加载动画内存泄漏

我已经编写了管理应用程序的所有网络调用的网络类。有两种方法 showLoadingAnimationView 和 hideLoadingAnimationView 这将在我当前的视图控制器上的淡入淡出背景的视图中显示uiActivityIndicatorView。在这两种方法中,我的记忆有漏洞。这是密码

-(void)showLoadingAnimationView
{ 
    textmeAppDelegate *textme = (textmeAppDelegate *)[[UIApplication sharedApplication] delegate];
    [[UIApplication sharedApplication] setNetworkActivityIndicatorVisible:YES];
    if(wrapperLoading != nil)
    {
        [wrapperLoading release];
    }
    wrapperLoading = [[UIView alloc] initWithFrame:CGRectMake(0.0, 0.0, 320.0, 480.0)];
    wrapperLoading.backgroundColor = [UIColor clearColor];
    wrapperLoading.alpha = 0.8;

    UIView *_loadingBG = [[UIView alloc] initWithFrame:CGRectMake(0.0, 0.0, 320.0, 480.0)];
    _loadingBG.backgroundColor = [UIColor blackColor];
    _loadingBG.alpha = 0.4;

    circlingWheel = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhiteLarge];
    CGRect wheelFrame = circlingWheel.frame;
    circlingWheel.frame = CGRectMake(((320.0 - wheelFrame.size.width) / 2.0), ((480.0 - wheelFrame.size.height) / 2.0), wheelFrame.size.width, wheelFrame.size.height);
    [wrapperLoading addSubview:_loadingBG]; 
    [wrapperLoading addSubview:circlingWheel];
    [circlingWheel startAnimating];
    [textme.window addSubview:wrapperLoading];
    [_loadingBG release];
    [circlingWheel release];
}

-(void)hideLoadingAnimationView
{   
    [[UIApplication sharedApplication] setNetworkActivityIndicatorVisible:NO];
    wrapperLoading.alpha = 0.0;

    [self.wrapperLoading removeFromSuperview];
    //[NSTimer scheduledTimerWithTimeInterval:0.8 target:wrapperLoading selector:@selector(removeFromSuperview) userInfo:nil repeats:NO];
}

以下是我如何称呼这两种方法

[NSThread detachNewThreadSelector:@selector(showLoadingAnimationView) toTarget:self withObject:nil];

然后在稍后的代码中,我使用下面的函数调用来隐藏动画。

[self hideLoadingAnimationView];

调用ShowLoadingAnimationView函数时,内存泄漏。代码中有什么错误,或者在进行网络调用时是否有更好的显示加载动画的技术?