1. 使用UIBarButtonItem 自定义图片时出现一个蓝色原点？
如下写法：
UIBarButtonItem*commitBarItem= [[UIBarButtonItem alloc]initWithImage:[UIImage imageNamed:@"confirm_submit"] style:UIBarButtonItemStylePlain target:self action:@selector(commitAlarmListToServer)];
解决办法：（http://www.cocoachina.com/bbs/read.php?tid=180226）
UIImage*selectedImage=[UIImage imageNamed:@"confirm_submit"];
selectedImage = [selectedImage imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];
UIBarButtonItem*commitBarItem= [[UIBarButtonItem alloc]initWithImage:selectedImage style:UIBarButtonItemStylePlain target:self action:@selector(commitAlarmListToServer)];
self.navigationItem.rightBarButtonItem= commitBarItem;
2. NSArray/NSDictionary 数组或字典 转成json
（1） NSDictionary 转成NSString json
+ (NSString *)dictToJsonString:(NSDictionary *)dict
{
NSString *jsonStr = @"数据异常，无法转成JSON";
BOOL isValidJson =[NSJSONSerialization isValidJSONObject:dict];
if (isValidJson) {
NSData *jsonData = [NSJSONSerialization dataWithJSONObject:dict options:NSJSONWritingPrettyPrinted error:nil];
jsonStr = [[NSString alloc]initWithData:jsonData encoding:NSUTF8StringEncoding];
}
return jsonStr;
}
（2） // 将JSON转成对象
+ (NSDictionary *)parseJsonFromStringOrObject:(NSString *)data
{
NSData *newData = [data dataUsingEncoding:NSUTF8StringEncoding allowLossyConversion:YES];
NSDictionary * dict = [NSJSONSerialization JSONObjectWithData:newData options:NSJSONReadingAllowFragments error:nil];
return dict;
}
(3) 将任何对象转成json 字符串。（包括数组、字典，不包括自定义实体对象）
+ (NSString *)JSONString:(id)data
{
id result = [NSJSONSerialization dataWithJSONObject:data options:NSJSONWritingPrettyPrinted error:nil];
NSString *jsonStr = [[NSString alloc]initWithData:result encoding:NSUTF8StringEncoding];
return jsonStr;
}
注： 简书的文本编辑器不太好用，太麻烦了，搞定代码格式有点难看！！希望简书官方能够有所改之。
