ios：< Error&gt ;: CGAffineTransformInvert：奇异矩阵 [英] ios: <Error>: CGAffineTransformInvert: singular matrix

问题描述

发生此错误的任何原因CGAffineTransformInvert

我应该担心吗？

xib的视图，以及4个位于视图外但位于同一个xib中的webViews。然后在代码中我将webViews作为子视图添加到视图中的滚动视图。

代码如下：

  /调用先初始化这个类。此外，初始化nib文件和选项卡栏名称。 
  - （id）initWithNibName：（NSString *）nibNameOrNil bundle：（NSBundle *）nibBundleOrNil 
 {
 self = [super initWithNibName：nibNameOrNil bundle：nibBundleOrNil]; 
 if（self）{
 self.title = NSLocalizedString（@More，@More）; 
 self.tabBarItem.image = [UIImage imageNamed：@first]; 
} 
 return self; 
} 
 
 //初始化更多的标签标题和视图
  - （void）initViewsandTitles {
 MoreTabPages = [NSArray arrayWithObjects：self.aboutWebView，
 self.newsUpdateWebView，
 self.feedbackWebView，
 self.creditsResourceWebView，nil]; 
 titles = [[NSArray alloc] initWithObjects：@About Locavore，
 @新闻和更新，
 @反馈，
 @Credits and Resources零]; 
} 
 
 //初始化URL 
  - （void）initURLs {
 websites = [[NSArray alloc] initWithObjects：@http：//www.getlocavore .com /，
 @http://twitter.com/enjoy_locavore，
 @https://getsatisfaction.com/localdirt/products/localdirt_locavore，
 @http ：//www.getlocavore.com/about，nil]; 
} 
 
 //在控制器的视图加载到内存后调用。 
  - （void）viewDidLoad 
 {
 [super viewDidLoad]; //调用超类init方法
 [self setupSpinner]; //启动微调框animatio 
 [self initViewsandTitles]; //初始化视图和标题
 [self initURLs]; //初始化URL 
 [self setScrollandPageViewProperties]; //设置滚动和页面视图属性
 [self setUpPageViews]; //创建网页
} 
 
 // UIScrollViewDelegate协议参考。在用户滚动收件箱内的内容时调用
  - （void）scrollViewDidScroll：（UIScrollView *）sender {
 
 if（！pageControlBeingUsed）{
 
 //当上一页/下一页的50％以上可见时切换指示器
 CGFloat pageWidth = self.MoreTabScrollView.frame.size.width; 
 int page = floor（（self.MoreTabScrollView.contentOffset.x  -  pageWidth / 2）/ pageWidth）+ 1; 
 self.MoreTabPageControl.currentPage = page; 
 self.MoreTabTitle.text = [titles objectAtIndex：page]; 
} 
} 
 
 // UIScrollViewDelegate协议参考。当滚动视图即将开始滚动内容时调用
  - （void）scrollViewWillBeginDragging：（UIScrollView *）scrollView {
 pageControlBeingUsed = NO; 
} 
 
 // UIScrollViewDelegate协议参考。当滚动视图结束时调用
  - （void）scrollViewDidEndDecelerating：（UIScrollView *）scrollView {
 NSLog（@DID END SCROLLING）; 
 pageControlBeingUsed = NO; 
} 
 
 //页面控制值更改时调用
  - （IBAction）MoreTabChangePage {
 
 //将滚动视图更新到适当的页面
 CGRect框架; 
 frame.origin.x = self.MoreTabScrollView.frame.size.width * self.MoreTabPageControl.currentPage; 
 frame.origin.y = 0; 
 frame.size = self.MoreTabScrollView.frame.size; 
 [self.MoreTabScrollView scrollRectToVisible：frame animated：YES]; 
 
 self.MoreTabTitle.text = [titles objectAtIndex：self.MoreTabPageControl.currentPage]; 
 
 //跟踪响应页面控件的滚动情况
 //值更改。如果我们不这样做，会出现一个明显的闪烁
 //，因为滚动委托会临时切换回页面
 // number。 
 pageControlBeingUsed = YES; 
} 
 
 //为每个页面创建一个框架并将页面添加到滚动视图
  - （void）setUpPageViews {
 
 // Set up更多选项卡的所有页面视图
 for（int i = 0; i  
 //获取当前表视图控制器页
 UIWebView * webController = [MoreTabPages objectAtIndex：i]; 
 
