1. iOS有四个方向的旋转，为了保证自己的代码能够支持旋转，我们必须首先处理一个函数：
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
returnYES;
}
2. 这个函数时用来确定我们的应用所支持的旋转方向。如果想要支持每个方向则直接返回YES就行，还可以单独判断某一方向：
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
if(interfaceOrientation==UIInterfaceOrientationLandscapeLeft) {
//left
}
if(interfaceOrientation==UIInterfaceOrientationLandscapeRight) {
//right
}
if(interfaceOrientation==UIInterfaceOrientationPortrait) {
//up
}
if(interfaceOrientation==UIInterfaceOrientationPortraitUpsideDown) {
//down
}
returnYES;
}
3. 当然旋转还有一些函数可触发：
//旋转方向发生改变时
-(void)willAnimateRotationToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration {
}
//视图旋转动画前一半发生之前自动调用
-(void)willAnimateFirstHalfOfRotationToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration {
}
//视图旋转动画后一半发生之前自动调用
-(void)willAnimateSecondHalfOfRotationFromInterfaceOrientation:(UIInterfaceOrientation)fromInterfaceOrientation duration:(NSTimeInterval)duration {
}
//视图旋转之前自动调用
-(void)willRotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration {
}
//视图旋转完成之后自动调用
-(void)didRotateFromInterfaceOrientation:(UIInterfaceOrientation)fromInterfaceOrientation {
}
//视图旋转动画前一半发生之后自动调用
-(void)didAnimateFirstHalfOfRotationToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation {
}