java - 获取图片信息

Question

我正在尝试使用此代码获取图片的信息。我在获取图片链接时遇到问题。

import android.os.AsyncTask;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        DownloadTask task = new DownloadTask();
        task.execute("..."); //I'm not sharing the link here

    }

    public class DownloadTask extends AsyncTask<String, Void, String> {

        @Override
        protected String doInBackground(String... urls) {

            String result = "";
            URL url;
            HttpURLConnection urlConnection = null;

            try {
                url = new URL(urls[0]);

                urlConnection = (HttpURLConnection) url.openConnection();

                InputStream in = urlConnection.getInputStream();

                InputStreamReader reader = new InputStreamReader(in);

                int data = reader.read();

                while (data != -1) {

                    char current = (char) data;

                    result += current;

                    data = reader.read();

                }

                return result;

            } catch (MalformedURLException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            }

            return null;
        }

        @Override
        protected void onPostExecute(String result) {
            super.onPostExecute(result);

            try {

//问题一定出在这里:

                JSONObject jsonObject = new JSONObject(result);
                String data = jsonObject.getString("data");
                String images = jsonObject.getString("images");
                String standard_resolution = jsonObject.getString("standard_resolution");

                Log.i("Content", data);

                JSONArray arr = new JSONArray(standard_resolution);

                for (int i = 0; i < arr.length(); i++) {

                    JSONObject jsonPart = arr.getJSONObject(i);

                    Log.i("description", jsonPart.getString("url"));
                    Log.i("description", jsonPart.getString("description"));

//到这里

                }


            } catch (JSONException e) {
                e.printStackTrace();
            }



        }
    }


}

这是网页响应。

{
    "data": {
        "type": "image",
        "users_in_photo": [{
            "user": {
                "username": "kevin",
                "full_name": "Kevin S",
                "id": "3",
                "profile_picture": "..."
            },
            "position": {
                "x": 0.315,
                "y": 0.9111
            }
        }],
        "filter": "Walden",
        "tags": [],
        "comments": {
            "count": 2
        },
        "caption": null,
        "likes": {
            "count": 1
        },
        "link": "http://instagr.am/p/D/",
        "user": {
            "username": "kevin",
            "full_name": "Kevin S",
            "profile_picture": "...",
            "id": "3"
        },
        "created_time": "1279340983",
        "images": {
            "low_resolution": {
                "url": "http://distillery.s3.amazonaws.com/media/2010/07/16/4de37e03aa4b4372843a7eb33fa41cad_6.jpg",
                "width": 306,
                "height": 306
            },
            "thumbnail": {
                "url": "http://distillery.s3.amazonaws.com/media/2010/07/16/4de37e03aa4b4372843a7eb33fa41cad_5.jpg",
                "width": 150,
                "height": 150
            },
            "standard_resolution": {
                "url": "http://distillery.s3.amazonaws.com/media/2010/07/16/4de37e03aa4b4372843a7eb33fa41cad_7.jpg",
                "width": 612,
                "height": 612
            }
        },
        "id": "3",
        "location": null
    }
}

Answer 1

你要的数据路径中没有数组。只是对象

String resolution = "standard_resolution";
JSONObject jsonObject = new JSONObject(result);
JSONObject images = jsonObject.getJSONObject("data").getJSONObject("images");
String url  = images.getJSONObject(resolution).getString("url");