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
以下是我如何做到这一点的，这是Sam Ho和Marcel W的回答，以及我自己对蹩脚代码的一些错误修复。我用的是UITableViewController。当键盘显示时，表格现在可以正确地调整大小。
1)在viewDidLoad我添加:
self.tableView.autoresizingMask = UIViewAutoresizingFlexibleHeight;
2)我忘记在viewWillAppear和awakeFromNib中调用超等价物。我把这些加回来了。
其他回答
如果你的UITableView是由UITableViewController的子类管理的，而不是UITableView，并且文本字段委托是UITableViewController，它应该自动管理所有的滚动——所有这些其他注释在实践中是很难实现的。
有关一个好例子，请参阅apple示例代码项目:TaggedLocations。
你可以看到它自动滚动，但似乎没有任何代码做到这一点。该项目还具有自定义表视图单元格，因此，如果使用它作为指南构建应用程序，应该会得到预期的结果。
我在做一些非常相似的事情它是通用的，不需要为你的代码计算特定的东西。 只需检查代码上的注释:
在MyUIViewController.h
@interface MyUIViewController: UIViewController <UITableViewDelegate, UITableViewDataSource>
{
UITableView *myTableView;
UITextField *actifText;
}
@property (nonatomic, retain) IBOutlet UITableView *myTableView;
@property (nonatomic, retain) IBOutlet UITextField *actifText;
- (IBAction)textFieldDidBeginEditing:(UITextField *)textField;
- (IBAction)textFieldDidEndEditing:(UITextField *)textField;
-(void) keyboardWillHide:(NSNotification *)note;
-(void) keyboardWillShow:(NSNotification *)note;
@end
在MyUIViewController.m
@implementation MyUIViewController
@synthesize myTableView;
@synthesize actifText;
- (void)viewDidLoad
{
// Register notification when the keyboard will be show
[[NSNotificationCenter defaultCenter] addObserver:self
selector:@selector(keyboardWillShow:)
name:UIKeyboardWillShowNotification
object:nil];
// Register notification when the keyboard will be hide
[[NSNotificationCenter defaultCenter] addObserver:self
selector:@selector(keyboardWillHide:)
name:UIKeyboardWillHideNotification
object:nil];
}
// To be link with your TextField event "Editing Did Begin"
// memoryze the current TextField
- (IBAction)textFieldDidBeginEditing:(UITextField *)textField
{
self.actifText = textField;
}
// To be link with your TextField event "Editing Did End"
// release current TextField
- (IBAction)textFieldDidEndEditing:(UITextField *)textField
{
self.actifText = nil;
}
-(void) keyboardWillShow:(NSNotification *)note
{
// Get the keyboard size
CGRect keyboardBounds;
[[note.userInfo valueForKey:UIKeyboardFrameBeginUserInfoKey] getValue: &keyboardBounds];
// Detect orientation
UIInterfaceOrientation orientation = [[UIApplication sharedApplication] statusBarOrientation];
CGRect frame = self.myTableView.frame;
// Start animation
[UIView beginAnimations:nil context:NULL];
[UIView setAnimationBeginsFromCurrentState:YES];
[UIView setAnimationDuration:0.3f];
// Reduce size of the Table view
if (orientation == UIInterfaceOrientationPortrait || orientation == UIInterfaceOrientationPortraitUpsideDown)
frame.size.height -= keyboardBounds.size.height;
else
frame.size.height -= keyboardBounds.size.width;
// Apply new size of table view
self.myTableView.frame = frame;
// Scroll the table view to see the TextField just above the keyboard
if (self.actifText)
{
CGRect textFieldRect = [self.myTableView convertRect:self.actifText.bounds fromView:self.actifText];
[self.myTableView scrollRectToVisible:textFieldRect animated:NO];
}
[UIView commitAnimations];
}
-(void) keyboardWillHide:(NSNotification *)note
{
// Get the keyboard size
CGRect keyboardBounds;
[[note.userInfo valueForKey:UIKeyboardFrameBeginUserInfoKey] getValue: &keyboardBounds];
// Detect orientation
UIInterfaceOrientation orientation = [[UIApplication sharedApplication] statusBarOrientation];
CGRect frame = self.myTableView.frame;
[UIView beginAnimations:nil context:NULL];
[UIView setAnimationBeginsFromCurrentState:YES];
[UIView setAnimationDuration:0.3f];
// Increase size of the Table view
if (orientation == UIInterfaceOrientationPortrait || orientation == UIInterfaceOrientationPortraitUpsideDown)
frame.size.height += keyboardBounds.size.height;
else
frame.size.height += keyboardBounds.size.width;
// Apply new size of table view
self.myTableView.frame = frame;
[UIView commitAnimations];
}
@end
Swift 1.2+版本:
class ViewController: UIViewController, UITextFieldDelegate {
@IBOutlet weak var activeText: UITextField!
