注意点
1、使用ALAssetsLibrary需要强引用。
2、使用changeDetailsForFetchResult:时，PHFetchResult要强引用。
3、textField相关
3.1、textField右对齐状态下，输入空格后，光标跳转至左侧。
3.2、textField右对齐状态下，手写输入会产生一个中文空格。
3.3、直接对textField.text赋值光标会跳到右侧。
3.4、textField:shouldChangeCharactersInRange:replacementString:方法在iOS10之前输入中文不会触发。
3.5、textField右对齐状态下，在光标前面无字符的情况下，无法输入空格，需使用\u00a0替代。
4、使用ALAssetsLibrary获取到image后直接使用，当在PC端删除图片并在手机端使用Layer动画时，Cell会闪烁。
5、转场动画过程中截屏需使用GCD，否则有可能会有黑屏。
// To avoid a blank snapshot, defer snapshotting the incoming view until it
// has had a chance to perform layout and drawing (1 run-loop cycle).
dispatch_async(dispatch_get_main_queue(), ^{
UIGraphicsBeginImageContextWithOptions(containerView.bounds.size, YES, containerView.window.screen.scale);
[toView drawViewHierarchyInRect:containerView.bounds afterScreenUpdates:NO];
toViewSnapshot = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
});
6、删除cookie
NSHTTPCookieStorage *storage = [NSHTTPCookieStorage sharedHTTPCookieStorage];
NSArray *cookies = [[storage cookies] copy];
for (NSHTTPCookie *cookie in cookies) {
[storage deleteCookie:cookie];
}
7、web认证
UIWebView:使用NSURLConnection
WKWebView:使用
- (void)webView:(WKWebView *)webView didReceiveAuthenticationChallenge:(NSURLAuthenticationChallenge *)challenge completionHandler:(void (^)(NSURLSessionAuthChallengeDisposition, NSURLCredential *))completionHandler {
}
8、使用FLEX时，在转场动画时旋转屏幕，
iOS8状态栏会跟着转
iOS9以上，屏幕会一起转，出现黑屏
9、
NSString *someString = nil;
if (NSNotFound != [someString rangeOfString:@"swift"].location) {
NSLog(@"Someone mentioned swift!");
}
如果 someString 是 nil，那么 rangeOfString: 消息将返回一个值都为零的NSRange。也就是说.location 将为零，而 NSNotFound 被定义为 NSIntegerMax。这样一来，当 someString 是 nil 时，if 语句的内容将被执行。
小技巧
1、横屏显示状态栏
非刘海屏：
[[UIApplication sharedApplication] setStatusBarHidden:YES withAnimation:UIStatusBarAnimationNone];
[[UIApplication sharedApplication] setStatusBarHidden:NO withAnimation:UIStatusBarAnimationNone];
刘海屏：
暂时没有办法，下图是苹果给的答复。
WechatIMG381.jpeg
2、设置UserAgent
[self.webViewAdapter stringByJavaScriptFromString:@"navigator.userAgent" handler:^(id _Nonnull result) {
NSString *appCurVersion = [[[NSBundle mainBundle] infoDictionary] objectForKey:@"CFBundleShortVersionString"];
NSString *UserAgentValue = [NSString stringWithFormat:@"XXX %@ %@", appCurVersion, result];
NSDictionary *dictionary = [[NSDictionary alloc] initWithObjectsAndKeys:UserAgentValue, @"UserAgent", nil];
[[NSUserDefaults standardUserDefaults] registerDefaults:dictionary];
[[NSUserDefaults standardUserDefaults] synchronize];
ws.webViewAdapter = nil;
}];
3、设置textField光标位置
@interface UITextField (Cursor)
- (NSInteger)cursorIndex;
- (void)setCursorIndex:(NSInteger)index;
@end
@implementation UITextField (Cursor)
- (NSInteger)cursorIndex {
UITextPosition *beginning = self.beginningOfDocument;
UITextRange *selectedRange = self.selectedTextRange;
UITextPosition *selectionStart = selectedRange.start;
return [self offsetFromPosition:beginning toPosition:selectionStart];
}
- (void)setCursorIndex:(NSInteger)index {
UITextPosition *beginning = self.beginningOfDocument;
UITextPosition *position = [self positionFromPosition:beginning offset:index];
UITextRange *selectionRange = [self textRangeFromPosition:position toPosition:position];
[self setSelectedTextRange:selectionRange];
}
@end
4、判断字符串是否包含Emoji
@interface NSString (Emoji)
+ (BOOL)stringContainsEmoji:(NSString *)string;
@end
@implementation NSString (Emoji)
+ (BOOL)stringContainsEmoji:(NSString *)string {
__block BOOL containsEmoji = NO;
[string enumerateSubstringsInRange:NSMakeRange(0, [string length])
options:NSStringEnumerationByComposedCharacterSequences
usingBlock:^(NSString *substring, NSRange substringRange, NSRange enclosingRange, BOOL *stop) {
const unichar hs = [substring characterAtIndex:0];
// surrogate pair
if (0xd800 <= hs && hs <= 0xdbff) {
if (substring.length > 1) {
const unichar ls = [substring characterAtIndex:1];
const int uc = ((hs - 0xd800) * 0x400) + (ls - 0xdc00) + 0x10000;
if (0x1d000 <= uc && uc <= 0x1f9c0) {
containsEmoji = YES;
}
}
} else if (substring.length > 1) {
const unichar ls = [substring characterAtIndex:1];
if (ls == 0x20e3 || ls == 0xfe0f || ls == 0xd83c) {
containsEmoji = YES;
}
} else {
// non surrogate
if (0x2100 <= hs && hs <= 0x278a) {
containsEmoji = YES;
} else if (0x2793 <= hs && hs <= 0x27ff) {
containsEmoji = YES;
} else if (0x2B05 <= hs && hs <= 0x2b07) {
containsEmoji = YES;
} else if (0x2934 <= hs && hs <= 0x2935) {
containsEmoji = YES;
} else if (0x3297 <= hs && hs <= 0x3299) {
containsEmoji = YES;
} else if (hs == 0xa9 || hs == 0xae || hs == 0x303d || hs == 0x3030 || hs == 0x2b55 || hs == 0x2b1c || hs == 0x2b1b || hs == 0x2b50) {
containsEmoji = YES;
}
}
if (containsEmoji) {
*stop = YES;
}
}];
return containsEmoji;
}
@end
5.1、给WKWebView添加Cookie
NSMutableURLRequest *mutableURLRequest = [[NSMutableURLRequest alloc] initWithURL:request.URL];
NSString *cookie = [self p_getCurrentCookieWithUrl:request.URL];
if (![cookie isEqualToString:@""]) {
[mutableURLRequest addValue:cookie forHTTPHeaderField:@"Cookie"];
}
[self.wkWebView loadRequest:mutableURLRequest];
- (NSString *)p_getCurrentCookieWithUrl:(NSURL *)url {
NSMutableString *cookieStr = [[NSMutableString alloc] init];
NSArray *array = [[NSHTTPCookieStorage sharedHTTPCookieStorage] cookiesForURL:url];
if ([array count] > 0) {
for (NSHTTPCookie *cookie in array) {
[cookieStr appendFormat:@"%@=%@;",cookie.name, cookie.value];
}
[cookieStr deleteCharactersInRange:NSMakeRange(cookieStr.length - 1, 1)];
}
return cookieStr;
}
6、使用动态阈值加载数据
- (void)scrollViewDidScroll:(UIScrollView *)scrollView {
CGFloat threshold = 0.7;
CGFloat itemPerPage = 10;
CGFloat current = scrollView.contentOffset.y + scrollView.frame.size.height;
CGFloat total = scrollView.contentSize.height;
CGFloat ratio = current / total;
CGFloat needRead = [self.dataArray count] - itemPerPage * (1 - threshold) + 1;
CGFloat totalItem = [self.dataArray count] + 1;
CGFloat newThreshold = needRead / totalItem;
if (ratio >= newThreshold) {
// load next page
}
}
7、查看源码
clang -rewrite-objc main.m
8、升级了Xcode并且改了名
sudo xcode-select -switch /Applications/Xcode8.3.app/Contents/Developer
9、WKWebview中部分链接无法打开
- (WKWebView *)webView:(WKWebView *)webView createWebViewWithConfiguration:(WKWebViewConfiguration *)configuration forNavigationAction:(WKNavigationAction *)navigationAction windowFeatures:(WKWindowFeatures *)windowFeatures {
if (!navigationAction.targetFrame) {
[webView loadRequest:navigationAction.request];
}
return nil;
}
10、安装cocoapods
sudo gem install -n /usr/local/bin cocoapods
11、获取当前的Wifi名
- (NSString *)getCurrentWifiHotSpotName {
NSString *wifiName = nil;
NSArray *ifs = (__bridge_transfer id)CNCopySupportedInterfaces();
for (NSString *ifnam in ifs) {
NSDictionary *info = (__bridge_transfer id)CNCopyCurrentNetworkInfo((__bridge CFStringRef)ifnam);
if (info[@"SSID"]) {
wifiName = info[@"SSID"];
}
}
return wifiName;
}
12、连接Wifi（iOS 11）
1）打开Capabilities中的Hotspot Configuration
An application that needs access to the NEHotspotConfiguration API must have
the “com.apple.developer.networking.HotspotConfiguration” entitlement.
2）连接代码
if (@available(iOS 11.0, *)) {
NEHotspotConfiguration *hotspotConfig = [[NEHotspotConfiguration alloc] initWithSSID:@"123" passphrase:@"12356789" isWEP:NO];
NEHotspotConfigurationManager *hotspotManager = [NEHotspotConfigurationManager sharedManager];
[hotspotManager applyConfiguration:hotspotConfig completionHandler:^(NSError * _Nullable error) {
NSLog(@"%@", error ? : @"Success");
}];
} else {
NSLog(@"系统版本低于iOS 11.");
}
未完待续 、
