我使用EFCircularSlider显示圆线和用户将移动处理程序如下:为什么CGContext没有绘制循环?
我已经完成了,除了在动画行为显示红线所有用户的需求。我无法改变我的代码。我试图逐渐画出这条弧线。我正在使用CGContext并在循环中显示圆,而不是使用动画。但它在循环结束时绘制图像。我跟踪下来,并确保环路得到正确调用如下:
我打电话的方法:
int tmp = self.angleFromNorth;
while (tmp<360) {
NSLog(@"tmp == %d",tmp);
tmp+=10;
[NSThread sleepForTimeInterval: 0.1];
[EFCircularTrig drawUnfilledArcInContext:ctx
center:self.centerPoint
radius:self.radius
lineWidth:self.lineWidth
fromAngleFromNorth:self.angleFromNorth
toAngleFromNorth:tmp];
[self setNeedsDisplay];
}
,然后它会正确打印线,但循环结束之后。当打印出所有的值时,它将显示该行。但我想让它与动画类似。
+(void) drawUnfilledArcInContext:(CGContextRef)ctx
center:(CGPoint)center
radius:(CGFloat)radius
lineWidth:(CGFloat)lineWidth
fromAngleFromNorth:(CGFloat)fromAngleFromNorth
toAngleFromNorth:(CGFloat)toAngleFromNorth
{
float cartesianFromAngle = CompassToCartesian(ToRad(fromAngleFromNorth));
float cartesianToAngle = CompassToCartesian(ToRad(toAngleFromNorth));
CGContextAddArc(ctx,
center.x, // arc start point x
center.y, // arc start point y
radius, // arc radius from center
cartesianFromAngle, cartesianToAngle,
0); // iOS flips the y coordinate so anti-clockwise (specified here by 0) becomes clockwise (desired)!
CGContextSetLineWidth(ctx, lineWidth);
CGContextSetLineCap(ctx, kCGLineCapButt);
CGContextSetShadowWithColor(ctx, CGSizeMake(0,0), 1, [UIColor colorWithRed:(0/255.0) green:(173/255.0) blue:(238/255.0) alpha:1.0].CGColor);
CGContextDrawPath(ctx, kCGPathStroke);
NSLog(@"HERE");
}
输出:
2016-09-06 22:52:48.950 EFCircularSlider[38301:288182] tmp == 22
2016-09-06 22:52:49.056 EFCircularSlider[38301:288182] HERE
2016-09-06 22:52:49.056 EFCircularSlider[38301:288182] tmp == 32
2016-09-06 22:52:49.161 EFCircularSlider[38301:288182] HERE
2016-09-06 22:52:49.162 EFCircularSlider[38301:288182] tmp == 42
2016-09-06 22:52:49.265 EFCircularSlider[38301:288182] HERE
2016-09-06 22:52:49.266 EFCircularSlider[38301:288182] tmp == 52
2016-09-06 22:52:49.371 EFCircularSlider[38301:288182] HERE
2016-09-06 22:52:49.372 EFCircularSlider[38301:288182] tmp == 62
2016-09-06 22:52:49.475 EFCircularSlider[38301:288182] HERE
2016-09-06 22:52:49.475 EFCircularSlider[38301:288182] tmp == 72
2016-09-06 22:52:49.580 EFCircularSlider[38301:288182] HERE
但是一旦循环完成图纸会出现。我想让它逐渐显现。我很感激任何人都可以在这里添加他们的经验。
我还补充说: