如何從“本地天氣”應用程序的下拉菜單中顯示一個國家的信息？

Question

我正在創建一個“本地天氣”應用程序，並且創建了一個下拉菜單，您可以在其中單擊一個位置，然后顯示諸如城市，國家和溫度的信息。 但是，每次單擊位置時，我都無法顯示信息。

這是我的代碼。

如您所見，我能夠加載當前位置和溫度。 我要做的是列出全局變量，然后在function getLocation()調用它們，然后在function getWeather()運行信息。 對於下拉菜單，我創建了一個名為mainCities的數組，並將城市追加到function testMenu()下拉菜單中。 在此函數中，我添加了onclick=testWeather('place') 。 為此，我創建了另一個名為function testWeather(cityLocation)在該function testWeather(cityLocation)中，我再次列出了全局變量的信息，並嘗試在function getWeather()再次運行它，但是它不起作用。 我錯過了什么？

您可以在以下位置看到我的代碼在運行： http : //codepen.io/kikibres/pen/EZMJZw

 $(document).ready(function() { var currentLat; var currentLong; var currentCity; var currentRegion; var currentCountry; var mainCities = { 'San_Francisco': { 'region': 'California', 'country': "United States", 'lat': 37.7749300, 'lon': -122.4194200 }, 'St._Louis': { 'region': 'Missouri', 'country': "United States", 'lat': 38.6272700, 'lon': -90.1978900 }, 'Miami': { 'region': 'Florida', 'country': "United States", 'lat': 25.7742700, 'lon': -80.1936600 }, 'Tokyo': { 'region': 'Tokyo', 'country': "Japan", 'lat': 35.689500, 'lon': 139.6917100 } }; function testMenu() { for (var place in mainCities) { var city = place.replace(/_/g, ' '); $('#testMenu').append("<li onclick=testWeather('" + place + "');><a href='#'>" + city + "</a></li>"); } }; function testWeather(cityLocation) { currentLat = testLocation[cityLocation].lat; currentLong = testLocation[cityLocation].lon; currentRegion = testLocation[cityLocation].region; currentCity = testLocation[cityLocation]; currentCountry = testLocation[cityLocation].country; getWeather(); }; function getLocation() { $.getJSON('http://ip-api.com/json/?callback=?', function(data) { currentRegion = data.regionName; currentCity = data.city; currentCountry = data.country; currentLat = data.lat; currentLong = data.lon; //$("#cityname").text(currentCity); getWeather(); }); }; function getWeather() { $("#cityname").text(currentCity); $("#state").text(currentRegion); $("#country").text(currentCountry); $.getJSON('http://api.openweathermap.org/data/2.5/weather?lat=' + currentLat + '&lon=' + currentLong + '&units=imperial&APPID=e656b9ee098cf2341fcfdb365b96b4a8', function(json) { var showfahrenheit = true; var tempfahrenheit = Math.round(json.main.temp); var temcelcius = Math.round((tempfahrenheit - 32) * 5/9); $("#temp").html(tempfahrenheit); $('#unit-switch').on('click', function() { if (showfahrenheit === false) { $("#temp").html(tempfahrenheit); showfahrenheit = true; } else { $("#temp").html(temcelcius); showfahrenheit = false; } $("#unit-toggle").toggleClass("toggle"); //$('#temp').toggleClass('toggle'); }); }); }; $(".cityarea").html(getLocation); testMenu(); }); 

