How can I skip unwanted values using JsonReader?-Collection of common programming errors

I was trying to parse a JSON file with JsonReader. I use the skipvalue() function to go to the next key, but instead of going to the next key, the parser jumps to the end of file.

The file looks like this:

{
   "data":{
      "current_condition":[
         {
            "cloudcover":"100",
            "humidity":"74",
            "observation_time":"01:28 PM",
            "precipMM":"0.4",
            "pressure":"1005",
            "temp_C":"-3",
            "temp_F":"27",
            "visibility":"6",
            "weatherCode":"326",
            "weatherDesc":[
               {
                  "value":"Light snow"
               }
            ],
            "weatherIconUrl":[
               {
                  "value":"http:\/\/www.worldweatheronline.com\/images\/wsymbols01_png_64\/wsymbol_0011_light_snow_showers.png"
               }
            ],
            "winddir16Point":"NE",
            "winddirDegree":"50",
            "windspeedKmph":"15",
            "windspeedMiles":"9"
         }
      ],
      "request":[
         {
            "query":"Minsk, Belarus",
            "type":"City"
         }
      ],
      "weather":[
         {
            "date":"2013-03-20",
            "precipMM":"4.4",
            "tempMaxC":"-4",
            "tempMaxF":"25",
            "tempMinC":"-13",
            "tempMinF":"10",
            "weatherCode":"326",
            "weatherDesc":[
               {
                  "value":"Light snow"
               }
            ],
            "weatherIconUrl":[
               {
                  "value":"http:\/\/www.worldweatheronline.com\/images\/wsymbols01_png_64\/wsymbol_0011_light_snow_showers.png"
               }
            ],
            "winddir16Point":"NE",
            "winddirDegree":"40",
            "winddirection":"NE",
            "windspeedKmph":"17",
            "windspeedMiles":"11"
         },
         {
            "date":"2013-03-21",
            "precipMM":"0.6",
            "tempMaxC":"-5",
            "tempMaxF":"23",
            "tempMinC":"-15",
            "tempMinF":"5",
            "weatherCode":"326",
            "weatherDesc":[
               {
                  "value":"Light snow"
               }
            ],
            "weatherIconUrl":[
               {
                  "value":"http:\/\/www.worldweatheronline.com\/images\/wsymbols01_png_64\/wsymbol_0011_light_snow_showers.png"
               }
            ],
            "winddir16Point":"NE",
            "winddirDegree":"38",
            "winddirection":"NE",
            "windspeedKmph":"12",
            "windspeedMiles":"7"
         },
         {
            "date":"2013-03-22",
            "precipMM":"0.1",
            "tempMaxC":"-9",
            "tempMaxF":"17",
            "tempMinC":"-19",
            "tempMinF":"-2",
            "weatherCode":"119",
            "weatherDesc":[
               {
                  "value":"Cloudy"
               }
            ],
            "weatherIconUrl":[
               {
                  "value":"http:\/\/www.worldweatheronline.com\/images\/wsymbols01_png_64\/wsymbol_0003_white_cloud.png"
               }
            ],
            "winddir16Point":"NE",
            "winddirDegree":"51",
            "winddirection":"NE",
            "windspeedKmph":"19",
            "windspeedMiles":"12"
         },
         {
            "date":"2013-03-23",
            "precipMM":"0.0",
            "tempMaxC":"-8",
            "tempMaxF":"18",
            "tempMinC":"-13",
            "tempMinF":"8",
            "weatherCode":"116",
            "weatherDesc":[
               {
                  "value":"Partly Cloudy"
               }
            ],
            "weatherIconUrl":[
               {
                  "value":"http:\/\/www.worldweatheronline.com\/images\/wsymbols01_png_64\/wsymbol_0002_sunny_intervals.png"
               }
            ],
            "winddir16Point":"NNE",
            "winddirDegree":"12",
            "winddirection":"NNE",
            "windspeedKmph":"16",
            "windspeedMiles":"10"
         }
      ]
   }
}

This is my code:

String json_url = "http://free.worldweatheronline.com/feed/weather.ashx?q="+city+"&format=json&num_of_days="+Integer.toString(days)+"&key=0592d3cc1b151105131103";
JsonReader forecastJsonReader = new JsonReader(new InputStreamReader(getUrlData(json_url)));
forecastJsonReader.beginArray();
while (forecastJsonReader.hasNext()) {
    String name = forecastJsonReader.nextName();
    if (name.equals("date")) {
        Log.d("WEATHER",forecastJsonReader.nextString());
    } else if(name.equals("tempMaxC")) {
        Log.d("WEATHER",forecastJsonReader.nextString());
    } else { 
        forecastJsonReader.skipValue();
    }

}
forecastJsonReader.endObject();
forecastJsonReader.close();

1. I don’t think that’s the right way to parse json using jsonreader first your json starts with an object not an array this is an example how you parse your json

   main function

   reader.beginObject();
   
           while (reader.hasNext()) {
   
               String name = reader.nextName();
   
               if (name.equals("data")) {
                   readData(reader);
               } else {
                   reader.skipValue(); // avoid some unhandle events
               }
           }
   
   reader.endObject();
   reader.close();
   

   read data function

   private void readData(JsonReader reader) throws IOException {
       reader.beginObject();
       while(reader.hasNext()) {
       String name = reader.nextName();
       if(name.equals("weather")) {
       reader.beginArray();
       while (reader.hasNext()) {
               reader.beginObject();
           String objectWeatherName = reader.nextName();
           if (objectWeatherName .equals("date")) {
                Log.d("WEATHER",reader.nextString());
           } else if (objectWeatherName .equals("tempMaxC")) {
                Log.d("WEATHER",reader.nextString());
           } else {
                reader.skipValue();
           }
               reader.endObject();
       }
       reader.endArray();
       } else {
           reader.skipValue();
       }
   
       }
       reader.endObject();
   }
   

   that’s if you want to read date and tempMaxC in weather object that located in data object, I hope you understand my answer but if you have any question feel free to ask in the comment 🙂

Originally posted 2013-12-02 20:57:47.