如何从Objective C中的NSData Hex值获取索引的Bit值

Question

我有NSData Hex

  

＆lt; 80140142 0073ffff ffff04ff＆gt;

我可以通过索引获取Byte值

  

NSData * commandIDData = [mqttResponseData subdataWithRange：NSMakeRange（3,1）];   ＆LT; 42＆GT; // 66

如何通过索引获取Bit值？

  

0100 0010

e.g

  

指数[0] = 0   指数[1] = 1
  指数[2] = 0
  指数[4] = 0

Answer 1

NSData *statusData = [mqttResponseData subdataWithRange:NSMakeRange(3,1)];

const unsigned char *statusByte = [statusData bytes];//Hex<4F>/Decimal-79/Binary-01001111

for (int i = 0 ; i < 8; i++) {
    bool chanelValue = [[NSNumber numberWithChar:(*statusByte >> i) & 0x01] boolValue];//i = 0 right most bit
    NSLog(@"chanelValue %d: %d",i+1,chanelValue);//1 1 1 1 0 0 1 0
}