在设备方向上设置UITextVIew位置

Question

我将UITextView定位在屏幕中央，无论我是在横向还是纵向位置（iPhone或iPad），它都能正常工作。问题是，当我旋转设备时，它不会停留在中心。我以为它会自动保持在中心。

由于文本视图是在viewWillAppear中创建的，我想知道是否有一种方法可以在设备方向上刷新视图。或者可能只是为了转移视线。

我下面的代码：

-(void)viewWillAppear:(BOOL)animated{
    [super viewWillAppear:animated];
    UITextView *infoTextView = [[UITextView alloc] init];
    infoTextView.frame = CGRectMake(0, 0, 300.0, 300.0);
    infoTextView.center = CGPointMake(CGRectGetWidth(self.view.bounds)/2.0f, CGRectGetHeight(self.view.bounds)/2.0f);
    infoTextView.backgroundColor = [UIColor clearColor];
    NSString *anotherViewText = @"This is the content";
    infoTextView.dataDetectorTypes = UIDataDetectorTypeLink;
    infoTextView.text = anotherViewText;
    [infoTextView setFont:[UIFont fontWithName:@"ArialMT" size:18]];
    infoTextView.editable = NO;
    infoTextView.textAlignment=NSTextAlignmentCenter;
    [self.view addSubview:infoTextView];  
}

Answer 1

在UIView的情况下，在layoutSubviews中布局子视图是一种很好的做法，在UIViewController的情况下在viewDidLayoutSubviews中布局。所以在你的情况下，你可以简单地做：

- (void)viewDidLayoutSubviews {
  [super viewDidLayoutSubviews];
  self.infoTextViewCenter = self.view.center;
}

That's assuming you have infoTextView on a property.

Alternative and better approach is to use Autolayout and add horizontal and vertical position constraints to your view.

Answer 2

Another solution is just to set constraints on your textView and tell it to be vertically and horizontally aligned on your superview.

Answer 3

Replace the code with this:

UITextView *infoTextView = [[UITextView alloc] init];
infoTextView.frame = CGRectMake(0, 0, 300.0, 300.0);
infoTextView.center = self.view.center;
infoTextView.autoresizingMask = UIViewAutoresizingNone;
infoTextView.backgroundColor = [UIColor clearColor];
NSString *anotherViewText = @"This is the content";
infoTextView.dataDetectorTypes = UIDataDetectorTypeLink;
infoTextView.text = anotherViewText;
[infoTextView setFont:[UIFont fontWithName:@"ArialMT" size:18]];
infoTextView.editable = NO;
infoTextView.textAlignment=NSTextAlignmentCenter;
[self.view addSubview:infoTextView];

Answer 4

在代码中使用这些方法。并在-（void）landScapeFrame中为您编写横向代码，在-（虚空）potraitFrame 中编写纵向代码

#pragma mark - Auto rotate methods
#pragma mark for pre - iOS 6
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
BOOL returnval=NO;
if (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad)
{
    if(interfaceOrientation==UIInterfaceOrientationPortrait||interfaceOrientation==UIInterfaceOrientationPortraitUpsideDown)
    {
        [self potraitFrame];
    }
    else
    {
        [self landScapeFrame];
    }
    returnval = YES;
}
else
{
    [self landScapeFrame];
    returnval= (interfaceOrientation==UIInterfaceOrientationLandscapeLeft || interfaceOrientation==UIInterfaceOrientationLandscapeRight);
}
return returnval;
}
 #pragma mark for - iOS 6
 -(BOOL)shouldAutorotate
 {
return YES;
 }
 -(void)willRotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation  duration:(NSTimeInterval)duration {
if (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad)
{
           if(toInterfaceOrientation==UIInterfaceOrientationPortrait||toInterfaceOrientation==UIInterfaceOrientationPortraitUpsideDown)
    {
        [self potraitFrame];
    }
    else
    {
        [self landScapeFrame];
    }
}
else
{
    [self landScapeFrame];
}

}

-(void)willAnimateRotationToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration {
}
-(UIInterfaceOrientation)preferredInterfaceOrientationForPresentation
{
 UIInterfaceOrientationLandscapeLeft;
if (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad)
{
    return self.interfaceOrientation;
}
else
{
    UIInterfaceOrientation crntOrntatn = self.interfaceOrientation;
    return UIInterfaceOrientationIsLandscape(crntOrntatn) ? crntOrntatn : UIInterfaceOrientationLandscapeLeft;
}

}

 -(NSUInteger)supportedInterfaceOrientations
 {
if (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad)
{
    return UIInterfaceOrientationMaskAll;   
}
else
{
    return UIInterfaceOrientationMaskLandscape;
}
}