 //请求URL并加载请求
 NSURL * urll = [NSURL URLWithString：[websites objectAtIndex：i]]; 
 
 //在单独的线程中运行请求
 dispatch_queue_t queue = dispatch_get_global_queue（DISPATCH_QUEUE_PRIORITY_HIGH，0）; 
 
 dispatch_async（queue，^ {
 
 NSURLRequest * firstReq = [NSURLRequest requestWithURL：urll]; 
 [webController loadRequest：firstReq]; 
 
 dispatch_sync（dispatch_get_main_queue（），^ {
 //为当前表视图控制器创建一个框架
 CGRect frame = webController.frame; 
 frame.origin.x = self.MoreTabScrollView。 frame.size.width * i; 
 frame.origin.y = 0; 
 frame.size = self.MoreTabScrollView.frame.size; 
 webController.frame = frame; 
 
 //将当前表视图控制器页面添加到滚动视图
 [self.MoreTabScrollView addSubview：webController]; 
 
 //释放控制器对象不再需要
 [webController release]; 
 
 if（i == 3）{
 [spinner stopAnimating]; 
} 
}）; 
 
}）; 
 
} 
} 
 
 //设置滚动视图和页面控制的属性
  - （void）setScrollandPageViewProperties {
 self .MoreTabScrollView.contentSize = CGSizeMake（self.MoreTabScrollView.frame.size.width * MoreTabPages.count，
 self.MoreTabScrollView.frame.size.height）; 
 self.MoreTabScrollView.scrollsToTop = NO; 
 self.MoreTabScrollView.contentOffset = CGPointMake（self.MoreTabScrollView.frame.size.width，0）; 
 self.MoreTabPageControl.numberOfPages = MoreTabPages.count; 
} 
 
  - （void）setupSpinner {
 spinner.hidesWhenStopped = YES; 
 [spinner startAnimating]; 
} 
 
 //如果应用程序收到内存警告，调用
  - （void）didReceiveMemoryWarning 
 {
 [super didReceiveMemoryWarning]; 
 //处理可以重新创建的任何资源。 
} 
 
 //当UIViewController的引用计数变为零时调用
  - （void）dealloc {
 [super dealloc]; 
 [MoreTabPageControl release]; 
 [MoreTabScrollView release]; 
 [MoreTabTitle release]; 
 [MoreTabPages release]; 
 [titles release]; 
 [网站发布]; 
 [spinner release]; 
} 
 @end 
  

解决方案

请尝试为每个网页视图设置最小缩放比例。

  [self.aboutWebView.scrollView setMinimumZoomScale： 0.1] 
  

在零缩放。

Any reason for this error "CGAffineTransformInvert"

Should I be worried?

I have a .xib with a view, and 4 webViews located outside of the view but within the same xib. Then in the code I add the webViews as subviews to a scroll view inside the view. Would that cause the problem?

Code is below:

//Called first to initialize  this class. Also, initializes the nib file and tab bar name.
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        self.title = NSLocalizedString(@"More", @"More");
        self.tabBarItem.image = [UIImage imageNamed:@"first"];
    }
    return self;
}

//Initialize the more tab titles and views
-(void)initViewsandTitles{
    MoreTabPages = [NSArray arrayWithObjects:self.aboutWebView,
                    self.newsUpdateWebView,
                    self.feedbackWebView,
                    self.creditsResourceWebView, nil];
    titles = [[NSArray alloc] initWithObjects:@"About Locavore",
              @"News and Updates",
              @"Feedback",
              @"Credits and Resources", nil];
}

//Initialize the URLs
-(void)initURLs{
    websites = [[NSArray alloc] initWithObjects:@"http://www.getlocavore.com/",
                @"http://twitter.com/enjoy_locavore",
                @"https://getsatisfaction.com/localdirt/products/localdirt_locavore",
                @"http://www.getlocavore.com/about", nil];
}

//Called after the controller's view is loaded into memory.
- (void)viewDidLoad
{
    [super viewDidLoad];                    //Call the super class init method
    [self setupSpinner];                    //Start the spinner animatio
    [self initViewsandTitles];              //Initialize the views and titles
    [self initURLs];                        //Initialize the URLs
    [self setScrollandPageViewProperties];  //Set the scroll and page view properties
    [self setUpPageViews];                  //Create the web pages
}

