iOS键盘自适应弹出效果

#import <UIKit/UIKit.h>@interface ViewController : UIViewController<UITextFieldDelegate>@end

#import "ViewController.h"@interface ViewController ()@end@implementation ViewController- (void)viewDidLoad {  [super viewDidLoad];  // Do any additional setup after loading the view, typically from a nib.      UITextField *field=[[UITextField alloc]initWithFrame:CGRectMake(100, 300, 50, 50)];  field.backgroundColor=[UIColor redColor];  field.delegate=self;  [self.view addSubview:field];        [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillShow:) name:UIKeyboardWillShowNotification object:nil];  [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillHide:) name:UIKeyboardWillHideNotification object:nil];  }#pragma -mark -keyboard notificatin- (void)keyboardWillShow:(NSNotification *)notification {  NSDictionary *info = [notification userInfo];  // keyboardHeight 为键盘高度  CGSize keyboardSize = [[info objectForKey:UIKeyboardFrameEndUserInfoKey] CGRectValue].size;  [self animateViewWithKeyboardHeight:keyboardSize.height];}- (void)keyboardWillHide:(NSNotification *)notification {  [self animateViewWithKeyboardHeight:0.0];}- (void)animateViewWithKeyboardHeight:(CGFloat)keyboardHeight {  NSTimeInterval animationDuration = 0.3f;  CGFloat height = self.view.bounds.size.height;  CGFloat width = self.view.bounds.size.width;  CGFloat topSize = 0.0;  CGFloat viewH = self.view.frame.size.height-64;  CGFloat deviceHeight = [UIScreen mainScreen].bounds.size.height;  CGFloat animateH = deviceHeight - viewH - keyboardHeight;  if (animateH >= 0) {    topSize = 0;    CGRect toRect = CGRectMake(0, topSize, width, height);    self.view.frame = toRect;      } else {    topSize = animateH;    CGRect toRect = CGRectMake(0, topSize, width, height);    [UIView animateWithDuration:animationDuration animations:^{      self.view.frame = toRect;    }];  }}#pragma -mark -UITextFieldDelegate-(BOOL)textFieldShouldReturn:(UITextField *)textField{  [textField resignFirstResponder];    return YES;}- (void)didReceiveMemoryWarning {  [super didReceiveMemoryWarning];  // Dispose of any resources that can be recreated.}@end