Question

我一直在关注如何在Android上显示Json数组的教程，我经常得到＆＃34;无法从服务器获取json。检查互联网连接！＆＃34;我无法弄清楚原因。我的Json是从一个php文件生成的，当我在浏览器上创建一个列表时，这个工作正常。所以我确定我的Json有效。

编辑：我需要做哪些调整才能从这个网址中读取数据？

来自＆＃34; https://www.googleapis.com/books/v1/volumes?q=bond＆＃34;

的JSON数组

机器人：

import android.app.ProgressDialog;

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

import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import android.widget.Toast;

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

import java.util.ArrayList;
import java.util.HashMap;

public class HomeScreen extends AppCompatActivity{

private ListView lv;
private ProgressDialog progress;

private String url="https://www.googleapis.com/books/v1/volumes?q=bond";

ArrayList<HashMap<String,String>> booklist;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_home_screen);
    booklist=new ArrayList<>();
    lv= (ListView) findViewById(R.id.list);
    new getBooks().execute();
}

public class getBooks extends AsyncTask<Void,Void,Void> {
protected void onPreExecute(){
    super.onPreExecute();
    progress=new ProgressDialog(HomeScreen.this);
    progress.setMessage("Fetching JSON.,.");
    progress.setCancelable(false);
    progress.show();
}
protected Void doInBackground(Void...arg0){
    HTTP_Handler hh = new HTTP_Handler();
    String jString = hh.makeHTTPCall(url);

    if (jString != null) {
        try {
            JSONObject jObj = new JSONObject(jString);
            JSONArray books = jObj.getJSONArray("bookinfo");
            for (int i = 0; i < books.length(); i++) {
                JSONObject book = books.getJSONObject(i);

                String name=book.getString("name");
                String author=book.getString("author");


                HashMap<String, String> bookdata = new HashMap<>();


                bookdata.put("name", name);
                bookdata.put("author", author);


                booklist.add(bookdata);
            }
        } catch (final JSONException e) {

            runOnUiThread(new Runnable() {
                @Override
                public void run() {
                    Toast.makeText(getApplicationContext(),
                            "Json parsing error: " + e.getMessage(),
                            Toast.LENGTH_LONG)
                            .show();
                }
            });
        }
    } else {

        runOnUiThread(new Runnable() {
            @Override
            public void run() {Toast.makeText(getApplicationContext(),
                    "Couldn't get json from server. Check internet connection!",
                    Toast.LENGTH_LONG).show();
            }
        });
    }
    return null;
}
protected void onPostExecute(Void Result){
    super.onPostExecute(Result);
    if(progress.isShowing()){
        progress.dismiss();
    }
    ListAdapter adapter=new SimpleAdapter(
            HomeScreen.this,
            booklist,
            R.layout.bucket_list,
            new String[]{"name","author"},
            new int[]{R.id.list_Name,R.id.list_author);
    lv.setAdapter(adapter);
}
}
 }

Answer 1

您的浏览器是否必须针对＆＃39; website / filename.php＆＃39;进行身份验证？返回JSON？我在代码中看不到任何身份验证步骤。如果您的代码是免费提供的，这可能不是问题。乍一看，似乎现在从服务器返回JSON，这可能是一个问题。

如何实现json到android正确？

1 个答案: