Drawing and hiding the toolbar

I am working on my application, I want to hide the bottom toolbar so I can draw where that is, but I can't figure out how to do this.

Also, I used a tutorial to help with the drawing, but I can't figure out why it is stopping the drawing at the top of the screen.

- (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.ima开发者_如何转开发ge = 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();
    }
}

In your viewDidLoad you have:

drawImage.frame = self.view.frame;

To get rid of the gap at the top of your drawing, you should actually have:

drawImage.frame = self.view.bounds;

To understand why this works, you need to understand what the meaning of frame versus bounds is. See perhaps this question: Do I have the right understanding of frames and bounds in UIKit?

As for getting rid of the toolbar -- you need to tell us more about how your UI is set up. Is the view in your screenshot set up in interface builder?