android - Json 从 Android 中的 Url 解析，不工作

Question

我正在解析来自 URL 的数据，出现下面提到的错误。

原始数据从服务器完美显示。无法使用 Json 解析拆分数据。

请帮我解决这个错误

编辑:1

来自 URL 的 Json 响应

[
    {
        "ID": 4,
        "Name": "Vinoth",
        "Contact": "1111111111",
        "Msg": "1"
    },
    {
        "ID": 5,
        "Name": "Mani",
        "Contact": "22222222",
        "Msg": "1"
    },
    {
        "ID": 6,
        "Name": "Manoj",
        "Contact": "33333333333",
        "Msg": "1"
    }
]

错误:

org.json.JSONException: Value [{"ID":1,"Name":"Lalita","Contact":"9997162499","Msg":"1"},{"ID":2,"Name":"kumar","Contact":"123456789","Msg":"1"}] of type java.lang.String cannot be converted to JSONArray
12-11 18:23:27.249 30195-30195/com.knowledgeflex.restapidemo W/System.err:     at org.json.JSON.typeMismatch(JSON.java:111)
12-11 18:23:27.249 30195-30195/com.knowledgeflex.restapidemo W/System.err:     at org.json.JSONArray.<init>(JSONArray.java:96)
12-11 18:23:27.249 30195-30195/com.knowledgeflex.restapidemo W/System.err:     at org.json.JSONArray.<init>(JSONArray.java:108)
12-11 18:23:27.249 30195-30195/com.knowledgeflex.restapidemo W/System.err:     at com.knowledgeflex.restapidemo.MainActivity$LoadService.onPostExecute(MainActivity.java:135)
12-11 18:23:27.249 30195-30195/com.knowledgeflex.restapidemo W/System.err:     at com.knowledgeflex.restapidemo.MainActivity$LoadService.onPostExecute(MainActivity.java:58)
12-11 18:23:27.249 30195-30195/com.knowledgeflex.restapidemo W/System.err:     at android.os.AsyncTask.finish(AsyncTask.java:632)
12-11 18:23:27.249 30195-30195/com.knowledgeflex.restapidemo W/System.err:     at android.os.AsyncTask.access$600(AsyncTask.java:177)
12-11 18:23:27.249 30195-30195/com.knowledgeflex.restapidemo W/System.err:     at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:645)
12-11 18:23:27.249 30195-30195/com.knowledgeflex.restapidemo W/System.err:     at android.os.Handler.dispatchMessage(Handler.java:102)
12-11 18:23:27.249 30195-30195/com.knowledgeflex.restapidemo W/System.err:     at android.os.Looper.loop(Looper.java:136)
12-11 18:23:27.249 30195-30195/com.knowledgeflex.restapidemo W/System.err:     at android.app.ActivityThread.main(ActivityThread.java:5584)
12-11 18:23:27.249 30195-30195/com.knowledgeflex.restapidemo W/System.err:     at java.lang.reflect.Method.invokeNative(Native Method)
12-11 18:23:27.249 30195-30195/com.knowledgeflex.restapidemo W/System.err:     at java.lang.reflect.Method.invoke(Method.java:515)
12-11 18:23:27.249 30195-30195/com.knowledgeflex.restapidemo W/System.err:     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1268)
12-11 18:23:27.259 30195-30195/com.knowledgeflex.restapidemo W/System.err:     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1084)
12-11 18:23:27.259 30195-30195/com.knowledgeflex.restapidemo W/System.err:     at dalvik.system.NativeStart.main(Native Method)

主 Activity .java

public class MainActivity extends Activity {

    TextView name1,email,status,face;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        final Button GetServerData = (Button) findViewById(R.id.button1);


      name1 = (TextView)findViewById(R.id.sname);
       email = (TextView)findViewById(R.id.email);
         status = (TextView)findViewById(R.id.status);
       face = (TextView)findViewById(R.id.fb);

        GetServerData.setOnClickListener(new OnClickListener() {
            public void onClick(View v) {

                // Server Request URL
                String serverURL = "http://webapp/api/values";

                // Create Object and call AsyncTask execute Method
                new LoadService().execute(serverURL);

            }
        });

    }


    // Class with extends AsyncTask class
    private class LoadService extends AsyncTask<String, Void, Void> {

        private final HttpClient Client = new DefaultHttpClient();
        private String Content;
        private String Error = null;
        private final String TAG = null;
        String name = null;
        private ProgressDialog Dialog = new ProgressDialog(MainActivity.this);

        TextView uiUpdate = (TextView) findViewById(R.id.textView2);

        protected void onPreExecute() {
            // NOTE: You can call UI Element here.

            // UI Element
            uiUpdate.setText("");
            Dialog.setMessage("Loading service..");
            Dialog.show();
        }

        // Call after onPreExecute method
        protected Void doInBackground(String... urls) {
            try {

                // NOTE: Don't call UI Element here.

                HttpGet httpget = new HttpGet(urls[0]);
                ResponseHandler<String> responseHandler = new BasicResponseHandler();
                Content = Client.execute(httpget, responseHandler);

            } catch (ClientProtocolException e) {
                Error = e.getMessage();
                cancel(true);
            } catch (IOException e) {
                Error = e.getMessage();
                cancel(true);
            }

            return null;
        }

        protected void onPostExecute(Void unused) {
            // Close progress dialog
            Dialog.dismiss();
            Log.e(TAG, "------------------------------------- Output: " + Content);


            try {
                JSONArray jArr=new JSONArray(Content);
                for(int i=0;i<jArr.length();i++) {
                    JSONObject json=jArr.getJSONObject(i);


                    name1.setText(json.getString("Name"));
                    email.setText(json.getString("ID"));
                    status.setText(json.getString("Contact"));
                    face.setText(json.getString("Msg"));

                }

            } catch (JSONException e) {
                e.printStackTrace();
                Log.i("EXCEPTION   ","");
            }

            uiUpdate.setText("Raw Output : " + Content);
        }



    }


}

Answer 1

根据您的回答，JSONArray 和 gson 库更适合在 json 数据解析时使用，因此将下面的类用于任何类型的数据

import com.google.gson.Gson;
import com.google.gson.JsonArray;
import com.google.gson.annotations.Expose;
import com.google.gson.annotations.SerializedName;

import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.util.ArrayList;
import java.util.List;


public class ApiData {
    @SerializedName("data")
    @Expose
    private JsonArray Data;

    public <T> List<T> getData(Class<T> c) {
        Type type = new ListParams(c);
        return new Gson().fromJson(Data, type);
    }

    private class ListParams implements ParameterizedType {

        private Type type;

        private ListParams(Type type) {
            this.type = type;
        }

        @Override
        public Type[] getActualTypeArguments() {
            return new Type[]{type};
        }

        @Override
        public Type getRawType() {
            return ArrayList.class;
        }

        @Override
        public Type getOwnerType() {
            return null;
        }


        @Override
        public boolean equals(Object o) {
            return super.equals(o);
        }

    }
}

像这样创建模型类:

public class Model{
   String ID;
   String Name;
   String Contact;
   String msg;
}

现在像这样解析你的数据:

ApiData apiData = new Gson().fromJson(Content, ApiData.class);
Lis<Model> models = apiData.getData(Model.class);