当组件0被更改时(为了避免由于indexOutOfRange引起的可能错误),我无法弄清楚如何将PickerView的第一个组件中使用的数组重置为组件0。
这是我数据的结构
let bananas = ["banana1", "banana2"]
let fruitArray = ["banana1" : ["cherry1","cherry2"], "banana2" : ["cherry1", "cherry2", "cherry3"]]
func numberOfComponents(in pickerView: UIPickerView) -> Int {
return 2
}
func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
if component == 0 {
return bananas.count
}
else {
let selectedBanana = pickerView.selectedRow(inComponent: 0)
return fruitArray[banana[selectedBanana]]!.count
}
}
func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
let selectedBanana = pickerView.selectedRow(inComponent: 0)
let selectedCherry = pickerView.selectedRow(inComponent: 1)
bananaPicked = bananas[selectedBanana]
cherryPicked = fruitArray[bananaPicked]![selectedCherry]
pickerView.reloadAllComponents()
}
func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
if component == 0 {
return bananas[row]
}
else {
let selectedBanana = pickerView.selectedRow(inComponent: 0)
return fruitArray[selectedBanana]![row]
}
}
现在,当我(我要说)在banana2和cherry3中,但我切换到banana1时,我得到一个indexOutOfRange错误,因为当然第一个香蕉阵列没有第三个项目。我希望每当香蕉行被改为重置为0樱桃行。
__________更新______________这是另一个错误,导致我发现崩溃(indexOutOfRange),我发布了截图。
当组件0更改时,在组件1中将所选行设置为0。
此外,无需重新加载所有组件。只有组件1需要重新加载。
func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
if component == 0 {
pickerView.selectRow(0, inComponent: 1, animated: false)
}
let selectedBanana = pickerView.selectedRow(inComponent: 0)
let selectedCherry = pickerView.selectedRow(inComponent: 1)
bananaPicked = bananas[selectedBanana]
cherryPicked = fruitArray[bananaPicked]![selectedCherry]
//pickerView.reloadAllComponents()
pickerView.reloadComponent(1)
}
对于你的第二次崩溃,尝试一些防御性编程以避免崩溃:
func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
if component == 0 {
return bananas[row]
}
else {
let selectedBanana = pickerView.selectedRow(inComponent: 0)
let rowData = fruitArray[bananas[selectedBanana]]!
if rowData.indices.contains(row) {
return rowData[row]
} else {
return nil
}
}
}