我有一个leafs数组，我想删除数组中的一些对象。
数组中有 50个对象，我只想在数组中有大约10个;数组中想要的10个对象在数组中的50个对象中混合。
我在我的项目中使用RestKit，并将leafs放入表视图中。
ViewController.m
@property (strong, nonatomic) NSArray *springs;
@property (strong, nonatomic) NSMutableArray *leafs;
@end
@synthesize tableView=_tableView;
@synthesize springs;
@synthesize leafs;
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view.
[self configureRestKit];
[self loadLeafs];
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
- (void)configureRestKit {
// initialize AFNetworking HTTPClient
NSURL *baseURL = [NSURL URLWithString:@"https://api.e.com"];
AFHTTPClient *client = [[AFHTTPClient alloc] initWithBaseURL:baseURL];
// initialize RestKit
RKObjectManager *objectManager = [[RKObjectManager alloc] initWithHTTPClient:client];
// setup object mappings
RKObjectMapping *springMapping = [RKObjectMapping mappingForClass:[Spring class]];
[springMapping addAttributeMappingsFromArray:@[@"name"]];
RKObjectMapping *leafMapping = [RKObjectMapping mappingForClass:[Leaf class]];
[leafMapping addAttributeMappingsFromArray:@[@"abbreviation", @"shortName", @"id"]];
[springMapping addPropertyMapping:[RKRelationshipMapping relationshipMappingFromKeyPath:@"leafs" toKeyPath:@"leafs" withMapping:leafMapping]];
// Wain, this is where I'm getting that error:
// "property discardsinvalidobjectsoninsert not found on object of type RKObjectMapping"
springMapping.discardsInvalidObjectsOnInsert = YES;
// register mappings with the provider using a response descriptor
RKResponseDescriptor *responseDescriptor =
[RKResponseDescriptor responseDescriptorWithMapping:springMapping
method:RKRequestMethodGET
pathPattern:nil
keyPath:@"springs"
statusCodes:[NSIndexSet indexSetWithIndex:200]];
[objectManager addResponseDescriptor:responseDescriptor];
}
- (void)loadLeafs {
NSString *apikey = @kCLIENTKEY;
NSDictionary *queryParams = @{@"apikey" : apikey,};
[[RKObjectManager sharedManager] getObjectsAtPath:@"v1/springs/"
parameters:queryParams
success:^(RKObjectRequestOperation *operation, RKMappingResult *mappingResult) {
springs = mappingResult.array;
[self.tableView reloadData];
}
failure:^(RKObjectRequestOperation *operation, NSError *error) {
NSLog(@"No springs?': %@", error);
}];
}
#pragma mark - Table View
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
return springs.count;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
Spring *spring = [springs objectAtIndex:section];
return spring.leafs.count;
}
- (NSString *)tableView:(UITableView *)tableView titleForHeaderInSection:(NSInteger)section {
Spring *spring = [springs objectAtIndex:section];
return spring.name;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = @"standardCell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
Spring *spring = [spring objectAtIndex:indexPath.section];
Leaf *leaf = [spring.leafs objectAtIndex:indexPath.row];
cell.textLabel.text = leaf.shortName;
return cell;
}
Spring.h
@property (nonatomic) NSString *name;
@property (nonatomic) NSNumber *id;
@property (nonatomic) NSArray *leafs;
Leaf.h
@property (nonatomic) NSString *name;
@property (nonatomic) NSString *abbreviation;
@property (nonatomic) NSString *shortName;
@property (nonatomic) NSNumber *id;
Per Wain，我在Spring.h中添加了这个
@property (nonatomic, assign) BOOL discardsInvalidObjectsOnInsert;
Per Wain，我在Spring.m中添加了这类东西
- (BOOL)validateName:(id *)ioValue error:(NSError **)outError {
if([(NSString *)*ioValue isEqualToString:@"cricket"]){
NSLog(@"old name: %@, new name: %@", self.name, *ioValue);
// Wain: set the names to nil for the objects you don't want
ioValue = nil;
return NO;
// Wain: should I keep this line?
self.discardsInvalidObjectsOnInsert = YES;
}
else{
return YES;
}
}
Per Wain，我在我的ViewController.m
中添加了这个- (void)loadLeafs {
NSString *apikey = @kCLIENTKEY;
NSDictionary *queryParams = @{@"apikey" : apikey,};
[[RKObjectManager sharedManager] getObjectsAtPath:@"v1/springs/"
parameters:queryParams
success:^(RKObjectRequestOperation *operation, RKMappingResult *mappingResult) {
springs = mappingResult.array;
[self.tableView reloadData];
}
failure:^(RKObjectRequestOperation *operation, NSError *error) {
NSLog(@"No springs?': %@", error);
}];
// Wain: filter (using a predicate) the mapping array (name != nil)
NSPredicate *bPredicate = [NSPredicate predicateWithValue:NO];
self.filteredArray = [self.sports filteredArrayUsingPredicate:bPredicate];
}
成功阻止
NSPredicate *filterPredicate = [NSPredicate predicateWithFormat:@"name != nil"];
springs = [mappingResult.array filteredArrayUsingPredicate:filterPredicate];
// You need to loop over the springs after you filter them and then filter the leafs of each spring
for (Spring *spring in springs) {
for (Leaf *leaf in spring.leafs){
NSPredicate *filterPredicate2 = [NSPredicate predicateWithFormat:@"shortName != nil"];
leafs = [spring.leafs filteredArrayUsingPredicate:filterPredicate2];
}
}
[self.tableView reloadData];
答案 0 :(得分：2)
如果要在映射期间过滤掉项目，请查看使用RestKit进行KVC验证。
如果您希望设备上的所有项目都可用且仅过滤显示，请使用谓词来过滤数组。
答案 1 :(得分：1)
按照以下方式执行操作的简单方法如下：
for (Leaf *leaf in leafs) {
if (![leaf.shortName isEqualToString:@"aaa"] && ![leaf.shortName isEqualToString:@"bbb"] && ![leaf.shortName isEqualToString:@"ccc"] && ![leaf.shortName isEqualToString:@"ddd"]) {
[leafs removeObject:leaf];
}
}
它基本上遍历你的叶子对象数组，如果它遇到一个叶子对象，其shortName属性不是那四个字符串，那么该对象将被删除。