从另一个类改变ViewController框架 - iOS

Question

我正在尝试从另一个名为DownViewController的viewcontroller移动SensorViewController框架。我创建了一个委托对象并尝试更改框架，但它没有改变。

AppDelegate.h

#import <UIKit/UIKit.h>
#import "SensorsViewController.h"

@class ViewController;

@interface AppDelegate : UIResponder <UIApplicationDelegate>

@property (strong, nonatomic) UIWindow *window;

@property (strong, nonatomic) ViewController *viewController;
@property (strong, nonatomic) SensorsViewController  *sensorViewController;

@end

AppDelegate.m

#import "AppDelegate.h"

#import "ViewController.h"

@implementation AppDelegate
@synthesize sensorViewController;
    - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    sensorViewController = [[SensorsViewController alloc] initWithNibName:@"SensorsViewController" bundle:[NSBundle mainBundle]];

}

DownViewController.m

- (void)viewDidLoad
{
    [super viewDidLoad];

    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardDidShow:) name:UIKeyboardDidShowNotification object:nil];
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardDidHide:) name:UIKeyboardDidHideNotification object:nil];
    // Do any additional setup after loading the view from its nib.
}
- (void)keyboardDidShow:(NSNotification *)notification
{
    //Assign new frame to your view
    AppDelegate* appDelegate = [[UIApplication sharedApplication] delegate];
// the following part should change SensorViewController but, it is not!

    [[appDelegate sensorViewController].view setFrame:CGRectMake(0,-260,1030,768)];
}

-(void)keyboardDidHide:(NSNotification *)notification
{
   [self.view setFrame:CGRectMake(0,0,1030,768)];
}