同步适配器与内容提供者数据循环和删除

Question

我正在尝试使用 ContentProvider 和 SyncAdapter，我设置了所有文件，一切正常。我实际上在做的是，我正在使用同步适配器将数据发送到我的服务器，但我希望它在发送后将其删除，但相反，它会不断重复发送数据，直到它收到此错误并崩溃：

09-02 21:34:57.207: E/dalvikvm-heap(8505): Generating hprof for process: com.deliveryscience.track:sync PID: 8505
09-02 21:35:12.113: E/dalvikvm(8505): can't open /data/misc/app_oom.hprof: Permission denied
09-02 21:35:12.183: E/dalvikvm-heap(8505):  hprofDumpHeap failed with result: -1 
09-02 21:35:12.183: E/dalvikvm-heap(8505): After hprofDumpHeap for process
09-02 21:35:12.183: E/dalvikvm(8505): Out of memory: Heap Size=196608KB, Allocated=189573KB, Limit=196608KB, Proc Limit=196608KB
09-02 21:35:12.193: E/dalvikvm(8505): Extra info: Footprint=195472KB, Allowed Footprint=196608KB, Trimmed=16KB

下面也是我的代码，我只想让它循环并删除数据库中循环的每一行。

public void sendData(ContentProviderClient provider){

        Uri uri = Uri.parse("content://com.example.track.services/ds");
        Log.d("Uri Url:", uri.toString());
        try {
            Log.e("Oya:", "I'm here in the sync");
            final Cursor cursor = provider.query(uri, null, "", null, "");
            //cursor
            int j = cursor.getCount();

            if (cursor.getCount() == 0) {
                Account newAccount = new Account("dummyAcct", "com.example.track");
                AccountManager mgr = (AccountManager) getContext().getSystemService(Context.ACCOUNT_SERVICE);
                // If the account already exists no harm is done but
                // a warning will be logged.
                mgr.addAccountExplicitly(newAccount, null, null);
                int syncOnOff = 0;
                ContentResolver.setIsSyncable(newAccount, "com.example.track.services", syncOnOff);
            }else {

                Log.w("colum", String.valueOf(cursor.getCount()));
                if (cursor.moveToFirst()) {
                    do {
                        String link = cursor.getString(cursor.getColumnIndex("token_id"));
                        String URL_Update = "http://dev.tracking.co/locations/add.json?token=" + link;
                        Log.d("Sync Url:", URL_Update);
                        StringRequest req = new StringRequest(Request.Method.POST ,URL_Update, 
                                new Response.Listener<String>() {

                                    @Override
                                    public void onResponse(String response) {
                                        // TODO Auto-generated method stub
                                        Log.e("str Response:", response);
                                    }

                        }, new Response.ErrorListener() {

                            @Override
                            public void onErrorResponse(VolleyError error) {
                                // TODO Auto-generated method stub

                            }


                        }){
                            @Override
                            protected Map<String,String> getParams(){
                                Map<String,String> params = new HashMap<String, String>();
                                params.put("device_id",cursor.getString(cursor.getColumnIndex("device_id")));
                                params.put("latitude",cursor.getString(cursor.getColumnIndex("lat")));
                                params.put("longitude", cursor.getString(cursor.getColumnIndex("long")));
                                params.put("time", cursor.getString(cursor.getColumnIndex("time")));
                     Log.d("Parameter", params.toString());
                                return params;
                            }
                        };

                        AppController.getInstance().addToRequestQueue(req);
                        //Uri id = Uri.parse(cursor.getString(cursor.getColumnIndex(MyContract._ID)));
                        //provider.delete(id, null, null);
                        cursor.moveToNext();
                    } while (cursor.moveToLast());
                }
            }

        } catch (RemoteException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

另外，如何将 3 个内容提供程序附加到一个同步适配器。而且，在我手机的同步部分查看我的应用程序，它只允许“删除”，“立即同步”选项被禁用，但如果我按下通用同步按钮，它会同步

Answer 1

你的循环永远持续的原因是使用while(cursor.moveToLast()) - 当你一遍又一遍地移动到最后一行时，这总是成功的。您应该改用isAfterLast() 来检查您是否处理完所有数据。

当然，您的删除语句可能应该在onResponse 中，因此在成功发送记录之前您不会删除记录。

Answer 2

你应该应用你的 cursor 循环类似的东西......

final Cursor cursor = provider.query(uri, null, "", null, "");

 int j = cursor.getCount();

 if(j==0){
  //do your stuff
} else {

  cursor.moveToFirst();

 do {

  //do your stuff

  cursor.moveToNext(); //Note that this statement should be the last one for your particular iteration of the loop

} while(!cursor.isAfterLast());

}

已编辑： 根据android开发者文档

Sync adapters run asynchronously, so you should use them with the expectation that they transfer data regularly and efficiently, but not instantaneously. If you need to do real-time data transfer, you should do it in an AsyncTask or an IntentService.

见this链接