Question

我是Objective-C的新手，我的应用程序遇到了一些问题。我将UIView子类化并覆盖drawRect：方法以绘制三角形。然后我厌倦了通过旋转三角形并在屏幕上移动三角形来制作动画。为此，我使用了NSTimer类并将其设置为每1/100秒触发一次。我的应用程序中有更多NSTimers，我用它们来制作视图并计算得分但是我注意到NSTimer在短时间内不是很准确，比如1/100秒和特别是当你有一个以上时。

我想问是否有更好的方法来做我想做的事情？如果有更准确的计时器用于此类任务？或者定时器不是最好的方法吗？

这是spinningTriangle.h：

#import <UIKit/UIKit.h>

@interface SPDSpinningTriangleView : UIView
{
    int changeInDegrees ;
    CGPoint triangleCenter ;
    UISwipeGestureRecognizer *swipe ;

    float score ;
}


@end

这里是spinningTriangle.m：

@implementation SPDSpinningTriangleView

const float MAX_SCORE = 10.0 ;


- (id)initWithFrame:(CGRect)frame
{
    self = [super initWithFrame:frame];
    if (self) {


        // Initialization code
        [self setBackgroundColor:[UIColor clearColor]] ;

        CGRect triangleFrame = CGRectMake(0, 0, 80, 80) ;

        [self setFrame:triangleFrame] ;

        changeInDegrees = 0 ;
        score = 0.0 ;

        [NSTimer scheduledTimerWithTimeInterval:1/100.0 target:self selector:@selector(updateView:) userInfo:nil repeats:YES] ;

    }
    return self;
}

- (void)drawRect:(CGRect)rect
{
    const float HALF_FRAME = rect.size.height / 2.0 ;

    if(changeInDegrees == 0)
    {
        swipe = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(swipped:)] ;
        [[self superview] addGestureRecognizer:swipe] ;

        UIView *superView = [self superview] ;
        float randomY = arc4random() % (int)[superView frame].size.height + HALF_FRAME;
        while (randomY > CGRectGetMaxY([superView frame]) - HALF_FRAME) {
            randomY = arc4random() % (int)[superView frame].size.height + HALF_FRAME;
        }
        triangleCenter = CGPointMake(CGRectGetMinX([superView frame]),randomY) ;

        [self setCenter:triangleCenter] ;
    } else {
        triangleCenter.x += 2 ;
        [self setCenter:triangleCenter] ;
    }

    // Drawing code
    CGContextRef ctx = UIGraphicsGetCurrentContext() ;



    CGContextTranslateCTM(ctx, CGRectGetMidX(rect), CGRectGetMidY(rect)) ;
    CGContextRotateCTM(ctx,changeInDegrees * M_PI / 180.0) ;
    CGContextTranslateCTM(ctx, -CGRectGetMidX(rect), -CGRectGetMidY(rect)) ;

    CGContextBeginPath(ctx) ;

    CGPoint center = CGPointMake(CGRectGetMidX(rect), CGRectGetMidY(rect)) ;

    CGPoint vertex1 = CGPointMake(center.x, center.y - HALF_FRAME) ;
    CGPoint vertex2 = CGPointMake(center.x - (HALF_FRAME * 1.5 * tanf(30.0 * M_PI / 180.0)), vertex1.y + HALF_FRAME * 1.5) ;
    CGPoint vertex3 = CGPointMake(center.x + (HALF_FRAME * 1.5 * tanf(30.0 * M_PI / 180.0)), vertex2.y) ;



    CGContextMoveToPoint(ctx, vertex1.x, vertex1.y) ;
    CGContextAddLineToPoint(ctx,vertex2.x, vertex2.y) ;
    CGContextAddLineToPoint(ctx, vertex3.x, vertex3.y) ;


    CGContextClosePath(ctx) ;

    CGContextSetRGBFillColor(ctx, 0.5, 0.0, 1.0, 1.0) ;

    CGContextFillPath(ctx) ;
}
-(void) swipped:(UIGestureRecognizer *) gesture
{
    NSLog(@"swipe") ;
    [self clearsContextBeforeDrawing] ;
    [[self superview] removeGestureRecognizer:gesture] ;

    [self removeFromSuperview] ;
}
-(void) dealloc
{
    NSLog(@"Spinning triangle destroyed") ;

        [[SPDScoreManager scoreManger] addToScore:score] ;
}
-(void) updateView: (NSTimer *) t
{
    if (triangleCenter.x < CGRectGetMaxX([[self superview] frame]))
    {
        [self setNeedsDisplay] ;
        changeInDegrees += 5 ;

        score = MAX_SCORE - (triangleCenter.x / [self frame].size.width) * MAX_SCORE ;
    }
    else
    {

        NSLog(@"Faild") ;

        [t invalidate] ;

        [[SPDScoreManager scoreManger] addToFails] ;

        [[self superview] removeGestureRecognizer:swipe] ;
        [self removeFromSuperview] ;
    }

}

@end

Objective-C中的计时器问题

0 个答案: