在 xcode 中单击按钮后绘制一个圆圈
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/9344556/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
Drawing a circle after button click in xcode
提问by user1217340
I am trying to draw a circle after clicking a button. I can create a rectangle but cannot draw a circle.
单击按钮后，我试图画一个圆圈。我可以创建一个矩形，但不能画一个圆。
Is there a way to make this:
有没有办法做到这一点：
-(IBAction) buttonTouched
{
}
call or signal this to work:
调用或发出信号使其工作：
- (void)drawRect:(CGRect)rect
{
}
Thanks for any input!
感谢您提供任何意见！
*Edit**Sorry, it's not working. Not sure what I'm doing wrong:
*编辑* *抱歉，它不起作用。不知道我做错了什么：
1) Created a new view-based project named "test". 2) Created a Objective-C class UIView named "view". 3) In IB dragged a button onto the view, linked it to "buttonTouched" - Touched Up Inside.
1) 创建了一个名为“test”的基于视图的新项目。2）创建了一个名为“view”的Objective-C类UIView。3）在IB中将一个按钮拖到视图上，将其链接到“buttonTouched” - 在里面触摸。
testViewController.h
#import <UIKit/UIKit.h>
#import "view.h"
@interface testViewController : UIViewController {
}
-(IBAction) buttonTouched;
@end
testViewController.m
#import "testViewController.h"
#import "view.h"
@implementation testViewController
- (IBAction)buttonTouched {
[[self view] setNeedsDisplay];
}
view.m
#import "view.h"
@implementation view
- (id)initWithFrame:(CGRect)frame {
self = [super initWithFrame:frame];
if (self) {
}
return self;
}
- (void)drawRect:(CGRect)rect {
CGContextRef contextRef = UIGraphicsGetCurrentContext();
CGContextFillEllipseInRect(contextRef, CGRectMake(100, 100, 25, 25));
CGContextSetRGBFillColor(contextRef, 0, 0, 255, 1.0);
CGContextStrokeEllipseInRect(contextRef, CGRectMake(100, 100, 25, 25));
CGContextSetRGBFillColor(contextRef, 0, 0, 255, 1.0);
}
- (void)dealloc {
[super dealloc];
}
@end
回答by BDGapps
This should do what you want it to. Check Sample code
这应该做你想要的。检查示例代码
// The color is by this line CGContextSetRGBFillColor( context , red , green , blue , alpha);
// Draw a circle (filled)
CGContextFillEllipseInRect(contextRef, CGRectMake(100, 100, 25, 25));
CGContextSetRGBFillColor(contextRef, 0, 0, 255, 1.0);
// Draw a circle (border only)
CGContextStrokeEllipseInRect(contextRef, CGRectMake(100, 100, 25, 25));
CGContextSetRGBFillColor(contextRef, 0, 0, 255, 1.0);
回答by rob mayoff
If you want the system to call drawRect:, you call setNeedsDisplay:
如果您希望系统调用drawRect:，请调用setNeedsDisplay：
// In your view controller...
- (IBAction)buttonTouched {
[self.view setNeedsDisplay];
}
// In your UIView subclass...
- (void)drawRect:(CGRect)rect {
[UIColor.redColor setFill];
[[UIBezierPath bezierPathWithOvalInRect:self.bounds] fill];
}
回答by SachinVsSachin
-(void)drawRect:(CGRect)rect {
CGContextRef contextRef = UIGraphicsGetCurrentContext();
CGContextSetRGBFillColor(contextRef, 0, 0, 255, 0.1);
CGContextSetRGBStrokeColor(contextRef, 0, 0, 255, 0.5);
// Draw a circle (filled)
CGContextFillEllipseInRect(contextRef, CGRectMake(100, 100, 25, 25));
// Draw a circle (border only)
CGContextStrokeEllipseInRect(contextRef, CGRectMake(100, 100, 25, 25));
// Get the graphics context and clear it
CGContextRef ctx = UIGraphicsGetCurrentContext();
CGContextClearRect(ctx, rect);
// Draw a green solid circle
CGContextSetRGBFillColor(ctx, 0, 255, 0, 1);
CGContextFillEllipseInRect(ctx, CGRectMake(100, 100, 25, 25));
// Draw a yellow hollow rectangle
CGContextSetRGBStrokeColor(ctx, 255, 255, 0, 1);
CGContextStrokeRect(ctx, CGRectMake(195, 195, 60, 60));
// Draw a purple triangle with using lines
CGContextSetRGBStrokeColor(ctx, 255, 0, 255, 1);
CGPoint points[6] = {
CGPointMake(100, 200), CGPointMake(150, 250),
CGPointMake(150, 250), CGPointMake(50, 250),
CGPointMake(50, 250), CGPointMake(100, 200)
};
CGContextStrokeLineSegments(ctx, points, 6);
}
