Question

我正在使用UITableView和UIRefreshControl开发iOS App。

我想将UIRefreshControl指标的初始位置从默认值下调50px。我写下以下代码。

但是，初始位置没有改变。它保持原状。

你能告诉我如何解决这个问题吗？

CGFloat customRefreshControlHeight = 50.0f;
CGFloat customRefreshControlWidth = 320.0f;
CGRect customRefreshControlFrame = CGRectMake(0.0f,
                                              customRefreshControlHeight,
                                              customRefreshControlWidth,
                                              customRefreshControlHeight);
UIRefreshControl *refreshControl = [[UIRefreshControl alloc] initWithFrame:customRefreshControlFrame];
refreshControl.tintColor = [UIColor blackColor];
[refreshControl addTarget:self action:@selector(onRefresh:) forControlEvents:UIControlEventValueChanged];
[self.tableView addSubview:refreshControl];

Answer 1

直接设置框架是行不通的，但是您仍然可以随时使用AutoLayout来放置refreshControl。只是不要忘记将translatesAutoresizingMaskIntoConstraints设置为false。

例如，此代码在屏幕中间设置了refreshControl。

let refreshControl = UIRefreshControl()
collectionView.refreshControl = refreshControl
refreshControl.translatesAutoresizingMaskIntoConstraints = false

NSLayoutConstraint(item: refreshControl, attribute: .centerX, relatedBy: .equal, toItem: view, attribute: .centerX, multiplier: 1.0, constant: 0).isActive = true
NSLayoutConstraint(item: refreshControl, attribute: .centerY, relatedBy: .equal, toItem: view, attribute: .centerY, multiplier: 1.0, constant: 0).isActive = true

Answer 2

简单（Swift）

   override func viewDidLayoutSubviews() {
        super.viewDidLayoutSubviews()
        refreshController.frame = CGRectMake(refreshController.bounds.origin.x,
                                              50.0,
                                              refreshController.bounds.size.width,
                                              refreshController.bounds.size.height);
        refreshController.superview?.sendSubviewToBack(refreshController) // for fix overlap tableview
    }

Answer 3

我的解决方案是使用具有覆盖框架属性的自定义UIRefreshControl类。以下代码适用于所有情况。您可以尝试通过应用变换来实现它而不进行变换。自iOS 11起，无法在viewDidLayoutSubviews中设置框架。

class OffsetableRefreshControl: UIRefreshControl {

  var offset: CGFloat = 64
  override var frame: CGRect {
    set {
      var rect = newValue
      rect.origin.y += offset
      super.frame = rect
    }
    get {
      return super.frame
    }
  }

}

更改iOS App中UIRefreshControl指示器的初始位置

3 个答案: