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IOS NSNotification 键盘遮挡问题的解决办法

2017-09-30 11:12 891 查看

IOS NSNotification 键盘遮挡问题的解决办法

从键盘通知中获得键盘尺寸

键盘尺寸存在于NSNotification中。

1；在AddDrinkViewController中添加keyboardDidShow和keyboardDidHide方法

2；在viewWillAppear中注册UIKeyboardDidshowNotification与UIKeyboardDidHideNotification。

3；在viewWillDisappear中取消对所有事件的订阅注册

4；在AddDrinkViewController中添加一个Bool成员，跟踪键盘是否可见的状态。

//
// ViewController.h
// scrol
//
// Created by gao wuhang on 12-12-5.
// Copyright (c) 2012年 gao wuhang. All rights reserved.
//
#import
@interface ViewController : UIViewController{
BOOL keyboardVisible;
UIScrollView *scrollView;
}
- (void)keyboardDidShow: (NSNotification*) notif;
- (void)keyboardDidHide: (NSNotification*) notif;
@property (nonatomic, retain) UIScrollView *scrollView;
@end
//
// ViewController.m
// scrol
//
// Created by gao wuhang on 12-12-5.
// Copyright (c) 2012年 gao wuhang. All rights reserved.
//
#import "ViewController.h"
@interface ViewController ()
@end
@implementation ViewController
@synthesize scrollView;
- (void)viewWillAppear:(BOOL)animated{
[super viewWillAppear:animated];
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardDidShow:) name:UIKeyboardDidShowNotification object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardDidHide:) name:UIKeyboardDidHideNotification object:nil];
}
- (void)viewWillDisappear:(BOOL)animated{
[[NSNotificationCenter defaultCenter] removeObserver:self];
}
- (void) keyboardDidShow:(NSNotification *)notif {
NSLog(@"%@", @"Received UIKeyboardDidShowNotification");
if (keyboardVisible) {
NSLog(@"%@", @"Keyboard is already visible. Ignoring notifications.");
return;
}
// The keyboard wasn't visible before
NSLog(@"Resizing smaller for keyboard");
// Get the origin of the keyboard when it finishes animating
NSDictionary *info = [notif userInfo];
NSValue *aValue = [info objectForKey:UIKeyboardFrameEndUserInfoKey];
// Get the top of the keyboard in view's coordinate system.
// We need to set the bottom of the scrollview to line up with it
CGRect keyboardRect = [aValue CGRectValue];
keyboardRect = [self.view convertRect:keyboardRect fromView:nil];
CGFloat keyboardTop = keyboardRect.origin.y;
// Resize the scroll view to make room for the keyboard
CGRect viewFrame = self.view.bounds;
viewFrame.size.height = keyboardTop - self.view.bounds.origin.y;
self.scrollView.frame = viewFrame;
keyboardVisible = YES;
}
- (void) keyboardDidHide:(NSNotification *)notif {
NSLog(@"%@", @"Received UIKeyboardDidHideNotification");
if (!keyboardVisible) {
NSLog(@"%@", @"Keyboard already hidden. Ignoring notification.");
return;
}
// The keyboard was visible
NSLog(@"%@", @"Resizing bigger with no keyboard");
// Resize the scroll view back to the full size of our view
self.scrollView.frame = self.view.bounds;
keyboardVisible = NO;
}
- (void)viewDidLoad
{
scrollView = [[UIScrollView alloc] initWithFrame:CGRectMake(0, 0, 320, 460)];
//  scroll.contentSize = CGSizeMake(1000, 1000);
[self.view addSubview:scrollView];
//  UIButton *button = [[UIButton alloc] initWithFrame:CGRectMake(100, 100, 100, 100)];
//  [button setBackgroundColor:[UIColor blackColor]];
//  [scroll addSubview:button];
UITextView *textView = [[UITextView alloc]initWithFrame:CGRectMake(100, 300, 100, 100)];
textView.text = @"222";
textView.font = [UIFont systemFontOfSize:20];
[scrollView addSubview:textView];
[super viewDidLoad];
[textView release];
self.scrollView.contentSize = self.view.frame.size;
// Do any additional setup after loading the view, typically from a nib.
}
- (void)dealloc
{
[scrollView release];
[super dealloc];
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
@end

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