//UIScrollViewDelegate Protocol Reference. Called whn the user scrolls the content within the reciever
- (void)scrollViewDidScroll:(UIScrollView *)sender {

        if (!pageControlBeingUsed) {

                // Switch the indicator when more than 50% of the previous/next page is visible
                CGFloat pageWidth = self.MoreTabScrollView.frame.size.width;
                int page = floor((self.MoreTabScrollView.contentOffset.x - pageWidth / 2) / pageWidth) + 1;
                self.MoreTabPageControl.currentPage = page;
        self.MoreTabTitle.text = [titles objectAtIndex:page];
        }
}

//UIScrollViewDelegate Protocol Reference. Called when the scroll view is about to start scolling content
- (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView {
        pageControlBeingUsed = NO;
}

//UIScrollViewDelegate Protocol Reference. Called when the scroll view has ended decelerating the scrolling movement
- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView {
    NSLog(@"DID END SCROLLING");
        pageControlBeingUsed = NO;
}

//Called when the page control value changes
- (IBAction)MoreTabChangePage {

        // Update the scroll view to the appropriate page
        CGRect frame;
        frame.origin.x = self.MoreTabScrollView.frame.size.width * self.MoreTabPageControl.currentPage;
        frame.origin.y = 0;
        frame.size = self.MoreTabScrollView.frame.size;
        [self.MoreTabScrollView scrollRectToVisible:frame animated:YES];

    self.MoreTabTitle.text = [titles objectAtIndex:self.MoreTabPageControl.currentPage];

        // Keep track of when scrolls happen in response to the page control
        // value changing. If we don't do this, a noticeable "flashing" occurs
        // as the the scroll delegate will temporarily switch back the page
        // number.
        pageControlBeingUsed=YES;
}

//Create a frame for each page and add the page to the scroll view
-(void)setUpPageViews{

    //Set up all page views for the more tab
    for (int i = 0; i < MoreTabPages.count; i++) {

        //Get the current table view controller page
        UIWebView *webController= [MoreTabPages objectAtIndex:i];

        //Request the URL and load the request
        NSURL *urll =[NSURL URLWithString:[websites objectAtIndex:i]];

        //Run requests in seperate thread
        dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0);

        dispatch_async(queue, ^{

            NSURLRequest *firstReq = [NSURLRequest requestWithURL:urll];
            [webController loadRequest:firstReq];

            dispatch_sync(dispatch_get_main_queue(), ^{
                //Create a frame for the current table view controller
                CGRect frame = webController.frame;
                frame.origin.x = self.MoreTabScrollView.frame.size.width * i;
                frame.origin.y = 0;
                frame.size = self.MoreTabScrollView.frame.size;
                webController.frame = frame;

                //Add the the current table view controller page to the scroll view
                [self.MoreTabScrollView addSubview:webController];

                //Release the controller object it is no longer needed
                [webController release];

                if(i == 3){
                    [spinner stopAnimating];
                }
            });

        });

    }
}

//Set al the properties for the scroll view and page controll
-(void)setScrollandPageViewProperties{
    self.MoreTabScrollView.contentSize = CGSizeMake(self.MoreTabScrollView.frame.size.width * MoreTabPages.count,
                                                    self.MoreTabScrollView.frame.size.height);
    self.MoreTabScrollView.scrollsToTop = NO;
    self.MoreTabScrollView.contentOffset = CGPointMake(self.MoreTabScrollView.frame.size.width, 0);
        self.MoreTabPageControl.numberOfPages = MoreTabPages.count;
}

-(void)setupSpinner{
    spinner.hidesWhenStopped = YES;
    [spinner startAnimating];
}

//Called if the application receives a memory warning
- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

//Called when the UIViewController's reference count goes to zero
- (void)dealloc {
    [super dealloc];
    [MoreTabPageControl release];
    [MoreTabScrollView release];
    [MoreTabTitle release];
    [MoreTabPages release];
    [titles release];
    [websites release];
    [spinner release];
}
@end

解决方案

try setting the minimum zoom scale for your each webview.

[self.aboutWebView.scrollView setMinimumZoomScale:0.1]

it will throw the same error if the scrollview reaches zero at zero zoom.

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