ios - 如何在 uipickerview (swift 4) 上居中工具栏按钮

Question

我想让按钮在工具栏上居中。目前该按钮会自动转到右侧。

let toolbar = UIToolbar()
toolbar.sizeToFit()

Answer 1

您只需在按钮之间添加 2 个 flexSpace 即可。

例如:

let toolbar = UIToolbar(frame: CGRect(x: 0, y: UIApplication.shared.statusBarFrame.height, width: view.bounds.width, height: 44))

var items = [UIBarButtonItem]()

items.append( UIBarButtonItem(barButtonSystemItem: .flexibleSpace, target: self, action: nil) )
items.append( UIBarButtonItem(barButtonSystemItem: .add, target: self, action: #selector(test)) )
items.append( UIBarButtonItem(barButtonSystemItem: .flexibleSpace, target: self, action: nil) )

toolbar.items = items
self.view.addSubview(toolbar)