iOS-Tips

记录一些不常用,容易忘记的知识点

1.调用系统相机显示中文

在info.plist中添加Localized resources can be mixed这一项并设置为YES

2.计算文字宽度(高度)

方法一:
CGFloat fontSize = 14;
CGFloat height = 20;
NSString *string = @"想要计算宽度的文字";
CGFloat width = [string boundingRectWithSize:CGSizeMake(CGFLOAT_MAX, height) options:NSStringDrawingUsesLineFragmentOrigin|NSStringDrawingUsesFontLeading attributes:@{NSFontAttributeName:[UIFont systemFontOfSize:fontSize]} context:nil].size.width;

方法二:
NSString *text = @"想要计算宽度的文字";
CGSize size = [text sizeWithAttributes:@{NSFontAttributeName: [UIFont systemFontOfSize:14.0f]}];

3.Reveal使用

方法一:

1. 导入Reveal.framework
2. Link Binary With Libraries 删除Reveal.framework
3. Other Linker Flags + -ObjC -lz -framework Reveal
   方法二:

   pod 'Reveal-SDK', '4' //Mac版本Reveal,网上找到的是v4,这里要对应

4.判断是否有权限访问相册

#import <AssetsLibrary/AssetsLibrary.h>
ALAuthorizationStatus author = [ALAssetsLibrary authorizationStatus];
if (author == ALAuthorizationStatusRestricted || author == ALAuthorizationStatusDenied) {
    //无权限,提示用户打开
    UIAlertController *alert = [UIAlertController alertControllerWithTitle:[NSString stringWithFormat:@"请在\"隐式设置\"中允许\"%@\"访问您的相册", @"YourAppDisplayName"] message:nil preferredStyle:UIAlertControllerStyleAlert];
    [alert addAction:[UIAlertAction actionWithTitle:@"设置" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {
    //打开系统设置
    [[UIApplication sharedApplication] openURL:[NSURL URLWithString: [NSString stringWithFormat:@"prefs:root=%@", @"YourAppBundleId"]]];
    }]];
    [alert addAction:[UIAlertAction actionWithTitle:@"好" style:UIAlertActionStyleCancel handler:nil]];
    [self showDetailViewController:alert sender:self];
}

5.判断是否有权限访问相机

#import <AVFoundation/AVCaptureDevice.h>
#import <AVFoundation/AVMediaFormat.h>
AVAuthorizationStatus authStatus = [AVCaptureDevice authorizationStatusForMediaType:AVMediaTypeVideo];
if (authStatus == AVAuthorizationStatusRestricted || authStatus ==AVAuthorizationStatusDenied) {
    //无权限,提示用户打开,同上
}

6.检测ipa包是否包含P3图片

由于公司UI外包了,不切图,平时都是自己切图,找icon.有次在iconfont上找了个P3格式的图片,导致9.x系统的崩溃,现在每次加入新图片,上包前都要检测一下是否包含P3图片.

参考文章:https://www.ianisme.com/ios/2409.html

ED7ED320-496A-4C78-A1D9-1EAC605207F5.png

1. 终端cd到 ipa包的Payload文件夹下
2. $ find . -name 'Assets.car'

3. $ sudo xcrun --sdk iphoneos assetutil --info ./Assets.car > /tmp/Assets.json
   (/tmp/Assets.json是导出的文件路径)
   4.找到导出的文件,查找是否含有P3格式的文件
   5.如果找到了,则需要修改文件格式,直接command+F,查找"P3"
   对,就是这张图,从iconfont

   
   7F355FDF-BCF0-4C63-B598-0E139B2A7F72.png
   

   6.修改或替换
   找UI重新切图 或
   修改图片:在项目中找到这张图,右击用"色彩同步实用工具/ColorSync"应用打开,"指派描述文件"->"sRGB IEC61966-2.1",应用