 @import url('https://fonts.googleapis.com/css?family=Roboto:300,400'); body { position: relative; } html,body{ height:100%; } .wrapper { width: 100%; height: 100%; position: relative; } .container { position: relative; display: block; margin: 0 auto; width: 60%; } .header h1 { text-align: center; font-family: 'Roboto', sans-serif; font-weight: normal; margin: 0 0 10px 0; } .weatherbox { text-align: center; } .cityarea h2 { color: #000000; font-family: 'Roboto', sans-serif; font-weight: normal; font-size: 2em; margin: 0; } .countryarea { position: relative; display: -webkit-flex; display: flex; -webkit-justify-content: center; justify-content: center; margin: 0 auto; } .countryarea h3 { margin: 0 0 10px 0; font-family: 'Roboto', sans-serif; font-weight: normal; } .countryarea h3:first-child { margin-right: 8px; } .dropdown { position: relative; display: inline-block; font-size: 16px; color: #FFF; } .dropdown-header { display: block; padding: 3px 20px; font-size: 12px; line-height: 1.42857143; color: #777; white-space: nowrap; text-transform: uppercase; } input[type=checkbox]{ display: none; } label{ box-sizing: border-box; display: inline-block; width: 100%; background-color: #57A0D4; padding: 10px 20px; cursor: pointer; text-align: center; box-shadow: 0 1px 1px rgba(0, 0, 0, 0.2); border-radius: 5px; font-size: 20px; -webkit-user-select: none; -moz-user-select: none; -ms-user-select: none; user-select: none; } label .fa-globe { margin-right: 10px; } /* The ul will have display:none by default */ ul{ position: absolute; list-style: none; text-align: left; width: 100%; min-width: 160px; z-index: 1; padding: 5px 0; margin: 2px 0 0; font-size: 14px; text-align: left; box-shadow: 0px 1px 1px rgba(0, 0, 0, 0.2); display: none; background-color: #fff; border: 1px solid #ccc; border: 1px solid rgba(0,0,0,.15); border-radius: 4px; -webkit-box-shadow: 0 6px 12px rgba(0,0,0,.175); box-shadow: 0 6px 12px rgba(0,0,0,.175); } ul li{ /*padding: 15px;*/ background-color: #fff; color: #4FB9A7; margin-bottom: 1px; cursor: pointer; } ul li a { padding: 8px 20px; color: inherit; text-decoration: none; display: block; } ul li a:hover{ background-color: #4FB9A7; color: #FFF; } input[type=checkbox]:checked ~ label { background-color: #3D88BD; } input[type=checkbox]:checked ~ ul { display: block; } ul .divider { height: 1px; margin: 9px 0; overflow: hidden; background-color: #e5e5e5; } .temperaturearea span#temp { position: relative; color: #000000; font-size: 80px; } .temperaturearea #temp:after { content: ''; position: absolute; height: 10px; width: 10px; top: 16px; right: -17px; border: 3px solid #000000; border-radius: 50%; } .weather > span { position: relative; font-size: 1.2rem; } .weather > span:before { content: ''; position: absolute; left: -10px; top: 0px; height: 3px; width: 3px; border: 2px solid #000; border-radius: 50%; } .main-toggle span { margin: 0 0 0 16px; } .main-toggle span:last-child { margin-left: 11px; } .weather button { background: #6bbf6b; border: none; border-radius: 30px; outline: none; width: 45px; height: 20px; margin: 5px 5px 0; cursor: pointer; position: relative; transition: background .2s; } .weather button:active { background: #67b567; } .weather #unit-toggle { position: absolute; display: inline-block; left: -8px; top: 2px; width: 15px; height: 15px; background: #fff; border-radius: 50%; transition: left .2s; } #unit-toggle.toggle { left: 16px; } 

 <link href="https://maxcdn.bootstrapcdn.com/font-awesome/4.7.0/css/font-awesome.min.css" rel="stylesheet"/> <script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.1.1/jquery.min.js"></script> <div class="wrapper"> <div class="container"> <div class="header"><h1>Local Weather</h1></div> <div class="weatherbox"> <div class="cityarea"> <h2 id="cityname"></h2> </div> <div class="countryarea"> <h3 id="state"></h3> <h3 id="country"></h3> </div> <div class="dropdownlocation"> <div class="dropdown"> <input type="checkbox" id="checkbox-toggle"> <label for="checkbox-toggle"><i class="fa fa-globe" aria-hidden="true"></i><i class="fa fa-caret-down" aria-hidden="true"></i></label> <ul id="testMenu"> <li><a href="#">Current Location</a></li> <li class="divider"></li> <li class="dropdown-header">Main Cities</li> </ul> </div> </div> <div class="temperaturearea"> <div> <span id="wicon"></span> </div> <div id="wdescription"></div> <span id="temp"></span> <div class="weather main-toggle"> <!-- Begin Unit Switch --> <span>F</span> <button id="unit-switch"><span id="unit-toggle"></span></button> <span>C</span> </div> </div> </div> </div> </div> 

Answer 1

有幾個問題的代碼，因為你已經定義了里面所有的功能和可變document.ready您無法訪問任何這些函數和變量之外document.ready 。 這就是為什么當您在onclick li上調用“ testWeather ”時，它引發未定義“ testWeather ”的原因。 為了解決這個問題（您應該使變量和函數成為全局變量），您應該在document.ready之外定義所有變量。 只需在document.ready中保留下面兩行代碼即可。 $(".cityarea").html(getLocation); testMenu();

但這只會解決' testWeather '未定義的問題，並且代碼中還有更多問題，在testWeather函數中，您正在使用一個名為testLocation屬性，該屬性未定義，因此您將在此處遇到JavaScript錯誤。 您已將測試位置保存在mainCities變量中，因此應使用mainCities而不是testLocation 。 這兩項更改將使您的應用正常運行。 這是更正的JavaScript代碼。 您的代碼還有一個小錯誤，您讀取當前城市的方式不正確。

$(document).ready(function () { 
     $(".cityarea").html(getLocation);   
     testMenu();
 });
    var currentLat;
    var currentLong;
    var currentCity;
    var currentRegion;
    var currentCountry;

    var mainCities = {
        'San_Francisco': {
            'region': 'California',
            'country': "United States",
            'lat': 37.7749300,
            'lon': -122.4194200
        },
        'St._Louis': {
            'region': 'Missouri',
            'country': "United States",
            'lat': 38.6272700,
            'lon': -90.1978900
        },
        'Miami': {
            'region': 'Florida',
            'country': "United States",
            'lat': 25.7742700,
            'lon': -80.1936600
        },
        'Tokyo': {
            'region': 'Tokyo',
            'country': "Japan",
            'lat': 35.689500,
            'lon': 139.6917100
        }
    };

    function testMenu() {
        for (var place in mainCities) {
            var city = place.replace(/_/g, ' ');
            $('#testMenu').append("<li onclick=testWeather('" + place + "');><a href='#'>" + city + "</a></li>");
        }
    };

    function testWeather(cityLocation) {
        currentLat = mainCities[cityLocation].lat;
        currentLong = mainCities[cityLocation].lon;
        currentRegion = mainCities[cityLocation].region;
        currentCity = mainCities[cityLocation];
        currentCountry = mainCities[cityLocation].country;

        getWeather();

    };

    function getLocation() {
        $.getJSON('http://ip-api.com/json/?callback=?', function (data) {

            currentRegion = data.regionName;
            currentCity = data.city;
            currentCountry = data.country;
            currentLat = data.lat;
            currentLong = data.lon;

            //$("#cityname").text(currentCity);

            getWeather();

        });
    };

    function getWeather() {

        $("#cityname").text(currentCity);
        $("#state").text(currentRegion);
        $("#country").text(currentCountry);

        $.getJSON('http://api.openweathermap.org/data/2.5/weather?lat=' + currentLat + '&lon=' + currentLong + '&units=imperial&APPID=e656b9ee098cf2341fcfdb365b96b4a8', function (json) {

            var showfahrenheit = true;
            var tempfahrenheit = Math.round(json.main.temp);
            var temcelcius = Math.round((tempfahrenheit - 32) * 5 / 9);

            $("#temp").html(tempfahrenheit);

            $('#unit-switch').on('click', function () {
                if (showfahrenheit === false) {
                    $("#temp").html(tempfahrenheit);
                    showfahrenheit = true;
                } else {
                    $("#temp").html(temcelcius);
                    showfahrenheit = false;
                }

                $("#unit-toggle").toggleClass("toggle");
                //$('#temp').toggleClass('toggle');
            });

        });
    };