How to make iPhone app compatible with iOS 4?

Question

My iphoneos 3.1-based application does not work on iOS 4 GM: the camera does not display in full screen mode, it does not display compass information correctly, uiwebviews does not respond to touches (they do not scroll), and so on. He is completely broken! Now my question is: how can I develop an update using the latest xcode with ios 4 support? The latest iOS 4 xcode (3.2.3) provides no development method for iPhoneOS 3.x ("base sdk missing"). On the other hand, xcode 3.2.2 will not let me debug it on an iOS 4 device, so I cannot test it.

Answer 1

In Xcode, you can use the later base SDK when targeting an earlier version.

Go to your project settings and set to deploy iPhone OS for an earlier version, such as "iPhone OS 3.1."

Answer 2

I would create a second disk partition and install xcode 4.0 for it. Save version 3.2 on the main disk.

It may not be necessary to create a second disk partition, but it was easy to do.

Answer 3

Install 4.0 sdk in another folder, and then reinstall 3.2 sdk and develop in that.