以编程方式添加 UIView 不起作用（UIView 应显示 UIWebView 并打开 URL）

Question

目前正在为我的 iPhone 应用程序（如 Pocket，用户在第一次启动后进行一些动手操作）制作两个介绍页面（第一个显示图像，第二个应该显示一个网站）。 遇到了 Matthew York 的 GitHub 项目，它与 images 和 text 完美配合。 此外，我喜欢在介绍中展示一个网站，但我无法让它发挥作用。我的programmatically 创建的UIWebView 只是没有出现。

Matthew York 的GitHub 项目： https://github.com/MatthewYork/iPhone-IntroductionTutorial

显示两个介绍页面的完整代码如下所示。 请注意panelImage 可以按预期工作，但panelView 不能。 我看到第二页出现了，但没有UIWebView。 我想我将subview 添加到屏幕上不可见的view，因此我看不到它。我对吗？你能看看：[view addSubview:aWebView];method：showWebView

ViewController.m

- (void)showIntro
{
    MYIntroductionPanel *panelImage = [[MYIntroductionPanel alloc] initWithimage:[UIImage imageNamed:@"img.jpg"] description:@"TEST: IMAGE"];

    MYIntroductionPanel *panelView = [[MYIntroductionPanel alloc] initWitView:[self showWebView] description:@"TEST: VIEW"];

    MYIntroductionView *introductionView = [[MYIntroductionView alloc] initWithFrame:CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height) headerText:@"TESTING" panels:@[panelImage, panelView] languageDirection:MYLanguageDirectionLeftToRight];

    introductionView.BackgroundImageView.image = [UIImage imageNamed:@"BG_iPad_1024.png"];
    introductionView.delegate = self;
    [introductionView showInView:self.view];
}

- (UIView *)showWebView
{
    UIWebView *aWebView= [[UIWebView alloc] initWithFrame:CGRectMake(0, 0, 320, 290)];
    NSURLRequest *requestObj = [NSURLRequest requestWithURL:[NSURL URLWithString:@"http://www.google.com"]];
    [aWebView loadRequest:requestObj];

    UIView *view = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 320, 300)];
    [view addSubview:aWebView];

    return view;
}

MYIntroductionPanel.m

-(id)initWitView:(UIView *)view description:(NSString *)description{
    if (self = [super init]) {
        self.view = [[UIView alloc] init];
        self.Description = [[NSString alloc] initWithString:description];
    }
    return self;
}

-(id)initWithimage:(UIImage *)image title:(NSString *)title description:(NSString *)description{
    if (self = [super init]) {
        self.Image = [[UIImage alloc] init];
        self.Image = image;
        self.Title = title;
        self.Description = [[NSString alloc] initWithString:description];
    }
    return self;
}

Answer 1

您添加UIWebView 的视图永远不会添加到视图层次结构本身。您似乎正在将 UIWebView 的超级视图传递给 MyIntroductionPanel 的 initWithView:description: 方法，但该方法只是忽略其输入视图并使用 self.view = [[UIView alloc] init] 创建一个新视图。尝试在您的 initWithView:description: 方法中设置 self.view = view。

Answer 2

我并不喜欢作者的所有决定，而是遵循他的模式来实现您想要的。

添加了以下内容：

// MyIntroductionPanel.h
@property (nonatomic, retain) NSURL *url;

-(id)initWithURL:(NSURL *)url;

// MyIntroductionPanel.m
-(id)initWithURL:(NSURL *)url {

    if (self = [super init]) {
        _url = url;
    }
    return self;
}

这很容易。这不太容易 - 破解布局方法来处理带有 url 的面板。我没有太努力去理解这种方法，只是添加了我能做到的东西来让它工作。我的添加标记为 // DANH

//  MYIntroductionView.m

-(UIView *)PanelViewForPanel:(MYIntroductionPanel *)panel atXIndex:(CGFloat*)xIndex{

    // snipped original code    

    NSInteger descriptionHeight = panelDescriptionTextView.contentSize.height;
    int contentWrappedScrollViewHeight = 0;
    if ((imageHeight + descriptionHeight + panelTitleLabelFrame.size.height) > maxScrollViewHeight) {
        contentWrappedScrollViewHeight = maxScrollViewHeight;
        imageHeight = contentWrappedScrollViewHeight-descriptionHeight - panelTitleLabelFrame.size.height - 10;
    }
    else if ((imageHeight+descriptionHeight + panelTitleLabelFrame.size.height) <= maxScrollViewHeight){
        contentWrappedScrollViewHeight = imageHeight + panelTitleLabelFrame.size.height + descriptionHeight;
    }

    // DANH
    if (panel.url) {
        contentWrappedScrollViewHeight = 300;
        // you can certainly do a better job than I did here, but just to get going
    }

    panelView.frame = CGRectMake(*xIndex, 0, self.ContentScrollView.frame.size.width, contentWrappedScrollViewHeight);

    //Build image container
    UIImageView *panelImageView = [[UIImageView alloc] initWithFrame:CGRectMake(5, 0, self.ContentScrollView.frame.size.width - 10, imageHeight)];
    panelImageView.contentMode = UIViewContentModeScaleAspectFit;
    panelImageView.backgroundColor = [UIColor clearColor];
    panelImageView.image = panel.Image;
    panelImageView.layer.cornerRadius = 3;
    panelImageView.clipsToBounds = YES;
    [panelView addSubview:panelImageView];

    // DANH
    // add webview on top if we have a url
    if (panel.url) {
        UIWebView *webView = [[UIWebView alloc] initWithFrame:CGRectMake(0, 0, self.ContentScrollView.frame.size.width, 300)];
        [webView loadRequest:[NSURLRequest requestWithURL:panel.url]];
        [panelView addSubview:webView];
    }

    // snipped original code    

}

现在，用示例代码调用它......

// MYViewController.m

MYIntroductionPanel *panel3 = [[MYIntroductionPanel alloc] initWithURL:[NSURL URLWithString:@"http://www.google.com"]];

// ...
MYIntroductionView *introductionView = [[MYIntroductionView alloc] initWithFrame:CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height) headerText:@"MYIntroductionView" panels:@[panel, panel2, panel3] languageDirection:MYLanguageDirectionLeftToRight];