

    self.minimumTrackTintColor = [UIColor clearColor];
    self.maximumTrackTintColor = [UIColor clearColor];
    self.thumbTintColor = [UIColor clearColor];

    self.continuous = YES;
    self.thumbCenterPoint = CGPointZero;

    /**
     * This tapGesture isn't used yet but will allow to jump to a specific location in the circle
     */
    UITapGestureRecognizer *tapGestureRecognizer = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(tapGestureHappened:)];
    [self addGestureRecognizer:tapGestureRecognizer];

    UIPanGestureRecognizer *panGestureRecognizer = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(panGestureHappened:)];
    panGestureRecognizer.maximumNumberOfTouches = panGestureRecognizer.minimumNumberOfTouches;
    [self addGestureRecognizer:panGestureRecognizer];
}

/** @name Drawing methods */
#pragma mark - Drawing methods
#define kLineWidth 5.0
#define kThumbRadius 12.0
- (CGFloat)sliderRadius {
    CGFloat radius = MIN(self.bounds.size.width/2, self.bounds.size.height/2);
    radius -= MAX(kLineWidth, kThumbRadius);    
    return radius;
}
- (void)drawThumbAtPoint:(CGPoint)sliderButtonCenterPoint inContext:(CGContextRef)context {
    UIGraphicsPushContext(context);
    CGContextBeginPath(context);

    CGContextMoveToPoint(context, sliderButtonCenterPoint.x, sliderButtonCenterPoint.y);
    CGContextAddArc(context, sliderButtonCenterPoint.x, sliderButtonCenterPoint.y, kThumbRadius, 0.0, 2*M_PI, NO);

    CGContextFillPath(context);
    UIGraphicsPopContext();
}

- (CGPoint)drawCircularTrack:(float)track atPoint:(CGPoint)center withRadius:(CGFloat)radius inContext:(CGContextRef)context {
    UIGraphicsPushContext(context);
    CGContextBeginPath(context);

    float angleFromTrack = translateValueFromSourceIntervalToDestinationInterval(track, self.minimumValue, self.maximumValue, 0, 2*M_PI);

    CGFloat startAngle = -M_PI_2;
    CGFloat endAngle = startAngle + angleFromTrack;
    CGContextAddArc(context, center.x, center.y, radius, startAngle, endAngle, NO);

    CGPoint arcEndPoint = CGContextGetPathCurrentPoint(context);

    CGContextStrokePath(context);
    UIGraphicsPopContext();

    return arcEndPoint;
}

- (CGPoint)drawPieTrack:(float)track atPoint:(CGPoint)center withRadius:(CGFloat)radius inContext:(CGContextRef)context {
    UIGraphicsPushContext(context);

    float angleFromTrack = translateValueFromSourceIntervalToDestinationInterval(track, self.minimumValue, self.maximumValue, 0, 2*M_PI);

    CGFloat startAngle = -M_PI_2;
    CGFloat endAngle = startAngle + angleFromTrack;
    CGContextMoveToPoint(context, center.x, center.y);
    CGContextAddArc(context, center.x, center.y, radius, startAngle, endAngle, NO);

    CGPoint arcEndPoint = CGContextGetPathCurrentPoint(context);

    CGContextClosePath(context);
    CGContextFillPath(context);
    UIGraphicsPopContext();

    return arcEndPoint;
}

- (void)drawRect:(CGRect)rect {
    CGContextRef context = UIGraphicsGetCurrentContext();

    CGPoint middlePoint;
    middlePoint.x = self.bounds.origin.x + self.bounds.size.width/2;
    middlePoint.y = self.bounds.origin.y + self.bounds.size.height/2;

    CGContextSetLineWidth(context, kLineWidth);

    CGFloat radius = [self sliderRadius];
    switch (self.sliderStyle) {
        case UICircularSliderStylePie:
            [self.maximumTrackTintColor setFill];
            [self drawPieTrack:self.maximumValue atPoint:middlePoint withRadius:radius inContext:context];
            [self.minimumTrackTintColor setStroke];
            [self drawCircularTrack:self.maximumValue atPoint:middlePoint withRadius:radius inContext:context];
            [self.minimumTrackTintColor setFill];
            self.thumbCenterPoint = [self drawPieTrack:self.value atPoint:middlePoint withRadius:radius inContext:context];
            break;
        case UICircularSliderStyleCircle:
        default:
            [self.maximumTrackTintColor setStroke];
            [self drawCircularTrack:self.maximumValue atPoint:middlePoint withRadius:radius inContext:context];
            [self.minimumTrackTintColor setStroke];
            self.thumbCenterPoint = [self drawCircularTrack:self.value atPoint:middlePoint withRadius:radius inContext:context];
            break;
    }