@IBOutlet weak var tableView: UITableView!
override func viewDidLoad() {
NSNotificationCenter.defaultCenter().addObserver(self,
selector: Selector("keyboardWillShow:"),
name: UIKeyboardWillShowNotification,
object: nil)
NSNotificationCenter.defaultCenter().addObserver(self,
selector: Selector("keyboardWillHide:"),
name: UIKeyboardWillHideNotification,
object: nil)
}
func textFieldDidBeginEditing(textField: UITextField) {
activeText = textField
}
func textFieldDidEndEditing(textField: UITextField) {
activeText = nil
}
func keyboardWillShow(note: NSNotification) {
if let keyboardSize = (note.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.CGRectValue() {
var frame = tableView.frame
UIView.beginAnimations(nil, context: nil)
UIView.setAnimationBeginsFromCurrentState(true)
UIView.setAnimationDuration(0.3)
frame.size.height -= keyboardSize.height
tableView.frame = frame
if activeText != nil {
let rect = tableView.convertRect(activeText.bounds, fromView: activeText)
tableView.scrollRectToVisible(rect, animated: false)
}
UIView.commitAnimations()
}
}
func keyboardWillHide(note: NSNotification) {
if let keyboardSize = (note.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.CGRectValue() {
var frame = tableView.frame
UIView.beginAnimations(nil, context: nil)
UIView.setAnimationBeginsFromCurrentState(true)
UIView.setAnimationDuration(0.3)
frame.size.height += keyboardSize.height
tableView.frame = frame
UIView.commitAnimations()
}
}
}
以下是我的解决方案，灵感来自iOS7日历应用程序的“事件编辑”屏幕。
该解决方案的关键之一是当用户滚动表格时键盘被取消。
实现:
1)添加属性，将存储选定的文本字段:
@property (strong) UITextField *currentTextField;
和BOOL变量，我们将使用它来检查当用户滚动表时是否需要隐藏键盘。
BOOL hideKeyboardOnScroll;
2)处理UITextField委托回调:
#pragma mark - UITextFieldDelegate
- (void) textFieldDidBeginEditing: (UITextField *) textField {
self.currentTextField = textField;
}
- (void) textFieldDidEndEditing: (UITextField *) textField {
self.currentTextField = nil;
}
- (BOOL) textFieldShouldReturn: (UITextField *) textField {
[textField resignFirstResponder];
CGPoint newContentOffset = CGPointZero;
if (tableView.contentSize.height > tableView.frame.size.height) {
newContentOffset.y = MIN(tableView.contentOffset.y, tableView.contentSize.height - tableView.frame.size.height);
}
[tableView setContentOffset: newContentOffset animated: YES];
return YES;
}
3)处理UIScrollViewDelegate方法来检查用户滚动视图。
#pragma mark - UIScrollViewDelegate
- (void) scrollViewDidScroll: (UIScrollView *) scrollView {
if (hideKeyboardOnScroll == YES) {
[self.currentTextField resignFirstResponder];
}
}
4)在视图控制器的[viewWillAppear]方法中订阅键盘通知，并在[viewWillDisappear]方法中取消订阅。
- (void) viewWillAppear: (BOOL) animated {
[super viewWillAppear: animated];
[ [NSNotificationCenter defaultCenter] addObserver: self selector: @selector(keyboardWillShow:)
name: UIKeyboardWillShowNotification object: nil];
[ [NSNotificationCenter defaultCenter] addObserver: self selector: @selector(keyboardWillHide:)
name: UIKeyboardWillHideNotification object: nil];
}
- (void) viewWillDisappear: (BOOL) animated {
[super viewWillDisappear: animated];
[ [NSNotificationCenter defaultCenter] removeObserver: self name: UIKeyboardDidShowNotification object: nil];
[ [NSNotificationCenter defaultCenter] removeObserver: self name: UIKeyboardWillHideNotification object: nil];
}
5)处理键盘通知:
- (void) keyboardWillShow: (NSNotification *) notification {
CGRect keyboardFrame = [ [ [notification userInfo] objectForKey: UIKeyboardFrameBeginUserInfoKey] CGRectValue];
// Find cell with textfield.
CGRect textFieldFrame = [tableView convertRect: self.currentTextField.frame fromView: self.currentTextField];
NSIndexPath *indexPath = [tableView indexPathForRowAtPoint: textFieldFrame.origin];
UITableViewCell *cell = [tableView cellForRowAtIndexPath: indexPath];
//
// Shrink tableView size.
CGRect tableViewFrame = tableView.frame;
tableView.frame = CGRectMake(tableView.frame.origin.x, tableView.frame.origin.y, tableView.frame.size.width,
self.view.frame.size.height - tableView.frame.origin.y - keyboardFrame.size.height);
//
// Check if cell is visible in shrinked table size.
BOOL cellIsFullyVisible = YES;
if ( cell.frame.origin.y < tableView.contentOffset.y ||
(cell.frame.origin.y + cell.frame.size.height) > (tableView.contentOffset.y + tableView.frame.size.height) ) {
cellIsFullyVisible = NO;
}
//
// If cell is not fully visible when scroll table to show cell;
if (cellIsFullyVisible == NO) {
CGPoint contentOffset = CGPointMake(tableView.contentOffset.x, CGRectGetMaxY(cell.frame) - tableView.frame.size.height);
if (cell.frame.origin.y < tableView.contentOffset.y) {
contentOffset.y = cell.frame.origin.y;
}
contentOffset.y = MAX(0, contentOffset.y);
// For some reason [setContentOffset] is called without delay then
// this code may not work for some cells. That why we call it with brief delay.
dispatch_time_t popTime = dispatch_time(DISPATCH_TIME_NOW, (int64_t)(0.1 * NSEC_PER_SEC));
dispatch_after(popTime, dispatch_get_main_queue(), ^(void){
[UIView animateWithDuration: 0.5 animations:^{
[tableView setContentOffset: contentOffset animated: NO];
} completion: ^(BOOL finished) {
hideKeyboardOnScroll = YES;
}];
});
} else {
hideKeyboardOnScroll = YES;
}
//
// Finally restore original table frame.
tableView.frame = tableViewFrame;
//
}
- (void) keyboardWillHide: (NSNotification *) notification {
[super keyboardWillHide: notification];
hideKeyboardOnScroll = NO;
}
这非常有效，在iPad上也是如此。
- (BOOL)textFieldShouldReturn:(UITextField *)textField
{
if(textField == textfield1){
[accountName1TextField becomeFirstResponder];
}else if(textField == textfield2){
[self.tableView scrollToRowAtIndexPath:[NSIndexPath indexPathForRow:0 inSection:1] atScrollPosition:UITableViewScrollPositionTop animated:YES];
[textfield3 becomeFirstResponder];
}else if(textField == textfield3){
[self.tableView scrollToRowAtIndexPath:[NSIndexPath indexPathForRow:1 inSection:1] atScrollPosition:UITableViewScrollPositionTop animated:YES];
[textfield4 becomeFirstResponder];
}else if(textField == textfield4){
[self.tableView scrollToRowAtIndexPath:[NSIndexPath indexPathForRow:2 inSection:1] atScrollPosition:UITableViewScrollPositionTop animated:YES];
[textfield5 becomeFirstResponder];
}else if(textField == textfield5){
[self.tableView scrollToRowAtIndexPath:[NSIndexPath indexPathForRow:3 inSection:1] atScrollPosition:UITableViewScrollPositionTop animated:YES];
[textfield6 becomeFirstResponder];
}else if(textField == textfield6){
[self.tableView scrollToRowAtIndexPath:[NSIndexPath indexPathForRow:4 inSection:1] atScrollPosition:UITableViewScrollPositionTop animated:YES];
[textfield7 becomeFirstResponder];
}else if(textField == textfield7){
[self.tableView scrollToRowAtIndexPath:[NSIndexPath indexPathForRow:5 inSection:1] atScrollPosition:UITableViewScrollPositionTop animated:YES];
[textfield8 becomeFirstResponder];
}else if(textField == textfield8){
[self.tableView scrollToRowAtIndexPath:[NSIndexPath indexPathForRow:6 inSection:1] atScrollPosition:UITableViewScrollPositionTop animated:YES];
[textfield9 becomeFirstResponder];
}else if(textField == textfield9){
[self.tableView scrollToRowAtIndexPath:[NSIndexPath indexPathForRow:7 inSection:1] atScrollPosition:UITableViewScrollPositionTop animated:YES];
[textField resignFirstResponder];
}
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。
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