Question

我需要从JSON以下的Reg no: (Need to show callout) Lat : (Need to use drop pin on map) Long : (Need to use drop pin on map) Name : (Need to show callout) Age : (Need to show callout)响应中获取特定值，这些值是我在下面提到的

NOTE :

{ A = { school = ( { reg_no = 1; latitude = "22.345"; longitude = "-12.4567"; student = ( { name = "akila"; age = "23"; } ); city = "<null>"; state = TN; }, { reg_no = 2; latitude = "22.345"; longitude = "-12.4567"; student = ( { name = "sam"; age = "23"; } ); city = "<null>"; state = TN; }, { reg_no = 3; latitude = "22.345"; longitude = "-12.4567"; student = ( { name = "lansi"; age = "23"; } ); city = "<null>"; state = TN; } ); Schoolname = "Good School"; categories = school; }; }从服务器获取的数组值学校因此它将根据A，B和C类别增加。它不是静止的！

 if (data) {

           NSError *error;
            NSDictionary *JSON = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingMutableLeaves | NSJSONReadingMutableContainers error:&error];
            NSDictionary *response = JSON[@"response"];

           for (NSDictionary *entry in response[@"A"][@"school"]) {
                NSString *regNo = entry[@"reg_no"];
                NSString *name = entry[@"student"][@"name"];
                NSString *age = entry[@"student"][@"age"];
                double latitude = [entry[@"latitude"] doubleValue];
                double longitude = [entry[@"longitude"] doubleValue];
                MKPointAnnotation *myAnnotation = [[MKPointAnnotation alloc] init];
                myAnnotation.coordinate = CLLocationCoordinate2DMake(latitude, longitude);
                myAnnotation.title = name;
                myAnnotation.subtitle = [NSString stringWithFormat:@"Reg: %@, Age: %@", regNo, age];
                [mapView addAnnotation:myAnnotation];

            }

我的代码（代码不起作用）：

<android.support.design.widget.TabLayout
            android:id="@+id/tabs"
            android:layout_width="match_parent"
            android:layout_height="@dimen/custom_tab_layout_height"
            android:background="@color/tab_background_primary"
            app:tabGravity="fill"
            app:tabIndicatorColor="@color/primary_white"
            app:tabIndicatorHeight="3dp"
            app:tabMinWidth="120dp"
            app:tabMode="scrollable"
            app:tabPaddingStart="-1dp"
            app:tabPaddingEnd="-1dp"
            app:tabPaddingTop="1dp"
            app:tabPaddingBottom="1dp"
            />

Answer 1

尝试NSJSONSerialization

NSError *e = nil;
NSArray *jsonArray = [NSJSONSerialization JSONObjectWithData: data options: NSJSONReadingMutableContainers error: &e];

if (!jsonArray) {
  NSLog(@"Error parsing JSON: %@", e);
} else {
   for(NSDictionary *item in jsonArray) {
      NSLog(@"Item: %@", item);
   }
}

Answer 2

您可以使用NSJSONSerialization来解析JSON，然后使用Objective-C subscripting syntax可以在循环中访问所需的值。完成所有这些操作后，您可以在MKAnnotation上将条目添加为MKMapView以获得所需内容。请注意MKAnnotation是一个协议，因此您需要创建一个实现它的类。

MKMapView *mapView = [MKMapView new];
NSDictionary *parsedJSON = [NSJSONSerialization JSONObjectWithData:data options:0 error:nil];
for (NSDictionary *entry in parsedJSON[@"A"][@"school") {
    NSString *regNo = entry[@"reg_no"];
    NSString *name = entry[@"student"][@"name"];
    NSString *age = entry[@"student"][@"age"];
    double latitude = [entry[@"latitude"] doubleValue];
    double longitude = [entry[@"longitude"] doubleValue];
    id<MKAnnotation> annotation = [/*class implementing MKAnnotation*/ new];
    annotation.coordinate = CLLocationCoordinate2DMake(latitude, longitude);
    annotation.title = name;
    annotation.subtitle = [NSString stringWithFormat:@"Reg: %@, Age: %@", regNo, age];
    [mapView addAnnotation:annotation];
}

Answer 3

你应该迭代参赛作品[@“student”]来获取每个学生的数据即使条目[@“student”]只有一个

，[@“student”] [@“name”]也不会获得数据

Answer 4

您提供的JSON文件缺少响应＆＃39;关键在于它。但是，您搜索的是NSDictionary *response = JSON[@"response"];。这可能是问题所在。除此之外，您可以尝试使用 NSDictionary 的 valueForKey：方法深入搜索您的JSON。

如何使用Objective C从地图视图中获取JSON和Plot中的特定值？

4 个答案: