Question

我的UIscrollView有问题，这就是我所做的：每当用户通过Imagepicker在相机中选择图像（多个或单个）时，我想在我的Imagepicker中显示它UIScrollView的。我能够显示它，但是当我再次转到UIScrollView然后再次选择图片时，它不会更新[self createScrollView]，我尝试将viewDidAppear放入我的UIScrollView但它重新创建viewDidLoad但不更新它，因此旧图像和新图像组合在一起。所以我已将它们放在View Controller中，但它只会在我转到另一个UIScrollView然后再返回时更新。

//我的- (void) createScrollView { self.slotBg = [[UIView alloc] initWithFrame:CGRectMake(43, 370, 300, 143)]; CAGradientLayer *gradient = [CAGradientLayer layer]; gradient.frame = self.slotBg.bounds; gradient.colors = [NSArray arrayWithObjects:(id)[[UIColor grayColor] CGColor], (id)[[UIColor whiteColor] CGColor], nil]; [self.slotBg.layer insertSublayer:gradient atIndex:0]; [self.view addSubview:self.slotBg]; self.scrollView = [[UIScrollView alloc] initWithFrame:CGRectMake(0.0f,0.0f,300.0f,134.0f)]; [slotBg addSubview:self.scrollView]; int row = 0; int column = 0; for(int i = 0; i < _thumbs.count; ++i) { UIImage *thumb = [_thumbs objectAtIndex:i]; UIButton * button = [UIButton buttonWithType:UIButtonTypeCustom]; button.frame = CGRectMake(column*60+10, row*60+10, 60, 60); [button setImage:thumb forState:UIControlStateNormal]; [button addTarget:self action:@selector(buttonClicked:) forControlEvents:UIControlEventTouchUpInside]; button.tag = i; [scrollView addSubview:button]; if (column == 4) { column = 0; row++; } else { column++; } } [scrollView setContentSize:CGSizeMake(330, (row+1) * 60 + 10)]; }缩略图

- (void)viewDidLoad
{
       for(int i = 0; i <= 100; i++) 
        { 
            NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
            NSString *documentsDir = [paths objectAtIndex:0];

            NSString *savedImagePath = [documentsDir stringByAppendingPathComponent:[NSString stringWithFormat:@"oneSlotImages%d.png", i]]; 
            NSLog(@"savedImagePath=%@",savedImagePath);
            if([[NSFileManager defaultManager] fileExistsAtPath:savedImagePath]){ 
                [self addImage:[UIImage imageWithContentsOfFile:savedImagePath]]; 

                NSLog(@"file exists");
            } 
        } 
        NSLog(@"Count : %d", [_images count]);
        [self createScrollView];
}

//在我的viewDidLoad

中

- (void) viewDidLoad {
    [self createScrollView];

    [_thumbs removeAllObjects];
    UIView *removeView;
    for(int i = 0; i < _thumbs.count; ++i) {
    while((removeView = [scrollView viewWithTag:i]) != nil) {
        [removeView removeFromSuperview];
    }

        { 
            NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
            NSString *documentsDir = [paths objectAtIndex:0];

            NSString *savedImagePath = [documentsDir stringByAppendingPathComponent:[NSString stringWithFormat:@"oneSlotImages%d.png", i]]; 
            NSLog(@"savedImagePath=%@",savedImagePath);
            if([[NSFileManager defaultManager] fileExistsAtPath:savedImagePath]){ 
                [self addImage:[UIImage imageWithContentsOfFile:savedImagePath]]; 
                NSLog(@"file exists");
            } 
        } 
        NSLog(@"Count : %d", [_images count]);
    }
}

修改

{{1}}

Answer 1

有两点：

检查您的数据来源。如果图像已正确保存在文档目录中。
无需再次创建滚动视图及其父视图。将代码从createScrollView移至viewDidLoad。这些视图应该只创建一次。

self.slotBg = [[UIView alloc] initWithFrame：CGRectMake（43,370,300,143）]; CAGradientLayer * gradient = [CAGradientLayer layer]; gradient.frame = self.slotBg.bounds; gradient.colors = [NSArray arrayWithObjects：（id）[[UIColor grayColor] CGColor]，（id）[[UIColor whiteColor] CGColor]，nil]; [self.slotBg.layer insertSublayer：gradient atIndex：0]; [self.view addSubview：self.slotBg];

self.scrollView = [[UIScrollView alloc] initWithFrame:CGRectMake(0.0f,0.0f,300.0f,134.0f)];
[slotBg addSubview:self.scrollView];

现在，从viewDidAppear开始，首先更新_thumbs数组（数据源）。然后调用createScrollView函数。在此函数内，首先使用UIScrollView中的标记删除所有子视图。像你一样，再次添加所有的拇指。然后在从createScrollView返回之前调用[self setNeedsDisplay]。

UIScrollView无法正确更新和显示

1 个答案: