Question

我想从JSON获取数据然后在数组中返回它，但是数组总是以null返回，因为我的程序不会进入onResponse方法。

我想在RecyclerView中显示这些数据。起初它有效，但现在它不起作用我不知道为什么......

private SzabadEuMusorok[] getSzabadEuMusoroks(){
    if (isNetworkAvaible()){
        OkHttpClient client = new OkHttpClient();
        Request request = new Request.Builder().url("validurl").build();

        Call call = client.newCall(request);
        call.enqueue(new Callback() {
            @Override
            public void onFailure(Call call, IOException e) {
                alertUserAboutError();
            }

            @Override
            public void onResponse(Call call, Response response) throws IOException {
                try {
                    String jsonData = response.body().string();
                    Log.v("JSONDATA", jsonData);
                    if(response.isSuccessful()){
                        JSONArray jsonArray = new JSONArray(jsonData);

                        mSzabadEuMusoroks = new SzabadEuMusorok[jsonArray.length()];

                        for (int i = 0; i < jsonArray.length(); i++){
                            JSONObject jsonObject = jsonArray.getJSONObject(i);
                            SzabadEuMusorok szabadEuMusorok = new SzabadEuMusorok();
                            JSONArray elementTexts = jsonObject.getJSONArray("element_texts");

                            JSONObject titleObject = elementTexts.getJSONObject(0);
                            szabadEuMusorok.setTitile(titleObject.getString("text"));

                            JSONObject subjectObject = elementTexts.getJSONObject(3);
                            szabadEuMusorok.setSubject(subjectObject.getString("text"));

                            JSONObject mainObject = jsonObject.getJSONObject("files");
                            szabadEuMusorok.setVideoURL(mainObject.getString("url"));

                            mSzabadEuMusoroks[i] = szabadEuMusorok;
                        }
                    }
                } catch (JSONException e) {
                    Log.e("JSONEXCEPTION", "Exception caught: ", e);
                }
            }
        });
    }
    else{
        Toast.makeText(this, R.string.network_unavaible_message, Toast.LENGTH_LONG).show();
    }
    return mSzabadEuMusoroks;

Answer 1

您的代码在逻辑意义上是错误的。因为对Web服务的调用是异步的，所以当你使用“return”时，数组是空的，当你的数据在结果中无所谓时，因为你已经加载了RecyclerView。解决方案是在RecyclerView中实现回调函数或使用notifydatasetchanged。

检查链接。

Using callbacks in android

Using notifydatasetchanged

---------- notifydatasetchanged ----------

for (int i = 0; i < jsonArray.length(); i++){
  JSONObject jsonObject = jsonArray.getJSONObject(i);
  SzabadEuMusorok szabadEuMusorok = new SzabadEuMusorok();
  JSONArray elementTexts = jsonObject.getJSONArray("element_texts");

  JSONObject titleObject = elementTexts.getJSONObject(0);
  szabadEuMusorok.setTitile(titleObject.getString("text"));

  JSONObject subjectObject = elementTexts.getJSONObject(3);
  szabadEuMusorok.setSubject(subjectObject.getString("text"));

  JSONObject mainObject = jsonObject.getJSONObject("files");
  szabadEuMusorok.setVideoURL(mainObject.getString("url"));

  mSzabadEuMusoroks[i] = szabadEuMusorok;
}
//LINE ADDED-----------------------------------------------------
yourAdapterInTheRecyclerView.notifyDataSetChanged();
//LINE ADDED-----------------------------------------------------

为什么跳过onResponse方法？

1 个答案: