通过向 NSNotificationCenter 注册观察者监听键盘事件，根据键盘状态，从而动态调整 UITextView的 edgeInsets

#import "ViewController.h"@interface ViewController ()@property (nonatomic, strong) UITextView *myTextView;@end@implementation ViewController/* 1 *///- (void)viewDidLoad{//    [super viewDidLoad];//    //    self.myTextView = [[UITextView alloc] initWithFrame:self.view.bounds];//    self.myTextView.text = @"Some text here...";//    self.myTextView.contentInset = UIEdgeInsetsMake(10.0f, 0.0f, 0.0f, 0.0f);//    self.myTextView.font = [UIFont systemFontOfSize:16.0f];//    [self.view addSubview:self.myTextView];//    //}    /* 2 */- (void) handleKeyboardDidShow:(NSNotification *)paramNotification{        /* Get the frame of the keyboard */    NSValue *keyboardRectAsObject =    [[paramNotification userInfo]     objectForKey:UIKeyboardFrameEndUserInfoKey];        /* Place it in a CGRect */    CGRect keyboardRect = CGRectZero;        [keyboardRectAsObject getValue:&keyboardRect];        /* Give a bottom margin to our text view that makes it     reach to the top of the keyboard */    self.myTextView.contentInset =    UIEdgeInsetsMake(0.0f,                     0.0f,                     keyboardRect.size.height,                     0.0f);}    - (void) handleKeyboardWillHide:(NSNotification *)paramNotification{    /* Make the text view as big as the whole view again */    self.myTextView.contentInset = UIEdgeInsetsZero;}    - (void) viewWillAppear:(BOOL)paramAnimated{    [super viewWillAppear:paramAnimated];        [[NSNotificationCenter defaultCenter]     addObserver:self     selector:@selector(handleKeyboardDidShow:)     name:UIKeyboardDidShowNotification     object:nil];        [[NSNotificationCenter defaultCenter]     addObserver:self     selector:@selector(handleKeyboardWillHide:)     name:UIKeyboardWillHideNotification     object:nil];        self.myTextView = [[UITextView alloc] initWithFrame:self.view.bounds];    self.myTextView.text = @"Some text here...";    self.myTextView.font = [UIFont systemFontOfSize:16.0f];    [self.view addSubview:self.myTextView];    }    - (void) viewWillDisappear:(BOOL)paramAnimated{    [super viewWillDisappear:paramAnimated];        [[NSNotificationCenter defaultCenter] removeObserver:self];}@end