KVO踩過的坑

坑：-[NSNull rangeOfCharacterFromSet:]: unrecognized selector sent to instance

 

緣由是change[NSKeyValueChangeNewKey]的值是NSNull，因此須要作下面的判斷。

  

// 監聽baoDanModel的變化

    [self.baoDanModel addObserver:self forKeyPath:@"bankAccNo" options:(NSKeyValueObservingOptionNew) context:nil];

    [self.baoDanModel addObserver:self forKeyPath:@"bankBranch" options:(NSKeyValueObservingOptionNew) context:nil];

    [self.baoDanModel addObserver:self forKeyPath:@"payBankId" options:(NSKeyValueObservingOptionNew) context:nil];