UIBlurEffect *effect = [UIBlurEffect effectWithStyle:UIBlurEffectStyleDark];
UIVisualEffectView *test = [[UIVisualEffectView alloc] initWithEffect:effect];
test.frame = self.view.bounds;
test.alpha = 0;
[self.view addSubview:test];
_mytext = test;
UISlider *slidel = [[UISlider alloc]initWithFrame:CGRectMake(30, 300, 200, 20)];
slidel.backgroundColor = [UIColor purpleColor];
slidel.value = 0;
slidel.maximumValue = 1.0;
slidel.minimumValue = 0.0;
[self.view addSubview:slidel];
slidel.enabled = YES;
[slidel addTarget:self action:@selector(act:) forControlEvents:UIControlEventValueChanged];
- (void)act:(UISlider *)slider
{
_mytext.alpha = slider.value;
}
// 隐藏手机的状态栏
-(BOOL)prefersStatusBarHidden {
return YES;
}
self.automaticallyAdjustsScrollViewInsets = YES; // 不让系统帮咱们把scrollView及其子类的视图向下调整64
//状态栏显示网络请求提示器
[UIApplication sharedApplication].networkActivityIndicatorVisible = YES;
//将window显示在最外面.
[[[[UIApplication sharedApplication] delegate] window] addSubview:self.view];
//cell高度
-(CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
{
NSString *string = self.lrcArr[indexPath.row];
CGRect frame = [string boundingRectWithSize:CGSizeMake([UIScreen mainScreen].bounds.size.width, 10000) options:(NSStringDrawingUsesLineFragmentOrigin) attributes:[NSDictionary dictionaryWithObject:[UIFont systemFontOfSize:17] forKey:NSFontAttributeName] context:nil];
return frame.size.height;
}
// 在ARC工程中导入MRC的类 我们选中工程->选中targets中的工程,然后选中Build Phases->在导入的类后边加入标记 - fno-objc-arc
// 在MRC工程中导入ARC的类 路径与上面一致,在该类后面加上标记 -fobjc-arc
//通过AV框架中的AVMakeRectWithAspectRatioInsideRect这个函数,可以将一个图片按比例凡在视图的中间,不需要计算:
#import "ViewController.h"
#import <AVFoundation/AVFoundation.h>
@interface ViewController ()
@end
@implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
UIImageView *imageView = [[UIImageView alloc] initWithFrame:CGRectMake(100, 100, 300, 300)];
imageView.center = self.view.center;
imageView.backgroundColor = [UIColor redColor];
imageView.contentMode = UIViewContentModeScaleToFill;
UIImage *image = [UIImage imageNamed:@"1.jpg"];
imageView.image = image;
CGRect iamgeAspectRect = AVMakeRectWithAspectRatioInsideRect(image.size, imageView.bounds);
NSLog(@"iamgeAspectRect = %@, imageView =%@",NSStringFromCGRect(iamgeAspectRect),NSStringFromCGRect(imageView.frame));
[self.view addSubview:imageView];
}
上线之后自动关闭打印日志,节省资源
//NSLog
#if DEBUG
#define NSLog(FORMAT, ...) fprintf(stderr, "[%s:%d行] %s
",[[[NSString stringWithUTF8String:__FILE__] lastPathComponent] UTF8String], __LINE__, [[NSString stringWithFormat:FORMAT, ##__VA_ARGS__] UTF8String])
#else
#define NSLog(FORMAT, ...) nil
#endif
动态加载高度
转而用WKWebView，监听estimatedProgress（WKWebView的加载进度）属性。
[self.webView addObserver:self forKeyPath:@"estimatedProgress" options:NSKeyValueObservingOptionNew context:nil];添加监听。
-(void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary<NSKeyValueChangeKey,id> *)change context:(void *)context{
if (self.webView.estimatedProgress < 1.0){
return;
}
//完全加载后获取webview的高度
NSString *js = @"document.body.scrollHeight";
[self.webView evaluateJavaScript:js completionHandler:^(id _Nullable height, NSError * _Nullable error) {
NSLog(@"progress:%f height:%@",self.webView.estimatedProgress ,value);
}];
}
TableView不显示没内容的Cell怎么办？
