Question

我正在尝试在我的应用中创建图片库。我有JSON中的图像，我想从AsyncTask中的JSON对象创建一个字符串数组，这样我就可以将字符串数组弹出到Universal Image Loader中。我想我已经AsyncTask正确地获取了字符串，但是我很难过如何将字符串放入数组中。 images[]和imageDescriptions[]。我的JSON看起来像这样：

    { 
"gallery" :
        [
           {
              "id":"0001",
              "galleryurl":"http://www.mysite.com/apps/wcbc/images/building0001.jpg",
              "gallerydescr":"image description 1"
           },
           {
              "id":"0002",
              "galleryurl":"http://www.mysite.com/apps/wcbc/images/building00011.jpg",
              "gallerydescr":"image description 2"
           }
    ]
}

我希望生成的images[]看起来像这样：

public static final String[] IMAGES = new String[] {

        "http://www.mysite.com/apps/wcbc/images/building0001.jpg",
        "http://www.mysite.com/apps/wcbc/images/building00011.jpg"
};

这是我的AsyncTask课，我想将JSON解析为String[]：

    private class DownloadJSON extends AsyncTask<Void, Void, Void> {

    @Override
    protected Void doInBackground(Void... params) {
        galleryArrList = new ArrayList<HashMap<String, String>>();
        JGrid4Adapter jParser = new JGrid4Adapter();
        // getting JSON string from URL
        JSONObject jsonOb = jParser.getJSONFromUrl(jsonUrl);            
        try {
            JSArrGallery = jsonOb.getJSONArray(TAG_GALLERY);
            // looping through All gallery images
            for (int i = 0; i < JSArrGallery.length(); i++) {
                JSONObject galleryJO = JSArrGallery.getJSONObject(i);
                String idStr = galleryJO.getString(TAG_ID);
                String urlStr = galleryJO.getString(TAG_GALLERYURL);
                String descrStr = galleryJO.getString(TAG_GALLERYDESCR);
                //-- How to create String Array at this point?


            }// -- END for loop
        } catch (JSONException e) {
            e.printStackTrace();
        }// --- END Try
        return null;
    }

    @Override
    protected void onPostExecute(Void args) {
        //--- do stuff here

    }

}

任何帮助都会很酷。

Answer 1

使用数组

String AidStr[]=new String();
String  AurlStr[]=new String();
String AdescrStr[]=new String();

for (int i = 0; i < JSArrGallery.length(); i++) {
                        JSONObject galleryJO = JSArrGallery.getJSONObject(i);
                        String idStr = galleryJO.getString(TAG_ID);
                        String urlStr = galleryJO.getString(TAG_GALLERYURL);
                        String descrStr = galleryJO.getString(TAG_GALLERYDESCR);
                        //-- How to create String Array at this point?
                         AidStr[i]=idStr;
                         AurlStr[i]=urlStr;
                         AdescStr[i]=descrStr;


           }// -- END for loop

或

使用ArrayList

    ArrayList<String> AidStr=new ArrayList<String>();
    ArrayList<String> AurlStr=new ArrayList<String>();
    ArrayList<String>AdescrStr =new ArrayList<String>();


            for (int i = 0; i < JSArrGallery.length(); i++) {
                            JSONObject galleryJO = JSArrGallery.getJSONObject(i);
                            String idStr = galleryJO.getString(TAG_ID);
                            String urlStr = galleryJO.getString(TAG_GALLERYURL);
                            String descrStr = galleryJO.getString(TAG_GALLERYDESCR);
                            //-- How to create String Array at this point?
                             AidStr.add(idstr);
                             AurlStr.add(urlStr);
                             AdescStr.add(descrStr);


                    }// -- END for loop

Answer 2

您需要有一种方法从AsyncTask中检索String数组。为此，请对代码进行以下更改：

private class DownloadJSON extends AsyncTask<Void, Void, Object[]> {//-------THIS LINE

    private Callback callback;//---THIS LINES

    public DownloadJSON(Callback callback) {//---THESE LINES
        this.callback = callback;
    }

    @Override
    protected Void doInBackground(Void... params) {
        galleryArrList = new ArrayList<HashMap<String, String>>();
        JGrid4Adapter jParser = new JGrid4Adapter();
        // getting JSON string from URL
        JSONObject jsonOb = jParser.getJSONFromUrl(jsonUrl);            
        try {
            JSArrGallery = jsonOb.getJSONArray(TAG_GALLERY);
            // looping through All gallery images
                            String[] imagesArray = new String[JSArrGallery.length()];//------THIS LINE
                            String[] descriptionsArray = new String[JSArrGallery.length()];//------THIS LINE TOO
            for (int i = 0; i < JSArrGallery.length(); i++) {
                JSONObject galleryJO = JSArrGallery.getJSONObject(i);
                String idStr = galleryJO.getString(TAG_ID);
                String urlStr = galleryJO.getString(TAG_GALLERYURL);
                String descrStr = galleryJO.getString(TAG_GALLERYDESCR);
                imagesArray[i] = urlStr;//-------THIS LINE
                descriptionsArray[i] = descrStr;//----THIS LINE TOO

            }// -- END for loop
            return new Object[]{imagesArray, descriptionsArray};//----THIS LINE
        } catch (JSONException e) {
            e.printStackTrace();
        }// --- END Try
        return null;
    }

    @Override
    protected void onPostExecute(Object[] args) {
        //---THESE LINES
        if (args == null)
            callback.call(null, null);
        else
            callback.call(args[0], args[1]);
    }

    //-----THESE LINES
    public interface Callback {
        public void call(String[] imageURLs, String[] imageDescriptions);
    }

}

最后，为了实现这一切，请执行：

new DownloadJSON(new DownloadJSON.Callback() {
    public void call(String[] imageURLs, String[] imageDescriptions) {
        //TODO handle these arrays now
    }
}).execute();

Answer 3

在将数组中的元素添加为：

之前，使用JSArrGallery.length()初始化IMAGES数组

        JSArrGallery = jsonOb.getJSONArray(TAG_GALLERY);
         IMAGES=new String[JSArrGallery.length()];  //<< initialize array here
        for (int i = 0; i < JSArrGallery.length(); i++) {
             //..your code to get image url fom JSONObject...

             // add url to Array
           IMAGES[i]=urlStr;

           }

如果ArrayList尺寸是动态的，

而不是数组使用JSONArray来存储图片网址

Android：从JSON对象创建String数组

3 个答案: