UItextview在iPhone应用程序中上下移动（当键盘出现并消失时）

Question

当键盘出现和消失时，如何在iphone应用程序中将UItextview在UIScrollView中上下移动。

Answer 1

只需添加通知观察员键盘的行动-viewDidLoad或-viewWillAppear:：

NSNotificationCenter * notificationCetner = [NSNotificationCenter defaultCenter]; 
[notificationCetner addObserver:self 
         selector:@selector(_keyboardWasShown:) 
          name:UIKeyboardDidShowNotification 
         object:nil]; 
[notificationCetner addObserver:self 
         selector:@selector(_keyboardWillHide:) 
          name:UIKeyboardWillHideNotification 
         object:nil]; 

然后在-_keyboardWasShown: & -_keyboardWillHide:方法更新文本视图的框架。

Answer 2

有一个很好的库叫TPKeyboardAvoiding，你可以使用（找到它here）。

或者，您可以自己编程并使用UIScrollView的contentOffset属性向下或向上移动内容。然后您应该听取键盘的keyboardDidShow和keyboardWillHide方法。

希望它有帮助！

Answer 3

其中一个方法是--->在viewDidLoad中或viewWillAppear中添加这些观察员

NSNotificationCenter *center = [NSNotificationCenter defaultCenter]; 
[center addObserver:self selector:@selector(keyboardDisappeared) name:UIKeyboardWillHideNotification object:nil]; 
[center addObserver:self selector:@selector(keyboardAppeared) name:UIKeyboardWillShowNotification object:nil]; 

比写keyboardDisappeared和keyboardAppeared如下

-(void) keyboardDisappeared 
{ 
    [UIView beginAnimations:@"animate" context:nil]; 
    [UIView setAnimationDuration:0.2f]; 
    [UIView setAnimationBeginsFromCurrentState: NO]; 
    self.view.frame = CGRectMake(self.view.frame.origin.x, self.view.frame.origin.y+100(same as you do in keyboardAppeared), self.view.frame.size.width, self.view.frame.size.height); 
    [UIView commitAnimations]; 
} 

-(void) keyboardAppeared 
{ 
    [UIView beginAnimations:@"animate" context:nil]; 
    [UIView setAnimationDuration:0.2f]; 
    [UIView setAnimationBeginsFromCurrentState: NO]; 
    self.view.frame = CGRectMake(self.view.frame.origin.x, self.view.frame.origin.y-(as much you want), self.view.frame.size.width, self.view.frame.size.height); 
    [UIView commitAnimations]; 
} 

不要忘记删除观察者！ ！

Answer 4

第一组的TextView的委托，然后尝试实现这些方法....

- (BOOL)textViewShouldBeginEditing:(UITextView *)textView 
    { 
     [self scrollViewToCenterOfScreen:textView]; 
     return YES; 
    } 

    - (void) scrollViewToCenterOfScreen:(UIView *)theView 
    { 
     CGFloat viewCenterY = theView.center.y; 
     CGRect applicationFrame = [[UIScreen mainScreen] applicationFrame]; 

     CGFloat availableHeight = applicationFrame.size.height - 300;   // Remove area covered by keyboard 

     CGFloat y = viewCenterY - availableHeight/2.0; 

     if (y < 0) 
     { 
      y = 0; 
     } 
     [scrollView setContentOffset:CGPointMake(0, y) animated:YES]; 
    } 

// -------- Modified -------- 


    - (BOOL)textView:(UITextView *)txtView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)tempText 
{ 
    if([tempText rangeOfCharacterFromSet:[NSCharacterSet newlineCharacterSet]].location == NSNotFound) 
    { 
     return YES; 
    } 

    [txtView resignFirstResponder]; 
    [self.scrollView setContentOffset:CGPointMake(0.0f, 0.0f) animated:TRUE]; 
    return NO; 
}