如何在调用肥皂网络服务时显示图像？

Question

我正在构建一个使用来自 Soap Web 服务的数据的应用程序，我只想在屏幕上显示几个图像，让用户知道数据是从网络下载的，我该怎么做？

Answer 1

我建议你试试MBProgressHUD。当工作在后台线程中完成时，Tt 会显示一个带有指示器和/或标签的半透明 HUD。它工作得很好。请探索它！

或者，您可以尝试这个自定义加载叠加层。我一直在我的一个项目中使用它，效果很好。在这里，在图像视图中，我为 10 个不同的图像设置动画，以便在屏幕上看起来不错。您可以根据需要删除动画并传递自己的图像。

#import "MyLoadingOverlay.h"

@implementation MyLoadingOverlay

+ (id)loadingOverlayInView:(UIView *)iSuperview {
    return [MyLoadingOverlay loadingOverlayInView:iSuperview title:nil fullScreen:NO spinner:YES showCustomImages:NO];
}


+ (id)loadingOverlayInView:(UIView *)iSuperview title:(NSString *)iTitle fullScreen:(BOOL)iFullscreen spinner:(BOOL)iShowSpinner {
    return [MyLoadingOverlay loadingOverlayInView:iSuperview title:iTitle fullScreen:iFullscreen spinner:iShowSpinner showCustomImages:NO];
}


+ (id)loadingOverlayInView:(UIView *)iSuperview title:(NSString *)iTitle fullScreen:(BOOL)iFullscreen spinner:(BOOL)iShowSpinner showCustomImages:(BOOL)iShowCustomImages {
    MyLoadingOverlay *anOverlay = [[MyLoadingOverlay alloc] initWithFrame:[iSuperview bounds]];

    if (!anOverlay) {
        return nil;
    }

    // Set our full screen attribute
    anOverlay.fullScreen = iFullscreen;
    anOverlay.showSpinner = iShowSpinner;

    anOverlay.userInteractionEnabled = YES;
    anOverlay.opaque = NO;
    anOverlay.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;

    [iSuperview addSubview:anOverlay];

    CGFloat theLabelWidth = anOverlay.frame.size.width;
    const CGFloat DEFAULT_LABEL_HEIGHT = 50.0;
    CGRect aFrame = CGRectMake(0, 0, theLabelWidth, DEFAULT_LABEL_HEIGHT);

    UILabel *aLabel = [[UILabel alloc] initWithFrame:aFrame];

    if (iTitle) {
        aLabel.text = iTitle;
        aLabel.textColor = [UIColor whiteColor];
        aLabel.backgroundColor = [UIColor clearColor];
        aLabel.textAlignment = NSTextAlignmentCenter;
        aLabel.font = [UIFont boldSystemFontOfSize:[UIFont smallSystemFontSize]];
        aLabel.shadowColor = [UIColor blackColor];
        aLabel.shadowOffset = CGSizeMake(0.0f, 1.0f);
        aLabel.autoresizingMask = UIViewAutoresizingFlexibleLeftMargin | UIViewAutoresizingFlexibleRightMargin | UIViewAutoresizingFlexibleTopMargin | UIViewAutoresizingFlexibleBottomMargin;

        [anOverlay addSubview:aLabel];
    }

    CGFloat aLabelYOffset = 0;

    if (anOverlay.showSpinner && !iShowCustomImages) {
        UIActivityIndicatorView *aSpinner = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhiteLarge];
        [anOverlay addSubview:aSpinner];
        aSpinner.autoresizingMask = UIViewAutoresizingFlexibleLeftMargin | UIViewAutoresizingFlexibleRightMargin | UIViewAutoresizingFlexibleTopMargin | UIViewAutoresizingFlexibleBottomMargin;
        [aSpinner startAnimating];

