经过大量的试验和错误,我放弃了,并提出了这个问题。我见过很多人有类似的问题,但不能得到所有的答案工作正确。
我有一个由自定义单元格组成的UITableView。单元格由相邻的5个文本字段组成(有点像网格)。
当我试图滚动和编辑UITableView底部的单元格时,我不能设法让我的单元格正确地定位在键盘上方。
我看到过很多关于改变视图大小的回答……但到目前为止,没有一种效果很好。
谁能用一个具体的代码示例来阐明这样做的“正确”方式?
经过大量的试验和错误,我放弃了,并提出了这个问题。我见过很多人有类似的问题,但不能得到所有的答案工作正确。
我有一个由自定义单元格组成的UITableView。单元格由相邻的5个文本字段组成(有点像网格)。
当我试图滚动和编辑UITableView底部的单元格时,我不能设法让我的单元格正确地定位在键盘上方。
我看到过很多关于改变视图大小的回答……但到目前为止,没有一种效果很好。
谁能用一个具体的代码示例来阐明这样做的“正确”方式?
当前回答
我想我已经想出了与苹果应用程序行为相匹配的解决方案。
首先,在viewWillAppear:订阅键盘通知,这样你就知道什么时候键盘会显示和隐藏,系统会告诉你键盘的大小,但不要忘记在viewWillDisappear:中取消注册。
[[NSNotificationCenter defaultCenter]
addObserver:self
selector:@selector(keyboardWillShow:)
name:UIKeyboardWillShowNotification
object:nil];
[[NSNotificationCenter defaultCenter]
addObserver:self
selector:@selector(keyboardWillHide:)
name:UIKeyboardWillHideNotification
object:nil];
实现类似于下面的方法,以便在键盘显示时调整tableView的大小以匹配可见区域。这里我单独跟踪键盘的状态,所以我可以自己选择何时将tableView设置为全高度,因为你在每个字段更改时都会收到这些通知。不要忘记实现keyboardWillHide:并选择适当的地方来修复你的tableView大小。
-(void) keyboardWillShow:(NSNotification *)note
{
CGRect keyboardBounds;
[[note.userInfo valueForKey:UIKeyboardBoundsUserInfoKey] getValue: &keyboardBounds];
keyboardHeight = keyboardBounds.size.height;
if (keyboardIsShowing == NO)
{
keyboardIsShowing = YES;
CGRect frame = self.view.frame;
frame.size.height -= keyboardHeight;
[UIView beginAnimations:nil context:NULL];
[UIView setAnimationBeginsFromCurrentState:YES];
[UIView setAnimationDuration:0.3f];
self.view.frame = frame;
[UIView commitAnimations];
}
}
现在这是滚动位,我们先计算出一些大小,然后我们看到我们在可见区域中的位置,并设置我们想要滚动的矩形,根据它在视图中的位置,将它设置为文本字段中间上方或下方的半视图。在本例中,我们有一个UITextFields数组和一个用于跟踪它们的enum,因此用rowHeight乘以行号就得到了这个外部视图中帧的实际偏移量。
- (void) textFieldDidBeginEditing:(UITextField *)textField
{
CGRect frame = textField.frame;
CGFloat rowHeight = self.tableView.rowHeight;
if (textField == textFields[CELL_FIELD_ONE])
{
frame.origin.y += rowHeight * CELL_FIELD_ONE;
}
else if (textField == textFields[CELL_FIELD_TWO])
{
frame.origin.y += rowHeight * CELL_FIELD_TWO;
}
else if (textField == textFields[CELL_FIELD_THREE])
{
frame.origin.y += rowHeight * CELL_FIELD_THREE;
}
else if (textField == textFields[CELL_FIELD_FOUR])
{
frame.origin.y += rowHeight * CELL_FIELD_FOUR;
}
CGFloat viewHeight = self.tableView.frame.size.height;
CGFloat halfHeight = viewHeight / 2;
CGFloat midpoint = frame.origin.y + (textField.frame.size.height / 2);
if (midpoint < halfHeight)
{
frame.origin.y = 0;
frame.size.height = midpoint;
}
else
{
frame.origin.y = midpoint;
frame.size.height = midpoint;
}
[self.tableView scrollRectToVisible:frame animated:YES];
}
这似乎工作得很好。
其他回答
另一个简单的方法(只适用于一个部分)
//cellForRowAtIndexPath
UItextField *tf;
[cell addSubview:tf];
tf.tag = indexPath.row;
tf.delegate = self;
//textFieldDidBeginEditing:(UITextField *)text
[[self.tableView scrollToRowsAtIndexPath:[NSIndexPath indexPathForRow:text.tag in section:SECTIONINTEGER] animated:YES];
Swift 3-4动画和键盘帧改变的解决方案:
首先,创建Bool类型:
// MARK: - Private Properties
private var isKeyboardShowing = false
其次,在系统键盘通知中添加观察者:
// MARK: - Overriding ViewController Life Cycle Methods
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow), name: .UIKeyboardWillShow, object: nil)
NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillHide), name: .UIKeyboardWillHide, object: nil)
NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillChangeFrame), name: .UIKeyboardWillChangeFrame, object: nil)
}
第三,准备动画功能:
func adjustTableViewInsets(keyboardHeight: CGFloat, duration: NSNumber, curve: NSNumber){
var extraHeight: CGFloat = 0
if keyboardHeight > 0 {
extraHeight = 20
isKeyboardShowing = true
} else {
isKeyboardShowing = false
}
let contentInset = UIEdgeInsets(top: 0, left: 0, bottom: keyboardHeight + extraHeight, right: 0)
func animateFunc() {
