无需Jsoup：从ASP.NET页面向Android App获取数据及JSON方案咨询

Hey there! Let's break down your questions and give you practical, actionable guidance:

1. Is using JSON data fetching & parsing feasible? #

Absolutely! This is actually a far more reliable approach than Jsoup for your use case, especially if your college's website relies on JavaScript to load grades. Here's why:

• If your college's backend uses an internal API to serve grade data (you can spot this by checking your browser's DevTools Network tab for XHR/fetch requests when you manually look up grades), you can call this API directly from your Android app. This avoids the fragility of parsing HTML—small UI changes on the college site won't break your app.
• Jsoup only retrieves static HTML content. So if grades are loaded dynamically with JavaScript (which sounds like the root of your earlier issue), Jsoup can't access that dynamically rendered data. Fetching JSON directly from the source API bypasses this problem entirely.

2. Implementing user-selectable login credentials #

This is straightforward to add to your app:

• Build a simple input screen where users can enter their unique credentials (like roll number, student ID, or password).
• Store these credentials securely (use encrypted SharedPreferences or Android's Keystore system for sensitive data) so users don't have to re-enter them every session.
• When making your API request to fetch grades, include these stored credentials as request parameters or in the request body—match whatever format the college's API expects for authentication.

3. Note on your provided Jsoup code #

The Jsnippet you shared is built to scrape Google Play app version info, which doesn't align with your grade-checking use case. More importantly, as you discovered, it won't work for JS-heavy sites because Jsoup can't execute JavaScript to load dynamic content. If you ever wanted to use Jsoup for a static site, you'd need to adjust the selectors to target grade elements on your college's page—but again, JSON is the better, more stable choice here.

Quick example of JSON fetching with OkHttp (Android) #

Here's a basic snippet to send a POST request with your parameters and parse the JSON response:

// First add OkHttp dependency to your app's build.gradle
OkHttpClient client = new OkHttpClient();

// Build request parameters (include user credentials here too)
RequestBody formBody = new FormBody.Builder()
        .add("Stream", "Degree science")
        .add("Class", "F.Y.B.Sc")
        .add("Division", "CPM(A)")
        .add("Roll no", "1743")
        .add("username", userEnteredUsername) // Pull from user input
        .add("password", userEnteredPassword) // Pull from user input
        .build();

Request request = new Request.Builder()
        .url("YOUR_COLLEGE_GRADE_API_ENDPOINT") // Replace with actual API URL from DevTools
        .post(formBody)
        .build();

// Execute request asynchronously (never run network calls on the main thread!)
client.newCall(request).enqueue(new Callback() {
    @Override
    public void onFailure(Call call, IOException e) {
        e.printStackTrace();
        // Handle error (show a toast, update UI with error message)
    }

    @Override
    public void onResponse(Call call, Response response) throws IOException {
        if (response.isSuccessful()) {
            String jsonResponse = response.body().string();
            // Parse JSON using Gson or JSONObject
            JSONObject jsonObject = new JSONObject(jsonResponse);
            String studentGrade = jsonObject.getString("grade"); // Adjust key to match API response
            // Update UI on the main thread
            runOnUiThread(() -> {
                // Display the grade to the user
            });
        }
    }
});

Don't forget to:

• Replace YOUR_COLLEGE_GRADE_API_ENDPOINT with the actual API URL you find in your browser's Network tab (look for requests that fire when you submit the grade form).
• Add the internet permission to your AndroidManifest.xml: <uses-permission android:name="android.permission.INTERNET" />

内容的提问来源于stack exchange，提问作者Mahesh Jadhav