Question

我的项目中有这个代码，它创建了带有来自Web服务的值的标签和图像的UIButtons。

- (void)getMoviePosterImages
{
    for (int i = 0; i < [self.rowCount intValue]; i++)
    {
        NSArray *postersArray = [self.jsonMutableArray objectAtIndex:i];
        AFImageRequestOperation *operation  = [AFImageRequestOperation imageRequestOperationWithRequest:[NSURLRequest requestWithURL:[NSURL URLWithString:[postersArray objectAtIndex:6]]] imageProcessingBlock:nil
        success:^(NSURLRequest *request, NSHTTPURLResponse *response, UIImage *image)
        {
            [moviePosterButton setBackgroundImage:image forState:UIControlStateNormal];
        }
        failure:nil];

        [operation start];
    }
}

这是我创建UILabels的代码：

- (void)displayMovieTitlesAndFrames
{
    int imageCount = [self.rowCount intValue];
    int offset_x = 21;
    int offset_y = 24;

    for (int i = 0; i < imageCount; i++)
    {
        // compute x & y offset
        if (i % 3 == 0)
        {
            offset_x = 21;
        }
        else if (i % 3 == 1)
        {
            offset_x = 115;
        }
        else
        {
            offset_x = 210;
        }

        whiteBackgroundLabel = [[[UILabel alloc] initWithFrame:CGRectMake(offset_x, offset_y, MOVIE_THUMBNAIL_W, MOVIE_THUMBNAIL_H)] autorelease];
        whiteBackgroundLabel.backgroundColor = [UIColor whiteColor];
        whiteBackgroundLabel.layer.cornerRadius = 3.0;
        whiteBackgroundLabel.layer.borderColor = [[UIColor lightGrayColor] CGColor];
        whiteBackgroundLabel.layer.borderWidth = 1.0;
        [scrollview addSubview:whiteBackgroundLabel];

        moviePosterButton = [[UIButton buttonWithType:UIButtonTypeCustom] retain];
        moviePosterButton.frame = CGRectMake(offset_x + 5, offset_y + 5, MOVIE_THUMBNAIL_W - 10, MOVIE_THUMBNAIL_H - 10);
        moviePosterButton.backgroundColor = [UIColor clearColor];
        [moviePosterButton setBackgroundImage:[UIImage imageNamed:@"placeholder.png"] forState:UIControlStateNormal];
        moviePosterButton.tag = i;
        [moviePosterButton addTarget:self
                              action:@selector(imageButtonPressed:)
                    forControlEvents:UIControlEventTouchUpInside];
        [scrollview addSubview:moviePosterButton];

        movieTitleLabel = [[[UILabel alloc] initWithFrame:CGRectMake(offset_x, offset_y + 143, 90, 20)] autorelease];
        movieTitleLabel.backgroundColor = [UIColor whiteColor];
        movieTitleLabel.layer.cornerRadius = 3.0;
        movieTitleLabel.layer.borderColor = [[UIColor lightGrayColor] CGColor];
        movieTitleLabel.layer.borderWidth = 1.0;
        movieTitleLabel.font = [UIFont fontWithName:@"Helvetica" size:11.0];
        movieTitleLabel.textColor = [UIColor darkGrayColor];
        movieTitleLabel.textAlignment = UITextAlignmentCenter;
        movieTitleLabel.numberOfLines = 1;
        movieTitleLabel.text = [[self.jsonMutableArray objectAtIndex:i] objectAtIndex:1];
        [scrollview addSubview:movieTitleLabel];

        quickBuyButton = [[UIButton buttonWithType:UIButtonTypeCustom] retain];
        quickBuyButton.frame = CGRectMake(offset_x + 1 + (MOVIE_THUMBNAIL_W - QUICK_BUY_BUTTON_W - 2), offset_y - 1 + 2, QUICK_BUY_BUTTON_W, QUICK_BUY_BUTTON_H);
        quickBuyButton.backgroundColor = [UIColor clearColor];
        [quickBuyButton setBackgroundImage:QUICK_BUY_BUTTON forState:UIControlStateNormal];
        quickBuyButton.tag = i;
        [quickBuyButton addTarget:self
                           action:@selector(quickBuyButtonPressed:)
                 forControlEvents:UIControlEventTouchUpInside];
        [scrollview addSubview:quickBuyButton];

        // increment offset
        if (offset_x == 210)
        {
            offset_y += 171;
        }
    }

    if ((offset_x == 21) || (offset_x == 115))
    {
        offset_y += 171;
    }

    [self adjustScrollViewAndBackground:offset_y];
}

我的所有UIButtons都是使用各自的标签创建的，我想将它们的图像放在这些按钮上。上面的代码仅适用于最后创建的UIButton。我想使用上面的代码用图像填充我的所有按钮。有人能告诉我在哪里弄错了吗？

Answer 1

在getMoviePosterImages方法中，您将图像设置为moviePosterButton，这可能是您刚创建的最后一个按钮，因此如果只有最后一个按钮获取其图像，这是正常的。您需要按标签检索每个按钮，或者使用所有按钮构建阵列，以便轻松访问它们。你也许可以这样做：

- (void)getMoviePosterImages
{
    for (int i = 0; i < [self.rowCount intValue]; i++)
    {
        NSArray *postersArray = [self.jsonMutableArray objectAtIndex:i];
        AFImageRequestOperation *operation  = [AFImageRequestOperation imageRequestOperationWithRequest:[NSURLRequest requestWithURL:[NSURL URLWithString:[postersArray objectAtIndex:6]]] imageProcessingBlock:nil
        success:^(NSURLRequest *request, NSHTTPURLResponse *response, UIImage *image)
        {
            [(UIButton *)buttonsArray[i] setBackgroundImage:image forState:UIControlStateNormal];
            // or
            // [(UIButton *)[self.view viewWithTag:i] setBackgroundImage:image forState:UIControlStateNormal];
        }
        failure:nil];

        [operation start];
    }
}

希望这会有所帮助;）

使用AFNetworking设置UIButton图像

1 个答案: