10、查看系统所有字体
// 打印字体
for (id familyName in [UIFont familyNames]) {
NSLog(@"%@", familyName);
for (id fontName in [UIFont fontNamesForFamilyName:familyName]) NSLog(@" %@", fontName);
}
// 也可以进入这个网址查看 http://iosfonts.com/
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11、获取随机数
NSInteger i = arc4random();
12、获取随机数小数(0-1之间)
#define ARC4RANDOM_MAX 0x100000000
double val = ((double)arc4random() / ARC4RANDOM_MAX);
13、AVPlayer视频播放完成的通知监听
[[NSNotificationCenter defaultCenter]
addObserver:self
selector:@selector(videoPlayEnd)
name:AVPlayerItemDidPlayToEndTimeNotification
object:nil];
14、判断两个rect是否有交叉
if (CGRectIntersectsRect(rect1, rect2)) {
}
15、判断一个字符串是否为数字
NSCharacterSet *notDigits = [[NSCharacterSet decimalDigitCharacterSet] invertedSet];
if ([str rangeOfCharacterFromSet:notDigits].location == NSNotFound)
{
// 是数字
} else
{
// 不是数字
}
16、将一个view保存为pdf格式
- (void)createPDFfromUIView:(UIView*)aView saveToDocumentsWithFileName:(NSString*)aFilename
{
NSMutableData *pdfData = [NSMutableData data];
UIGraphicsBeginPDFContextToData(pdfData, aView.bounds, nil);
UIGraphicsBeginPDFPage();
CGContextRef pdfContext = UIGraphicsGetCurrentContext();
[aView.layer renderInContext:pdfContext];
UIGraphicsEndPDFContext();
NSArray* documentDirectories = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask,YES);
NSString* documentDirectory = [documentDirectories objectAtIndex:0];
NSString* documentDirectoryFilename = [documentDirectory stringByAppendingPathComponent:aFilename];
[pdfData writeToFile:documentDirectoryFilename atomically:YES];
NSLog(@"documentDirectoryFileName: %@",documentDirectoryFilename);
}
17、让一个view在父视图中心
child.center = [parent convertPoint:parent.center fromView:parent.superview];
18、获取当前导航控制器下前一个控制器
- (UIViewController *)backViewController
{
NSInteger myIndex = [self.navigationController.viewControllers indexOfObject:self];
if ( myIndex != 0 && myIndex != NSNotFound ) {
return [self.navigationController.viewControllers objectAtIndex:myIndex-1];
} else {
return nil;
}
}
19、保存UIImage到本地
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *filePath = [[paths objectAtIndex:0] stringByAppendingPathComponent:@"Image.png"];
[UIImagePNGRepresentation(image) writeToFile:filePath atomically:YES];
20、键盘上方增加工具栏
UIToolbar *keyboardDoneButtonView = [[UIToolbar alloc] init];
[keyboardDoneButtonView sizeToFit];
UIBarButtonItem *doneButton = [[UIBarButtonItem alloc] initWithTitle:@"Done"
style:UIBarButtonItemStyleBordered target:self
action:@selector(doneClicked:)];
[keyboardDoneButtonView setItems:[NSArray arrayWithObjects:doneButton, nil]];
txtField.inputAccessoryView = keyboardDoneButtonView;
21、copy一个view
因为UIView没有实现copy协议，因此找不到copyWithZone方法，使用copy的时候导致崩溃
但是我们可以通过归档再解档实现copy，这相当于对视图进行了一次深拷贝，代码如下
id copyOfView =
[NSKeyedUnarchiver unarchiveObjectWithData:[NSKeyedArchiver archivedDataWithRootObject:originalView]];
22、在image上绘制文字并生成新的image
UIGraphicsBeginImageContext(image.size);
[image drawInRect:CGRectMake(0,0,image.size.width,image.size.height)];
CGRect rect = CGRectMake(point.x, point.y, image.size.width, image.size.height);
[[UIColor whiteColor] set];
[text drawInRect:CGRectIntegral(rect) withFont:font];
UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
23、判断一个view是否为另一个view的子视图
// 如果myView是self.view本身，也会返回yes
BOOL isSubView = [myView isDescendantOfView:self.view];
24、判断一个字符串是否包含另一个字符串
// 方法一、这种方法只适用于iOS8之后，如果是配iOS8之前用方法二
if ([str containsString:otherStr]) NSLog(@"包含");
// 方法二
NSRange range = [str rangeOfString:otherStr];
if (range.location != NSNotFound) NSLog(@"包含");
25、UICollectionView自动滚动到某行
// 重写viewDidLayoutSubviews方法
-(void)viewDidLayoutSubviews {
[super viewDidLayoutSubviews];
[self.collectionView scrollToItemAtIndexPath:indexPath atScrollPosition:
UICollectionViewScrollPositionCenteredVertically animated:NO];
}
26、修改系统UIAlertController
// 但是据说这种方法会被App Store拒绝(慎用！)
UIAlertController *alertVC = [UIAlertController alertControllerWithTitle:
@"" message:@"" preferredStyle:UIAlertControllerStyleActionSheet];
NSMutableAttributedString *hogan =
[[NSMutableAttributedString alloc] initWithString:@"我是一个大文本"];
[hogan addAttribute:NSFontAttributeName
value:[UIFont systemFontOfSize:30]
range:NSMakeRange(4, 1)];
[hogan addAttribute:NSForegroundColorAttributeName
value:[UIColor redColor]
range:NSMakeRange(4, 1)];
[alertVC setValue:hogan forKey:@"attributedTitle"];
UIAlertAction *button = [UIAlertAction actionWithTitle:
@"Label text" style:UIAlertActionStyleDefault handler:^(UIAlertAction *action){ }];
UIImage *accessoryImage = [UIImage imageNamed:@"1"];
[button setValue:accessoryImage forKey:@"image"];
[alertVC addAction:button];
[self presentViewController:alertVC animated:YES completion:nil];
27、判断某一行的cell是否已经显示
CGRect cellRect = [tableView rectForRowAtIndexPath:indexPath];
BOOL completelyVisible = CGRectContainsRect(tableView.bounds, cellRect);
28、让导航控制器pop回指定的控制器
NSMutableArray *allViewControllers = [NSMutableArray arrayWithArray:[self.navigationController viewControllers]];
for (UIViewController *aViewController in allViewControllers) {
if ([aViewController isKindOfClass:[RequiredViewController class]]) {
[self.navigationController popToViewController:aViewController animated:NO];
}
}
29、动画修改label上的文字
// 方法一
CATransition *animation = [CATransition animation];
animation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut];
animation.type = kCATransitionFade;
animation.duration = 0.75;
[self.label.layer addAnimation:animation forKey:@"kCATransitionFade"];
self.label.text = @"New";
// 方法二
[UIView transitionWithView:self.label
duration:0.25f
options:UIViewAnimationOptionTransitionCrossDissolve
animations:^{
self.label.text = @"Well done!";
} completion:nil];
// 方法三
[UIView animateWithDuration:1.0
animations:^{
self.label.alpha = 0.0f;
self.label.text = @"newText";
self.label.alpha = 1.0f;
}];
30、判断字典中是否包含某个key值
if ([dic objectForKey:@"yourKey"]) {
NSLog(@"有这个值");
} else {
NSLog(@"没有这个值");
}