android - 从 Parse.com 拉取图像

Question

我已将一些图像从我的移动相册保存到 Parse.com，我正在尝试在另一个 Activity 中获取图像并将其显示在 ListView 中，但我无法做到。我已经搜索了文档但无法解决它。这是我的类(class)。

public class GetImage extends Activity {
// Declare Variables
ListView listview;
List<ParseObject> ob;
ProgressDialog mProgressDialog;
ListAdapter adapter;

private ArrayList imagelist = null;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    // Get the view from listview_main.xml
    setContentView(R.layout.listview_main);
    // Execute RemoteDataTask AsyncTask
    new RemoteDataTask().execute();
}

借助AsyncTask

private class RemoteDataTask extends AsyncTask<Void, Void, Void> {
    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        // Create a progressdialog
        mProgressDialog = new ProgressDialog(GetImage.this);
        // Set progressdialog title
        mProgressDialog.setTitle("Parse.com Custom ListView");
        // Set progressdialog message
        mProgressDialog.setMessage("Loading...");
        mProgressDialog.setIndeterminate(false);
        // Show progressdialog
        mProgressDialog.show();
    }

    @Override
    protected Void doInBackground(Void... params) {
        // Create the array
        imagelist = new ArrayList<Images>();
        try {
            // Locate the class table named "Country" in Parse.com
            ParseQuery<ParseObject> query = new ParseQuery<ParseObject>(
                    "Image");              
            query.orderByAscending("ImageFile");
            ob = query.find();
            for (ParseObject pb : ob) {

                ParseFile image = (ParseFile) Image.get("ImageFile");

            }
        } catch (ParseException e) {
            Log.e("Error", e.getMessage());
            e.printStackTrace();
        }
        return null;
    }

    @Override
    protected void onPostExecute(Void result) {
        // Locate the listview in listview_main.xml
        listview = (ListView) findViewById(R.id.listView1);
        // Pass the results into ListViewAdapter.java
        adapter = new ListAdapter(GetImage.this,
                imagelist);
        // Binds the Adapter to the ListView
        listview.setAdapter(adapter);
        // Close the progressdialog
        mProgressDialog.dismiss();
    }
}}

如果有任何用于访问 Parse.com 上的数据的 API，请帮忙谢谢!

Answer 1

在您的代码中，一切都很好。你必须填写

imagelist = new ArrayList<Images>(); 

当您在 doInBackground(Void... params) 中获取图像时，尝试添加 imagelist.add(Image.get("ImageFile")); 在您的 Async 的 Task doInBackground(Void... params) 方法。就这些。