鍵盤顯示時在 iPad 上滑動 UITextField

Question

我有來自 Cocoa 的代碼，當鍵盤出現時，它會滾動 UITextField，這樣鍵盤就不會覆蓋 UITextField。

這是代碼：

- (void)textFieldDidBeginEditing:(UITextField *)textField
{
    CGRect textFieldRect = [self.view.window convertRect:textField.bounds fromView:textField];
    CGRect viewRect = [self.view.window convertRect:self.view.bounds fromView:self.view];

    CGFloat midline = textFieldRect.origin.y + 0.5 * textFieldRect.size.height;

    // Issue is that numerator isn't big enough for bottom 3rd of the screen

    CGFloat numerator = midline - viewRect.origin.y - MINIMUM_SCROLL_FRACTION * viewRect.size.height;

    CGFloat denominator = (MAXIMUM_SCROLL_FRACTION - MINIMUM_SCROLL_FRACTION) * viewRect.size.height;

    CGFloat heightFraction = numerator / denominator;

    NSLog(@"Midline: %g Fraction: %g / %g", midline, numerator, denominator);

    if (heightFraction < 0.0)
    {
        heightFraction = 0.0;
    }
    else if (heightFraction > 1.0)
    {
        heightFraction = 1.0;
    }

    UIInterfaceOrientation orientation =
    [[UIApplication sharedApplication] statusBarOrientation];
    if (orientation == UIInterfaceOrientationPortrait ||
        orientation == UIInterfaceOrientationPortraitUpsideDown)
    {
        animatedDistance = floor(PORTRAIT_KEYBOARD_HEIGHT * heightFraction);
    }
    else
    {
        animatedDistance = floor(LANDSCAPE_KEYBOARD_HEIGHT * heightFraction);
    }

    CGRect viewFrame = self.view.frame;
    viewFrame.origin.y -= animatedDistance;


    [UIView beginAnimations:nil context:NULL];
    [UIView setAnimationBeginsFromCurrentState:YES];
    [UIView setAnimationDuration:KEYBOARD_ANIMATION_DURATION];

    [self.view setFrame:viewFrame];

    [UIView commitAnimations];
}

出於調試目的，我 output 中線等，看看發生了什么。 這是從上到下的制表符。 您可以看到大約第 6 個分子變為負數，因為為其父視圖轉換的 UITExtField.size.height 是一個低數字。 我無法弄清楚為什么這個數字會是負數。 高度應該像所有其他人一樣向上，就像您在視圖中的 go 一樣。

2011-05-24 09:36:08.600 Baby Bloom[27794:207] 中線 = 246 + 0.5 * 167

2011-05-24 09:36:08.601 Baby Bloom[27794:207] 中線：329.5 分數：22.3 / 409.6

2011-05-24 09:36:09.535 Baby Bloom[27794:207] 中線 = 246 + 0.5 * 167

2011-05-24 09:36:09.536 Baby Bloom[27794:207] 中線：329.5 分數：22.3 / 409.6

2011-05-24 09:36:09.929 Baby Bloom[27794:207] 中線 = 246 + 0.5 * 246

2011-05-24 09:36:09.930 Baby Bloom[27794:207] 中線：369 分數：61.8 / 409.6

2011-05-24 09:36:10.313 Baby Bloom[27794:207] 中線 = 246 + 0.5 * 246

2011-05-24 09:36:10.314 Baby Bloom[27794:207] 中線：369 分數：61.8 / 409.6

2011-05-24 09:36:10.793 Baby Bloom[27794:207] 中線 = 246 + 0.5 * 97

2011-05-24 09:36:10.794 Baby Bloom[27794:207] 中線：294.5 分數：-12.7 / 409.6

2011-05-24 09:36:11.785 Baby Bloom[27794:207] 中線 = 246 + 0.5 * 148

2011-05-24 09:36:11.786 Baby Bloom[27794:207] 中線：320 分數：12.8 / 409.6

Answer 1

事實證明，當在 iPad 上的景觀中時，它會切換原點（x 現在是 y，寬度現在是高度。

這是使其工作的代碼：

- (void)textFieldDidBeginEditing:(UITextField *)textField
{
    CGRect textFieldRect = [self.view.window convertRect:textField.bounds fromView:textField];
    CGRect viewRect = [self.view.window convertRect:self.view.bounds fromView:self.view];

    float origin;
    float textFieldHeight;
    float viewOrigin;
    float viewHeight;

    UIInterfaceOrientation orientation =
    [[UIApplication sharedApplication] statusBarOrientation];


    if (orientation == UIInterfaceOrientationPortrait ||
        orientation == UIInterfaceOrientationPortraitUpsideDown)
    {
        textFieldHeight = textFieldRect.size.height;
        origin = textFieldRect.origin.y;
        viewOrigin = viewRect.origin.y;
        viewHeight = viewRect.size.height;
    }
    else
    {
        textFieldHeight = textFieldRect.size.width;
        viewOrigin = viewRect.origin.x;
        viewHeight = viewRect.size.width;
        origin = viewHeight - textFieldRect.origin.x;
    }


    CGFloat midline = origin + 0.5 * textFieldHeight;

    // Take the current middle y location of the textfield
    // If it is in the top 20% of the view don't move it
    // If it is in the middle 60% move it by a fraction of the keyboard size
    // If it is in the bottom 20% move it by the whole size of the keyboard


    CGFloat numerator = midline - viewOrigin - MINIMUM_SCROLL_FRACTION * viewHeight;

    CGFloat denominator = (MAXIMUM_SCROLL_FRACTION - MINIMUM_SCROLL_FRACTION) * viewHeight;

    CGFloat heightFraction = numerator / denominator;


    if (heightFraction < 0.0)
    {
        heightFraction = 0.0;
    }
    else if (heightFraction > 1.0)
    {
        heightFraction = 1.0;
    }

    if (orientation == UIInterfaceOrientationPortrait ||
        orientation == UIInterfaceOrientationPortraitUpsideDown)
    {
        animatedDistance = floor(PORTRAIT_KEYBOARD_HEIGHT * heightFraction);
    }
    else
    {
        animatedDistance = floor(LANDSCAPE_KEYBOARD_HEIGHT * heightFraction);
    }



    CGRect viewFrame = self.view.frame;
    viewFrame.origin.y -= animatedDistance;

    //NSLog(@"Denom: %g", denominator);
    //NSLog(@"Distance: %g", animatedDistance);

    [UIView beginAnimations:nil context:NULL];
    [UIView setAnimationBeginsFromCurrentState:YES];
    [UIView setAnimationDuration:KEYBOARD_ANIMATION_DURATION];

    [self.view setFrame:viewFrame];

    [UIView commitAnimations];
}

Answer 2

origin = viewHeight - textFieldRect.origin.x;

我認為你不需要這個，因為它會產生不正確的字段原點和非常大的中間值，這會在不需要的地方執行滾動。 所以通常你應該只使用 x 原點作為 y。

origin = textFieldRect.origin.x;