    [self.thumbTintColor setFill];
    [self drawThumbAtPoint:self.thumbCenterPoint inContext:context];
}

/** @name Thumb management methods */
#pragma mark - Thumb management methods
- (BOOL)isPointInThumb:(CGPoint)point {
    CGRect thumbTouchRect = CGRectMake(self.thumbCenterPoint.x - kThumbRadius, self.thumbCenterPoint.y - kThumbRadius, kThumbRadius*2, kThumbRadius*2);
    return CGRectContainsPoint(thumbTouchRect, point);
}

/** @name UIGestureRecognizer management methods */
#pragma mark - UIGestureRecognizer management methods
- (void)panGestureHappened:(UIPanGestureRecognizer *)panGestureRecognizer {
    CGPoint tapLocation = [panGestureRecognizer locationInView:self];
   /* UILabel* percentlbl =(UILabel*) [self.superview viewWithTag:10];
    NSLog(@"percentlbl frame %f",percentlbl.frame.origin.y
          );
    if (CGRectContainsPoint(percentlbl.frame, tapLocation)) {
        NSLog(@"Tapped label");
    }*/


    switch (panGestureRecognizer.state) {
        case UIGestureRecognizerStateChanged: {
            CGFloat radius = [self sliderRadius];
            CGPoint sliderCenter = CGPointMake(self.bounds.size.width/2, self.bounds.size.height/2);
            CGPoint sliderStartPoint = CGPointMake(sliderCenter.x, sliderCenter.y - radius);
            CGFloat angle = angleBetweenThreePoints(sliderCenter, sliderStartPoint, tapLocation);

            if (angle < 0) {
                angle = -angle;
            }
            else {
                angle = 2*M_PI - angle;
            }

            self.value = translateValueFromSourceIntervalToDestinationInterval(angle, 0, 2*M_PI, self.minimumValue, self.maximumValue);
            break;
        }
        case UIGestureRecognizerStateEnded:
            if (!self.isContinuous) {
                [self sendActionsForControlEvents:UIControlEventValueChanged];
            }
            if ([self isPointInThumb:tapLocation]) {
                [self sendActionsForControlEvents:UIControlEventTouchUpInside];
            }
            else {
                [self sendActionsForControlEvents:UIControlEventTouchUpOutside];
            }
            break;
        default:
            break;
    }
}
- (void)tapGestureHappened:(UITapGestureRecognizer *)tapGestureRecognizer {
    if (tapGestureRecognizer.state == UIGestureRecognizerStateEnded) {
        CGPoint tapLocation = [tapGestureRecognizer locationInView:self];
        if ([self isPointInThumb:tapLocation]) {
        }
        else {
        }
    }
}

/** @name Touches Methods */
#pragma mark - Touches Methods
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
    [super touchesBegan:touches withEvent:event];

    UITouch *touch = [touches anyObject];
    CGPoint touchLocation = [touch locationInView:self];
    if ([self isPointInThumb:touchLocation]) {
        [self sendActionsForControlEvents:UIControlEventTouchDown];
    }
}

@end

/** @name Utility Functions */
#pragma mark - Utility Functions
float translateValueFromSourceIntervalToDestinationInterval(float sourceValue, float sourceIntervalMinimum, float sourceIntervalMaximum, float destinationIntervalMinimum, float destinationIntervalMaximum) {
    float a, b, destinationValue;

    a = (destinationIntervalMaximum - destinationIntervalMinimum) / (sourceIntervalMaximum - sourceIntervalMinimum);
    b = destinationIntervalMaximum - a*sourceIntervalMaximum;

    destinationValue = a*sourceValue + b;

    return destinationValue;
}

CGFloat angleBetweenThreePoints(CGPoint centerPoint, CGPoint p1, CGPoint p2) {
    CGPoint v1 = CGPointMake(p1.x - centerPoint.x, p1.y - centerPoint.y);
    CGPoint v2 = CGPointMake(p2.x - centerPoint.x, p2.y - centerPoint.y);

    CGFloat angle = atan2f(v2.x*v1.y - v1.x*v2.y, v1.x*v2.x + v1.y*v2.y);

    return angle;
}

1 个答案:

答案 0 :(得分：0)

您需要做的是在手势识别中添加一个阶段，以确定用户是在增加还是减少计数器。如果减少，一旦值降到零以下就不响应减少变化（可能你想要能够变为零，尽管问题是什么，但不能停在一个？）。如果增加，一旦价值达到100％，就不会对增加的变化作出反应。当然，您需要确保在最大值时，如果用户更改为减少值，则会继续响应，同样在零时增加。

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