ios 基础工具类总结

ios 基础工具类总结。

uitableview的group样式下顶部空白处理

//分组列表头部空白处理

uiview *view = [[uiview alloc] initwithframe:cgrectmake(0, 0, 0, 0.1)];

self.tableview.tableheaderview = view;

uitableview的plain样式下，取消区头停滞效果

- (void)scrollviewdidscroll:(uiscrollview *)scrollview

{

cgfloat sectionheaderheight = sectionhead.height;

if (scrollview.contentoffset.y<=sectionheaderheight&&scrollview;.contentoffset.y>=0)

{

scrollview.contentinset = uiedgeinsetsmake(-scrollview.contentoffset.y, 0, 0, 0);

}

else if(scrollview.contentoffset.y>=sectionheaderheight)

{

scrollview.contentinset = uiedgeinsetsmake(-sectionheaderheight, 0, 0, 0);

}

}

获取某个view所在的控制器

- (uiviewcontroller *)viewcontroller

{

uiviewcontroller *viewcontroller = nil;

uiresponder *next = self.nextresponder;

while (next)

{

if ([next iskindofclass:[uiviewcontroller class]])

{

viewcontroller = (uiviewcontroller *)next;

break;

}

next = next.nextresponder;

}

return viewcontroller;

}

两种方法删除nsuserdefaults所有记录

//方法一

nsstring *appdomain = [[nsbundle mainbundle] bundleidentifier];

[[nsuserdefaults standarduserdefaults] removepersistentdomainforname:appdomain];

//方法二

- (void)resetdefaults

{

nsuserdefaults * defs = [nsuserdefaults standarduserdefaults];

nsdictionary * dict = [defs dictionaryrepresentation];

for (id key in dict)

{

[defs removeobjectforkey:key];

}

[defs synchronize];

}

打印所有已注册的字体名称

#pragma mark - 打印系统所有已注册的字体名称

void enumeratefonts()

{

for(nsstring *familyname in [uifont familynames])

{

nslog(@"%@",familyname);

nsarray *fontnames = [uifont fontnamesforfamilyname:familyname];

for(nsstring *fontname in fontnames)

{

nslog(@"\t|- %@",fontname);

}

}

}

取图片某一像素点的颜色 在uiimage的分类中

- (uicolor *)coloratpixel:(cgpoint)point

{

if (!cgrectcontainspoint(cgrectmake(0.0f, 0.0f, self.size.width, self.size.height), point))

{

return nil;

}

cgcolorspaceref colorspace = cgcolorspacecreatedevicergb();

int bytesperpixel = 4;

int bytesperrow = bytesperpixel * 1;

nsuinteger bitspercomponent = 8;

unsigned char pixeldata[4] = {0, 0, 0, 0};

cgcontextref context = cgbitmapcontextcreate(pixeldata,

1,

1,

bitspercomponent,

bytesperrow,

colorspace,

kcgimagealphapremultipliedlast | kcgbitmapbyteorder32big);

cgcolorspacerelease(colorspace);

cgcontextsetblendmode(context, kcgblendmodecopy);

cgcontexttranslatectm(context, -point.x, point.y - self.size.height);

cgcontextdrawimage(context, cgrectmake(0.0f, 0.0f, self.size.width, self.size.height), self.cgimage);

cgcontextrelease(context);

cgfloat red = (cgfloat)pixeldata[0] / 255.0f;

cgfloat green = (cgfloat)pixeldata[1] / 255.0f;

cgfloat blue = (cgfloat)pixeldata[2] / 255.0f;

cgfloat alpha = (cgfloat)pixeldata[3] / 255.0f;

return [uicolor colorwithred:red green:green blue:blue alpha:alpha];

}

字符串反转

第一种：

- (nsstring *)reversewordsinstring:(nsstring *)str

{

nsmutablestring *newstring = [[nsmutablestring alloc] initwithcapacity:str.length];

for (nsinteger i = str.length - 1; i >= 0 ; i --)

{

unichar ch = [str characteratindex:i];

[newstring appendformat:@"%c", ch];

}

return newstring;

}

//第二种：

- (nsstring*)reversewordsinstring:(nsstring*)str

{

nsmutablestring *reverstring = [nsmutablestring stringwithcapacity:str.length];

[str enumeratesubstringsinrange:nsmakerange(0, str.length) options:nsstringenumerationreverse | nsstringenumerationbycomposedcharactersequences usingblock:^(nsstring *substring, nsrange substringrange, nsrange enclosingrange, bool *stop) {

[reverstring appendstring:substring];

}];

return reverstring;

}

禁止锁屏，

默认情况下，当设备一段时间没有触控动作时，ios会锁住屏幕。但有一些应用是不需要锁屏的，比如视频播放器。

[uiapplication sharedapplication].idletimerdisabled = yes;

或

[[uiapplication sharedapplication] setidletimerdisabled:yes];

模态推出透明界面

uiviewcontroller * = [[uiviewcontroller alloc] init];

uinavigationcontroller *na = [[uinavigationcontroller alloc] initwithrootviewcontroller:vc];

if ([[[uidevice currentdevice] systemversion] floatvalue] >= 8.0)

{

na.modalpresentationstyle = uimodalpresentationovercurrentcontext;

}

else

{

self.modalpresentationstyle=uimodalpresentationcurrentcontext;

}

[self presentviewcontroller:na animated:yes completion:nil];

xcode调试不显示内存占用

editscheme 里面有个选项叫叫做enable zoombie objects 取消选中

显示隐藏文件

//显示

defaults write com.apple.finder appleshowallfiles -bool true

killall finder

//隐藏

defaults write com.apple.finder appleshowallfiles -bool false

killall finder