无论地图是否显示,我都想在我的 iphone 应用程序中计算行驶距离。以前,我看到了一些可以完成这项工作的 javascript。这是html中javascript的源代码:
<html>
<head>
<meta name="viewport" content="initial-scale=1.0, user-scalable=no"/>
<title>Distance Calculator</title>
<script type="text/javascript" src="http://maps.google.com/maps/api/js?sensor=false"></script>
<style type="text/css">
#map_canvas {
height: 100%;
}
</style>
<script type="text/javascript">
var directionDisplay;
var directionsService = new google.maps.DirectionsService();
var map;
function initialize() {
directionsDisplay = new google.maps.DirectionsRenderer();
var melbourne = new google.maps.LatLng(-37.813187, 144.96298);
var myOptions = {
zoom:12,
mapTypeId: google.maps.MapTypeId.ROADMAP,
center: melbourne
}
map = new google.maps.Map(document.getElementById("map_canvas"), myOptions);
directionsDisplay.setMap(map);
}
function calcRoute() {
var start = document.getElementById("start").value;
var end = document.getElementById("end").value;
var distanceInput = document.getElementById("distance");
var request = {
origin:start,
destination:end,
travelMode: google.maps.DirectionsTravelMode.DRIVING
};
directionsService.route(request, function(response, status) {
if (status == google.maps.DirectionsStatus.OK) {
directionsDisplay.setDirections(response);
distanceInput.value = response.routes[0].legs[0].distance.value / 1000;
}
});
}
</script>
</head>
<body onload="initialize()">
<div>
<p>
<label for="start">Start: </label>
<input type="text" name="start" id="start" />
<label for="end">End: </label>
<input type="text" name="end" id="end" />
<input type="submit" value="Calculate Route" onclick="calcRoute()" />
</p>
<p>
<label for="distance">Distance (km): </label>
<input type="text" name="distance" id="distance" readonly="true" />
</p>
</div>
<div id="map_canvas"></div>
</body>
然后我想知道如何在我的 iphone Objective-c 文件中调用 javascript 函数。
我在 ViewController.m 中尝试这个:
[webView loadHTMLString:@"<script src=\"calDistance.js\"></script>" baseURL:[NSURL fileURLWithPath:[[NSBundle mainBundle] resourcePath]]];
NSString *function = [[NSString alloc] initWithFormat: @"calcRoute('%@', '%@')", address1,address2];
NSString *result = [webView stringByEvaluatingJavaScriptFromString:function];
self.distance.text = result;
其中 calDistance.js 是一个 javascript 文件,其中包含上述 2 个函数:initialize()、calcRoute(),并且我还重写了 calcRoute() 函数以传递 2 个地址字符串。“距离”是应该显示行驶距离的标签。但是它不起作用。
它与最初在javascript文件中的以下行有关吗?
<script type="text/javascript" src="http://maps.google.com/maps/api/js?sensor=false"></script>
因为我不知道如何插入这个“ http://maps.google.com/maps/api/js?sensor=false ”链接。我应该怎么办?我的代码中还有其他问题吗?我的方法计算行驶距离是否正确?