Question

我有一张表格,在一行点击时,我去了另一种观点;导航部分的代码如下所示;

ShowImageController *showImageController = [[HowItWorksViewController alloc] initWithNibName:nil bundle:nil];

[self.navigationController pushViewController:showImageController  animated:YES];

另一种观点含有一种形象,即把形象添加到其观点中。并在此附上该守则

 UIImageView *imageView=[[UIImageView alloc] initWithImage:[UIImage imageNamed:@"hello.png"]];
    [imageView setFrame:CGRectMake(o, o, 200, 300)];

[[self view] addSubview:imageView ];

问题在于,在一行点击时,需要很长的时间(极慢),才能去其他屏幕。

注:Ros在另一种观点中的形象没有问题。为什么发生这种情况? 如何确定?

Answer 1

a. 将图像装入一个星号或星号:

Answer 2

象图像这样的明显声音是大的,因此在装上。我建议你要么使用较小的图像,要么如果你不控制这些图像,那么你可能会试图在背景中填满图像。下面是一些守则,使你开始装上底线:

- (void)decodeImageInBackgroundThread:(UIImage*)decodedImage forImageView:(UIImageView*)imageView {
    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_LOW, 0), ^{
        CGImageRef originalImage = [decodedImage CGImage];

        CFDataRef imageData = CGDataProviderCopyData(CGImageGetDataProvider(originalImage));
        CGDataProviderRef imageDataProvider = CGDataProviderCreateWithCFData(imageData);

        if (imageData != NULL) {
            CFRelease(imageData);
        }

        CGImageRef image = CGImageCreate(CGImageGetWidth(originalImage),
                                         CGImageGetHeight(originalImage),
                                         CGImageGetBitsPerComponent(originalImage),
                                         CGImageGetBitsPerPixel(originalImage),
                                         CGImageGetBytesPerRow(originalImage),
                                         CGImageGetColorSpace(originalImage),
                                         CGImageGetBitmapInfo(originalImage),
                                         imageDataProvider,
                                         CGImageGetDecode(originalImage),
                                         CGImageGetShouldInterpolate(originalImage),
                                         CGImageGetRenderingIntent(originalImage));

        if (imageDataProvider != NULL) {
            CGDataProviderRelease(imageDataProvider);
        }

        dispatch_async(dispatch_get_main_queue(), ^{
            [imageView setImage:[UIImage imageWithCGImage:image]];
            CGImageRelease(image);
        });
    });
}

你们可以这样作:

- (void)viewDidLoad {
    ...

    UIImage *image = [UIImage imageNamed:@"hello.png"];

    UIImageView *imageView = [[UIImageView alloc] initWithImage:nil];
    [imageView setFrame:CGRectMake(0.0f, 0.0f, 200.0f, 300.0f)];
    [[self view] addSubview:imageView];

    [self decodeImageInBackgroundThread:image forImageView:imageView];
}

友情链接