Objective c 如何清除绘图视图?
我目前正在尝试刷新或清除我的Objective c 如何清除绘图视图?,objective-c,ios,cocoa-touch,drawing,draw,Objective C,Ios,Cocoa Touch,Drawing,Draw,我目前正在尝试刷新或清除我的UIViewdraw,但很多方法都不起作用。我试过: self.Draw.ClearContextBeforeDrawing [self.Draw设置需要显示] self.Draw.removeFromSuperview 我的代码: -(void)drawPoint:(UITouch *)touch { PointLocation *currentLoc = [[PointLocation alloc] init]; currentLoc.loc
UIView
draw,但很多方法都不起作用。我试过:
self.Draw.ClearContextBeforeDrawing
[self.Draw设置需要显示]代码>
self.Draw.removeFromSuperview代码>
-(void)drawPoint:(UITouch *)touch
{
PointLocation *currentLoc = [[PointLocation alloc] init];
currentLoc.location = [touch locationInView:self];
self.previousPoint = self.point;
self.point = currentLoc;
[self drawToBuffer];
[self setNeedsDisplay];
}
有没有办法清除我的指纹?或者至少重新加载它?这里有一些基本问题 如何申报抽签?遵循cocoa命名约定。只有类名应该大写。类的实例应以小写字母开头 我想你想要的是:
@interface Draw: UIView
@end
@implementation Draw
- (void) drawRect: (CGRect) r {
// here you will draw whatever you want in your view.
}
@end
Draw* draw;
在您的drawPoint方法中:
[draw setNeedsDisplay];
有关详细信息,请参见视图图形周期:
要获得额外积分,请将您的观点命名为比画图更具描述性的内容。它是一个视图,一个包含一些内容的窗口。它不是一个动词。它的{CGImageRef cgImage=CGBitmapContextCreateImage(offScreenBuffer);UIImage*UIImage=[[UIImage alloc]initWithCGImage:cgImage];CGImageRelease(cgImage);[undoManager beginUndoGrouping];[UIImage drawInRect:self.bounds];}