iOS 开发杂记

抛出异常

NSException* ex = [NSException exceptionWithName:@"name" reason:@"reason" userInfo:nil];
[ex raise];

UILabel文字添加删除线

    NSAttributedString* attrStr =
        [[NSAttributedString alloc] initWithString:@"ddddd"
                                        attributes:
                                            @{ NSFontAttributeName : [UIFont systemFontOfSize:20.f],
                                                NSForegroundColorAttributeName : [UIColor redColor],
                                                NSStrikethroughStyleAttributeName : @(NSUnderlineStyleSingle | NSUnderlinePatternSolid),
                                                NSStrikethroughColorAttributeName : [UIColor blueColor] }];
    self.label.attributedText = [attrStr copy];

自定义控件的数据源设置

自定义控件应该自己定义相关的数据源，
然后其他数据源想要使用这个自定义控件，
就把自定义控件的模型放到数据源模型中，
然后通过setValue ：forKey ：来进行对自定义控件的模型赋值。

NSString

//去掉空格
NSString* _titleLabelOutSpace = [text stringByReplacingOccurrencesOfString:@" " withString:@""];
//NSString －>NSInteger
[_titleLabelOutSpace integerValue];

NSArray

//NSString  NSArray  互转
NSArray *arr = [@"a,b,c" componentsSeparatedByString:@","];


- (void)hasString:(NSString*)str1 string2:(NSString*)str2
{
    NSString* string1 = str1;
    NSString* string2 = str2;
    NSRange range = [string1 rangeOfString:string2];
    NSUInteger location = range.location;
    NSUInteger length = range.length;
    NSString* astring = [[NSString alloc] initWithString:[NSString stringWithFormat:@"Location:%zd,Leight:%zd", location, length]];
    NSLog(@"astring:%@", astring);
}
    [self hasString:@"1111111" string2:@"2"];
   //astring:Location:9223372036854775807, length:0
    [self hasString:@"11111112" string2:@"2"];
   //astring:Location:8,Leight:1
可以根据length来判断是否有字段

数组排序

[self.HelpManager.PublishScopeList sortedArrayUsingComparator:^NSComparisonResult(PublishScopeListModel* obj1, PublishScopeListModel* obj2) {

        NSComparisonResult result = [obj1.num compare:obj2.num];
        return result == NSOrderedAscending; // 降序:NSOrderedAscending====升序:NSOrderedDescending
    }];

为UICollectionView添加头视图的两种方式

• 给UICollectionView添加：UICollectionElementKindSectionHeader
• 设置UICollectionView的：contentInset

- (UICollectionReusableView*)collectionView:(UICollectionView*)collectionView viewForSupplementaryElementOfKind:(NSString*)kind atIndexPath:(NSIndexPath*)indexPath
{
    UICollectionReusableView* cell = [collectionView dequeueReusableSupplementaryViewOfKind:kind withReuseIdentifier:@"_CollectionReusableViewIndetifier" forIndexPath:indexPath];
    return cell;
}
- (CGSize)collectionView:(UICollectionView*)collectionView layout:(UICollectionViewLayout*)collectionViewLayout referenceSizeForHeaderInSection:(NSInteger)section;
{
    return CGSizeMake(ScreenWidth, 44);
}

    CGFloat _adH = 120.0;
    self.collectionView.contentInset = UIEdgeInsetsMake(_adH, 0, 0, 0);
    [self.adImgeView setFrame:CGRectMake(0, CGRectGetMinY(self.collectionView.frame) - _adH, CGRectGetWidth(self.collectionView.frame), _adH)];

TableViewCell创建技巧

#import 
static NSString* SEGPictorialDetailADCellIdentifier = @"SEGPictorialDetailADCellIdentifier";

static NSString* SEGHelpViewCellIdentifier = @"_SEGHelpViewCellIdentifier";  
static NSString* SEGHelpViewCellDetailTopIdentifier = @"_SEGHelpViewCellDetailTopIdentifier";  
static NSString* SEGHelpViewCellDetailDwonIdentifier = @"_SEGHelpViewCellDetailDwonIdentifier";   


@interface SEGPictorialDetailADCell : UITableViewCell
+ (instancetype)cellWithTableView:(UITableView*)tableView;
+ (instancetype)cellWithTableView:(UITableView*)tableView reuseIdentifier:(NSString*)reuseIdentifier;
@end

#import "SEGPictorialDetailADCell.h"

@implementation SEGPictorialDetailADCell

+ (instancetype)cellWithTableView:(UITableView*)tableView
{
    SEGPictorialDetailADCell* cell = [tableView dequeueReusableCellWithIdentifier:SEGPictorialDetailADCellIdentifier];

    if (cell == nil) {

        cell = [[SEGPictorialDetailADCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:SEGPictorialDetailADCellIdentifier];
    }


    return cell;
}

+ (instancetype)cellWithTableView:(UITableView*)tableView reuseIdentifier:(NSString*)reuseIdentifier
{
    SEGHelpViewCell* cell = [tableView dequeueReusableCellWithIdentifier:reuseIdentifier];

    if (cell == nil) {
        cell = [[SEGHelpViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:reuseIdentifier];
    }

    return cell;
}

- (instancetype)initWithStyle:(UITableViewCellStyle)style reuseIdentifier:(NSString*)reuseIdentifier
{
    self.CellIdentifier = reuseIdentifier;//通过记录不同的ID来布置对应的界面
    if (self == [super initWithStyle:style reuseIdentifier:reuseIdentifier]) {
    }

    return self;
}
@end

TableHeaderView动态改变高度

[self.tableView beginUpdates];
[self.tableView setTableHeaderView:self.webView];
[self.tableView endUpdates];

去掉多余的空白的cell

self.contactsTableView.tableFooterView = [[UIView alloc] initWithFrame:CGRectZero];

切割图片

UIImage* Image = [UIImage imageNamed:@"RedButton"];
Image = [logBackgroundImage stretchableImageWithLeftCapWidth:logBackgroundImage.size.width * 0.5 topCapHeight:logBackgroundImage.size.height * 0.5];
[self.loginBtn setBackgroundImage:Image forState:UIControlStateNormal];

实现跳转safari，phone或message

//调用 电话phone
[[UIApplication sharedApplication] openURL:[NSURL URLWithString:@"tel://10086"]];

//调用自带 浏览器 safari
[[UIApplication sharedApplication] openURL:[NSURL URLWithString:@"http://www.baidu.com"]];

//调用 自带mail
[[UIApplication sharedApplication] openURL:[NSURL URLWithString:@"mailto://[email protected]"]];

//调用 SMS
[[UIApplication sharedApplication] openURL:[NSURL URLWithString:@"sms://111111"]];

//跳转到系统设置相关界面
[[UIApplication sharedApplication] openURL:[NSURL URLWithString:@"prefs:root=WIFI"]];

程序中获取软件的版本号和app名称

应用程序的名称和版本号等信息都保存在mainBundle的infoDictionary字典中，用下面代码可以取出来。  
NSDictionary* infoDict =[[NSBundle mainBundle] infoDictionary];  
NSString* versionNum =[infoDict objectForKey:@"CFBundleVersion"];//版本名称  
NSString*appName =[infoDict objectForKey:@"CFBundleDisplayName"];//app名称 

在有uinavigation,uitoolbar的情况下，如何添加一个全屏的 uiview （作为显示一个进度框，任何区域无法触摸而使用）

[[UIApplication sharedApplication].keyWindow addSubview:waitingview]; 

在项目用代码打开AppStore

NSString *url = [NSString stringWithFormat:@"http://itunes.apple.com/cn/app/huo-xing-she-xin-dian/id549425594?l=en&mt=8"];  
[[UIApplication sharedApplication] openURL:[NSURL URLWithString:url]];

使屏幕一直保持唤醒状态？（就是不自动黑屏）

[[UIApplication sharedApplication] setIdleTimerDisabled:YES];

隐藏UINavigationBar

- (void)viewWillAppear:(BOOL)animated
{
    [self.navigationControllersetNavigationBarHidden:YESanimated:YES]; //设置隐藏
    [super viewWillAppear:animated];
}
- (void)viewWillDisappear:(BOOL)animated
{
    [self.navigationControllersetNavigationBarHidden:NOanimated:YES];//设置显示
    [super viewWillDisappear:animated];
}

在navigationviewcontroller中，pop到指定的VC

NSArray *viewControllers=[self.navigationController viewControllers];  
UIViewController *controller=[viewControllers objectAtIndex:1];  //跳转到第一个VC
[self.navigationController popToViewController:controller animated:YES];  

获取手机硬件信息

[[UIDevice currentDevice] systemName];[[UIDevice currentDevice] systemVersion];
[[UIDevice currentDevice] uniqueIdentifier];
[[UIDevice currentDevice] model];
[[UIDevice currentDevice] name];

真机上结果：
System Name: iPhone OSSystem 
Version: 4.2.1
Unique ID: 9b5ded78d5fa0ac96250f8b4af0e46f40b96ea6d
Model: iPhone
Name: “wwk”的 iPhone

模拟器上结果：
System Name: iPhone OSSystem 
Version: 4.2
Unique ID: 21FFE0FF-429B-5D0B-96D2-EADCA3203260
Model: iPhone Simulator
Name: iPhone Simulator

URL编码、解码

// 1. URL编码：ios中http请求遇到汉字的时候，需要转化成UTF-8：
 NSString* urlString = @"http://www.baidu.com!name=小明";
NSString * encodingString = [urlString stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
//结果：http://www.baidu.com!name=%E5%B0%8F%E6%98%8E

// 2.URL解码：请求后，返回的数据，如何显示的是这样的格式：%3A%2F%2F，此时需要我们进行UTF-8解码，用到的方法是：
NSString *str = [encodingString stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding];

获取URL中的细节

NSURL* url = [NSURL URLWithString:@"http://www.baidu.com/s?tn=baiduhome_pg&bs=NSRUL&f=8&rsv_bp=1&rsv_spt=1&wd=NSurl&inputT=2709"];
    NSLog(@"Scheme: %@", [url scheme]);
    NSLog(@"Host: %@", [url host]);
    NSLog(@"Port: %@", [url port]);
    NSLog(@"Path: %@", [url path]);
    NSLog(@"Relative path: %@", [url relativePath]);
    NSLog(@"Path components as array: %@", [url pathComponents]);
    NSLog(@"Parameter string: %@", [url parameterString]);
    NSLog(@"Query: %@", [url query]);
    NSLog(@"Fragment: %@", [url fragment]);
    NSLog(@"User: %@", [url user]);
    NSLog(@"Password: %@", [url password]);

/*
2016-05-27 11:38:23.503 FourNews[2358:116708] Scheme: http
2016-05-27 11:38:23.504 FourNews[2358:116708] Host: www.baidu.com
2016-05-27 11:38:23.504 FourNews[2358:116708] Port: (null)
2016-05-27 11:38:23.504 FourNews[2358:116708] Path: /s
2016-05-27 11:38:23.504 FourNews[2358:116708] Relative path: /s
2016-05-27 11:38:23.504 FourNews[2358:116708] Path components as array: (
    "/",
    s
)
2016-05-27 11:38:23.504 FourNews[2358:116708] Parameter string: (null)
2016-05-27 11:38:23.505 FourNews[2358:116708] Query: tn=baiduhome_pg&bs=NSRUL&f=8&rsv_bp=1&rsv_spt=1&wd=NSurl&inputT=2709
2016-05-27 11:38:23.505 FourNews[2358:116708] Fragment: (null)
2016-05-27 11:38:23.505 FourNews[2358:116708] User: (null)
2016-05-27 11:38:23.505 FourNews[2358:116708] Password: (null)
*/

获取URL中的参数

- (NSDictionary*)dictionaryFromQuery:(NSString*)query usingEncoding:(NSStringEncoding)encoding
{
    NSCharacterSet* delimiterSet = [NSCharacterSet characterSetWithCharactersInString:@"&;"];
    NSMutableDictionary* pairs = [NSMutableDictionary dictionary];
    NSScanner* scanner = [[NSScanner alloc] initWithString:query];
    while (![scanner isAtEnd]) {
        NSString* pairString = nil;
        [scanner scanUpToCharactersFromSet:delimiterSet intoString:&pairString];
        [scanner scanCharactersFromSet:delimiterSet intoString:NULL];
        NSArray* kvPair = [pairString componentsSeparatedByString:@"="];
        if (kvPair.count == 2) {
            NSString* key = [[kvPair objectAtIndex:0]
                stringByReplacingPercentEscapesUsingEncoding:encoding];
            NSString* value = [[kvPair objectAtIndex:1]
                stringByReplacingPercentEscapesUsingEncoding:encoding];
            [pairs setObject:value forKey:key];
        }
    }

    return [NSDictionary dictionaryWithDictionary:pairs];
}

[**ViewController respondsToSelector:]: message sent to deallocated instance崩溃问题解决方法

这是因为这个UIViewController释放后，又再次向这个VC调用了某些请求导致的，一般出现这种报错是UIViewController里面有设置xxx.delegate=self，这些代理有延时方法，例如等待网络返回等
当导航栏直接返回时，UIViewController已经被销毁，延时方法再调用此野指针VC，便会导致崩溃
解决方法：
1 在dealloc中设置xx.delegate = nil ，这个是程序没有使用ARC才可以
2 在viewWillDisappear方法中把所有xxx.delegate=self的具有延时方法的delegate置nil，我的做法是不过有没有延时方法，

UIView有关的杂技

//设置View的圆角：
[view.layer setCornerRadius:15.0];