iOS适配各版本

if (isBeforeIOS7)
{
UIImagePickerController * photoPicker=[[UIImagePickerController alloc]init];
if ([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]){
photoPicker.sourceType=UIImagePickerControllerSourceTypeCamera;
photoPicker.delegate = self;
[self presentViewController:photoPicker animated:YES completion:nil];
}
}else
{
if ([self shouldPhoto])
{
UIImagePickerController * photoPicker=[[UIImagePickerController alloc]init];
if ([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]){
photoPicker.sourceType=UIImagePickerControllerSourceTypeCamera;
photoPicker.delegate = self;
[self presentViewController:photoPicker animated:YES completion:nil];
}
}else
{
UIAlertView *al=[[UIAlertView alloc]initWithTitle:@"权限受限" message:@"设置-手机梵讯-隐私" delegate:nil cancelButtonTitle:@"确定" otherButtonTitles:nil];
[al show];
}
}