//refresh constraints
//self.view.layoutSubviews()
tableView.contentInset = contentInset
}
UIView.animate(withDuration: TimeInterval(duration), delay: 0, options: [UIViewAnimationOptions(rawValue: UInt(curve))], animations: animateFunc, completion: nil)
}
然后添加target/action方法(由观察者调用):
// MARK: - Target/Selector Actions
func keyboardWillShow(notification: NSNotification) {
if !isKeyboardShowing {
if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue {
let keyboardHeight = keyboardSize.height
let duration = notification.userInfo?[UIKeyboardAnimationDurationUserInfoKey] as! NSNumber
let curve = notification.userInfo?[UIKeyboardAnimationCurveUserInfoKey] as! NSNumber
adjustTableViewInsets(keyboardHeight: keyboardHeight, duration: duration, curve: curve)
}
}
}
func keyboardWillHide(notification: NSNotification) {
let duration = notification.userInfo?[UIKeyboardAnimationDurationUserInfoKey] as! NSNumber
let curve = notification.userInfo?[UIKeyboardAnimationCurveUserInfoKey] as! NSNumber
adjustTableViewInsets(keyboardHeight: 0, duration: duration, curve: curve)
}
func keyboardWillChangeFrame(notification: NSNotification) {
if isKeyboardShowing {
let duration = notification.userInfo?[UIKeyboardAnimationDurationUserInfoKey] as! NSNumber
let curve = notification.userInfo?[UIKeyboardAnimationCurveUserInfoKey] as! NSNumber
if let newKeyboardSize = (notification.userInfo?[UIKeyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue {
let keyboardHeight = newKeyboardSize.height
adjustTableViewInsets(keyboardHeight: keyboardHeight, duration: duration, curve: curve)
}
}
}
最后,不要忘记在deinit或viewWillDisappear中删除观察者:
deinit {
NotificationCenter.default.removeObserver(self)
}
一个更加流线型的解决方案。它滑入UITextField委托方法,所以它不需要搞砸/ UIKeyboard通知。
实现注意事项:
kSettingsRowHeight——UITableViewCell的高度。
offsetTarget和offsetThreshold基于kSettingsRowHeight。如果使用不同的行高,则将这些值设置为point的y属性。[alt:以不同的方式计算行偏移量。]
- (BOOL)textFieldShouldBeginEditing:(UITextField *)textField {
CGFloat offsetTarget = 113.0f; // 3rd row
CGFloat offsetThreshold = 248.0f; // 6th row (i.e. 2nd-to-last row)
CGPoint point = [self.tableView convertPoint:CGPointZero fromView:textField];
[UIView beginAnimations:nil context:nil];
[UIView setAnimationDuration:0.2];
[UIView setAnimationCurve:UIViewAnimationCurveEaseOut];
CGRect frame = self.tableView.frame;
if (point.y > offsetThreshold) {
self.tableView.frame = CGRectMake(0.0f,
offsetTarget - point.y + kSettingsRowHeight,
frame.size.width,
frame.size.height);
} else if (point.y > offsetTarget) {
self.tableView.frame = CGRectMake(0.0f,
offsetTarget - point.y,
frame.size.width,
frame.size.height);
} else {
self.tableView.frame = CGRectMake(0.0f,
0.0f,
frame.size.width,
frame.size.height);
}
[UIView commitAnimations];
return YES;
}
- (BOOL)textFieldShouldReturn:(UITextField *)textField {
[textField resignFirstResponder];
[UIView beginAnimations:nil context:nil];
[UIView setAnimationBeginsFromCurrentState:YES];
[UIView setAnimationDuration:0.2];
[UIView setAnimationCurve:UIViewAnimationCurveEaseOut];
CGRect frame = self.tableView.frame;
self.tableView.frame = CGRectMake(0.0f,
0.0f,
frame.size.width,
frame.size.height);
[UIView commitAnimations];
return YES;
}
我将把我的解决方案(或者QuickDialog的)扔进帽子里。基本上是等待动画到滚动。获得键盘动画JIT而不是神奇的数字会很好。
-(void)textFieldDidBeginEditing:(UITextField *)textField
{
if (textField == self.emailTextField) {
NSIndexPath *indexPath = [NSIndexPath indexPathForRow:0 inSection:0];
dispatch_time_t popTime = dispatch_time(DISPATCH_TIME_NOW, 50 * USEC_PER_SEC);
dispatch_after(popTime, dispatch_get_main_queue(), ^(void){
[self.tableView scrollToRowAtIndexPath:indexPath atScrollPosition:UITableViewScrollPositionTop animated:YES];
});
}
}
如果你使用UITableViewController而不是UIViewController,它会自动这样做。