title: UIProgressView work not correctly when setFrame in UICollectionViewCell
body: <p>I create a UIProgressView inside UICollectionViewCell, I try to setFrame for UIProgressView to change position in UICollectionViewCell but when do that, some cells not display progressView.
  When I delete setFrame, It's OK but default width at the top of UICollectionViewCell</p>
  
  <p>What's the problem?How to change UIProgressView size, origin? Please help!</p>
  
  <pre><code>//Cell:UICollectionViewCell 
  //Cell.m
      - (id)initWithFrame:(CGRect)frame
      {
          self = [super initWithFrame:frame];
          if (self) {
             //ProgressView
             self.progressView = [[UIProgressView alloc] initWithProgressViewStyle:UIProgressViewStyleBar];
             [self.progressView setFrame:progressViewFrame];//Some cells not display progressView
             [self.progressView addSubview:self.downloadBar];
      }
          return self;
      }
  </code></pre>