1，设置edgesForExtendedLayout＝UIRectEdgeNone时会导致navigationbar和tarbar背景出现一条灰色的背景。解决办法：设置Translucent属性。代码：
self.navigationController.navigationBar.translucent=NO;
self.tabBarController.tabBar.translucent=NO;
2，textfield设置左右图片
UITextField*textField=[[UITextFieldalloc]init];
UIImageView*imgv=[[UIImageViewalloc]initWithImage:[UIImageimageNamed:@"right.png"]];
textField.rightView=imgv;
textField.rightViewMode=UITextFieldViewModeAlways;
3，
obj转json
NSData* jsonData = [NSJSONSerializationdataWithJSONObject:detailDicoptions:0error:nil];
NSString* myString = [[NSStringalloc]initWithData:jsonDataencoding:NSUTF8StringEncoding];
json转obj
NSDictionary* selectSimpleTest = [NSJSONSerializationJSONObjectWithData:[tizhiSimpleTest.detaildataUsingEncoding:NSUTF8StringEncoding]options:0error:nil];
4，归档解档保存本地数据
[NSKeyedArchiver archiveRootObject:obj toFile:filePath]//写
[NSKeyedUnarchiver unarchiveObjectWithFile:filePath];//读
