我想做什么(逐字):保持一个tableview单元格指定的时间。一旦达到该时间段,细胞高度逐渐增加。当我松开手指时,细胞高度停止增长。
我有什么: 我有几个tableViewCells。使用以下方法在单元格上按下指定的时间后:
let longPressRecognizer = UILongPressGestureRecognizer(target: self, action: Selector("longPress:"))
longPressRecognizer.minimumPressDuration = 1.0s
longPressRecognizer.delegate = self
self.view.addGestureRecognizer(longPressRecognizer)
我想增加细胞高度。但是,如果不知道触摸位于哪一行,我就无法做到,所以我到了这里:
func longPress(longPressGestureRecognizer: UILongPressGestureRecognizer) {
if longPressGestureRecognizer.state == UIGestureRecognizerState.began {
let touchPoint = longPressGestureRecognizer.location(in: self.tableView)
if let indexPath = tableView.indexPathForRow(at: touchPoint) {
//let cell = tableView.cellForRow(at: indexPath)
}
}
}
我考虑过控制rowHeight,但这只是在tableView函数中,所以我不知道如何调用它。
我不确定如何继续。我并不是在寻找与.beginUpdates和.endUpdates有关的任何内容,因为我希望细胞生长是渐进的,最好是动画。
非常感谢任何帮助,因为我一直在寻找这个特定问题的答案很长一段时间。
包含rowHeight声明的代码:
override func viewDidLoad() {
super.viewDidLoad()
// let longPressRecognizer = UILongPressGestureRecognizer(target: self, action: Selector("longPress:"))
// longPressRecognizer.minimumPressDuration = 1.0 // 1 second press
// longPressRecognizer.delegate = self
// self.view.addGestureRecognizer(longPressRecognizer)
tableView.delegate = self
tableView.dataSource = self
tableView.allowsSelection = false
self.tableView.reorder.delegate = self
view.backgroundColor = UIColor(red:0.64, green:0.93, blue:0.78, alpha:1.0)
tableView.backgroundColor = UIColor.clear
tableView.rowHeight = 84
tableView.rowHeight = UITableViewAutomaticDimension
// Do any additional setup after loading the view.
}
func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
return 100
}
答案 0 :(得分:1)
Declare property for height of the cell and return this property in the tableviews's delegate method heightForRowAtIndexPath method
var heightForCell = 100
func longPress(longPressGestureRecognizer: UILongPressGestureRecognizer) {
if longPressGestureRecognizer.state == UIGestureRecognizerState.began {
let touchPoint = longPressGestureRecognizer.location(in: self.tableView)
if let indexPath = tableView.indexPathForRow(at: touchPoint) {
self. heightForCell = // height you want to set
// now reload cell again
}
}
}
答案 1 :(得分:0)
我不想使用单词详细解释事情,因此我将只包含一个相对较短的代码(也可用gist),其中包含解释基本知识的注释。我还没有真正关注架构和清洁代码,我只专注于完成任务。以此为代码 - 尝试在代码库中做得更好。
无论如何,代码应该非常明确且不言自明,但我想在你深入研究之前为你画一幅大图。在解决方案中,我将高度保持在CGFloat
(变量cellHeights
)的数组中,并通过更改数组中的相应高度来修改给定行的高度。该数组作为heightForRowAt
实现的基础。
当长按开始时,我启动一个计时器,每0.1秒通过修改cellHeights
数组中的高度并告诉tableView
重绘自己来更新所选行的高度。直到达到该给定行的限制,然后我才取消(无效)计时器。
如果长按在达到极限高度之前结束,我只是明确取消定时器,以便在用户松开印刷机时单元停止放大。
就是这样。我建议您使用EnlargingCellsOnLongPressController
gist(或下面的代码,代码相同),在您自己的设备上试用,阅读代码以及评论,我相信您应该能够在你自己的情况下实现它。
import UIKit
class EnlargingCellsOnLongPressController: UITableViewController {
// this will hold the indexPath of the cell we are currently enlarging
var enlargingIndexPath: IndexPath?
// dummy data model
var modelItems: [String] = []
// we will need to keep the heights for each particular cell (since any can be resized)
var cellHeights: [CGFloat] = []
// some height limit, I will set it for myself to 200
let limitHeight = CGFloat(200)
// the enlarging itself will be done by a timer
weak var timer: Timer?
override func viewDidLoad() {
super.viewDidLoad()
// nothing special here
tableView.register(UITableViewCell.self, forCellReuseIdentifier: "cell")
tableView.estimatedRowHeight = 100
tableView.allowsSelection = false
// creating some dummy data, 30 items, and for each a cell height that will start at 100
for index in 0..<30 {
modelItems.append("Item \(index)")
// by default we will start with 100
cellHeights.append(CGFloat(100))
}
// please, use swift 4 and the new #selector syntax
let longPressRecognizer = UILongPressGestureRecognizer(target: self, action: #selector(longPress(longPressGestureRecognizer:)))
longPressRecognizer.minimumPressDuration = 1
self.view.addGestureRecognizer(longPressRecognizer)
}
// following three methods should be clear
override func numberOfSections(in tableView: UITableView) -> Int {
return 1
}
override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return modelItems.count
}
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "cell", for: indexPath)
cell.textLabel?.text = modelItems[indexPath.row]
return cell
}
// for height for row we will return a specific height from cellHeights array
override func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
return cellHeights[indexPath.row]
}
@objc func longPress(longPressGestureRecognizer: UILongPressGestureRecognizer) {
if longPressGestureRecognizer.state == UIGestureRecognizerState.began {
let touchPoint = longPressGestureRecognizer.location(in: self.tableView)
if let indexPath = tableView.indexPathForRow(at: touchPoint) {
//when the press starts on a cell, we will keep the indexPath for the cell
self.enlargingIndexPath = indexPath
// and turn on enlarging
self.startEnlarging()
}
} else if longPressGestureRecognizer.state == .ended {
// when the press is ended, we can stop enlarging
stopEnlarging()
}
}
func startEnlarging() {
// interval 0.1 second seems smooth enough (redraw seems to be animated anyway)
timer = Timer.scheduledTimer(withTimeInterval: 0.1, repeats: true, block: { [weak self] (timer) in
guard let strongSelf = self, let enlargingIndexPath = self?.enlargingIndexPath else { return }
let oldHeight = strongSelf.cellHeights[enlargingIndexPath.row]
// since the timer repeats every 0.1 second, this will enlarge the cell 20 points per second till limit
// in one cycle I will enlarge the cell by two points
let newHeight = oldHeight + 2
if newHeight < strongSelf.limitHeight {
// if the newHeight did not reach limit,
// update height and redraw tableView
strongSelf.cellHeights[enlargingIndexPath.row] = newHeight
strongSelf.tableView.beginUpdates()
strongSelf.tableView.setNeedsLayout()
strongSelf.tableView.endUpdates()
} else {
// reached maximum size, just cancel the timer
strongSelf.stopEnlarging()
}
})
}
func stopEnlarging() {
// this just cancels the timer
timer?.invalidate()
}
}
<强>更新强>
为了完整起见,我创建了gist使用autolayout和UITableViewAutomaticDimension
,如果您决定使用它而不是heightForRowAt
。但原则是一样的。