IOS：鍵盤出現時將TextField向上移動

Question

我使用以下方法在鍵盤出現時將視圖向上移動，以便鍵盤不會阻止文本字段。 基本上，我將文本字段嵌入到滾動視圖中，並在出現鍵盤時向上滾動。

// 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 app might not need or want this behavior.
    CGRect aRect = self.view.frame;
    aRect.size.height -= kbSize.height;
    if (!CGRectContainsPoint(aRect, _activeField.frame.origin) ) {
        [_scrollView scrollRectToVisible:_activeField.frame animated:YES];
    }
}

但是，當文本字段已經位於視圖的頂部並且不需要向上跳轉時，上面的代碼將導致其跳出視圖。

我記得在某處您可以添加一行來防止這種情況，但我不記得了。 基本上，它將測試文本字段是否已經足夠高到足以使鍵盤無法覆蓋它，因此不需要移動視圖。

上面代碼中的if語句似乎並未篩選出未隱藏文本字段的情況。

有人可以建議一種方法嗎？

謝謝。

Answer 1

如果使用自動布局，則應使用約束而不是框架來操縱視圖。 您可以根據需要嘗試操縱textField的底部間距或查看其超級視圖，然后將layoutIfNeeded調用放入動畫塊中。 您還可以檢查底部約束的值是否已經是特定值，或者在UIKeyboardWillHideNotification和UIKeyboardWillShowNotification上傳遞布爾值（如果是），則約束的值不應更改。 就像是：

-(void)showViewAnimatedly:(BOOL)show{

    if(show){
        [bottomConstraint setConstant:0];
    }else{
        [bottomConstraint setConstant:-160];
    }

    [UIView animateWithDuration:0.3f animations:^{

        [self.view layoutIfNeeded];

    }];
}

我還建議您使用UIKeyboardWillShowNotification而不是UIKeyboardDidShowNotification因為過渡似乎與鍵盤的出現更加UIKeyboardDidShowNotification 。 UIKeyboardDidShowNotification將在出現鍵盤后開始過渡。

Answer 2

簽出“ IQKeyboardManager”。 它是滿足您要求的絕佳控件。 而且您只需要一行代碼。 它適用於UITextFields和UITextViews。 它還具有上一個和下一個按鈕的選項。 您可以將它作為cocoapod安裝在項目中

https://www.cocoacontrols.com/controls/iqkeyboardmanager

Answer 3

它很簡單，當需要出現鍵盤時，可以通過動畫更改文本視圖或文本字段的y軸坐標。 您可以參考的代碼如下---->

-(void)keyboardWillShow {
    // Animate the current view out of the way
    if (self.view.frame.origin.y >= 0)
    {
        [self setViewMovedUp:YES];
    }
    else if (self.view.frame.origin.y < 0)
    {
        [self setViewMovedUp:NO];
    }
}

-(void)keyboardWillHide {
    if (self.view.frame.origin.y >= 0)
    {
        [self setViewMovedUp:YES];
    }
    else if (self.view.frame.origin.y < 0)
    {
        [self setViewMovedUp:NO];
    }
}

-(void)textFieldDidBeginEditing:(UITextField *)sender
{
    if ([sender isEqual:mailTf])
    {
        //move the main view, so that the keyboard does not hide it.
        if  (self.view.frame.origin.y >= 0)
        {
            [self setViewMovedUp:YES];
        }
    }
}

//method to move the view up/down whenever the keyboard is shown/dismissed
-(void)setViewMovedUp:(BOOL)movedUp
{
    [UIView beginAnimations:nil context:NULL];
    [UIView setAnimationDuration:0.3]; // if you want to slide up the view

    CGRect rect = self.view.frame;
    if (movedUp)
    {
        // 1. move the view's origin up so that the text field that will be hidden come above the keyboard 
        // 2. increase the size of the view so that the area behind the keyboard is covered up.
        rect.origin.y -= kOFFSET_FOR_KEYBOARD;
        rect.size.height += kOFFSET_FOR_KEYBOARD;
    }
    else
    {
        // revert back to the normal state.
        rect.origin.y += kOFFSET_FOR_KEYBOARD;
        rect.size.height -= kOFFSET_FOR_KEYBOARD;
    }
    self.view.frame = rect;

    [UIView commitAnimations];
}


- (void)viewWillAppear:(BOOL)animated
{
    [super viewWillAppear:animated];
    // register for keyboard notifications
    [[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];
    // unregister for keyboard notifications while not visible.
    [[NSNotificationCenter defaultCenter] removeObserver:self
                                             name:UIKeyboardWillShowNotification
                                           object:nil];

    [[NSNotificationCenter defaultCenter] removeObserver:self
                                             name:UIKeyboardWillHideNotification
                                           object:nil];
}