   
   4DDFB9F3-382E-4C5D-B22C-C25CE034AADB.png
   7.再次打包尝试

6.UITableView

1.修改UITableViewHeaderFooterView背景颜色

    headerView.backgroundView = [[UIView alloc] initWithFrame:self.bounds];
    headerView.backgroundView.backgroundColor = [UIColor groupTableViewBackgroundColor];

7.属性字符串

https://www.jianshu.com/p/824c5163878a

8.自定义UISegmentedControl

    UISegmentController *segmentCtrl = [[UISegmentedControl alloc] init];
    segmentCtrl.tintColor = [UIColor clearColor]; 
    //选中文字颜色
    NSDictionary *selectedTextAttr = @{NSFontAttributeName:[UIFont systemFontOfSize:13 weight:UIFontWeightBold], NSForegroundColorAttributeName:COLOR_WITH_HEX(0X333333)}; 
    [segmentCtrl setTitleTextAttributes:selectedTextAttr forState:UIControlStateSelected];
    //未选中文字颜色
    NSDictionary *deselectedTextAttr = @{NSFontAttributeName:[UIFont systemFontOfSize:13 weight:UIFontWeightLight], NSForegroundColorAttributeName:COLOR_WITH_HEX(0X333333)};
    [segmentCtrl setTitleTextAttributes:deselectedTextAttr forState:UIControlStateNormal];
    //调整内容位置
    CGFloat itemWidth = floor((SCREEN_WIDTH - 12*2)/4);
    CGSize size = [@"距离最近" sizeWithAttributes:@{NSFontAttributeName: [UIFont systemFontOfSize:13.0f weight:UIFontWeightBold]}];
    CGFloat offset_x = (itemWidth - size.width)/2;
    [segmentCtrl setContentPositionAdjustment:UIOffsetMake(-offset_x, 0) forSegmentType:UISegmentedControlSegmentAny barMetrics:UIBarMetricsDefault];
    [segmentCtrl addTarget:self action:@selector(segmentValueChanged:) forControlEvents:UIControlEventValueChanged];

9.动态修改状态栏颜色(随scrollview滑动改变)

@property (nonatomic, assign) UIStatusBarStyle statusBarStyle; //记录状态栏样式

- (void)scrollViewDidScroll:(UIScrollView *)scrollView {
    CGFloat y = scrollView.contentOffset.y;
    if (y <= 64) {
        self.statusBarStyle = UIStatusBarStyleLightContent;
    } else {
        self.statusBarStyle = UIStatusBarStyleDefault;
    }
    [self setNeedsStatusBarAppearanceUpdate];
}
- (UIStatusBarStyle)preferredStatusBarStyle {
    return self.statusBarStyle;
}

10.点击事件穿透视图在下一视图响应

- (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event{
    UIView *hitView = [super hitTest:point withEvent:event];
    if (hitView == self) {
        return nil;
    }
    return hitView;
}

11.UITableView setContentOffset: 无效

以下设置

    _tableView.estimatedRowHeight = 0;// default is UITableViewAutomaticDimension, set to 0 to disable
    _tableView.estimatedSectionHeaderHeight =0;// default is UITableViewAutomaticDimension, set to 0 to disable
    _tableView.estimatedSectionFooterHeight =0; // default is UITableViewAutomaticDimension, set to 0 to disable

12.设置某几个角为圆角

    UIView *view = [[UIView alloc] initWithFrame:CGRectMake:(0,0,200,100)];
    //右上右下圆角25
    UIBezierPath *maskPath = [UIBezierPath bezierPathWithRoundedRect:_doneBtn.bounds byRoundingCorners:UIRectCornerTopRight|UIRectCornerBottomRight cornerRadii:CGSizeMake(25, 25)];
    CAShapeLayer *maskLayer = [[CAShapeLayer alloc] init];
    maskLayer.frame = view.bounds;
    maskLayer.path = maskPath.CGPath;
    view.layer.mask = maskLayer;

13.UINavigationController push新的视图,原始图上的UIScrollView 自动回到原点

在添加完子视图后,先执行 [self layoutIfNeeded];

    [self layoutIfNeeded];
    self.contentSize = CGSizeMake(width, height);