繪圖和隱藏工具欄

Question

我正在處理我的應用程序，我想隱藏底部的工具欄，以便我可以繪製該位置，但我無法弄清楚如何執行此操作。

此外，我用一個教程來幫助繪圖，但我無法弄清楚爲什麼它會停止屏幕頂部的繪圖。

- (void)viewDidLoad { 
    [super viewDidLoad]; 
    drawImage = [[UIImageView alloc] initWithImage:nil]; 
    drawImage.frame = self.view.frame; 
    [self.view addSubview:drawImage]; 
    self.view.backgroundColor = [UIColor lightGrayColor]; 
    mouseMoved = 0; 
} 

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event { 

    mouseSwiped = NO; 
    UITouch *touch = [touches anyObject]; 

    if ([touch tapCount] == 2) { 
     drawImage.image = nil; 
     return; 
    } 

    lastPoint = [touch locationInView:self.view]; 
    lastPoint.y -= 20; 

} 


- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event { 
    mouseSwiped = YES; 

    UITouch *touch = [touches anyObject]; 
    CGPoint currentPoint = [touch locationInView:self.view]; 
    currentPoint.y -= 20; 


    UIGraphicsBeginImageContext(self.view.frame.size); 
    [drawImage.image drawInRect:CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height)]; 
    CGContextSetLineCap(UIGraphicsGetCurrentContext(), kCGLineCapRound); 
    CGContextSetLineWidth(UIGraphicsGetCurrentContext(), 5.0); 
    CGContextSetRGBStrokeColor(UIGraphicsGetCurrentContext(), 1.0, 0.0, 0.0, 1.0); 
    CGContextBeginPath(UIGraphicsGetCurrentContext()); 
    CGContextMoveToPoint(UIGraphicsGetCurrentContext(), lastPoint.x, lastPoint.y); 
    CGContextAddLineToPoint(UIGraphicsGetCurrentContext(), currentPoint.x, currentPoint.y); 
    CGContextStrokePath(UIGraphicsGetCurrentContext()); 
    drawImage.image = UIGraphicsGetImageFromCurrentImageContext(); 
    UIGraphicsEndImageContext(); 

    lastPoint = currentPoint; 

    mouseMoved++; 

    if (mouseMoved == 10) { 
     mouseMoved = 0; 
    } 

} 

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event { 

    UITouch *touch = [touches anyObject]; 

    if ([touch tapCount] == 2) { 
     drawImage.image = nil; 
     return; 
    } 


    if(!mouseSwiped) { 
     UIGraphicsBeginImageContext(self.view.frame.size); 
     [drawImage.image drawInRect:CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height)]; 
     CGContextSetLineCap(UIGraphicsGetCurrentContext(), kCGLineCapRound); 
     CGContextSetLineWidth(UIGraphicsGetCurrentContext(), 5.0); 
     CGContextSetRGBStrokeColor(UIGraphicsGetCurrentContext(), 1.0, 0.0, 0.0, 1.0); 
     CGContextMoveToPoint(UIGraphicsGetCurrentContext(), lastPoint.x, lastPoint.y); 
     CGContextAddLineToPoint(UIGraphicsGetCurrentContext(), lastPoint.x, lastPoint.y); 
     CGContextStrokePath(UIGraphicsGetCurrentContext()); 
     CGContextFlush(UIGraphicsGetCurrentContext()); 
     drawImage.image = UIGraphicsGetImageFromCurrentImageContext(); 
     UIGraphicsEndImageContext(); 
    } 
} 

Answer 1

在您的viewDidLoad您有：

drawImage.frame = self.view.frame; 

要在繪圖的頂部擺脫的差距，你實際上應該有：

drawImage.frame = self.view.bounds; 

要理解爲什麼這會起作用，您需要了解框架與邊界的含義是什麼。看到這個問題：Do I have the right understanding of frames and bounds in UIKit?

至於擺脫工具欄 - 你需要告訴我們更多關於你的UI設置。您的屏幕截圖中的視圖是否在界面構建器中設置？