值得收藏的iOS开发常用代码块

遍历可变数组的同时删除数组元素

nsmutablearray *copyarray = [nsmutablearray arraywitharray:array];  
nsstring *str1 = @“zhangsan”; 
for (addressperson *pername in copyarray) { 
  if ([[pername name] isequaltostring:str1]) { 
    [array removeobject:pername]; 
  } 
} 

获取系统当前语言

nsstring *currentlanguage = [[nslocale preferredlanguages] objectatindex:0];
nslog(@"currentlanguage = %@",currentlanguage);

if ([currentlanguage containsstring:@"zh-hans"]) {
  nslog(@"zh-hans简体中文");
}else if ([currentlanguage containsstring:@"zh-hant"]) {
  nslog(@"zh-hant繁体中文");
}

uitableview的group样式下顶部空白处理

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);
    }
  }
}

获取图片某一点的颜色

- (uicolor*) getpixelcoloratlocation:(cgpoint)point inimage:(uiimage *)image
{

  uicolor* color = nil;
  cgimageref inimage = image.cgimage;
  cgcontextref cgctx = [self createargbbitmapcontextfromimage:inimage];

  if (cgctx == null) {
    return nil; /* error */
  }
  size_t w = cgimagegetwidth(inimage);
  size_t h = cgimagegetheight(inimage);
  cgrect rect = {{0,0},{w,h}};

  cgcontextdrawimage(cgctx, rect, inimage);
  unsigned char* data = cgbitmapcontextgetdata (cgctx);
  if (data != null) {
    int offset = 4*((w*round(point.y))+round(point.x));
    int alpha = data[offset];
    int red = data[offset+1];
    int green = data[offset+2];
    int blue = data[offset+3];
    color = [uicolor colorwithred:(red/255.0f) green:(green/255.0f) blue:
         (blue/255.0f) alpha:(alpha/255.0f)];
  }
  cgcontextrelease(cgctx);
  if (data) {
    free(data);
  }
  return color;
}

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

//第一种
[uiapplication sharedapplication].idletimerdisabled = yes;
//第二种
[[uiapplication sharedapplication] setidletimerdisabled:yes];

 模态推出透明界面

uiviewcontroller *vc = [[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];

ios跳转到app store下载应用评分

[[uiapplication sharedapplication] openurl:[nsurl urlwithstring:@"itms-apps://itunes.apple.com/webobjects/mzstore.woa/wa/viewcontentsuserreviews?type=purple+software&id=appid"]];

 

手动更改ios状态栏的颜色

- (void)setstatusbarbackgroundcolor:(uicolor *)color
{
  uiview *statusbar = [[[uiapplication sharedapplication] valueforkey:@"statusbarwindow"] valueforkey:@"statusbar"];

  if ([statusbar respondstoselector:@selector(setbackgroundcolor:)])
  {
    statusbar.backgroundcolor = color;  
  }
}

判断当前viewcontroller是push还是present的方式显示

nsarray *viewcontrollers=self.navigationcontroller.viewcontrollers;

if (viewcontrollers.count > 1)
{
  if ([viewcontrollers objectatindex:viewcontrollers.count - 1] == self)
  {
    //push方式
    [self.navigationcontroller popviewcontrolleranimated:yes];
  }
}
else
{
  //present方式
  [self dismissviewcontrolleranimated:yes completion:nil];
}

 

获取实际使用的launchimage图片

- (nsstring *)getlaunchimagename
{
  cgsize viewsize = self.window.bounds.size;
  // 竖屏  
  nsstring *vieworientation = @"portrait"; 
  nsstring *launchimagename = nil;  
  nsarray* imagesdict = [[[nsbundle mainbundle] infodictionary] valueforkey:@"uilaunchimages"];
  for (nsdictionary* dict in imagesdict)
  {
    cgsize imagesize = cgsizefromstring(dict[@"uilaunchimagesize"]);
    if (cgsizeequaltosize(imagesize, viewsize) && [vieworientation isequaltostring:dict[@"uilaunchimageorientation"]])
    {
      launchimagename = dict[@"uilaunchimagename"];    
    }  
  }  
  return launchimagename;
}

ios在当前屏幕获取第一响应

uiwindow * keywindow = [[uiapplication sharedapplication] keywindow];
uiview * firstresponder = [keywindow performselector:@selector(firstresponder)];

 

判断对象是否遵循了某协议

if ([self.selectedcontroller conformstoprotocol:@protocol(refreshptotocol)])
{
   [self.selectedcontroller performselector:@selector(ontriggerrefresh)];
}

 

判断view是不是指定视图的子视图
bool isview = [textview isdescendantofview:self.view]; 

nsarray 快速求总和 最大值 最小值 和 平均值

nsarray *array = [nsarray arraywithobjects:@"2.0", @"2.3", @"3.0", @"4.0", @"10", nil];
cgfloat sum = [[array valueforkeypath:@"@sum.floatvalue"] floatvalue];
cgfloat avg = [[array valueforkeypath:@"@avg.floatvalue"] floatvalue];
cgfloat max =[[array valueforkeypath:@"@max.floatvalue"] floatvalue];
cgfloat min =[[array valueforkeypath:@"@min.floatvalue"] floatvalue];
nslog(@"%f\n%f\n%f\n%f",sum,avg,max,min);