self.tableView.tableFooterView = [[UIView alloc] init];
改变自定义返回按钮的frame,代码如下:
UIButton * backButton = [UIButton buttonWithType:UIButtonTypeCustom];
[backButton setFrame:CGRectMake(-15, 0, 60, 30)];
[backButton setTitle:@"返回" forState:UIControlStateNormal];
[backButton setTitleColor:[UIColor whiteColor] forState:UIControlStateNormal];
[backButton setImage:[UIImage imageNamed:@"返回.png"] forState:UIControlStateNormal];
[backButton setTitleColor:[UIColor lightGrayColor] forState:UIControlStateHighlighted];
[backButton addTarget:self action:@selector(backClick) forControlEvents:UIControlEventTouchUpInside];
UIView *view = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 60, 30)];
[view addSubview:backButton];
UIBarButtonItem *item = [[UIBarButtonItem alloc] initWithCustomView:view];
self.navigationItem.leftBarButtonItem = item;
iOS 判断字符串是纯汉字还是含有汉字
新建一个字符串的类别:
#import <Foundation/Foundation.h>
@interface NSString (China)
- (BOOL)isChinese;//判断是否是纯汉字
- (BOOL)includeChinese;//判断是否含有汉字
@end
#import "NSString+China.h"
@implementation NSString (China)
-(BOOL)isChinese
{
NSString *match = @"(^[u4e00-u9fa5]+$)";
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"SELF matches %@", match];
return [predicate evaluateWithObject:self];
}
-(BOOL)includeChinese
{
for(int i=0; i< [self length];i++)
{
int a =[self characterAtIndex:i];
if( a >0x4e00&& a <0x9fff){
return YES;
}
}
return NO;
}
@end
#import "ViewController.h"
#import "NSString+China.h"
@interface ViewController ()
@end
@implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
NSString *string1 = @"Liuzhiwu 纯汉字";
if (string1.isChinese) {
NSLog(@"纯汉字");
}
else if (string1.includeChinese)
{
NSLog(@"包含汉字");
}
else{
NSLog(@"纯字母");
}
}
隐藏tabbar的坑:
我们有的时候需要隐藏和显示tabbar,但有的时候会出现黑色的条.是因为push的时候有动画的效果,可以使用下面的这种方法,也就是隐藏tabbar的另一种方法
[self.navigationController setNavigationBarHidden:YES animated:animated];
快速查找工程文件
工程大了，常常不记得哪个文件在哪个文件夹的子目录下，或者记得也得不厌其烦地层层打开，可以 cmd + shift + O组合键调出Open Quickly窗口，快速查找所需文件。
禁止锁屏:
[UIApplication sharedApplication].idleTimerDisabled = YES;
或
[[UIApplication sharedApplication] setIdleTimerDisabled:YES];
判断视图是不是指定视图的子视图
BOOL isView = [textView isDescendantOfView:self.view];
防止scrollView手势覆盖侧滑手势
[scrollView.panGestureRecognizerrequireGestureRecognizerToFail:self.navigationController.interactivePopGestureRecognizer];
改变导航栏的alpha
-(void)scrollViewDidScroll:(UIScrollView *)scrollView
{
//第一种方法
// CGFloat offsetToShow = 200.0;//滑动多少就完全显示
// CGFloat alpha = 1 - (offsetToShow - scrollView.contentOffset.y) / offsetToShow;
// [[self.navigationController.navigationBar subviews] objectAtIndex:0].alpha = alpha;
//第二种方法
CGFloat offsetToShow = 200.0;
CGFloat alpha = (offsetToShow - scrollView.contentOffset.y) / offsetToShow - 1;
[self.navigationController.navigationBar setShadowImage:[UIImage new]];
[self.navigationController.navigationBar setBackgroundImage:[self imageWithColor:[[UIColor orangeColor]colorWithAlphaComponent:alpha]] forBarMetrics:UIBarMetricsDefault];
}
//生成一张纯色的图片
- (UIImage *)imageWithColor:(UIColor *)color
{
CGRect rect = CGRectMake(0.0f, 0.0f, 1.0f, 1.0f);
UIGraphicsBeginImageContext(rect.size);
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSetFillColorWithColor(context, [color CGColor]);
