从Yahoo Finance中获取数据并在Fragment中显示

Question

In Fragment of my android application I wanna show simple data from Yahoo Finance as price, company name, ticker etc with the help of csv (Comma-Separated Values). I have Error as NullPointerException when I tried to set values to TextView in my FinanceFragment. Can anyone show me correct way to do that or fix my code.

Thanks for any help!

Activity.java

        AlertDialog.Builder builder = new AlertDialog.Builder(this);

        LayoutInflater inflater = this.getLayoutInflater();
        View dialogView = inflater.inflate(R.layout.dialog_search_ticker, null);
        builder.setView(dialogView);

        final EditText input = (EditText) dialogView.findViewById(R.id.input_ticker);
        input.setInputType(InputType.TYPE_CLASS_TEXT);

        builder.setPositiveButton("SEARCH TICKER", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                final String SearchTicker = input.getText().toString();

                if(SearchTicker.matches("")) { //Check if EditText is empty / If empty show message
                    Toast.makeText(getApplicationContext(), "Space is empty. Please try enter again!", Toast.LENGTH_SHORT).show();
                }else{
                    if(new YahooAsyncTask().execute(SearchTicker) == null){
                        Toast.makeText(getApplicationContext(), "There is no such ticker. Please try enter again!", Toast.LENGTH_SHORT).show();
                    }else{
                        new YahooAsyncTask().execute(SearchTicker);
                    }
                }
            }
        });

private class YahooAsyncTask extends AsyncTask<String, String, Stock> {

        LinearLayout Progress = (LinearLayout) findViewById(R.id.Progress);
        LinearLayout NoInternetConnection = (LinearLayout) findViewById(R.id.NoInternetConnection);
        FrameLayout FragmentContainer = (FrameLayout) findViewById(R.id.FragmentContainer);

        @Override
        protected void onPreExecute() {
            // Sets company info invisible, and progress indicator visible
            Progress.setVisibility(View.VISIBLE);
            NoInternetConnection.setVisibility(View.INVISIBLE);
            FragmentContainer.setVisibility(View.GONE);
        }

        protected Stock doInBackground(String... ticker) {
            Stock stock = null;
            if (isNetworkAvailable()) {
                try {
                    stock = YahooFinanceInfo.getStockData(ticker[0]);
                } catch (Exception e) {
                    Log.d("YAHOO_ERROR", e.toString());
                }
            }
            return stock;
        }

        protected void onPostExecute(Stock stock) {
            Progress.setVisibility(View.GONE);
            if (stock != null) {
                // Create a new Fragment to be placed in the activity layout
                YahooFragment yahooFragment = YahooFragment.newInstance(stock);

                if (findViewById(R.id.FragmentContainer) != null) {
                    getSupportFragmentManager().beginTransaction().replace(R.id.FragmentContainer, yahooFragment).commit();
                } else {
                    getSupportFragmentManager().beginTransaction().add(R.id.FragmentContainer, yahooFragment).commit();
                }
                FragmentContainer.setVisibility(View.VISIBLE);
            } else {
                NoInternetConnection.setVisibility(View.VISIBLE);
            }
        }
    }

Answer 1

Please post the error code to be sure, but my guess is it is happening here:

LinearLayout HeaderProgress = (LinearLayout) getView().findViewById(R.id.progress_linear_layout);
LinearLayout NoInternetConnection = (LinearLayout) getView().findViewById(R.id.NoInternetConnection);
LinearLayout FragmentContainer = (LinearLayout) getView().findViewById(R.id.fragment_container);

this code will be executed before you return onCreateView() which means that getView() probably returns null.

try pulling out these attributes to your activity and initializing them before calling

new GetKeyStatsAsyncTask().execute(ticker);

Update

This is what i meant in my comment:

public class FinanceFragment extends Fragment {

TextView tvCompany;
TextView tvCompanyTicker;
TextView tvPrice;
TextView tvPriceChange;
TextView tvPrevClose;
TextView tvOpen;
TextView tvVolume;
TextView tvAvgDailyVolume;
TextView tvDaysRange;
TextView tvYearRange;
TextView tvOneYearTarget;
TextView tvMarketCap;

Stock stock;

String ticker;

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    View view = inflater.inflate(R.layout.fragment_finance, container, false);

    tvCompany        = (TextView) view.findViewById(R.id.tvCompany);
    tvCompanyTicker  = (TextView) view.findViewById(R.id.tvCompanyTicker);
    tvPrice          = (TextView) view.findViewById(R.id.tvPrice);
    tvPriceChange    = (TextView) view.findViewById(R.id.tvPriceChange);
    tvPrevClose      = (TextView) view.findViewById(R.id.tvPrevClose);
    tvOpen           = (TextView) view.findViewById(R.id.tvOpen);
    tvAvgDailyVolume = (TextView) view.findViewById(R.id.tvAvgDailyVolume);
    tvVolume         = (TextView) view.findViewById(R.id.tvVolume);
    tvDaysRange      = (TextView) view.findViewById(R.id.tvDaysRange);
    tvYearRange      = (TextView) view.findViewById(R.id.tvYearRange);
    tvMarketCap      = (TextView) view.findViewById(R.id.tvMarketCap);
    tvOneYearTarget  = (TextView) view.findViewById(R.id.tvOneYearTarget);


    updateView();


    // When application start working, search for Google ticker by default.
    ticker = "GOOG";
    new GetKeyStatsAsyncTask().execute(ticker);

    return view;
}
private void updateView() {
    if(stock == null) {
    // Sets company name, price, etc.
        tvCompany.setText("");
        tvCompanyTicker.setText("");
        tvPrice.setText("");
        tvPriceChange.setText("");
        tvPrevClose.setText("");
        tvOpen.setText("");
        tvAvgDailyVolume.setText("");
        tvVolume.setText("");
        tvDaysRange.setText("");
        tvYearRange.setText("");
        tvMarketCap.setText("");
        tvOneYearTarget.setText("");
    } else {

    // Sets company name, price, etc.
        tvCompany.setText(stock.getName());
        tvCompanyTicker.setText(stock.getTicker());
        tvPrice.setText(stock.getPrice());
        tvPriceChange.setText(stock.getPriceChange());
        tvPrevClose.setText(stock.getPrevClose());
        tvOpen.setText(stock.getOpen());
        tvAvgDailyVolume.setText(stock.getAvgDailyVolume());
        tvVolume.setText(stock.getVolume());
        tvDaysRange.setText(stock.getDaysRange());
        tvYearRange.setText(stock.getYearRange());
        tvMarketCap.setText(stock.getMarketCap());
        tvOneYearTarget.setText(stock.getOneYearTarget());

        // If price change is positive, set TextView to green. Otherwise Red.
        if (stock.getPriceChangeDirection() >= 0)
            tvPriceChange.setTextColor( getResources().getColor(R.color.finance_green));
        else
            tvPriceChange.setTextColor( getResources().getColor(R.color.finance_red));

    }
}
...

And change your onPostExecute:

protected void onPostExecute(Stock stock) {
    HeaderProgress.setVisibility(View.GONE);
    if (stock != null) {
        FragmentContainer.setVisibility(View.VISIBLE);
        updateView();
    } else {
        NoInternetConnection.setVisibility(View.VISIBLE);
    }
}

i did not try the code, so there is no guarantee it works