iOS编程学习过程中常见bug记录－持续记录

Undefined symbols for architecture armv7:
    "std::ios_base::Init::~Init()",referenced from:
        __GLOBAL__I_a in XXXXXX(dsi_debug.o)
    "std::ios_base::Init::Init()",referenced from:
    __GLOBAL__I_a in XXXXXX(dsi_debug.o)

//这种bug是因为缺少libstdc++.6.dylib库文件，解决方法Build Phases -> Link binary with Libraries中加一个libstdc++.6.dylib

__NSCFNumber isEqualToString:]: unrecognized selector sent to instance 0xb000000000000013

//此报错是因为dictionnary的value不能直接当成string类型使用，即不能直接用  isEqualtostring方法。需要用stringwithformat转换为string类型才行

 _state=[NSString stringWithFormat:@"%@",[loginDict objectForKey:@"State"]];
       // NSLog(@"%@",loginDict);
        if ([_state isEqualToString:@"1"]){}