JSON POST 请求从安卓服务器下载图像

Question

我需要下载图像并将其设置为imageview . 对于解析，我使用JSON POST request，为此我使用base64。我得到了base64 image 标签的类型数据来记录，但问题是如何分离该image的值并将其转换为string然后将其显示在列表视图中？有没有其他方法不使用base64来显示图像，那么请建议我们。

对于数据的解析，我将JSON parser与HttpPost一起使用。现在如何从我上面显示的响应JSON格式中获取image的值，混乱？？

提前感谢..

Answer 1

你可以

这样做。

在服务器中创建文件夹。 将图像放在该文件夹中。 获取图像的 URL 并插入到数据库中。然后获取该网址的 JSON 值添加此方法并将该 URL 传递给此方法。

Bitmap bitmap;
    void loadImage(String image_location) {
        URL imageURL = null;
        try {
            imageURL = new URL(image_location);
        }
        catch (MalformedURLException e) {
            e.printStackTrace();
        }
        try {
            HttpURLConnection connection = (HttpURLConnection) imageURL
                    .openConnection();
            connection.setDoInput(true);
            connection.connect();
            InputStream inputStream = connection.getInputStream();
            bitmap = BitmapFactory.decodeStream(inputStream);// Convert to
                                                                // bitmap
            imageView.setImageBitmap(bitmap);
        } catch (IOException e) {
            e.printStackTrace();
        }

       }

Answer 2

尝试以下代码：

JSONObject res = jsonObj.getJSONObject("root");
JSONObject data = jsonObj.getJSONObject("data");
JSONArray imgs= jsonObj.getJSONArray ("images");
for(int i=0;i<imgs.length();i++){
    JSONObject Ldetails = Ldtls.getJSONObject(i);
    String img= Ldetails.getString("image");
   byte[] decodedString = Base64.decode(img,Base64.NO_WRAP);
   InputStream inputStream  = new ByteArrayInputStream(decodedString);
   Bitmap bitmap  = BitmapFactory.decodeStream(inputStream);
   imagevw.setImageBitmap(bitmap);
}

其中imagevw是你的ImageView。

Answer 3

使用 Gson 解析器，然后将 base64 图像字符串解析为字节数组并应用于图像。

您的模型类将如下所示：

public class JsonWrapper
{
    private Root root ;
    public Root getroot()
    {
        return this.root;
    }
    public void setroot(Root root)
    {
        this.root = root;
    }
}


public class Root
{
    private Response response ;
    public Response getresponse()
    {
        return this.response;
    }
    public void setresponse(Response response)
    {
        this.response = response;
    }
}

public class Response
{
    private Message message ;
    public Message getmessage()
    {
        return this.message;
    }
    public void setmessage(Message message)
    {
        this.message = message;
    }
    private Data data ;
    public Data getdata()
    {
        return this.data;
    }
    public void setdata(Data data)
    {
        this.data = data;
    }
}
public class Message
{
    private String type ;
    public String gettype()
    {
        return this.type;
    }
    public void settype(String type)
    {
        this.type = type;
    }
    private String message ;
    public String getmessage()
    {
        return this.message;
    }
    public void setmessage(String message)
    {
        this.message = message;
    }
}
import java.util.ArrayList;

public class Data
{
    private ArrayList<Image> images ;
    public ArrayList<Image> getimages()
    {
        return this.images;
    }
    public void setimages(ArrayList<Image> images)
    {
        this.images = images;
    }
    private String last_synchronized_date ;
    public String getlast_synchronized_date()
    {
        return this.last_synchronized_date;
    }
    public void setlast_synchronized_date(String last_synchronized_date)
    {
        this.last_synchronized_date = last_synchronized_date;
    }
}
public class Image
{
    private String web_id ;
    public String getweb_id()
    {
        return this.web_id;
    }
    public void setweb_id(String web_id)
    {
        this.web_id = web_id;
    }
    private String blob_image ;
    public String getblob_image()
    {
        return this.blob_image;
    }
    public void setblob_image(String blob_image)
    {
        this.blob_image = blob_image;
    }
}

