问题
I am trying to develop a simple app with one screen for iOS and am running into a strange problem. Only half of the app is showing up. For example I have a screen with just one button in the center of the screen. When I run the app in the simulator I only see half the button and I cannot move it either.I can scroll the view in the simulator vertically but not horizontally. I am stumped. Will appreciate any pointers.
回答1:
I'm pretty sure you built your view using the main storyboard and put everything in the middle of it. The main storyboard is set to take all iOS format into account, iPhone and iPad. If you want your app to appear centered on your iOS device, you need to constraint the position of your different UI objects, using Auto Layout. That way it would appear centered automatically, whatever is the device you're using
回答2:
I reckon you've got AutoLayout turned on... but haven't set any constraints on your controls yet.
Try the following test:
- Go into your Storyboard file.
- Click on a blank area in your storyboard, then on your screen (so the border of your screen is blue - not black or gray).
- In the menu bar, click on Editor \ Resolve Auto Layout Issues, and then "Update Frames".
Alternatively, you can click on the following button, and select "Update Frames" from there (it doesn't matter which one):
When you do this, where does your "one button" end up ? Does it suddenly disappear off the screen, have a negative X or Y position, or a width/height of 0 ? If so, then AutoLayout is your problem.
With XCode 6.1, Apple has put a gun to developers' heads and demanded that when you add an object to a Storyboard, you must - straightaway - add some constraints to it.
I had this issue when I first upgraded to XCode 6.
I would add, say, a View to a screen, stretch it to a particular size, then drag a second control (perhaps a Label) onto the same screen. Suddenly, my View would resize itself to a height/width of zero, or be positioned way off the side of the screen... huh ?!
To get around this, when you add a control onto a Storyboard, you must add sufficient constraints to really let XCode calculate where to position it, based on which device/orientation the device is running on. And, yes, you sometimes need to do this straightaway before XCode ridiculously decides to mess up your control's position or size.
I really do loathe XCode. This isn't the way a development environment should behave in 2015...
回答3:
If I get your point of problem then
I m sure the problem is you have auto layout and size classes enabled.
check if you have Auto layout and size classes enabled ....???
If yes then you haven't set the constraints accurately. set the constraints for the UI Objects to show on your desired position in screen.
来源：https://stackoverflow.com/questions/28338623/ios-app-only-showing-half-in-simulator