webapp检测安卓app是否安装并launch

1. cordova插件

1）查看所有已安装的安卓app

https://www.npmjs.com/package/cordova-plugin-packagemanager

A simple plugin that will return a list of installed applications or all on your smartphone. Retuen uid, dataDir and packageName.

function successCallback(e) {
    alert(JSON.stringify(e));
}

function errorCallback(e) {
    alert('Error!' + e);
}

window.plugins.packagemanager.show(true, successCallback, errorCallback);

2）检测某安卓app是否已安装

https://www.npmjs.com/package/cordova-plugin-appavailability

从1）返回的list of installed applications中找到所需app的scheme，例如高德地图：com.autonavi.minimap。

var scheme;

if (device.platform === 'iOS') {
    scheme = 'iosamap://';
}
else if (device.platform === 'Android') {
    scheme = 'com.autonavi.minimap';
}

appAvailability.check(
    scheme,       // URI Scheme or Package Name 
    function () {  // Success callback 
        alert(scheme + ' is available :)');
    },
    function () {  // Error callback 
        alert(scheme + ' is not available :(');
    }
);

3）launch app

https://github.com/nchutchind/cordova-plugin-app-launcher

window.plugins.launcher.launch(
                { uri: 'androidamap://route?sourceApplication=cortanademoservice&slat=39.979366&slon=116.31028&sname=我的位置&dlat=39.980016&dlon=116.326568&dname=公安局&dev=0&t=0' },
                successCallback,
                errorCallback
            );

2. JavaScript的tricky实现方法

安装app的情况下，网页会进入后台打开app，网页进入后台后会挂起js的执行，但是这个期间有600-1000ms的时间js仍然会执行，可以利用打开app的延时来判断是否有该app。

var t = 1000, hasApp = true;
setTimeout(function () {
    if (!hasApp) {
        cordova.InAppBrowser.open('http://m.amap.com/navigation/carmap/saddr=116.310322%2C39.978957%2C%E5%BE%AE%E8%BD%AF%E5%A4%A7%E5%8E%A6&daddr=116.326568%2C39.980016%2C%E4%B8%AD%E5%85%B3%E6%9D%91%E6%B4%BE%E5%87%BA%E6%89%80&saddr_lonlat=116.310322%2C39.978957%2C%E5%BE%AE%E8%BD%AF%E5%A4%A7%E5%8E%A6&daddr_lonlat=116.326568%2C39.980016%2C%E4%B8%AD%E5%85%B3%E6%9D%91%E6%B4%BE%E5%87%BA%E6%89%80&saddr_typecode=120201&daddr_typecode=130501&saddr_poiid=B0FFFSPTNE&daddr_poiid=B000A7FCSP&maddr=&sort=&addPassing=remove');
    }
    $("#ifr").remove();
}, 2000);

var t1 = Date.now();
var ifr = $('<iframe id="ifr"></iframe>')
ifr.attr('src', 'androidamap://route?sourceApplication=cortanademoservice&slat=39.979366&slon=116.31028&sname=我的位置&dlat=39.980016&dlon=116.326568&dname=公安局&dev=0&t=0');
$('body').append(ifr);
setTimeout(function () {
    var t2 = Date.now();
    //delay time 30 may vary for different type of phones
    if (!t1 || t2 - t1 < t + 30) {
        hasApp = false;
    }
}, t);

利用iframe的动态加载来尝试打开app。