title: When set value to the tablecell's elements, it will crashed
body: <p>I want a tableview to show my car's status, it only have 7 cells. And the value is get through the network.When I get the value, and set the cell's label text, it will crash. </p>
  
  <h3>This is my Table View Controller code</h3>
  
  <pre><code>@interface CarStatusController ()
  
  @end
  
  @implementation CarStatusController
  
  - (instancetype)init {
      self = [super init];
      if (self) {
          //init the data
          _carStatuKey = [NSArray arrayWithObjects:@"Total_Km",@"Remain_L",@"Battery_V",@"Tyre_P",@"Cost_L",@"Door",@"Cover", nil];
          _carStatuValue = [NSMutableArray new];
          _resultData = [NSMutableData new];
      }
      return self;
  }
  
  - (void)viewDidLoad {
      [super viewDidLoad];
      [self.tableView registerClass:[CarStatuCell class] forCellReuseIdentifier:@"CarStatuCell"];
      [self postData];
  
  }
  
  - (void)didReceiveMemoryWarning {
      [super didReceiveMemoryWarning];
  }
  
  -(void)postData {
      NSURL *url = [[NSURL alloc] initWithString:[NSString stringWithFormat:@"%@DeviceInfo/GetVehicleStatus",API_PREFIX ]];
      NSDictionary *parametersDic = @{@"VehicleID":@"10000"};
      NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];
  //    [[UserLogin sharedInstance] LoginRequest];
      NSString *token = [[UserLogin sharedInstance] getToken];
      [request addValue:token forHTTPHeaderField:@"Authorization"];
      [request addValue:[NSString stringWithFormat:@"aaron-clark-aic-%@",token] forHTTPHeaderField:@"Expect"];
      [request addValue:@"Mobile" forHTTPHeaderField:@"DeviceType"];
      [request addValue:@"application/json" forHTTPHeaderField:@"Content-Type"];
      [request setHTTPBody:[NSJSONSerialization dataWithJSONObject:parametersDic options:NSJSONWritingPrettyPrinted error:nil]];
      [request setHTTPMethod:@"POST"];
      NSData *data = [NSURLConnection sendSynchronousRequest:request returningResponse:nil error:nil];
      NSLog(@"%@",[[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding]);
      [self ParseData:data];
  }
  
  - (void)ParseData: (NSData *)data{
      NSDictionary *dic = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingMutableLeaves error:nil];
      NSDictionary *resultDic = [[dic objectForKey:@"Data"] objectAtIndex:0];
      for (NSString *key in _carStatuKey) {
          NSLog(@"value:%@",resultDic[key]);
          [_carStatuValue addObject:resultDic[key]];
      }
  }
  
  #pragma mark - Table view data source
  
  - (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
      return 1;
  }
  
  - (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
      return _carStatuName.count;
  }
  
  
  - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
      CarStatuCell *cell = [tableView dequeueReusableCellWithIdentifier:@"CarStatuCell" forIndexPath:indexPath];
      cell.statuNameLabel.text = _carStatuName[indexPath.row];
      if (_carStatuValue.count  == 0) {
          cell.statuValueLabel.text = @"null";
      } else {
          cell.statuValueLabel.text = _carStatuValue[indexPath.row];//set value here will crash.
      }
  
      return cell;
  }
  @end
  </code></pre>
  
  <h3>this is the table cell code, the crash log has many information about the Autolayout Constraint.</h3>
  
  <pre><code>#import "CarStatuCell.h"
  #include &lt;Masonry.h&gt;
  
  @implementation CarStatuCell
  
  - (instancetype)initWithStyle:(UITableViewCellStyle)style reuseIdentifier:(NSString *)reuseIdentifier {
      self = [super initWithStyle:style reuseIdentifier:reuseIdentifier];
      if (self) {
          [self initSubViews];
          [self setLayout];
      }
      return self;
  }
  
  - (void)initSubViews {
      _statuNameLabel = [UILabel new];
      [self.contentView addSubview:_statuNameLabel];
      _statuValueLabel = [UILabel new];
      _statuValueLabel.lineBreakMode = NSLineBreakByWordWrapping;
      _statuValueLabel.numberOfLines = 0;
      _statuValueLabel.font = [UIFont systemFontOfSize:13];
      _statuValueLabel.text = @"Null";
      [self.contentView addSubview:_statuValueLabel];
  }
  
  - (void)setLayout {
      [_statuNameLabel mas_makeConstraints:^(MASConstraintMaker *make) {
          make.left.equalTo(_statuNameLabel.superview.mas_left).with.offset(50);
          make.centerY.equalTo(_statuNameLabel.superview.mas_centerY);
      }];
      [_statuValueLabel mas_makeConstraints:^(MASConstraintMaker *make) {
          make.right.equalTo(_statuValueLabel.superview.mas_right).with.offset(-50);
          make.centerY.equalTo(_statuValueLabel.superview.mas_centerY);
      }];
  }
  
  
  - (void)setSelected:(BOOL)selected animated:(BOOL)animated {
      [super setSelected:selected animated:animated];
  
