Question

我有一个捕获用户签名的应用程序，myviewcontroller显示签名捕获。我尝试在屏幕中心创建一个矩形，该矩形使用CGRect进行居中。当我运行这个时，我没有错误，但我得到了下面的图片，我无法弄清楚是什么导致了这一点。在CGRect代码中，我试图让创建的矩形在屏幕中间居中，目标设备是ipad。我发布了.h和.m文件，.m文件不完整，因为其余部分与用于捕获签名的代码有关，然后保存。

任何帮助将不胜感激。 Simulation

// MyViewController.h

    #import <UIKit/UIKit.h>
    #import <CoreData/CoreData.h>
    #import <Foundation/Foundation.h>

    @interface MyViewController : UIViewController <UIAlertViewDelegate>

    @property (nonatomic, strong) UIImageView *mySignatureImage;
    @property (nonatomic, assign) CGPoint lastContactPoint1, lastContactPoint2, currentPoint;
    @property (nonatomic, assign) CGRect imageFrame;
    @property (nonatomic, assign) BOOL fingerMoved;
    @property (nonatomic, assign) float navbarHeight;
    @property (nonatomic, assign) UIImageView* imageView;


    @property (nonatomic, retain) NSData*image;
    @property (strong, nonatomic) NSManagedObjectContext *managedObjectContext;

    //Save and cancel buttons

    - (IBAction)cancel:(id)sender;
    - (IBAction)save:(id)sender;


    @end

//MyViewController.m

#import "MyViewController.h"



@interface MyViewController ()

@end

@implementation MyViewController

@synthesize mySignatureImage;
@synthesize lastContactPoint1, lastContactPoint2, currentPoint;
@synthesize imageFrame;
@synthesize fingerMoved;
@synthesize navbarHeight;
@synthesize image;
@synthesize imageView;


- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        // Custom initialization
    }
    return self;
}

- (void)viewDidLoad
{
    [super viewDidLoad];
    self.view.backgroundColor = [UIColor lightGrayColor];
CGRect imageFrame = CGRectMake(
                                   CGRectGetMidX(self.view.frame) - CGRectGetMidX(imageView.frame),
                                   CGRectGetMidY(self.view.frame) - CGRectGetMidY(imageView.frame),
                                   CGRectGetWidth(imageView.frame),
                                   CGRectGetHeight(imageView.frame));

//    //allocate an image view and add to the main view
    mySignatureImage = [[UIImageView alloc] initWithImage:nil];
    mySignatureImage.frame = imageFrame;
    mySignatureImage.backgroundColor = [UIColor whiteColor];
    [self.view addSubview:mySignatureImage];


}

Answer 1

尝试替换此行：

mySignatureImage = [[UIImageView alloc] initWithImage:nil];

使用：

mySignatureImage = [[UIImageView alloc] init];

Answer 2

将[super viewDidLoad]中的代码（viewDidLoad除外）移至后一阶段，例如viewWillAppear。在viewDidLoad期间，视图的布局尚未完成，因此它们的边界/框架尚未设置为最终值。

创建不在模拟器中显示的图像帧

2 个答案: