这是我的第一个Android应用程序，我试图张贴摄像头（ICS 4.0）关于采取措施，Django的服务器映像。我一直得到一个空指针异常错误，但我不知道该在哪里发生。此外，当我没有应用程序崩溃试图上传时。我不知道是怎么回事。我使用的片段。

下面是我的Django后code：

  DEF后（个体经营，请求，* ARGS，** kwargs）：        图像= get_object_or_404（图，** kwargs）        研究所=实例（流= image.stream）        uploaded_file = \\            文件（ - 。JPG，self.FILES [0] .read（），图像/ JPEG'）        SETATTR（研究所，'全'，uploaded_file）        inst.save（）        返回的Htt presponse（状态= HTTP_201_CREATED） 

下面是我在我的片段相机操作后：

 公共无效的onActivityResult（INT申请code，INT结果code，意图数据）{    如果（要求code == CAPTURE_IMAGE_ACTIVITY_REQUEST_ code）{        如果（结果code == Activity.RESULT_OK）{            //把图像投影到服务器            text.setText（outputFileUri.toString（））;            尝试{                HttpClient的HttpClient的=新DefaultHttpClient（）;                HttpContext的localContext =新BasicHttpContext（）;                HttpPost postRequest =新HttpPost（http://192.168.1.2:8000/v1/14/1/imagesink/1/）;                MultipartEntity reqEntity =新MultipartEntity（HttpMultipartMode.BROWSER_COMPATIBLE）;                BM = BitmapFactory.de codeFILE（/ SD卡/ test.jpg放在）;                位图bmpCom pressed = Bitmap.createScaledBitmap（BM，640，480，TRUE）;                ByteArrayOutputStream BOS =新ByteArrayOutputStream（）;                bmpCom pressed.com preSS（比较pressFormat.JPEG，100，BOS）;                字节[]字节= bos.toByteArray（）;                reqEntity.addPart（MYIMAGE，新ByteArrayBody（字节temp.jpg））;                postRequest.setEntity（reqEntity）;                HTT presponse响应= httpClient.execute（postRequest，localContext）;                的BufferedReader读者=新的BufferedReader（新的InputStreamReader（response.getEntity（）的getContent（），UTF-8）。）;                串sResponse = reader.readLine（）;            }赶上（例外五）{                //这里处理异常                Log.v（对myApp，某些错误想出了）;            }        }否则如果（结果code == Activity.RESULT_CANCELED）{            //用户取消了图像采集        }其他{            //图像捕捉失​​败，提醒用户        }    }} 

在此先感谢！

ERROR：

  E / AndroidRuntime（19787）：致命异常：主要     了java.lang.RuntimeException：不提供结果ResultInfo {谁=安卓片段：0，请求= 1，结果= -1，数据= NULL}到活动{} com.prism.app/com.prism.app.PrismActivity：显示java.lang.NullPointerException：需要的println消息     在android.app.ActivityThread.deliverResults（ActivityThread.java:2976）     在android.app.ActivityThread.handleSendResult（ActivityThread.java:3019）     在android.app.ActivityThread.access $ 1100（ActivityThread.java:122）     在android.app.ActivityThread $ H.handleMessage（ActivityThread.java:1176）     在android.os.Handler.dispatchMessage（Handler.java:99）     在android.os.Looper.loop（Looper.java:137）     在android.app.ActivityThread.main（ActivityThread.java:4340）     在java.lang.reflect.Method.invokeNative（本机方法）     在java.lang.reflect.Method.invoke（Method.java:511）     在com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run（ZygoteInit.java:784） 在com.android.internal.os.ZygoteInit.main（ZygoteInit.java:551） 在dalvik.system.NativeStart.main（本机方法）         显示java.lang.NullPointerException：引起的println需要一个消息 在android.util.Log.println_native（本机方法） 在android.util.Log.e（Log.java:231） 在com.prism.app.OneFragmentTab.onActivityResult（OneFragmentTab.java:106）     在android.app.Activity.dispatchActivityResult（Activity.java:4653）     在android.app.ActivityThread.deliverResults（ActivityThread.java:2972）     ... 11更多 

解决方案

以下code是如何捕捉图像

 意图cameraIntent =新意图（android.provider.MediaStore.ACTION_IM​​AGE_CAPTURE）;    startActivityForResult（cameraIntent，CAMERA_REQUEST）;保护无效的onActivityResult（INT申请code，INT结果code，意图数据）{       如果（要求code == CAMERA_REQUEST）   {       。位图的照片=（位图）data.getExtras（）获得（数据）;   }} 

获取图像中的位图然后将其转换位图到字符串下面的方法的Base64编码后的位图转换为字符串

 公共字符串convert_bitmap_to_string（位图位图）    {            ByteArrayOutputStream full_stream =新ByteArrayOutputStream（）;        bitmap.com preSS（Bitmap.Com pressFormat.PNG，100，full_stream）;        字节[] = full_bytes full_stream.toByteArray（）;        字符串Str_image = Base64.en codeToString（full_bytes，Base64.DEFAULT）;        返回Str_image;    } 

然后转换使用和imagestring HTTP POST方法发送和imagestring后

 的HttpClient HttpClient的=新DefaultHttpClient（）;    HttpPost httppost =新HttpPost（HTTP：//www.URL ...）;    清单＆LT;＆的NameValuePair GT; namevaluepairs中=新的ArrayList＆LT;＆的NameValuePair GT;（1）;    nameValuePairs.add（新BasicNameValuePair（参数名，Str_image））;    HTT presponse响应= httpclient.execute（httppost）;      HttpEntity实体= response.getEntity（）;       字符串的responseText = EntityUtils.toString（实体）; 

This is my first android app and I am trying to POST images taken on the camera (ICS 4.0) to a Django server. I have been getting a NULL pointer exception error but I have no clue where this is occurring. Also, When I don't the app crashes when trying to upload. I'm not sure what is going on. I am using Fragments.

Here is my Django post code:

    def post(self, request, *args, **kwargs):
        image = get_object_or_404(Img, **kwargs)

        inst = Instance(stream=image.stream)
        uploaded_file = \
            File('-.jpg', self.FILES[0].read(), 'image/jpeg')
        setattr(inst, 'full', uploaded_file)
        inst.save()

        return HttpResponse(status=HTTP_201_CREATED)

Here is what I have in my Fragment after the camera action:

    public void onActivityResult(int requestCode, int resultCode, Intent data) {
    if (requestCode == CAPTURE_IMAGE_ACTIVITY_REQUEST_CODE) {
        if (resultCode == Activity.RESULT_OK) {
            // put the image onto server
            text.setText(outputFileUri.toString());

            try {
                HttpClient httpClient = new DefaultHttpClient();
                HttpContext localContext = new BasicHttpContext();
                HttpPost postRequest = new HttpPost("http://192.168.1.2:8000/v1/14/1/imagesink/1/");
                MultipartEntity reqEntity = new MultipartEntity(HttpMultipartMode.BROWSER_COMPATIBLE);

                bm = BitmapFactory.decodeFile("/sdcard/test.jpg");
                Bitmap bmpCompressed = Bitmap.createScaledBitmap(bm, 640, 480, true);
                ByteArrayOutputStream bos = new ByteArrayOutputStream();
                bmpCompressed.compress(CompressFormat.JPEG, 100, bos);
                byte[] bytes = bos.toByteArray();
                reqEntity.addPart("myImage", new ByteArrayBody(bytes, "temp.jpg")); 
                postRequest.setEntity(reqEntity);
                HttpResponse response = httpClient.execute(postRequest,localContext);

                BufferedReader reader = new BufferedReader(new InputStreamReader( response.getEntity().getContent(), "UTF-8"));  
                String sResponse = reader.readLine();

            } catch (Exception e) {
                // handle exception here
                Log.v("myApp", "Some error came up");  
            }

        } else if (resultCode == Activity.RESULT_CANCELED) {
            // User cancelled the image capture
        } else {
            // Image capture failed, advise user
        }
    }
}

Thanks in advance!

ERROR:

     E/AndroidRuntime(19787): FATAL EXCEPTION: main
     java.lang.RuntimeException: Failure delivering result ResultInfo{who=android:fragment:0, request=1, result=-1, data=null} to activity {com.prism.app/com.prism.app.PrismActivity}: java.lang.NullPointerException: println needs a message
     at android.app.ActivityThread.deliverResults(ActivityThread.java:2976)
     at android.app.ActivityThread.handleSendResult(ActivityThread.java:3019)
     at android.app.ActivityThread.access$1100(ActivityThread.java:122)
     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1176)
     at android.os.Handler.dispatchMessage(Handler.java:99)
     at android.os.Looper.loop(Looper.java:137)
     at android.app.ActivityThread.main(ActivityThread.java:4340)
     at java.lang.reflect.Method.invokeNative(Native Method)
     at java.lang.reflect.Method.invoke(Method.java:511)
     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
 at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
 at dalvik.system.NativeStart.main(Native Method)
         Caused by: java.lang.NullPointerException: println needs a message
 at android.util.Log.println_native(Native Method)
 at android.util.Log.e(Log.java:231)
 at com.prism.app.OneFragmentTab.onActivityResult(OneFragmentTab.java:106)
     at android.app.Activity.dispatchActivityResult(Activity.java:4653)
     at android.app.ActivityThread.deliverResults(ActivityThread.java:2972)
     ... 11 more

following code is how to capture image

    Intent cameraIntent = new Intent(android.provider.MediaStore.ACTION_IMAGE_CAPTURE); 
    startActivityForResult(cameraIntent, CAMERA_REQUEST); 

protected void onActivityResult(int requestCode, int resultCode, Intent data) 
{

       if (requestCode == CAMERA_REQUEST)
   {  
       Bitmap photo = (Bitmap) data.getExtras().get("data");  
   }    
}

after getting image in to bitmap then convert bitmap in to encoding Base64 in string following method is convert bitmap to string

  public String convert_bitmap_to_string(Bitmap bitmap)
    {
            ByteArrayOutputStream full_stream = new ByteArrayOutputStream();
        bitmap.compress(Bitmap.CompressFormat.PNG, 100, full_stream);
        byte[] full_bytes = full_stream.toByteArray();
        String Str_image = Base64.encodeToString(full_bytes, Base64.DEFAULT);

        return Str_image; 
    }

after converting ImageString then Send this ImageString using Http Post method

      HttpClient httpclient = new DefaultHttpClient();
    HttpPost httppost = new HttpPost("http://www.URL...");
    List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(1);

    nameValuePairs.add(new BasicNameValuePair("param name",Str_image));

    HttpResponse response = httpclient.execute(httppost);
      HttpEntity entity = response.getEntity();
       String responseText = EntityUtils.toString(entity);