IOS7、8模态半透明弹出框

//源Controller中跳转方法实现

MKDialogController *controller = [[MKDialogController alloc] init];

controller.modalTransitionStyle = UIModalTransitionStyleCrossDissolve;

if ([[UIDevice currentDevice].systemVersion floatValue] >= 8.0) {

　controller.providesPresentationContextTransitionStyle = YES;

　controller.definesPresentationContext = YES;

　controller.modalPresentationStyle = UIModalPresentationOverCurrentContext;

　[self presentViewController:controller animated:YES completion:nil];

} else {

　　 self.view.window.rootViewController.modalPresentationStyle = UIModalPresentationCurrentContext;

[self presentViewController:controller animated:NO completion:nil];

　　 self.view.window.rootViewController.modalPresentationStyle = UIModalPresentationFullScreen;

}

// 只不过跳转后没有动画效果，有待优化