CGContextFillRect(context, rect);
UIImage *theImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return theImage;
}
获取硬盘总容量与可用容量:
NSFileManager *fileManager = [NSFileManager defaultManager];
NSDictionary *attributes = [fileManager attributesOfFileSystemForPath:NSHomeDirectory() error:nil];
NSLog(@"容量%.2fG",[attributes[NSFileSystemSize] doubleValue] / (powf(1024, 3)));
NSLog(@"可用%.2fG",[attributes[NSFileSystemFreeSize] doubleValue] / powf(1024, 3));
//图片与字符串相互转换
-(NSString *)UIImageToBase64Str:(UIImage *) image
{
NSData *data = UIImageJPEGRepresentation(image, 1.0f);
NSString *encodedImageStr = [data base64EncodedStringWithOptions:NSDataBase64Encoding64CharacterLineLength];
return encodedImageStr;
}
//字符串转图片
-(UIImage *)Base64StrToUIImage:(NSString *)_encodedImageStr
{
NSData *_decodedImageData = [[NSData alloc] initWithBase64Encoding:_encodedImageStr];
UIImage *_decodedImage = [UIImage imageWithData:_decodedImageData];
return _decodedImage;
}
//根据Label文字,自适应高度
CGRect rect = [contentString boundingRectWithSize:CGSizeMake(tableView.bounds.size.width, MAXFLOAT) options:NSStringDrawingUsesLineFragmentOrigin | NSStringDrawingUsesFontLeading attributes:@{NSFontAttributeName :[UIFont systemFontOfSize:15]} context:nil] ;
@param CGSize 规定文本显示的最大范围
@param options 按照何种设置来计算范围
@param attributes 文本内容的一些属性,例如字体大小,字体类型等 (字体不一样,高度也不一样)
@parma context 上下文 可以规定一些其他的设置 但是一般都是nil
//导航栏渐变效果
-(void)scrollViewDidScroll:(UIScrollView *)scrollView
{
//第一种方法
// CGFloat offsetToShow = 200.0;//滑动多少就完全显示
// CGFloat alpha = 1 - (offsetToShow - scrollView.contentOffset.y) / offsetToShow;
// [[self.navigationController.navigationBar subviews] objectAtIndex:0].alpha = alpha;
//第二种方法
CGFloat offsetToShow = 200.0;
CGFloat alpha = (offsetToShow - scrollView.contentOffset.y) / offsetToShow - 1;
[self.navigationController.navigationBar setShadowImage:[UIImage new]];
[self.navigationController.navigationBar setBackgroundImage:[self imageWithColor:[[UIColor orangeColor]colorWithAlphaComponent:alpha]] forBarMetrics:UIBarMetricsDefault];
}
//生成一张纯色的图片
- (UIImage *)imageWithColor:(UIColor *)color
{
CGRect rect = CGRectMake(0.0f, 0.0f, 1.0f, 1.0f);
UIGraphicsBeginImageContext(rect.size);
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSetFillColorWithColor(context, [color CGColor]);
CGContextFillRect(context, rect);
UIImage *theImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return theImage;
}
//导航栏自动缩放效果
- (void)scrollViewDidScroll:(UIScrollView *)scrollView {
CGFloat offsetY = scrollView.contentOffset.y + scrollView.contentInset.top;
CGFloat scale = 1.0;
// 放大
if (offsetY < 0) {
// 允许下拉放大的最大距离为300
// 1.5是放大的最大倍数，当达到最大时，大小为：1.5 * 70 = 105
// 这个值可以自由调整
scale = MIN(1.5, 1 - offsetY / 300);
} else if (offsetY > 0) { // 缩小
// 允许向上超过导航条缩小的最大距离为300
// 为了防止缩小过度，给一个最小值为0.45，其中0.45 = 31.5 / 70.0，表示
// 头像最小是31.5像素
scale = MAX(0.45, 1 - offsetY / 300);
}
self.headerImageView.transform = CGAffineTransformMakeScale(scale, scale);
// 保证缩放后y坐标不变
CGRect frame = self.headerImageView.frame;
frame.origin.y = -self.headerImageView.layer.cornerRadius / 2;
self.headerImageView.frame = frame;
}
在使用SDWebImage加载较多图片造成内存警告时，定期调用
[[SDImageCache sharedImageCache] setValue:nil forKey:@"memCache"];
可解决。