用於計時器動畫的CABasicAnimation在iOS 8+上不起作用

Question

幾年前，我已經使用此代碼實現了計時器動畫。 是一個可愛的動畫，但不適用於iOS8>

應該會出現一個圓圈，每0.1秒丟失一個餅，但動畫不會開始。 它適用於我的iPhone 5 iOS 7.1

我試圖解決它，但2小時后我沒有解決方案。

可以在CABasicAnimation方面有更多經驗的人可以幫助我嗎？

謝謝。

這是代碼：

    //Animazione CRONOMETRO
-(void) startCronometro{

    //SetTime
    counterStart = TIME;

    [sfondoCronometro setImage:[UIImage imageNamed:@"cronoStart.png"]];

    maskLayer = [CAShapeLayer layer];

    CGFloat maskHeight = sfondoCronometro.frame.size.height;
    CGFloat maskWidth = sfondoCronometro.frame.size.width;


    CGPoint centerPoint;
    centerPoint = CGPointMake(sfondoCronometro.frame.size.width/2, (sfondoCronometro.frame.size.height/2));

    //Make the radius of our arc large enough to reach into the corners of the image view.
    CGFloat radius = sqrtf(maskWidth * maskWidth + maskHeight * maskHeight)/2;

    //Don't fill the path, but stroke it in black.
    maskLayer.fillColor = [[UIColor clearColor] CGColor];
    maskLayer.strokeColor = [[UIColor blackColor] CGColor];

    maskLayer.lineWidth = 25;

    CGMutablePathRef arcPath = CGPathCreateMutable();

    //Move to the starting point of the arc so there is no initial line connecting to the arc
    CGPathMoveToPoint(arcPath, nil, centerPoint.x, centerPoint.y-radius/2);

    //Create an arc at 1/2 our circle radius, with a line thickess of the full circle radius
    CGPathAddArc(arcPath, nil, centerPoint.x, centerPoint.y, radius/2, 3*M_PI/2, -M_PI/2, NO);

    maskLayer.path = arcPath;//[aPath CGPath];//arcPath;

    //Start with an empty mask path (draw 0% of the arc)
    maskLayer.strokeEnd = 0;

    CFRelease(arcPath);

    //Install the mask layer into out image view's layer.
    sfondoCronometro.layer.mask = maskLayer;

    //Set our mask layer's frame to the parent layer's bounds.
    sfondoCronometro.layer.mask.frame = sfondoCronometro.layer.bounds;

    //Create an animation that increases the stroke length to 1, then reverses it back to zero.
    CABasicAnimation *swipe = [CABasicAnimation animationWithKeyPath:@"strokeEnd"];
    swipe.duration = TIME;
    NSLog(@"TIME: %f", swipe.duration);
    swipe.delegate = self;
    // [swipe setValue:@"string" forKey:@"key"];
    swipe.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionLinear];
    swipe.fillMode = kCAFillModeForwards;
    swipe.removedOnCompletion = NO;
    swipe.toValue = [NSNumber numberWithFloat: 1.0];

    [maskLayer addAnimation: swipe forKey: @"strokeEnd"];

}

Answer 1

我似乎記得在某些時候CGPathAddArc的功能發生了變化，並且根據開始和結束角度的值，您必須在調用時翻轉順時針標志。 嘗試使用順時針= YES。

我只是在我的一個應用程序中做了一些測試，並確認了這一點。 對於您使用的角度，順時針NO不適用於iOS <= 7，但不適用於iOS> = 8。

將最后一個參數從“否”切換為“是”。