圆角图片生成，比较好的姿势：
^UIImage *(UIImage *image) {
UIImage *modifiedImage;
CGRect rect = CGRectMake(0, 0, image.size.width, image.size.height);
UIGraphicsBeginImageContextWithOptions(image.size, false, [[UIScreen mainScreen] scale]);
[[UIBezierPath bezierPathWithRoundedRect:rect cornerRadius:44.0] addClip];
[image drawInRect:rect];
modifiedImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return modifiedImage;
};
这里block 的参数 image 是原图，返回的就是一个有圆角的图了，这里圆角度数是 44！！
code 技巧
1：改变UISlider进度条高度重写 trackRectForBounds方法
比如：
- (CGRect)trackRectForBounds:(CGRect)bounds {
CGRect rect = [super trackRectForBounds:bounds];
rect.size.height = 4.0f;
rect.origin.y = (bounds.size.height - rect.size.height) * 0.5;
return rect;
}
2: 获取宽高尽量使用CGRectGetHeight/CGRectGetWidth
这两个函数返回的总是有效的数值，肯定不会为负数。
3:检查工程中无用的图片资源
使用 LSUnusedResources 检测工程中无用的图片资源。
4:UIWebView 获取 title的方法
[webView valueForKeyPath:@"documentView.webView.mainFrame.javaScriptContext"]
5:图片拉伸处理
- (UIImage *)__stretchImageImageName:(NSString *)name {
// 加载图片
UIImage *image = [UIImage imageNamed:name];
// 设置左边端盖宽度
NSInteger leftCapWidth = image.size.width * 0.5;
// 设置上边端盖高度
NSInteger topCapHeight = image.size.height * 0.5;
UIImage *newImage = [image stretchableImageWithLeftCapWidth:leftCapWidth topCapHeight:topCapHeight];
return newImage;
}
6: Charles破解
具体见 这里
Charles4.0.2破解.
7:使用NS_DESIGNATED_INITIALIZER指定构造函数
具体见 这里
NS_DESIGNATED_INITIALIZER使用](http://stackoverflow.com/questions/26185239/ios-designated-initializers-using-ns-designated-initializer).
8:通过自定义键盘发出系统键盘的声音
[[UIDevice currentDevice] playInputClick];
9:UIButton设置title 连续闪动解决方案
设置title连续闪动的问题：通常在一个定时器里面去改变一个button的title出出现，解决方案：设置 button的Type 为 Custom
屏幕快照 2017-03-31 上午11.30.33.png
10:xib使用技巧
xib中设置图片后直接command和=号，imageview大小就跟随image了，非常方便。
11：去掉导航栏下方的黑线
[bar setShadowImage:[[UIImage alloc] init]];此处bar 是UINavigationBar
12：提醒某个方法已经废弃
使用宏__deprecated_msg比如：
@property (nonatomic, assign) BOOL shouldUseCredentialStorage __deprecated_msg("Property deprecated. Does nothing. Kept only for backwards compatibility");
上面的代码是SDWebImage中的代码
13：指定初始化方法
使用宏
NS_DESIGNATED_INITIALIZER
14:iOS获取内核数目，以及CPU占有率
+ (NSUInteger)cpuCoreCount
{
host_basic_info_data_t hostInfo;
mach_msg_type_number_t infoCount = HOST_BASIC_INFO_COUNT;
host_info( mach_host_self(), HOST_BASIC_INFO, (host_info_t)&hostInfo, &infoCount);
return (NSUInteger)(hostInfo.max_cpus);
}
+ (float)cpuUsage
{
kern_return_t kr;
task_info_data_t tinfo;
mach_msg_type_number_t task_info_count;
task_info_count = TASK_INFO_MAX;
kr = task_info(mach_task_self(), TASK_BASIC_INFO, (task_info_t)tinfo, &task_info_count);
if (kr != KERN_SUCCESS) {
return 0.0f;
}
task_basic_info_t basic_info;
thread_array_t thread_list;
mach_msg_type_number_t thread_count;
thread_info_data_t thinfo;
mach_msg_type_number_t thread_info_count;
thread_basic_info_t basic_info_th;
uint32_t stat_thread = 0;
basic_info = (task_basic_info_t)tinfo;
// get threads in the task
kr = task_threads(mach_task_self(), &thread_list, &thread_count);
if (kr != KERN_SUCCESS) {
return 0.0f;
}
if (thread_count > 0)
stat_thread += thread_count;
long tot_sec = 0;
long tot_usec = 0;
float tot_cpu = 0;
int j;
for (j = 0; j < thread_count; j++)
{
thread_info_count = THREAD_INFO_MAX;
kr = thread_info(thread_list[j], THREAD_BASIC_INFO,
(thread_info_t)thinfo, &thread_info_count);
if (kr != KERN_SUCCESS) {
return 0.0f;
}
basic_info_th = (thread_basic_info_t)thinfo;
if (!(basic_info_th->flags & TH_FLAGS_IDLE)) {
tot_sec = tot_sec + basic_info_th->user_time.seconds + basic_info_th->system_time.seconds;
tot_usec = tot_usec + basic_info_th->system_time.microseconds + basic_info_th->system_time.microseconds;
tot_cpu = tot_cpu + basic_info_th->cpu_usage / (float)TH_USAGE_SCALE * 100.0;
}
}
kr = vm_deallocate(mach_task_self(), (vm_offset_t)thread_list, thread_count * sizeof(thread_t));
assert(kr == KERN_SUCCESS);
return (tot_cpu > 100.0f) ? 100.f : tot_cpu;
}
15:调用苹果自带的调式界面，添加如下代码即可：
oc代码
Class overlay = NSClassFromString(@"UIDebuggingInformationOverlay");
[[overlay class] performSelector:NSSelectorFromString(@"prepareDebuggingOverlay")];
UIWindow *overlayWindow = (UIWindow *)[[overlay class] performSelector:NSSelectorFromString(@"overlay")];
[overlayWindow performSelector:NSSelectorFromString(@"toggleVisibility")];
16:调试技巧
在Symbolic中填写如下方法签名： -[NSObject(NSObject) doesNotRecognizeSelector:] 快速定位
.unrecognized selector send to instancd
- 当发生crash的时候，我们可以使用thread backtrace查看堆栈调用
- 上面的命令等同于bt
- Debug的时候，也许会因为各种原因，我们不想让代码执行某个方法，或者要直接返回一个想要的值。这时候就该thread return上场了。
- 平时Debug的时候我们经常做的事就是查看变量的值，通过frame variable命令，可以打印出当前frame的所有变量 ,也可以给frame variable传入参数:
- 使用watchpoint定位内存释放时刻
17判断当前进程是否正在调试
BOOL isDebuggerPresent(){
int name[4]; //指定查询信息的数组
struct kinfo_proc info; //查询的返回结果
size_t info_size = sizeof(info);
info.kp_proc.p_flag = 0;
name[0] = CTL_KERN;
name[1] = KERN_PROC;
name[2] = KERN_PROC_PID;
name[3] = getpid();
if(sysctl(name, 4, &info, &info_size, NULL, 0) == -1){
NSLog(@"sysctl error ...");
return NO;
}
return ((info.kp_proc.p_flag & P_TRACED) != 0);
}
防止别人调试你的代码
AVFoundition
https://github.com/tapharmonic/Learning-AV-Foundation.git
tips:在文件所在的目录下 python -m SimpleHTTPServer 8000，然后在需要下载的设备上使用浏览器访问http://${ip}:8000 就能看到要传的文件了
