getDrawable 返回带有 'no properties' 的对象

Question

我正在尝试在可绘制的文件夹中使用PNG，检索并将其上传到我的服务器上，作为使用Backendless API绘制的可绘制。但是，它不喜欢这样，告诉我没有任何属性就无法更新对象。

I/System.out: fault!
I/System.out: BackendlessFault{ code: '1001', message: 'Cannot update object without any properties: image' }

代码：

try {
        Event ne = new Event();
        ne.title = "title of event";
        ne.desc = "short desc";
        ne.extDesc = "long desc";
        ne.image = getDrawable(R.drawable.palestra);
        System.out.println((ne.image != null ? "does" : "does not ") + "work");
        Backendless.Persistence.save(ne, new AsyncCallback<Event>() {
            @Override
            public void handleResponse(Event event) {
                System.out.println("successfull!");
            }
            @Override
            public void handleFault(BackendlessFault backendlessFault) {
                System.out.println("fault!");
                System.out.println(backendlessFault.toString());
            }
        });
    } catch (Exception e) {
        System.out.println("caught exception! " + e.toString());
    }

目的是向服务器发布一个示例事件，以便当我将事件拉动属性标题，desc，extdesc和image时，我可以相应地更新屏幕上的事件。但是，我似乎无法拍摄我本地拥有的图像，并将其作为可绘制的图像上传。

感谢您的任何帮助。

Answer 1

一种解决方案是获取图像位图并将其保存到后端的文件中：

        //The outer Backendless call saves the photo in the file and the inner Backendless
    //call saves the object to the table and gives ne.image a String reference
    //to the file path. the column type should be File Reference, saving the path
    //as a String willw ork
    Backendless.Files.Android.upload(mBitmap,
            Bitmap.CompressFormat.JPEG, //compression type
            100, //quality of image
            "mImageName", //What you want to call your file, eg timestamp + "app_image"
            "/my_images", //The path of the file in Backendless
            new AsyncCallback<BackendlessFile>() {
                @Override
                public void handleResponse(BackendlessFile response) {
                    ne.title = "title of event";
                    ne.desc = "short desc";
                    ne.extDesc = "long desc";
                    ne.image = (response.getFileURL());

                    Backendless.Persistence.of(Ids.class).save(ne, new AsyncCallback<Ids>() {
                        @Override
                        public void handleResponse(Ids response) {
                        }//end handleResponse
                        @Override
                        public void handleFault(BackendlessFault fault) {
                        }//end handleFault
                    });
                }//end handleResponse
                @Override
                public void handleFault(BackendlessFault fault) {
                }//end handleFault
            });

要从您将其保存到的URL上检索图像，您必须使用异步来从URL获取图像。

您可以创建以下类：

public class MyAsyncTask extends AsyncTask<String, Integer, Bitmap> {
ImageView ivMyImage;
private Bitmap myImage;
public MyAsyncTask(ImageView ivMyImage) {
    this.ivMyImage = ivMyImage;
}//end constructor
@Override
protected Bitmap doInBackground(String... urlString) {
    try {
        URL myImageUrl = new URL(urlString[0]);
        myImage = BitmapFactory.decodeStream(myImageUrl.openConnection().getInputStream());
    } //end try
    catch (Exception e) {
        e.printStackTrace();
    }//end catch
    return myImage;
}//end doInBackground
@Override
protected void onPostExecute(Bitmap bitmap) {
    ivMyImage.setImageBitmap(myImage);
    }//end onPostExecute
}//end class

并在要在何处使用以下代码来调用异步任务：

MyAsyncTask myAsyncTask = new MyAsyncTask(ivMyImage);
myAsyncTask.execute(ne.getImage());//ne.getImage() should retrieve the image url you saved

希望这有帮助