当键盘出现时如何滚动UIScrollView？

问题描述

我在使用我的代码时遇到问题。我正在尝试移动 UIScrollView 当我编辑一个 UITextField ，应该被键盘弹出隐藏。

我现在移动主框架，因为我不知道如何在代码中向上滚动。
所以，我做了一点代码，它的工作正常，但当我编辑一个UItextfield，我切换到另一个 UITextField ，没有按返回按钮

我做了一个 NSLog（）与我的变量大小，距离和textFieldRect.origin.y，你可以看到下面。当我把两个 UITextField 放在同一个地方（y origin），我做这个特殊的'switch'（wihtout按返回），我得到相同的数字，而我的代码工作

检查：

$ <$ p>

b
$ b

   - （void）textFieldDidBeginEditing：（UITextField *）textField {
 {
 int size; 
 CGRect textFieldRect = [self.view.window convertRect：textField.bounds fromView：textField]; 
 size = textFieldRect.origin.y + textFieldRect.size.height; 
 if（change == FALSE）
 {
 size = size  -  distance; 
} 
 if（size< PORTRAIT_KEYBOARD_HEIGHT）
 {
 distance = 0; 
} 
 else if（size> PORTRAIT_KEYBOARD_HEIGHT）
 {
 distance = size  -  PORTRAIT_KEYBOARD_HEIGHT + 5; // +5 px for more visibility 
} 
 NSLog（@origin％f，textFieldRect.origin.y）; 
 NSLog（@size％d，size）; 
 NSLog（@distance％d，distance）; 
 CGRect viewFrame = self.view.frame; 
 viewFrame.origin.y  -  = distance; 
 [UIView beginAnimations：nil context：NULL]; 
 [UIView setAnimationBeginsFromCurrentState：YES]; 
 [UIView setAnimationDuration：KEYBOARD_ANIMATION_DURATION]; 
 [self.view setFrame：viewFrame]; 
 [UIView commitAnimations]; 
 change = FALSE; 
} 
 
  - （void）textFieldDidEndEditing：（UITextField *）textField 
 {
 change = TRUE; 
 CGRect viewFrame = self.view.frame; 
 viewFrame.origin.y + = distance; 
 [UIView beginAnimations：nil context：NULL]; 
 [UIView setAnimationBeginsFromCurrentState：YES]; 
 [UIView setAnimationDuration：KEYBOARD_ANIMATION_DURATION]; 
 [self.view setFrame：viewFrame]; 
 [UIView commitAnimations]; 
} 
  

任何想法？

UIScrollView的 contentInset 。这是一个非常优雅的解决方案，因为你不必惹麻烦 contentSize 。
以下代码是从键盘编程指南 a>，其中解释了此问题的处理。你应该看看它。

  //在你的视图控制器设置代码中的某个地方调用这个方法。 
  - （void）registerForKeyboardNotifications 
 {
 [[NSNotificationCenter defaultCenter] addObserver：self 
 selector：@selector（keyboardWasShown :) 
 name：UIKeyboardDidShowNotification object：nil]; 
 [[NSNotificationCenter defaultCenter] addObserver：self 
 selector：@selector（keyboardWillBeHidden :) 
 name：UIKeyboardWillHideNotification object：nil]; 
} 
 
 //发送UIKeyboardDidShowNotification时调用。 
  - （void）keyboardWasShown：（NSNotification *）aNotification 
 {
 NSDictionary * info = [aNotification userInfo]; 
 CGSize kbSize = [[info objectForKey：UIKeyboardFrameBeginUserInfoKey] CGRectValue] .size; 
 UIEdgeInsets contentInsets = UIEdgeInsetsMake（0.0，0.0，kbSize.height，0.0）; 
 scrollView.contentInset = contentInsets; 
 scrollView.scrollIndicatorInsets = contentInsets; 
 
 //如果活动文本字段被键盘隐藏，滚动它，使其可见
 //您的应用程序可能不需要或不想要此行为。 
 CGRect aRect = self.view.frame; 
 aRect.size.height  -  = kbSize.height; 
 if（！CGRectContainsPoint（aRect，activeField.frame.origin））{
 CGPoint scrollPoint = CGPointMake（0.0，activeField.frame.origin.y-kbSize.height）; 
 [scrollView setContentOffset：scrollPoint animated：YES]; 
} 
} 
 
 //发送UIKeyboardWillHideNotification时调用
  - （void）keyboardWillBeHidden：（NSNotification *）aNotification 
 {
 UIEdgeInsets contentInsets = UIEdgeInsetsZero; 
 scrollView.contentInset = contentInsets; 
 scrollView.scrollIndicatorInsets = contentInsets; 
} 
  

I'm having trouble with my code. I'm trying to move the UIScrollView when I'm editing an UITextField that should be hidden by the keyboard pop.

I'm moving the main frame right now because I don't know how to 'scroll up' in the code.So, I did a little bit of code, it's working fine but when I edit an UItextfield and I switch to another UITextField without pressing on the 'return' button the main view goes waaayyyyy to far up.

I did an NSLog() with my variables size, distance and textFieldRect.origin.y as you can see below. When I put two UITextField at the same place (y origin) and I do this particular 'switch' (wihtout pressing return) , I get the same numbers, whereas my code worked fine for the first UITextField editing but not for the second editing.

Check this out:

- (void)textFieldDidBeginEditing:(UITextField *)textField {
{
    int size;
    CGRect textFieldRect = [self.view.window convertRect:textField.bounds fromView:textField];
    size = textFieldRect.origin.y + textFieldRect.size.height;
    if (change == FALSE)
    {
        size = size - distance;
    }
    if (size < PORTRAIT_KEYBOARD_HEIGHT)
    {
        distance = 0;
    }
    else if (size > PORTRAIT_KEYBOARD_HEIGHT)
    {
        distance = size - PORTRAIT_KEYBOARD_HEIGHT + 5; // +5 px for more visibility
    }
    NSLog(@"origin %f", textFieldRect.origin.y);
    NSLog(@"size %d", size);
    NSLog(@"distance %d", distance);
    CGRect viewFrame = self.view.frame;
    viewFrame.origin.y -= distance;
    [UIView beginAnimations:nil context:NULL];
    [UIView setAnimationBeginsFromCurrentState:YES];
    [UIView setAnimationDuration:KEYBOARD_ANIMATION_DURATION];
    [self.view setFrame:viewFrame];
    [UIView commitAnimations];
    change = FALSE;
}

- (void)textFieldDidEndEditing:(UITextField *)textField
{
    change = TRUE;
    CGRect viewFrame = self.view.frame;
    viewFrame.origin.y += distance;
    [UIView beginAnimations:nil context:NULL];
    [UIView setAnimationBeginsFromCurrentState:YES];
    [UIView setAnimationDuration:KEYBOARD_ANIMATION_DURATION];
    [self.view setFrame:viewFrame];
    [UIView commitAnimations];
}

Any ideas ?

解决方案

The recommended way from Apple is to change the contentInset of the UIScrollView. It is a very elegant solution, because you do not have to mess with the contentSize.Following code is copied from the Keyboard Programming Guide, where the handling of this issue is explained. You should have a look into it.

// Call this method somewhere in your view controller setup code.
- (void)registerForKeyboardNotifications
{
    [[NSNotificationCenter defaultCenter] addObserver:self
            selector:@selector(keyboardWasShown:)
            name:UIKeyboardDidShowNotification object:nil];
   [[NSNotificationCenter defaultCenter] addObserver:self
             selector:@selector(keyboardWillBeHidden:)
             name:UIKeyboardWillHideNotification object:nil];
}

// Called when the UIKeyboardDidShowNotification is sent.
- (void)keyboardWasShown:(NSNotification*)aNotification
{
    NSDictionary* info = [aNotification userInfo];
    CGSize kbSize = [[info objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue].size;
    UIEdgeInsets contentInsets = UIEdgeInsetsMake(0.0, 0.0, kbSize.height, 0.0);
    scrollView.contentInset = contentInsets;
    scrollView.scrollIndicatorInsets = contentInsets;

    // If active text field is hidden by keyboard, scroll it so it's visible
    // Your application might not need or want this behavior.
    CGRect aRect = self.view.frame;
    aRect.size.height -= kbSize.height;
    if (!CGRectContainsPoint(aRect, activeField.frame.origin) ) {
        CGPoint scrollPoint = CGPointMake(0.0, activeField.frame.origin.y-kbSize.height);
        [scrollView setContentOffset:scrollPoint animated:YES];
    }
}

// Called when the UIKeyboardWillHideNotification is sent
- (void)keyboardWillBeHidden:(NSNotification*)aNotification
{
    UIEdgeInsets contentInsets = UIEdgeInsetsZero;
    scrollView.contentInset = contentInsets;
    scrollView.scrollIndicatorInsets = contentInsets;
}

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