使用iOS SDK：
我有一个带UITextFields的UIView，可以启动键盘。我需要它能够：
启动键盘后，允许滚动UIScrollView的内容以查看其他文本字段自动“跳转”（通过向上滚动）或缩短
我知道我需要一个UIScrollView。我已经尝试将UIView的类更改为UIScrollView，但仍然无法上下滚动文本框。
我需要UIView和UIScrollView吗？一个在另一个里面吗？
要自动滚动到活动文本字段，需要执行哪些操作？
理想情况下，尽可能多的组件设置将在Interface Builder中完成。我只想编写需要的代码。
注意：我使用的UIView（或UIScrollView）是由一个选项卡（UITabBar）启动的，它需要正常工作。
我正在添加滚动条，只为键盘出现时使用。尽管不需要它，但我觉得它提供了一个更好的界面，例如，用户可以滚动和更改文本框。
当键盘上下移动时，我可以改变UIScrollView的框架大小。我只是在使用：
-(void)textFieldDidBeginEditing:(UITextField *)textField {
//Keyboard becomes visible
scrollView.frame = CGRectMake(scrollView.frame.origin.x,
scrollView.frame.origin.y,
scrollView.frame.size.width,
scrollView.frame.size.height - 215 + 50); // Resize
}
-(void)textFieldDidEndEditing:(UITextField *)textField {
// Keyboard will hide
scrollView.frame = CGRectMake(scrollView.frame.origin.x,
scrollView.frame.origin.y,
scrollView.frame.size.width,
scrollView.frame.size.height + 215 - 50); // Resize
}
然而，这不会自动“向上移动”或将可见区域中的下部文本字段居中，这是我真正想要的。
我在这里没有看到这种可能性，所以我添加了它，因为我尝试了答案中的方法，但几个小时后发现在iOS6/7中的XCode 5中有一种更简单的方法：使用NSLayoutConstraints。
请参见：自动布局约束-键盘
这是我的代码：
.m文件：
// Called when the UIKeyboardWillShowNotification is sent.
- (void)keyboardWillBeShown:(NSNotification*)aNotification
{
NSLog(@"keyboardWillBeShown:");
[self.PhoneNumberLabelOutlet setHidden:TRUE];
CGFloat heightOfLabel = self.PhoneNumberLabelOutlet.frame.size.height;
for( NSLayoutConstraint* thisConstraint in self.topElementsVerticalDistanceFromTopLayoutConstraint ) {
thisConstraint.constant -= heightOfLabel;
}
NSDictionary* info = [aNotification userInfo];
CGSize kbSize = [[info objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue].size;
CGFloat oldConstant = [self.SignInYConstraint constant];
self.SignInYConstraint.constant = oldConstant + kbSize.height;
[self.view setNeedsUpdateConstraints];
NSTimeInterval duration = [[info objectForKey:UIKeyboardAnimationDurationUserInfoKey] doubleValue];
[UIView animateWithDuration:duration animations:^{
[self.view layoutIfNeeded];
}];
}
.h文件：
#import <UIKit/UIKit.h>
@interface SignInViewController : UIViewController {
UITextField* _activeField;
}
- (void)signInCallback:(NSObject*)object;
@property (weak, nonatomic) IBOutlet UILabel *PhoneNumberLabelOutlet;
@property (weak, nonatomic) IBOutlet UIActivityIndicatorView *ActivityIndicatorOutlet;
@property (weak, nonatomic) IBOutlet UITextField *UserIDTextfieldOutlet;
@property (weak, nonatomic) IBOutlet UITextField *PasswordTextfieldOutlet;
@property (weak, nonatomic) IBOutlet UIButton *SignInButton;
@property (weak, nonatomic) IBOutlet NSLayoutConstraint *SignInYConstraint;
@property (strong, nonatomic) IBOutletCollection(NSLayoutConstraint) NSArray *topElementsVerticalDistanceFromTopLayoutConstraint;
@end
这里是我创建的UITextfield（和其他类似的字段）类别，它将使文本字段避开键盘，您应该能够将其按原样放置在视图控制器中，它应该可以工作。它将整个屏幕向上移动，使当前文本字段位于带有动画的键盘上方
#import "UIView+avoidKeyboard.h"
#import "AppDelegate.h"
@implementation UIView (avoidKeyboard)
- (void) becomeFirstResponder {
if(self.isFirstResponder)
return;
[super becomeFirstResponder];
if ([self isKindOfClass:[UISearchBar class]] ||
[self isKindOfClass:[UITextField class]] ||
[self isKindOfClass:[UITextView class]])
{
AppDelegate *appDelegate = [UIApplication sharedApplication].delegate;
CGRect screenBounds = appDelegate.window.frame;
CGFloat keyboardHeight;
CGFloat keyboardY;
CGFloat viewsLowestY;
CGPoint origin = [self.superview convertPoint:self.frame.origin toView:appDelegate.window]; //get this views origin in terms of the main screens bounds
if(UIInterfaceOrientationIsPortrait([[UIApplication sharedApplication] statusBarOrientation])){ //the window.frame doesnt take its orientation into account so if its sideways we must use the x value of the origin instead of the y
keyboardHeight = 216;
keyboardY = screenBounds.size.height - keyboardHeight; //find the keyboards y coord relative to how much the main window has moved up
viewsLowestY = origin.y + self.frame.size.height; //find the lowest point of this view
}
else {
keyboardHeight = 162;
keyboardY = screenBounds.size.width - keyboardHeight;
viewsLowestY = origin.x + self.frame.size.height;
}
CGFloat difference = viewsLowestY - keyboardY + 20; //find if this view overlaps with the keyboard with some padding
if (difference > 0){ //move screen up if there is an overlap
[UIView animateWithDuration:0.3 delay:0.0 options:UIViewAnimationOptionBeginFromCurrentState animations:^{
CGRect frame = appDelegate.window.frame;
if(UIInterfaceOrientationIsPortrait([[UIApplication sharedApplication] statusBarOrientation])){
frame.origin.y -= difference;
}
else {
frame.origin.x -= difference;
}
appDelegate.window.frame = frame;
}
completion:nil];
}
}
}
//look at appDelegate to see when the keyboard is hidden
@end
在appDelegate中添加此函数
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardHides:) name:UIKeyboardWillHideNotification object:nil]; //add in didFinishLaunchingWithOptions
...
- (void)keyboardHides:(NSNotification *)notification
{
[UIView animateWithDuration:0.3 animations:^{
[window setFrame: CGRectMake(0, 0, window.frame.size.width, window.frame.size.height)];
} completion:nil];
}
在（BOOL）textFieldShouldBeginEditing:（UITextField*）textField中
if (textField.frame.origin.y > self.view.frame.size.height - 216)
{
if (screenHeight>500)
scrollView.contentSize = CGSizeMake(0.0, scrollView.contentSize.height + 100);
else
scrollView.contentSize = CGSizeMake(0.0, scrollView.contentSize.height + 216);
CGPoint scrollPoint = CGPointMake(0.0,(textField.frame.origin.y - (self.view.frame.size.height - 216 - textField.frame.size.height - 20)));
[scrollView setContentOffset:scrollPoint animated:YES];
}
[scrollView setScrollEnabled:YES];
辞职时，你需要写以下代码
scrollView.contentSize = CGSizeMake(0.0, 640);
CGPoint scrollPoint = CGPointMake(0.0,0.0);
[scrollView setContentOffset:scrollPoint animated:YES];
