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我有一個UICollectionView
,並且在每個單元中予設定的UILabel
的文本中,在cellForItemAtIndexPath
,從數組:UICollectionView委託方法沒有被調用正確
let array = ["New York City", "Chicago", "San Francisco"]
細胞出現標記的正確屏幕上,但是當我嘗試在didSelectItemAtIndexPath
中記錄標籤的值,它將該值記錄爲nil
。如果我嘗試在didSelectItemAtIndexPath
中執行其他任何操作(例如更改單元格的不透明度),則不會執行任何更改。
這裏可能會出現什麼問題?
相關的代碼:
視圖控制器具有超UICollectionViewDataSource
和UICollectionViewDelegateFlowLayout
。
集合觀察室的類聲明:
class PickerCell: UICollectionViewCell {
var label = UILabel()
override init(frame: CGRect) {
super.init(frame: frame)
contentView.backgroundColor = UIColor.clearColor()
label.frame = contentView.bounds
label.textColor = UIColor.whiteColor()
label.textAlignment = NSTextAlignment.Left
label.font = font.body
contentView.addSubview(label)
}
required init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
}
}
創建集合視圖:
func createPickerView() {
let pickerFlowLayout: UICollectionViewFlowLayout = PickerLocationFlowLayout()
pickerFlowLayout.itemSize = CGSize(width: screenSize.width, height: 40)
pickerFlowLayout.minimumLineSpacing = 0
let pickerView: UICollectionView
pickerView = UICollectionView(frame: CGRectMake(0, 0, screenSize.width, screenSize.height), collectionViewLayout: pickerFlowLayout)
pickerView.registerClass(PickerCell.self, forCellWithReuseIdentifier: "PickerCellId")
pickerView.delegate = self
pickerView.dataSource = self
self.view.addSubview(pickerView)
}
選擇單元格:
func collectionView(collectionView: UICollectionView, didSelectItemAtIndexPath indexPath: NSIndexPath) {
let cell = collectionView.dequeueReusableCellWithReuseIdentifier("PickerCellId", forIndexPath: indexPath) as! PickerCell
print("indexpath: \(indexPath.row), label: \(cell.label.text)")
// Prints the correct row number, but nil for the label.
}
您是否添加了collectionView.delegate和.dataSource = self? – Lee
是的,如'createPickerView()'所示,委託和數據源確實設置爲'self'。 –