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问题 This question already has answers here : How do I return the response from an asynchronous call? (36 answers) Closed 6 years ago . I have a form on my page. When the user hits the Send button, in the background it also generates a unique_number by calling for a function that generates this number and also checks in the DB that this number doesn't exist; if it does - generates it again, if doesn't - returns this number. However, for some reason when I'm trying to print out this number to the

问题 Is undefined a data-type in php? Also, how does one check for it (on a variable, is or is not undefined)? 回答1: There is no "undefined" data type in PHP. You can check for a variable being set with isset, but this cannot distinguish between a variable not being set at all and it having a null value: var_dump(isset($noSuchVariable)); // false $nullVariable = null; var_dump(isset($nullVariable)); // also false However, there is a trick you can use with compact that allows you to determine if a

问题 I have a method, initializeViews , which encounters an ArrayAdapter constructor undefined error in its last line. The method is located in F1Fragment , which extends MainFragment . MainFragment is then attached to an Activity . Can we not give the context of a Fragment in the ArrayAdapter<string> constructor? I am new to Android. Please correct me. Thanks in advance. private void initializeViews(RelativeLayout contentLayout) { leaguesListView = ( ListView ) contentLayout.findViewById ( R.id

问题 This question already has answers here : In Javascript, How to determine if an object property exists and is not empty? (4 answers) Closed 3 years ago . I want to check my data is blank or undefined but my if block execute even my data is not blank ... Code is : router.post('/addNewGrade',function(req , res){ var errorMsg = []; console.log(req.body.gradeName) if(req.body.gradeName == '' || req.body.gradeName === undefined){ errorMsg.push("please enter grade name"); } if(req.body

问题 I have a model which returns a username of the person that has logged into the website to a controller. I am trying to save the username into a variable which i can user to then insert back into another table, however i am having no luck saving the data. Below is my model and controller classes. Model: function is_loggedin() { $session_id = $this->session->userdata('session_id'); $res = $this->db->get_where('logins',array('session_id' => $session_id)); if ($res->num_rows() == 1) { $row = $res

问题 NoMethodError in Quantifieds#index undefined method `date_value' for #Quantified:0x007ff3fe7d6c08 How do I define date_value & result_value so it works in the quantifieds index? <!-- Default bootstrap panel contents --> <div id="values" class="panel panel-default"> <div class="panel-heading"><h4><b>AVERAGE</b></h4></div> <!-- Table --> <table> <% @averaged_quantifieds.each do |averaged| %> <% if averaged.user == current_user %> <th class="value"> <%= link_to edit_quantified_path(averaged) do

问题 I'm trying to copy the code from this video. It's old so I changed the url for the SDK. Here's the JS code: function playSomeSound(genre){ SC.get('/tracks', { genres: genre, bpm: { from: 40 } }, function(tracks){ var random = Math.floor(Math.random() * 49); SC.oEmbed(tracks[random].uri, { auto_play: true}, document.getElementByID('target')); }); } window.onload = function(){ SC.initialize({ client_id: '1166055b8d5ca23b9c265bf8846d1102' }); var menuLinks = document.getElementsByClassName(

问题 Why is the value for undefined considered Finite in javascript while null is not? This is a very basic question, which has thwarted my googlefoo (too much noise). isFinite(undefined); // false isFinite(null); // true I do not understand as I would expect null and undefined to be handled in the same manner. 回答1: This is because Number(null) === 0 . http://es5.github.io/#x9.3 回答2: isFinite (number) Returns false if the argument coerces to NaN, +∞, or −∞, and otherwise returns true. isFinite

问题 Im having this error showing up every time I try to view my time feed. I dont know whats wrong with the code. Can someone help? My code is below. Line 134 will be added first, then the rest of the code public function do_news_feed($user_id) { $status_objects = $this->get_status_objects($user_id); foreach ( $status_objects as $status ) {?> <div class="status_item"> Line 134 -----> <?php $user = $this->load_user_object($status->user_id); ?> <h3><a href="/social/profile-view.php?uid=<?php echo

问题 I did everything that was correct and for some reason Eclipse thinks that the the method gameRender() is undefined for the type GamePanel : package Game_Package; import java.awt.Color; import java.awt.Dimension; import javax.swing.JPanel; public class GamePanel extends JPanel implements Runnable{ private static final int PWIDTH = 900; private static final int PHIEGHT = 900; private Thread animator; private volatile boolean running = false; private volatile boolean gameOver = false; public