iOS小技巧总结
UITableView的Group样式下顶部空白处理
//分组列表头部空白处理
UIView *view = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 0, 0.1)];
self.tableView.tableHeaderView = view;
UITableView的plain样式下,取消区头停滞效果
- (void)scrollViewDidScroll:(UIScrollView *)scrollView
{
CGFloat sectionHeaderHeight = sectionHead.height;
if (scrollView.contentOffset.y<=sectionHeaderHeight&&scrollView;.contentOffset.y>=0)
{
scrollView.contentInset = UIEdgeInsetsMake(-scrollView.contentOffset.y, 0, 0, 0);
}
else if(scrollView.contentOffset.y>=sectionHeaderHeight)
{
scrollView.contentInset = UIEdgeInsetsMake(-sectionHeaderHeight, 0, 0, 0);
}
}
那个,其实,还是用Group样式吧哈哈。
获取某个view所在的控制器
- (UIViewController *)viewController
{
UIViewController *viewController = nil;
UIResponder *next = self.nextResponder;
while (next)
{
if ([next isKindOfClass:[UIViewController class]])
{
viewController = (UIViewController *)next;
break;
}
next = next.nextResponder;
}
return viewController;
}
两种方法删除NSUserDefaults所有记录
//方法一
NSString *appDomain = [[NSBundle mainBundle] bundleIdentifier];
[[NSUserDefaults standardUserDefaults] removePersistentDomainForName:appDomain];
//方法二
- (void)resetDefaults
{
NSUserDefaults * defs = [NSUserDefaults standardUserDefaults];
NSDictionary * dict = [defs dictionaryRepresentation];
for (id key in dict)
{
[defs removeObjectForKey:key];
}
[defs synchronize];
}
打印系统所有已注册的字体名称
#pragma mark - 打印系统所有已注册的字体名称
void enumerateFonts()
{
for(NSString *familyName in [UIFont familyNames])
{
NSLog(@"%@",familyName);
NSArray *fontNames = [UIFont fontNamesForFamilyName:familyName];
for(NSString *fontName in fontNames)
{
NSLog(@" |- %@",fontName);
}
}
}
获取图片某一点的颜色
- (UIColor*) getPixelColorAtLocation:(CGPoint)point inImage:(UIImage *)image
{
UIColor* color = nil;
CGImageRef inImage = image.CGImage;
CGContextRef cgctx = [self createARGBBitmapContextFromImage:inImage];
if (cgctx == NULL) {
return nil; /* error */
}
size_t w = CGImageGetWidth(inImage);
size_t h = CGImageGetHeight(inImage);
CGRect rect = {{0,0},{w,h}};
CGContextDrawImage(cgctx, rect, inImage);
unsigned char* data = CGBitmapContextGetData (cgctx);
if (data != NULL) {
int offset = 4*((w*round(point.y))+round(point.x));
int alpha = data[offset];
int red = data[offset+1];
int green = data[offset+2];
int blue = data[offset+3];
color = [UIColor colorWithRed:(red/255.0f) green:(green/255.0f) blue:
(blue/255.0f) alpha:(alpha/255.0f)];
}
CGContextRelease(cgctx);
if (data) {
free(data);
}
return color;
}
字符串反转
第一种:
- (NSString *)reverseWordsInString:(NSString *)str
{
NSMutableString *newString = [[NSMutableString alloc] initWithCapacity:str.length];
for (NSInteger i = str.length - 1; i >= 0 ; i --)
{
unichar ch = [str characterAtIndex:i];
[newString appendFormat:@"%c", ch];
}
return newString;
}
//第二种:
- (NSString*)reverseWordsInString:(NSString*)str
{
NSMutableString *reverString = [NSMutableString stringWithCapacity:str.length];
[str enumerateSubstringsInRange:NSMakeRange(0, str.length) options:NSStringEnumerationReverse | NSStringEnumerationByComposedCharacterSequences usingBlock:^(NSString *substring, NSRange substringRange, NSRange enclosingRange, BOOL *stop) {
[reverString appendString:substring];
}];
return reverString;
}
禁止锁屏,
默认情况下,当设备一段时间没有触控动作时,iOS会锁住屏幕。但有一些应用是不需要锁屏的,比如视频播放器。
[UIApplication sharedApplication].idleTimerDisabled = YES;
或
[[UIApplication sharedApplication] setIdleTimerDisabled:YES];
模态推出透明界面
UIViewController *vc = [[UIViewController alloc] init];
UINavigationController *na = [[UINavigationController alloc] initWithRootViewController:vc];
if ([[[UIDevice currentDevice] systemVersion] floatValue] >= 8.0)
{
na.modalPresentationStyle = UIModalPresentationOverCurrentContext;
}
else
{
self.modalPresentationStyle=UIModalPresentationCurrentContext;
}
[self presentViewController:na animated:YES completion:nil];
Xcode调试不显示内存占用
editSCheme 里面有个选项叫叫做enable zoombie Objects 取消选中
显示隐藏文件
//显示
defaults write com.apple.finder AppleShowAllFiles -bool true
killall Finder
//隐藏
defaults write com.apple.finder AppleShowAllFiles -bool false
killall Finder
字符串按多个符号分割

image.png
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