使用 Gson 进行 json 解析后，如下所示：

JsonWrapper jsonWrapper = new JsonWrapper();
Gson gsonParser = new Gson();
jsonWrapper = gsonParser.fromJson(data, jsonWrapper.getClass());

接下来，您可以循环访问所有图像

ArrayList<Image> images = jsoinWrapper.getRoot().getResponse().getData().getImages();
for(Image image : images)
{
  byte[] decodedString = Base64.decode(image.getblob_image(), Base64.DEFAULT);
                Bitmap decodedByte = BitmapFactory.decodeByteArray(decodedString, 0, decodedString.length); 
if (decodedString != null) {
                    imageViewtype.setImageBitmap(decodedByte);
                }
}

Answer 4

public class SingleContactActivity extends Activity implements OnClickListener {
private static final String TAG_ImageList = "CatList";
private static final String TAG_ImageID = "ID";
private static final String TAG_ImageUrl = "Name";
private static String url_MultiImage;
TextView uid, pid;
JSONArray contacts = null;
private ProgressDialog pDialog;
String details;
// String imagepath = "http://test2.sonasys.net/Content/WallPost/b3.jpg";
String imagepath = "";
String imagepath2;
Bitmap bitmap;
ImageView image;
SessionManager session;
TextView myprofileId;
TextView pending;
TextView Categories, visibleTo;
int count = 0;
ImageButton btn;
// -----------------------
ArrayList<HashMap<String, String>> ImageList;
JSONArray JsonArray = null;
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_single_contact);
    url_MultiImage = "http://test2.sonasys.net/Android/GetpostImg?UserID=1&PostId=80";
    new MultiImagePath().execute();
    ImageList = new ArrayList<HashMap<String, String>>();
}
private class MultiImagePath extends AsyncTask<Void, Void, Void> {
    @Override
    protected void onPreExecute() {
        super.onPreExecute();
    }
    @Override
    protected Void doInBackground(Void... params) {
        // TODO Auto-generated method stub
        // Creating service handler class instance
        ServiceHandler sh = new ServiceHandler();
        // Making a request to url and getting response
        String jsonStr = sh.makeServiceCall(url_MultiImage,
                ServiceHandler.GET);
        Log.d("Response: ", "> " + jsonStr);
        if (jsonStr != null) {
            try {
                JSONObject jsonObj = new JSONObject(jsonStr);
                // Getting JSON Array node
                JsonArray = jsonObj.getJSONArray(TAG_ImageList);
                if (JsonArray.length() != 0) {
                    for (int i = 0; i < JsonArray.length(); i++) {
                        JSONObject c = JsonArray.getJSONObject(i);
                        String Img_ID = c.getString(TAG_ImageID);
                        String Img_Url = c.getString(TAG_ImageUrl);
                        // tmp hashmap for single contact
                        HashMap<String, String> contact = new HashMap<String, String>();
                        // adding each child node to HashMap key => value
                        contact.put(TAG_ImageID, Img_ID);
                        contact.put(TAG_ImageUrl, Img_Url);
                        // adding contact to contact list
                        ImageList.add(contact);
                    }
                }
                Log.e("JsonLength", "length is ZERO");
            } catch (JSONException e) {
                e.printStackTrace();
            }
        } else {
            Log.e("ServiceHandler", "Couldn't get any data from the url");
        }
        return null;
    }
    @Override
    protected void onPostExecute(Void result) {
        super.onPostExecute(result);
        AutoGenImgBtn();
    }
}
@SuppressWarnings("deprecation")
public void AutoGenImgBtn() {
    int count = ImageList.size();
    LinearLayout llimage = (LinearLayout) findViewById(R.id.llimage);
    ImageButton[] btn = new ImageButton[count];
    for (int i = 0; i < count; i++) {
        btn[i] = new ImageButton(this);
        btn[i].setId(Integer.parseInt(ImageList.get(i).get(TAG_ImageID)));
        btn[i].setOnClickListener(this);
        btn[i].setTag("" + ImageList.get(i).get(TAG_ImageUrl));
        btn[i].setLayoutParams(new LayoutParams(LayoutParams.WRAP_CONTENT,
                LayoutParams.WRAP_CONTENT));
        btn[i].setImageDrawable(getResources().getDrawable(drawable.di1));
        btn[i].setAdjustViewBounds(true);
        // btn[i].setTextColor(getResources().getColor(color.white));
        llimage.addView(btn[i]);
    }
}
@SuppressWarnings("deprecation")
@Override
public void onClick(View v) {
    // TODO Auto-generated method stub
    btn = (ImageButton) v;
    String s = btn.getTag().toString();
    new ImageDownloader().execute(s);
}
private class ImageDownloader extends AsyncTask<String, Void, Bitmap> {
    @Override
    protected Bitmap doInBackground(String... param) {
        // TODO Auto-generated method stub
        return downloadBitmap(param[0]);
    }
    @Override
    protected void onPreExecute() {
        Log.i("Async-Example", "onPreExecute Called");
        pDialog = new ProgressDialog(SingleContactActivity.this);
        pDialog.setMessage("Loading...");
        pDialog.setCancelable(true);
        pDialog.setTitle("In progress...");
        // pDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
        pDialog.setIcon(android.R.drawable.stat_sys_download);
        pDialog.setMax(100);
        // pDialog.setTitle("Post Details");
        pDialog.show();
    }
    @Override
    protected void onPostExecute(Bitmap result) {
        Log.i("Async-Example", "onPostExecute Called");
        if (bitmap != null) {
            btn.setImageBitmap(bitmap);
        }
        if (pDialog.isShowing())
            pDialog.dismiss();
    }
    private Bitmap downloadBitmap(String url) {
        // initilize the default HTTP client object
        final DefaultHttpClient client = new DefaultHttpClient();
        // forming a HttoGet request
        final HttpGet getRequest = new HttpGet(url);
        try {
            HttpResponse response = client.execute(getRequest);
            // check 200 OK for success
            final int statusCode = response.getStatusLine().getStatusCode();
            if (statusCode != HttpStatus.SC_OK) {
                Log.w("ImageDownloader", "Error " + statusCode
                        + " while retrieving bitmap from " + url);
                return null;
            }
            final HttpEntity entity = response.getEntity();
            if (entity != null) {
                InputStream inputStream = null;
                try {
                    // getting contents from the stream
                    inputStream = entity.getContent();
                    // decoding stream data back into image Bitmap that
                    // android understands
                    bitmap = BitmapFactory.decodeStream(inputStream);
                    return bitmap;
                } finally {
                    if (inputStream != null) {
                        inputStream.close();
                    }
                    entity.consumeContent();
                }
            }
        } catch (Exception e) {
            // You Could provide a more explicit error message for
            // IOException
            getRequest.abort();
            Log.e("ImageDownloader", "Something went wrong while"
                    + " retrieving bitmap from " + url + e.toString());
        }
        return null;
    }
}

  #  Add Service Handler Class#
 public class ServiceHandler {
static String response = null;
public final static int GET = 1;
public final static int POST = 2;
public ServiceHandler() {
}
/*
 * Making service call
 * @url - url to make request
 * @method - http request method
 * */
public String makeServiceCall(String url, int method) {

    return this.makeServiceCall(url, method, null);
}
/*
 * Making service call
 * @url - url to make request
 * @method - http request method
 * @params - http request params
 * 
 * */
public String makeServiceCall(String url, int method,List<NameValuePair> params) {
    try {
        // http client
        DefaultHttpClient httpClient = new DefaultHttpClient();
        HttpEntity httpEntity = null;
        HttpResponse httpResponse = null;
        // Checking http request method type
        if (method == POST) {
            HttpPost httpPost = new HttpPost(url);
            // adding post params
            if (params != null) {               
                httpPost.setEntity(new UrlEncodedFormEntity(params));
            }
            httpResponse = httpClient.execute(httpPost);
        } else if (method == GET) {
            // appending params to url
            if (params != null) {
                String paramString = URLEncodedUtils.format(params, "utf-8");
                url += "?" + paramString;
            }
            HttpGet httpGet = new HttpGet(url);
            httpResponse = httpClient.execute(httpGet);
        }
        httpEntity = httpResponse.getEntity();
        response = EntityUtils.toString(httpEntity);
    } catch (UnsupportedEncodingException e) {
        e.printStackTrace();
    } catch (ClientProtocolException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }
    return response;
}