Question

就我而言,这是我第一次与JSON、Volley或AsyncTask合作。

面对一个编码挑战,我必须从尿素中下载一个JSON阵列,并在进行一些编辑和过滤后显示项目清单。我通过瓦 Java的Volley与JSON案连接。我在我的JSONArrayRequest的“Response”方法中,拿走了JSON的物品,将其改装成java的物品,然后将这些物品添加到一个会议室KQ数据库。这一繁重任务导致国家情报和安全局的成立,因此,我把转换和转入数据库的工作转到ASyncTask。它仍在造成国家情报局。如果所有重型方法在阿森古兰经发生,这种可能性如何? 相关守则和以下守则的解释:

这是我对我的控制人员采取的直线方法,我称之为AsyncTask:

StrictMode.setVmPolicy(new StrictMode.VmPolicy.Builder()
                .detectLeakedClosableObjects()
                .penaltyLog()
                .build());


        repository = new Repository(getApplication());
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_item_list_screen);


        itemRV = findViewById(R.id.itemListRecyclerView);
        progressBar = findViewById(R.id.progressBar1);

        RequestQueue queue1 = Volley.newRequestQueue(ItemListScreen.this);
        queue = queue1;

        final ItemAdapter itemAdapter = new ItemAdapter(this);
        getSupportActionBar().setDisplayHomeAsUpEnabled(true);
        RecyclerView recyclerView  = findViewById(R.id.itemListRecyclerView);
        recyclerView.setAdapter(itemAdapter);
        recyclerView.setLayoutManager(new LinearLayoutManager(this));

        if(repository.getAllItems().isEmpty()) {
            //moves the download of the json file offof the UI thread
            startAsyncTask();
        }
        //fills GUI table with database data

        items = repository.getAllItems();
        itemAdapter.setItems(items);
    }

PHOTO VERSION:

https://i.stack.imgur.com/hHsoL.png” rel=“nofollow noreferer”>。

下面是利用新创建的物品执行和填充会议室KQ数据库的方法。这一点在AsyncTask内部提出。

private void getData () throws InterruptedException {
        //fills database with JSON objects
        JsonArrayRequest jsonArrayRequest = new JsonArrayRequest(Request.Method.GET, url, null, new Response.Listener<JSONArray>() {
            @Override
            public void onResponse(JSONArray response) {
                for (int i = 0; i < response.length(); i++) {
                    try {
                        JSONObject responseObj = response.getJSONObject(i);
                        int id = responseObj.getInt("id");
                        int listId = responseObj.getInt("listId");
                        String name = responseObj.getString("name");
                        Item item = new Item(id, listId, name);
                        repository.insert(item);

                    } catch (JSONException e) {
                        throw new RuntimeException(e);
                    }
                }
            }
            }, new Response.ErrorListener() {
                @Override
                public void onErrorResponse(VolleyError error) {
                        Toast.makeText(ItemListScreen.this, "Failed to get the data", Toast.LENGTH_SHORT).show();
                    }
                });
        //Thread.sleep(1000);
            queue.add(jsonArrayRequest);
    }

PHOTO VERSION:

https://i.stack.imgur.com/ZFqfM.png” rel=“nofollow noreferer”>。

这是我的阿辛克·塔克,用我的控制器的OnCreate方法。预先审查应转而讨论进展情况,然后由DoInBackground进行数据转让,然后,员额应在DoInBackground完成后进行,并放弃进展。之后,该法典应重新采用“OnCreate”方法,并在“ASyncTask”号以下填写:

public void startAsyncTask(){
        ItemsAsyncTask itemsAsyncTask = new ItemsAsyncTask(this);
        //not sure what this integerparameter does but a youtube video said this was very important to have.
        itemsAsyncTask.execute(10);
    }
    private static class ItemsAsyncTask extends AsyncTask<Integer, Integer, String>{

        private WeakReference<ItemListScreen> reference;

        ItemsAsyncTask(ItemListScreen activity){
            reference = new WeakReference<ItemListScreen>(activity);
        }
        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            ItemListScreen activity = reference.get();
            if (activity == null || activity.isFinishing()){
            return;
            }
            //This should begin the progress bar on the screen, which should continue throughout the doInBackground method.
            activity.itemRV.setVisibility(View.INVISIBLE);
            activity.progressBar.setVisibility(View.VISIBLE);
        }

        @Override
        protected String doInBackground(Integer... integers) {
            //this calls the getData method that performs the data transfer away from the UI thread.
            try {
                ItemListScreen activity = reference.get();
                if (activity == null || activity.isFinishing()){
                    return "return";
                }
                activity.getData();
            } catch (InterruptedException e) {
                throw new RuntimeException(e);
            }
            return "return";        }



        @Override
        protected void onPostExecute(String s) {
            //After the doInBackground method is complete, this should remove the progress bar
            // and then continue on to the rest of the OnCreate method where the GUI table will be filled witht he database objects
            super.onPostExecute(s);
            ItemListScreen activity = reference.get();
            if (activity == null || activity.isFinishing()){
                return;
            }
            activity.itemRV.setVisibility(View.VISIBLE);
            activity.progressBar.setVisibility(View.INVISIBLE);
        }
    }

PHOTO VERSION:

https://i.stack.imgur.com/qSvwK.png” rel=“nofollow noreferer”>。

因此,摘要我的格利请求造成国家自然资源局,尽管它属于ASyncTask公司。在ANR(我对位于A/61/3室的数据库进行观察)时,JSON仍被下载到数据库中,而甲状腺素装置和刺.装置正在显示一种流行的信息,说“应用不是反应的”,但“预先和邮政”方法在屏幕上即刻出现,然后立即再次出现。因此,在DoInBackground完成或做一些事情之前,它就象邮政方法一样。是否有任何人知道这种情况发生?

此外,在申请首次大量下载后,一旦进一步开放数据库,国家情报和安全局即已全部启用。这只是第一次使用该数字,必须履行从月球下载JSON的挑战要求。

我对Async进行了审判,但ANR仍在审理之中。

友情链接