对于android中的某些数据，JSONObject数组返回null

我对Android的JSON有问题。出于某种原因，当我使用JSONObject.getInt方法接收某些数据时，它会返回一些空数据。并不是我接收到的所有数据都返回null，似乎只有返回null的数据类型是整数，我还有其他整数数据，它们接收到的数据很好，没有任何null。它似乎只与3个整数变量一致。我在某个地方读过这篇文章，认为它是一个bug，但我不确定是否是这样。顺便说一下，我用的是安卓截击

有更好的方法吗

        StringRequest strReq = new StringRequest(Request.Method.POST,
            AppConfig.URL_LOGIN, new Response.Listener<String>() {

        @Override
        public void onResponse(String response) {
            Log.d(TAG, "Login Response: " + response.toString());
            hideDialog();

            try {
                JSONObject jObj = new JSONObject(response);
                boolean error = jObj.getBoolean("error");

                // Check for error node in json
                if (!error) {
                    // user successfully logged in
                    // Create login session
                    session.setLogin(true);

                    String uid = jObj.getString("uid");

                    JSONObject user = jObj.getJSONObject("user");


                    ...(OTHER Variables that return fine)


                    int activitylvl = user.getInt("activitylvl");//get null
                    int meal_plan = user.getInt("meal_plan");//get null
                    int workout_plan = user.getInt("workout_plan");//get null


        Continues.....};

PHP

---

如果您确定响应中的数据不是空的，但在尝试解析数据时，数据将变为空，并且您也确定数据字段名称正确，则可以执行以下操作作为替代解决方案：

if (user.getString("activitylvl") != null && !user.getString("activitylvl").equalsIgnoreCase("")) {
    int activitylvl = Integer.parseInt(user.getString("activitylvl"));
}

---

它将

JSON

字段作为字符串对象获取，然后将其转换为整数对象。

我发现问题出在用户响应名称上，这是一个php问题：

在getUserByEmailAndPassword函数中有一个方法 叫

mysqli_获取_数组（mysqli_查询）

这将获取列名，并将其设置在一个数组中，该数组的键名为mysql数据库中的列名，因为我的名称不正确

不正确

$response[“user”][“activitylvl”]=$user[“activitylvl”]

$response[“用户”][“膳食计划”]=$user[“膳食计划”]

$response[“用户”][“训练计划”]=$user[“训练计划”]

正确的

$response[“user”][“activitylvl”]=$user[“activity”]

$response[“用户”][“膳食计划”]=$user[“膳食计划”]

---

$response[“用户”][“训练计划”]=$user[“训练计划”]

整数（int）不能为null，因为它有一些值或它保持零。发布您的回复结构。编辑您的问题，使用另一个应用程序获取json并将其发布到问题上。

 // get the user by email and password
$user = $db->getUserByEmailAndPassword($email, $password);

if ($user != false) {
    // use is found
    $response["error"] = FALSE;
    $response["uid"] = $user["unique_id"];
    $response["user"]["name"] = $user["name"];
    $response["user"]["email"] = $user["email"];
    $response["user"]["goal"] = $user["goal"];
    $response["user"]["image"] = $user["image"];
    $response["user"]["gender"] = $user["gender"];
    $response["user"]["birthdate"] = $user["birthdate"];
    $response["user"]["height_cm"] = $user["height_cm"];
    $response["user"]["height_ft"] = $user["height_ft"];
    $response["user"]["height_in"] = $user["height_in"];
    $response["user"]["weight_kg"] = $user["weight_kg"];
    $response["user"]["weight_lbs"] = $user["weight_lbs"];
    $response["user"]["activitylvl"] = $user["activitylvl"];
    $response["user"]["calories"] = $user["calories"];
    $response["user"]["meal_plan"] = $user["meal_plan"];
    $response["user"]["workout_plan"] = $user["workout_plan"];
    $response["user"]["adjust_calories_wd"] = $user["adjust_calories_wd"];
    $response["user"]["adjust_calories_nwd"] = $user["adjust_calories_nwd"];
    $response["user"]["workout_week"] = $user["workout_week"];
    $response["user"]["created_at"] = $user["created_at"];
    $response["user"]["updated_at"] = $user["updated_at"];
    echo json_encode($response);
} else {
    // user is not found with the credentials
    $response["error"] = TRUE;
    $response["error_msg"] = "Login credentials are wrong. Please try again!";
    echo json_encode($response);
}

public function getUserByEmailAndPassword($email, $password) {
    //DO this for users db as well
    $result = mysqli_query($this->conn,"SELECT * FROM users WHERE email = '$email'") or die(mysqli_connect_errno());

    // check for result
    $no_of_rows = mysqli_num_rows($result);

    if ($no_of_rows > 0) {
        $result = mysqli_fetch_array($result);
        $salt = $result['salt'];
        $encrypted_password = $result['encrypted_password'];
        $hash = $this->checkhashSSHA($salt, $password);

        // check for password
        if ($encrypted_password == $hash) {
            return $result;
        }

    } else {
        return false;
    }

}

if (user.getString("activitylvl") != null && !user.getString("activitylvl").equalsIgnoreCase("")) {
    int activitylvl = Integer.parseInt(user.getString("activitylvl"));
}