Question

我正在尝试从json文件中读取，该文件在JSONObject内部有JSONArray，它正在读取第一个JSONObject值而不是从内部读取的内容称为“zoom”，你能帮我吗？

    {
   "@file_name": "materials",
   "materials": [
        {
            "@site_name": "N/A",
            "@site_icon_iPad_xPosition": "150",
            "@site_icon_iPad_yPosition": "150",
            "@site_icon_Android_xPosition": "215",
            "@site_icon_Android_yPosition": "206",
            "zoom": 
                {
                    "@zoom_name": "Main Reservoir",
                    "@zoom_number": "zoom1"

                }

        },
        {
            "@site_name": "Building Applications",
            "@site_icon_iPad_xPosition": "636",
            "@site_icon_iPad_yPosition": "313",
            "@site_icon_Android_xPosition": "215",
            "@site_icon_Android_yPosition": "206",
            "zoom": [
                {
                    "@zoom_name": "Rooftop Reservoir &amp; Pump Station",
                    "@zoom_number": "zoom10-1"

                },
                {
                    "@zoom_name": "Compact Zone PRV System",
                    "@zoom_number": "zoom10-2"

                },
                {
                    "@zoom_name": "Basement Reservoir &amp; Pump Room",
                    "@zoom_number": "zoom10-3"

                }
            ]           
        }
   ]
}

我的代码：

 JSONParser jParser = new JSONParser();
         JSONObject json = jParser.getJSONFromUrl(Environment.getExternalStorageDirectory().getPath()+"/Materials.json");

            try {


                JSONArray materials = json.getJSONArray("materials");
                for(int i = 0; i < materials.length(); i++){

                    JSONObject c = materials.getJSONObject(i);

                    // Storing each json item in variable
                    String a1= c.getString("@site_name");
                    String a2 = c.getString("@site_icon_Android_xPosition");
                    String a3 = c.getString("@site_icon_Android_yPosition");

                    Log.d(TAG, a1+" "+a2+" "+a3);


                    JSONArray zoom = c.getJSONArray("zoom");
                    Log.d(TAG, ""+zoom.length());
                    for(int j = 0; j < zoom.length(); j++){

                        JSONObject d = zoom.getJSONObject(j);
                         String b1 = d.getString("@zoom_name");
                         String b2 = d.getString("@zoom_number");
                         Log.d(TAG, b1+" "+b2);
                    }

                   Log.d(TAG, "--------------------------------");


                }
            } catch (JSONException e) {
                 Log.d(TAG, "exeption");
                e.printStackTrace();
            }

我的输出：

Applications 215 206
exeption

例外：

03-24 11:29:01.188: W/System.err(17952): org.json.JSONException: Value {"@zoom_number":"zoom1","@zoom_name":"Main Reservoir"} at zoom of type org.json.JSONObject cannot be converted to JSONArray
03-24 11:29:01.198: W/System.err(17952):    at org.json.JSON.typeMismatch(JSON.java:100)
03-24 11:29:01.198: W/System.err(17952):    at org.json.JSONObject.getJSONArray(JSONObject.java:548)
03-24 11:29:01.198: W/System.err(17952):    at com.weterworks.MainActivity.onCreate(MainActivity.java:120)
03-24 11:29:01.198: W/System.err(17952):    at android.app.Activity.performCreate(Activity.java:4465)
03-24 11:29:01.198: W/System.err(17952):    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1049)
03-24 11:29:01.198: W/System.err(17952):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1920)
03-24 11:29:01.198: W/System.err(17952):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1981)
03-24 11:29:01.198: W/System.err(17952):    at android.app.ActivityThread.access$600(ActivityThread.java:123)
03-24 11:29:01.198: W/System.err(17952):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1147)
03-24 11:29:01.198: W/System.err(17952):    at android.os.Handler.dispatchMessage(Handler.java:99)
03-24 11:29:01.198: W/System.err(17952):    at android.os.Looper.loop(Looper.java:137)
03-24 11:29:01.198: W/System.err(17952):    at android.app.ActivityThread.main(ActivityThread.java:4424)
03-24 11:29:01.198: W/System.err(17952):    at java.lang.reflect.Method.invokeNative(Native Method)
03-24 11:29:01.198: W/System.err(17952):    at java.lang.reflect.Method.invoke(Method.java:511)
03-24 11:29:01.198: W/System.err(17952):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
03-24 11:29:01.198: W/System.err(17952):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
03-24 11:29:01.198: W/System.err(17952):    at dalvik.system.NativeStart.main(Native Method)

Answer 1

您的代码中有一个小错误。在处理zoom属性的内部循环中，您指的是错误的数组对象。

for (int j = 0; j < zoom.length(); j++) {

    JSONObject d = materials.getJSONObject(j); // <-- Should refer to zoom, not materials
    String b1 = d.getString("@zoom_name");
    String b2 = d.getString("@zoom_number");
    Log.d(TAG, b1 + " " + b2);
}

Android从JSONObject读取JSONArray

1 个答案: