uikeyboardwillshownotification和uikeyboarddidshownotification报告错误的键盘高度

Question

以下代码（对不起，长度）在iOS 4.3（也许还有其他版本）下显示出奇怪的行为。在此示例中，有三个 UITextFieldS具有三个不同尺寸的键盘。如果您开始编辑一个文本字段，然后触摸“返回”键盘，则每次正确返回键盘大小时 UIKeyboardWillShowNotification 和 UIKeyboardDidShowNotification 使用 UIKeyboardFrameBeginUserInfoKey.

见下文：

- (void) keyboardWillShowNotification:(NSNotification *)aNotification

和

- (void) keyboardDidShowNotification:(NSNotification *)aNotification

请注意，这是预期的行为。

action                 reported keyboard size  expected keyboard size  
---------------------  ----------------------  ----------------------
touch one    & return  100                     100
touch two    & return  200                     200
touch normal & return  216                     216
n            & return  keyboard size(n)        keyboard size(n)

意外的行为是，如果您开始编辑文本字段，则报告了第一个键盘的大小（预期）。当您触摸第二个文本字段（无触摸返回）时，报告了第一个键盘的大小（意外），而不是第二个键盘的大小。当您触摸第三个文本字段（无触摸返回）时，报告了第二个键盘大小的大小（意外），而不是第三个大小。在第二次到第n次，似乎正在报告以前的键盘大小而不是将要显示的大小。

action        reported keyboard size  expected keyboard size  
------------  ----------------------  ----------------------
touch one     100                     100
touch two     100                     200
touch normal  200                     216
touch one     216                     100
n             keyboard size(n-1)      keyboard size(n)

在发送错误报告之前，我只想确保我没有看任何东西。

仅供参考，我在尝试做正确的事情时对此表示不适（使用 UIKeyboardWillShowNotification 或者 UIKeyboardDidShowNotification 和 UIKeyboardFrameBeginUserInfoKey 为了获取键盘的大小）时，可以看到键盘遮盖的文本字段。参考：

出现键盘时如何使Uitextfield向上移动？

iOS库：iOS的文本，网络和编辑编程指南 - >管理键盘

iOS库：iOS滚动查看编程指南 - >创建和配置滚动视图

bugvc.h

#import <UIKit/UIKit.h>

@interface BugVC : UIViewController <UITextFieldDelegate> {
    UITextField *oneTF;
    UITextField *twoTF;
    UITextField *normalTF;
    UILabel *keyboardWillShowNotificationL;
    UILabel *keyboardDidShowNotificationL;
}

- (void) oneReturnTouchDown:(id)sender;
- (void) twoReturnTouchDown:(id)sneder;
- (void) keyboardWillShowNotification:(NSNotification *)aNotification;
- (void) keyboardDidShowNotification:(NSNotification *)aNotification;

@end

bugvc.m

#import "BugVC.h"

@implementation BugVC

- (id) init
{
    if ( !(self = [super init]) )
    {
        return self;
    }

    // = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
    // One text field with 100 height keyboard
    oneTF = [[UITextField alloc] initWithFrame:CGRectMake(10, 10, 300, 30)];
    oneTF.borderStyle = UITextBorderStyleRoundedRect;
    oneTF.text = @"100";
    oneTF.delegate = self;
    // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    // Custom input view for the above text field
    UIView *oneInputView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 320, 100)];
    oneInputView.backgroundColor = [UIColor redColor];
    UIButton *oneReturnB = [UIButton buttonWithType:UIButtonTypeRoundedRect];
    oneReturnB.frame = CGRectMake(10, 10, 300, 30);
    [oneReturnB setTitle:@"return" forState:UIControlStateNormal];
    [oneReturnB addTarget:self
                   action:@selector(oneReturnTouchDown:)
         forControlEvents:UIControlEventTouchDown];
    [oneInputView addSubview:oneReturnB];
    oneTF.inputView = oneInputView;
    [oneInputView release];
    [self.view addSubview:oneTF];

    // = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
    // Two text field with 200 height keyboard
    twoTF = [[UITextField alloc] initWithFrame:CGRectMake(10, 50, 300, 30)];
    twoTF.borderStyle = UITextBorderStyleRoundedRect;
    twoTF.text = @"200";
    twoTF.delegate = self;
    // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    // Custom input view for the above text field
    UIView *twoInputView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 320, 200)];
    twoInputView.backgroundColor = [UIColor blueColor];
    UIButton *twoReturnB = [UIButton buttonWithType:UIButtonTypeRoundedRect];
    twoReturnB.frame = CGRectMake(10, 10, 300, 30);
    [twoReturnB setTitle:@"return" forState:UIControlStateNormal];
    [twoReturnB addTarget:self
                   action:@selector(twoReturnTouchDown:)
         forControlEvents:UIControlEventTouchDown];
    [twoInputView addSubview:twoReturnB];
    twoTF.inputView = twoInputView;
    [twoInputView release];
    [self.view addSubview:twoTF];

    // = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
    // normal text field with normal keyboard (216 height keyboard)
    normalTF = [[UITextField alloc] initWithFrame:CGRectMake(10, 90, 300, 30)];
    normalTF.borderStyle = UITextBorderStyleRoundedRect;
    normalTF.text = @"normal";
    normalTF.delegate = self;
    [self.view addSubview:normalTF];

    // = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
    // Label that displays the keyboard height from keyboardWillShowNotification
    keyboardWillShowNotificationL = [[UILabel alloc] initWithFrame:CGRectMake(10, 130, 300, 30)];
    keyboardWillShowNotificationL.font = [UIFont systemFontOfSize:14];
    keyboardWillShowNotificationL.text = @"keyboardWillShowNotification kbHeight:";
    [self.view addSubview:keyboardWillShowNotificationL];

    // = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
    // Label that displays the keyboard height from keyboardDidShowNotification
    keyboardDidShowNotificationL = [[UILabel alloc] initWithFrame:CGRectMake(10, 170, 300, 30)];
    keyboardDidShowNotificationL.font = [UIFont systemFontOfSize:14];
    keyboardDidShowNotificationL.text = @"keyboardDidShowNotification kbHeight:";
    [self.view addSubview:keyboardDidShowNotificationL];

    // = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
    // Register for keyboard notifications.
    [[NSNotificationCenter defaultCenter]
     addObserver:self
        selector:@selector(keyboardWillShowNotification:)
            name:UIKeyboardWillShowNotification object:nil];

    [[NSNotificationCenter defaultCenter]
     addObserver:self
        selector:@selector(keyboardDidShowNotification:)
            name:UIKeyboardDidShowNotification object:nil];

    return self;
}

- (void) dealloc
{
    // = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
    // Deregister for keyboard notifications
    [[NSNotificationCenter defaultCenter]
     removeObserver:self
               name:UIKeyboardWillShowNotification object:nil];

    [[NSNotificationCenter defaultCenter]
     removeObserver:self
               name:UIKeyboardDidShowNotification object:nil];

    [oneTF release];
    [twoTF release];
    [normalTF release];
    [keyboardWillShowNotificationL release];
    [keyboardDidShowNotificationL release];

    [super dealloc];
}

- (BOOL) textFieldShouldReturn:(UITextField *)textField
{
    [textField resignFirstResponder];

    return YES;
}

- (void) oneReturnTouchDown:(id)sender
{
    [oneTF.delegate textFieldShouldReturn:oneTF];
}

- (void) twoReturnTouchDown:(id)sneder
{
    [twoTF.delegate textFieldShouldReturn:twoTF];
}

- (void) keyboardWillShowNotification:(NSNotification *)aNotification
{
    NSDictionary *info = [aNotification userInfo];
    CGFloat kbHeight =
        [[info objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue].size.height;

    NSString *string = [[NSString alloc] initWithFormat:@"keyboardWillShowNotification kbHeight: %.2f", kbHeight];
    NSLog(@"%@", string);
    keyboardWillShowNotificationL.text = string;
    [string release];
}

- (void) keyboardDidShowNotification:(NSNotification *)aNotification
{
    NSDictionary *info = [aNotification userInfo];
    CGFloat kbHeight =
        [[info objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue].size.height;

    NSString *string = [[NSString alloc] initWithFormat:@"keyboardDidShowNotification kbHeight: %.2f", kbHeight];
    NSLog(@"%@", string);
    keyboardDidShowNotificationL.text = string;
    [string release];
}

@end

Answer 1

如报道 这个问题, ， 这 start frame （由 UIKeyboardFrameBeginUserInfoKey）是键盘在 开始 动画。 UIKeyboardFrameEndUserInfoKey 应该给你 end frame 反而。大概的尺寸在框架之间也有所不同。

关键参考： http://developer.apple.com/library/ios/#documentation/uikit/reference/uiwindow_class/uiwindowclassreference/uiwindowclassreference.html#//pec.html#/