1:xcode工程文件乱序
选中文件夹、右键–>sort by name(sort by type)
2.编译报错：Illegal redeclaration of property in class extension ‘XXXXTableViewCell’ (attribute must be ‘readwrite’, while its primary must be ‘readonly’)
原因是我们 重复声明 了该属性，
解决办法：
删掉.h或者.m文件中多余的属性即可
3.编译报错Safe Area Layout Guide before iOS 9.0 [12]
XCode9以上引用了新特性的功能Safe Area，该特性不支持iOS9.0以下的系统
将该特性调成9.0以后的系统，正确做法如下
Builds for 默认会选中xcode的deployment target,Sage Area特效不支持9之下的，所以改成9.0以上的，当比9.0之下的app使用这个xib时，xcode也能够毫无问题地部署，
4.知识点集:信号量(dispatch_semaphore_signal)
dispatch_semaphore_wait 在哪个线程，就会堵塞到哪个线程
//crate的value表示，最多几个资源可访问
dispatch_semaphore_t semaphore = dispatch_semaphore_create(0);
dispatch_queue_t quene = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);
//任务1
dispatch_async(quene, ^{
NSLog(@"zhouzhou -- run task 1");
sleep(5);
NSLog(@"zhouzhou -- complete task 1");
dispatch_semaphore_signal(semaphore);
});
dispatch_semaphore_wait(semaphore, DISPATCH_TIME_FOREVER);
NSLog(@"zhouzhou -- all complete return");
5.知识点集:监听任务完成 (dispatch_group_notify)
dispatch_queue_t queue = dispatch_get_main_queue();//dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);
dispatch_group_t group = dispatch_group_create();
dispatch_group_enter(group);
dispatch_group_async(group, queue, ^{
});
dispatch_group_notify(group, queue, ^{
});
6.知识点集:高德地图点击指南针后方向指示不动(不能转向)的问题
原因：当点击指南针图片后，会走这个方法，这个时候发现mode 已变成MAUserTrackingModeFollow，所以再设置回来手机移动方向指示就对了
6.编辑报错: Support Files/Pods-xx/Pods-xx.debug.xcconfig: unable to open file (in target “xx” in project “xx”) (in target ‘xx’)
解决：pod install (可能还会遇到7、8、9错误，往下看)
7.控制台报错:执行 pod install报错RuntimeError - [!] Xcodeproj doesn’t know about the following attributes {“inputFileListPaths”=>[], “outputFileListPaths”=>[]} for the ‘PBXShellScriptBuildPhase’ isa.
解决：gem update xcodeproj
8.控制台报错:执行 gem update xcodeproj报错Updating installed gems
ERROR: While executing gem … (Gem::RemoteFetcher::FetchError)
bad response Not Found 404 (https://gems.ruby-china.org/specs.4.8.gz)
原因：服务域名更换公告. 因域名备案问题， .org 域名无法继续提供RubyGems 镜像服务，我们提供 .com 代替 .org 的域名，其他一切不变！！ 详情访问.
解决：
gem sources --remove https://gems.ruby-china.org/
gem sources -a https://gems.ruby-china.com
gem sources -l
如果输出：
*** CURRENT SOURCES ***
https://gems.ruby-china.com
表示正确了
9.控制台报错:执行 gem update xcodeproj报错Updating installed gems
Updating xcodeproj
Fetching: nanaimo-0.2.6.gem (100%)
ERROR: While executing gem … (Gem::FilePermissionError)
You don’t have write permissions for the /Library/Ruby/Gems/2.3.0 directory.
解决：sudo gem update xcodeproj
10.控制台报错:执行 sudo gem update --system报错YAML safe loading is not available. Please upgrade psych to a version that supports safe loading (>= 2.0).
ERROR: SSL verification error at depth 1: unable to get local issuer certificate (20)
ERROR: You must add /O=Digital Signature Trust Co./CN=DST Root CA X3 to your local trusted store
Updating rubygems-update
ERROR: While executing gem … (Errno::EPERM)
Operation not permitted - /usr/bin/update_rubygems
解决：sudo gem update -n /usr/local/bin --system
11.控制台报错:执行 pod install报错You have either:
out-of-date source repos which you can update with pod repo update or with pod install --repo-update.
mistyped the name or version.
not added the source repo that hosts the Podspec to your Podfile.
Note: as of CocoaPods 1.0, pod repo update does not happen on pod install by default.
解决：sudo gem update -n /usr/local/bin --system
12.控制台报错:执行 pod search AFNetworking报错[!] Unable to find a pod with name, author, summary, or description matching AFNetworking
解决：rm ~/Library/Caches/CocoaPods/search_index.json
13.控制台报错:执行 pod install报错[!]/Library/Ruby/Site/2.0.0/rubygems.rb:289:in find_spec_for_exe: can’t find gem cocoapods (>= 0.a) with executable pod (Gem::GemNotFoundException)
from /Library/Ruby/Site/2.0.0/rubygems.rb:308:in activate_bin_path
from /usr/local/bin/pod:23:in
解决：udo gem install -n /usr/local/bin cocoapods