        CGRect aSpinnerRect = aSpinner.frame;
        aSpinnerRect.origin.x = floorf(0.5 * (anOverlay.frame.size.width - aSpinnerRect.size.width));
        aSpinnerRect.origin.y = floorf(0.5 * (anOverlay.frame.size.height - aSpinnerRect.size.height));
        aSpinner.frame = aSpinnerRect;

        aLabelYOffset = aSpinnerRect.origin.y + 32.0;
    } else {
        UIImage *aMyImage = [UIImage animatedImageNamed:@"My_Loading_" duration:1.0];
        aLabel.textColor = [UIColor colorWithRed:185.0/255.0 green:185.0/255.0 blue:185.0/255.0 alpha:1.0];
        UIImageView *anImageView = [[UIImageView alloc] initWithImage:aMyImage];
        anImageView.autoresizingMask = UIViewAutoresizingFlexibleLeftMargin | UIViewAutoresizingFlexibleRightMargin | UIViewAutoresizingFlexibleTopMargin | UIViewAutoresizingFlexibleBottomMargin;
        [anOverlay addSubview:anImageView];

        CGRect anImageRect = anImageView.frame;
        anImageRect.origin.x = floorf(0.5 * (anOverlay.frame.size.width - anImageRect.size.width));
        anImageRect.origin.y = floorf(0.5 * (anOverlay.frame.size.height - anImageRect.size.height));
        anImageView.frame = anImageRect;

        aLabelYOffset = anImageRect.origin.y + 32.0;    
    }

    aFrame.origin.x = floorf(0.5 * (anOverlay.frame.size.width - theLabelWidth));
    aFrame.origin.y = aLabelYOffset;    
    aLabel.frame = aFrame;

    // Set up the fade-in animation
    CATransition *aTransition = [CATransition animation];
    [aTransition setType:kCATransitionFade];
    [[iSuperview layer] addAnimation:aTransition forKey:@"layerAnimation"];

    return anOverlay;
}


#pragma mark -
#pragma instance methods

- (void)addToView:(UIView *)iSuperview {
    [iSuperview addSubview:self];
    // Set up the fade-in animation
    CATransition *aTransition = [CATransition animation];
    [aTransition setType:kCATransitionFade];
    [[iSuperview layer] addAnimation:aTransition forKey:@"layerAnimation"];
}


- (void)removeView {
    if (self.fullScreen) {
        [UIView animateWithDuration:0.3 animations:^{
            self.alpha = 0.0;
        } completion:^(BOOL finished) {
            [self removeFromSuperview];
        }];
    } else {
        UIView *aSuperview = [self superview];
        [super removeFromSuperview];
        // Set up the animation for image loading overlay
        CATransition *aTransition = [CATransition animation];
        [aTransition setType:kCATransitionFade];

        [[aSuperview layer] addAnimation:aTransition forKey:@"layerAnimation"];
    }
}


- (void)drawRect:(CGRect)iRect {
    if (!self.fullScreen) {
        iRect.size.height -= 1;
        iRect.size.width -= 1;

        const CGFloat RECT_PADDING = 4.0;
        iRect = CGRectInset(iRect, RECT_PADDING, RECT_PADDING);

        const CGFloat ROUND_RECT_CORNER_RADIUS = 5.0;
        CGPathRef aPath = copyPathWithRoundRect(iRect, ROUND_RECT_CORNER_RADIUS);

        CGContextRef aContext = UIGraphicsGetCurrentContext();

        const CGFloat BACKGROUND_OPACITY = 0.0;
        CGContextSetRGBFillColor(aContext, 0, 0, 0, BACKGROUND_OPACITY);
        CGContextAddPath(aContext, aPath);
        CGContextFillPath(aContext);

        const CGFloat STROKE_OPACITY = 0.25;
        CGContextSetRGBStrokeColor(aContext, 1, 1, 1, STROKE_OPACITY);
        CGContextAddPath(aContext, aPath);
        CGContextStrokePath(aContext);
        CGPathRelease(aPath);
    } else {
        CGContextRef aContext = UIGraphicsGetCurrentContext();
        const CGFloat BACKGROUND_OPACITY = 0.75;
        CGContextSetRGBFillColor(aContext, 0, 0, 0, BACKGROUND_OPACITY);
        CGContextFillRect(aContext, iRect);
    }
}


@end