Question

我正在尝试从GSON中的URL获取数据并将这些值放入TextView中。我正在使用ArrayList从GSON添加值。以下是处理该问题的AsyncTask<>代码：

private class getData extends AsyncTask<Void, Void, Void> {

    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        pDialog = new ProgressDialog(CardViewExpandCollapse.this);
        pDialog.setMessage("Please wait...");
        pDialog.setCancelable(false);
        pDialog.show();
    }

    @Override
    protected Void doInBackground(Void... voids) {

        HttpHandler httpHandler = new HttpHandler();

        String s = httpHandler.makeServiceCall(mUrl);

        Gson gson = new Gson();
        AccountDetail[] accountDetails = gson.fromJson(s, AccountDetail[].class);

        ArrayList<AccountDetail> details = new ArrayList<>(Arrays.asList(accountDetails));

        HashMap<String, String> accDetails = new HashMap<>();

        String address = details.get(0).getRow().getBillToAddress();

        Double balance = details.get(0).getRow().getTotalAccountBalance();

        Double invoices = details.get(0).getRow().getTotalOpenInvoicesValue();

        Log.e(Tag, "Response from URL " + s);

        Log.e(Tag, "Address is " + address);
        Log.e(Tag, "Balance is " + balance);
        Log.e(Tag, "Invoice is " + invoices);

        accDetails.put("billToAddress", address);
        accDetails.put("totalAccountBalance", balance + "\tUSD");
        accDetails.put("totalOpenInvoicesValue", invoices + "\tUSD");

        hashMap.add(accDetails); // size = 3

        return null;
    }

    @Override
    protected void onPostExecute(Void values) {
        super.onPostExecute(values);
        if (pDialog.isShowing()) {
            pDialog.dismiss();
        }

        /*How can I add values from hash map to TextView here?*/

    }
}

在doInBackground()方法中，我从Gson获取数据并将其添加到哈希映射中。在onPostExecute()方法中，我想将GSON的值添加到TextView。如何将hashMap中的值添加到TextView？

Answer 1

你的AsyncTask的doInBackground（）方法应该返回一个HashMap。

然后你的onPostExecute（）方法会收到它，并且应该更新你的TextView。

以下是代码示例：

<!DOCTYPE html>
<HTML lang="en">
    <HEAD>
        <title>My webpage</title>
    </HEAD>
    <BODY>
        <IMG src="sunset.png" width="500" height="400" alt="missing">
    </BODY>  
</HTML>

Answer 2

您的doInBackground函数需要返回hashMap变量才能在onPostExecute中访问它。

更改protected Void doInBackground(Void... voids)

到protected HashMap<String, String> doInBackground(Void... voids)

然后让您在该函数中返回return hashMap;

接下来更改您的protected void onPostExecute(Void values)

至protected void onPostExecute(HashMap<String, String> hashMap)

最后，将您的班级声明更改为private class getData extends AsyncTask<Void, Void, HashMap<String, String>>

将GSON中的值放入android中的TextView中

2 个答案: