IOS 監聽slider滑動

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// 監聽slider滑動- (IBAction)valueChnage:(UISlider *)sender;@property (weak, nonatomic) IBOutlet NJView *circleView;@end@implementation NJViewController- (IBAction)valueChnage:(UISlider *)sender {//    NSLog(@"%.1f", sender.value);    // 1.傳遞改變後的值給自訂view    self.circleView.radius = sender.value;    // 2.通知自訂view重新繪製圖形//    [self.circleView setNeedsDisplay];    }

- (void)setRadius:(float)radius{    _radius = radius;        // 2.通知自訂view重新繪製圖形    [self setNeedsDisplay];}- (void)awakeFromNib{    self.radius = 10;}- (void)drawRect:(CGRect)rect{    // 1.擷取上下文    CGContextRef ctx = UIGraphicsGetCurrentContext();    // 2.繪圖//    CGContextAddEllipseInRect(ctx, CGRectMake(0, 0, 200, 200));    CGContextAddArc(ctx, 100, 100, self.radius, 0, 2 * M_PI, 0);        [[UIColor purpleColor] set];    // 3.渲染    CGContextFillPath(ctx);        }

 

IOS 監聽slider滑動