如何删除视图并重绘它

Question

我有一个可以绘制的视图。当用户单击取消按钮时，视图被清除并在该视图中绘制新图像。我正在发布我的代码。有人可以帮忙吗？

#import "SignatureViewController.h"


@implementation SignatureViewController
@synthesize salesToolBar;



-(void)buttonpressed
{
    NSString *allElements = [myarray componentsJoinedByString:@""];
    NSLog(@"%@", allElements);}


-(void)buttonclear{

        [drawImage removeFromSuperview];

    //UIGraphicsBeginImageContext(CGSizeMake(self.view.frame.size.height, self.view.frame.size.width));       
     drawImage = [[UIImageView alloc] initWithImage:nil];
    [drawImage.image drawInRect:CGRectMake(0, 0, self.view.frame.size.height, self.view.frame.size.width )];
    drawImage.frame = self.view.frame;
   [self.view addSubview:drawImage];
    self.view.backgroundColor = [UIColor greenColor];
    mouseMoved = 0;
        //[super viewDidLoad];

}

-(void)buttoncancel{
    [[self navigationController] popViewControllerAnimated: YES];
     [UIApplication sharedApplication].statusBarOrientation = UIInterfaceOrientationPortrait;

}


- (void)viewDidLoad {
    [super viewDidLoad];
    myarray = [[NSMutableArray alloc] init];


    CGFloat x = self.view.bounds.size.width / 2.0;
    CGFloat y = self.view.bounds.size.height / 2.0;
    CGPoint center = CGPointMake(y, x);

    // set the new center point
    self.view.center = center;

    CGAffineTransform transform = self.view.transform;
        transform = CGAffineTransformRotate(transform, -(M_PI / 2.0));

    self.view.transform = transform;

    self.view.backgroundColor = [UIColor greenColor];
    self.title = @"Signature";

    [self createToolbar];

    NSLog(@"View Did Load Run");


}

- (void)viewDidAppear:(BOOL)animated {
    NSLog(@"Self.view.frame.height = %f and width = %f ", self.view.frame.size.height, self.view.frame.size.width);
    NSLog(@"View Did Appear Run");
    self.navigationController.navigationBarHidden=TRUE;
    [UIApplication sharedApplication].statusBarOrientation = UIInterfaceOrientationLandscapeLeft;



    [super viewDidLoad];

}

Answer 1

听起来您需要在视图上调用 setNeedsDisplay:。 :)