 

修改uitextfield中placeholder的文字颜色
[textfield setvalue:[uicolor redcolor] forkeypath:@"_placeholderlabel.textcolor"]; 

获取一个类的所有子类

+ (nsarray *) allsubclasses
{
  class myclass = [self class];
  nsmutablearray *mysubclasses = [nsmutablearray array];
  unsigned int numofclasses;
  class *classes = objc_copyclasslist(&numofclasses;);
  for (unsigned int ci = 0; ci < numofclasses; ci++)
  {
    class superclass = classes[ci];
    do{
      superclass = class_getsuperclass(superclass);
    } while (superclass && superclass != myclass);

    if (superclass)
    {
      [mysubclasses addobject: classes[ci]];
    }
  }
  free(classes);
  return mysubclasses;
}

阿拉伯数字转中文格式

+(nsstring *)translation:(nsstring *)arebic
{ 
  nsstring *str = arebic;
  nsarray *arabic_numerals = @[@"1",@"2",@"3",@"4",@"5",@"6",@"7",@"8",@"9",@"0"];
  nsarray *chinese_numerals = @[@"一",@"二",@"三",@"四",@"五",@"六",@"七",@"八",@"九",@"零"];
  nsarray *digits = @[@"个",@"十",@"百",@"千",@"万",@"十",@"百",@"千",@"亿",@"十",@"百",@"千",@"兆"];
  nsdictionary *dictionary = [nsdictionary dictionarywithobjects:chinese_numerals forkeys:arabic_numerals];

  nsmutablearray *sums = [nsmutablearray array];
  for (int i = 0; i < str.length; i ++) {
    nsstring *substr = [str substringwithrange:nsmakerange(i, 1)];
    nsstring *a = [dictionary objectforkey:substr];
    nsstring *b = digits[str.length -i-1];
    nsstring *sum = [a stringbyappendingstring:b];
    if ([a isequaltostring:chinese_numerals[9]])
    {
      if([b isequaltostring:digits[4]] || [b isequaltostring:digits[8]])
      {
        sum = b;
        if ([[sums lastobject] isequaltostring:chinese_numerals[9]])
        {
          [sums removelastobject];
        }
      }else
      {
        sum = chinese_numerals[9];
      }

      if ([[sums lastobject] isequaltostring:sum])
      {
        continue;
      }
    }

    [sums addobject:sum];
  }

  nsstring *sumstr = [sums componentsjoinedbystring:@""];
  nsstring *chinese = [sumstr substringtoindex:sumstr.length-1];
  nslog(@"%@",str);
  nslog(@"%@",chinese);
  return chinese;
}

 

取消uicollectionview的隐式动画

//方法一
[uiview performwithoutanimation:^{
  [collectionview reloaditemsatindexpaths:@[[nsindexpath indexpathforitem:index insection:0]]];
}];

//方法二
[uiview animatewithduration:0 animations:^{
  [collectionview performbatchupdates:^{
    [collectionview reloaditemsatindexpaths:@[[nsindexpath indexpathforitem:index insection:0]]];
  } completion:nil];
}];

//方法三
[uiview setanimationsenabled:no];
[self.trackpanel performbatchupdates:^{
  [collectionview reloaditemsatindexpaths:@[[nsindexpath indexpathforitem:index insection:0]]];
} completion:^(bool finished) {
  [uiview setanimationsenabled:yes];
}];

判断邮箱格式是否正确的代码

-(bool)isvalidateemail:(nsstring *)email

　　{

　　nsstring *emailregex = @"[a-z0-9a-z._%+-]+@[a-za-z0-9.-]+\\.[a-za-z]{2,4}";

　　nspredicate *emailtest = [nspredicate predicatewithformat:@"self matches%@",emailregex];

　　return [emailtest evaluatewithobject:email];

　　}

ios中uitextfield的字数限制

//在viewdidload中注册<uitextfieldtextdidchangenotification>通知
[[nsnotificationcenter defaultcenter]addobserver:self selector:@selector(textfilededitchanged:) 
     name:@"uitextfieldtextdidchangenotification" object:mytextfield];
//实现监听方法
#pragma mark - notification method
-(void)textfieldeditchanged:(nsnotification *)obj
{
  uitextfield *textfield = (uitextfield *)obj.object;
  nsstring *tobestring = textfield.text;

  //获取高亮部分
  uitextrange *selectedrange = [textfield markedtextrange];
  uitextposition *position = [textfield positionfromposition:selectedrange.start offset:0];

  // 没有高亮选择的字，则对已输入的文字进行字数统计和限制
  if (!position)
  {
    if (tobestring.length > max_starwords_length)
    {
      nsrange rangeindex = [tobestring rangeofcomposedcharactersequenceatindex:max_starwords_length];
      if (rangeindex.length == 1)
      {
        textfield.text = [tobestring substringtoindex:max_starwords_length];
      }
      else
      {
        nsrange rangerange = [tobestring rangeofcomposedcharactersequencesforrange:nsmakerange(0, max_starwords_length)];
        textfield.text = [tobestring substringwithrange:rangerange];
      }
    }
  }
}

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