  }
  
  @end
  </code></pre>
  
  <h3>the crash log :</h3>
  
  <pre><code>[__NSCFNumber length]: unrecognized selector sent to instance 0xb0000000000a1605
  2016-07-08 10:34:19.660 ChangHongYema[4216:239738] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[__NSCFNumber length]: unrecognized selector sent to instance 0xb0000000000a1605'
  *** First throw call stack:
  (
  0   CoreFoundation                      0x00000001062b8d85 __exceptionPreprocess + 165
  1   libobjc.A.dylib                     0x00000001059a6deb objc_exception_throw + 48
  2   CoreFoundation                      0x00000001062c1d3d -[NSObject(NSObject) doesNotRecognizeSelector:] + 205
  3   CoreFoundation                      0x0000000106207cfa ___forwarding___ + 970
  4   CoreFoundation                      0x00000001062078a8 _CF_forwarding_prep_0 + 120
  5   UIKit                               0x000000010469c8f6 -[UILabel _textRectForBounds:limitedToNumberOfLines:includingShadow:] + 84
  6   UIKit                               0x000000010469c747 -[UILabel textRectForBounds:limitedToNumberOfLines:] + 76
  7   UIKit                               0x00000001046a140d -[UILabel _intrinsicSizeWithinSize:] + 173
  8   UIKit                               0x00000001046a14e4 -[UILabel intrinsicContentSize] + 72
  9   UIKit                               0x0000000104d1808b -[UIView(UIConstraintBasedLayout) _generateContentSizeConstraints] + 35
  10  UIKit                               0x0000000104d17d57 -[UIView(UIConstraintBasedLayout) _updateContentSizeConstraints] + 619
  11  UIKit                               0x0000000104d20e93 -[UIView(AdditionalLayoutSupport) updateConstraints] + 224
  12  UIKit                               0x00000001046a12c6 -[UILabel updateConstraints] + 256
  13  UIKit                               0x0000000104d201be -[UIView(AdditionalLayoutSupport) _internalUpdateConstraintsIfNeededAccumulatingViewsNeedingSecondPassAndViewsNeedingBaselineUpdate:forSecondPass:] + 550
  14  UIKit                               0x0000000104d20489 -[UIView(AdditionalLayoutSupport) _updateConstraintsIfNeededAccumulatingViewsNeedingSecondPassAndViewsNeedingBaselineUpdate:forSecondPass:] + 198
  15  UIKit                               0x0000000104d200cd -[UIView(AdditionalLayoutSupport) _internalUpdateConstraintsIfNeededAccumulatingViewsNeedingSecondPassAndViewsNeedingBaselineUpdate:forSecondPass:] + 309
  16  Foundation                          0x00000001039253d3 -[NSISEngine withBehaviors:performModifications:] + 155
  17  UIKit                               0x0000000104d1fadb -[UIView(AdditionalLayoutSupport) _withAutomaticEngineOptimizationDisabledIfEngineExists:] + 58
  18  UIKit                               0x0000000104d2045d -[UIView(AdditionalLayoutSupport) _updateConstraintsIfNeededAccumulatingViewsNeedingSecondPassAndViewsNeedingBaselineUpdate:forSecondPass:] + 154
  19  UIKit                               0x0000000104d200cd -[UIView(AdditionalLayoutSupport) _internalUpdateConstraintsIfNeededAccumulatingViewsNeedingSecondPassAndViewsNeedingBaselineUpdate:forSecondPass:] + 309
  20  UIKit                               0x0000000104d20489 -[UIView(AdditionalLayoutSupport) _updateConstraintsIfNeededAccumulatingViewsNeedingSecondPassAndViewsNeedingBaselineUpdate:forSecondPass:] + 198
  21  UIKit                               0x0000000104d20ac1 __60-[UIView(AdditionalLayoutSupport) updateConstraintsIfNeeded]_block_invoke + 98
  22  UIKit                               0x0000000104d1fae4 -[UIView(AdditionalLayoutSupport) _withAutomaticEngineOptimizationDisabledIfEngineExists:] + 67
  23  UIKit                               0x0000000104d2061e -[UIView(AdditionalLayoutSupport) updateConstraintsIfNeeded] + 254
  24  UIKit                               0x0000000104d21333 -[UIView(AdditionalLayoutSupport) _updateConstraintsAtEngineLevelIfNeeded] + 272
  25  UIKit                               0x00000001044d5a96 -[UIView(Hierarchy) _updateConstraintsAsNecessaryAndApplyLayoutFromEngine] + 159
  26  UIKit                               0x00000001044e59a9 -[UIView(CALayerDelegate) layoutSublayersOfLayer:] + 744
  27  QuartzCore                          0x0000000109268c00 -[CALayer layoutSublayers] + 146
  28  QuartzCore                          0x000000010925d08e _ZN2CA5Layer16layout_if_neededEPNS_11TransactionE + 366
  29  QuartzCore                          0x000000010925cf0c _ZN2CA5Layer28layout_and_display_if_neededEPNS_11TransactionE + 24
  30  QuartzCore                          0x00000001092513c9 _ZN2CA7Context18commit_transactionEPNS_11TransactionE + 277
  31  QuartzCore                          0x000000010927f086 _ZN2CA11Transaction6commitEv + 486
  32  UIKit                               0x000000010442572e _UIApplicationHandleEventQueue + 7135
  33  CoreFoundation                      0x00000001061de301 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 17
  34  CoreFoundation                      0x00000001061d422c __CFRunLoopDoSources0 + 556
  35  CoreFoundation                      0x00000001061d36e3 __CFRunLoopRun + 867
  36  CoreFoundation                      0x00000001061d30f8 CFRunLoopRunSpecific + 488
  37  GraphicsServices                    0x000000010912bad2 GSEventRunModal + 161
  38  UIKit                               0x000000010442af09 UIApplicationMain + 171
  39  ChangHongYema                       0x00000001030455df main + 111
  40  libdyld.dylib                       0x000000010702492d start + 1
  )
  libc++abi.dylib: terminating with uncaught exception of type NSException
  </code></pre>