Question

我正在尝试加载滚动视图50 png图像，我选择通过延迟加载来执行此操作。但是我仍然有很大的内存问题，当我滚动30页时我的应用程序崩溃了。

请帮助我理解为什么会这样，我的代码是：

UIImage *1 = [UIImage imageWithContentsOfFile:[[NSBundle mainBundle] pathForResource:@"30" ofType:@"png"]];
....
imageArray = [NSArray arrayWithObjects:1,2,3,4, ...];

- (void)loadPage:(NSInteger)page 
{
    if (page < 0 || page >= imageArray.count) 
    {
        return;
    }

    UIView *pageView = [pageViews objectAtIndex:page];
    if ((NSNull*)pageView == [NSNull null]) 
    {

        CGRect frame = self.scrollView.bounds;
        frame.origin.x = frame.size.width * page;
        frame.origin.y = 0.0f;


        UIImageView *newPageView = [[UIImageView alloc] initWithImage:[imageArray objectAtIndex:page]];
        newPageView.contentMode = UIViewContentModeScaleAspectFit;
        newPageView.frame = frame;
        [self.scrollView addSubview:newPageView];
        [pageViews replaceObjectAtIndex:page withObject:newPageView];
    }
}


- (void)purgePage:(NSInteger)page 
{
    if (page < 0 || page >= imageArray.count) 
    {
        return;
    }

    UIView *pageView = [pageViews objectAtIndex:page];
    if ((NSNull*)pageView != [NSNull null]) 
    {
        [pageView removeFromSuperview];
        [pageViews replaceObjectAtIndex:page withObject:[NSNull null]];
    }
}


- (void)loadVisiblePages 
{
    CGFloat pageWidth = self.scrollView.frame.size.width;
    NSInteger page = (NSInteger)floor((self.scrollView.contentOffset.x * 2.0f + pageWidth) / (pageWidth * 2.0f));

    self.pageControl.currentPage = page;

    // Work out which pages you want to load
    NSInteger firstPage = page - 1;
    NSInteger lastPage = page + 1;

    // Purge anything before the first page
    for (NSInteger i=0; i<firstPage; i++) 
    {
        [self purgePage:i];
    }

    for (NSInteger i=firstPage; i<=lastPage; i++) 
    {
        [self loadPage:i];
    }

    for (NSInteger i=lastPage+1; i<imageArray.count; i++) 
    {
        [self purgePage:i];
    }

    NSString *string = [NSString stringWithFormat:@"%i.png",page+1];
    layer = [UIImage imageNamed:string];
}

Answer 1

将其添加到pageViews数组后，应该发布newPageView。

Answer 2

我发现了问题，它正在创建newPageView。所以我将其更改为以下内容，我的应用程序现在不会崩溃。

UIImageView *newPageView = [[UIImageView alloc] initWithImage:[UIImage imageWithContentsOfFile:[[NSBundle mainBundle] pathForResource:string ofType:@"png"]]];

感谢您的帮助。

ScrollView内存问题

2 个答案: