如何在PWABuilder构建的Android TWA中实现渠道区分及通知适配

我使用PWABuilder开发Trusted Web Activity (TWA)应用，核心需求是区分通过原生TWA访问的用户与直接访问Web应用的用户，以此实现：

1. 合理请求通知权限：iOS用APN，Android用WebPush；
2. 准确将订阅信息保存至数据库。

已实现的React端区分逻辑 #

React代码中已经写好了平台判断逻辑，但Android TWA环境下无法像iOS那样通过WebView设置自定义User-Agent来标识用户：

{isIOSApp() && (
    <APNPermission />
)}
{isAndroidApp() && (
    <WebPush />
)}

已尝试但失败的方案 #

• 依赖document.referrer：从外部链接加载或Google登录后，该值不可靠；
• 修改manifest.json的start_url：外部来源的链接已有查询参数，无法追加自定义参数；
• 重写com.google.androidbrowserhelper.trusted.LauncherActivity类的多个方法，均未找到设置自定义标识的有效途径：
  • onCreate(Bundle savedInstanceState)：仅能跟踪Intent额外数据和保存状态，与请求头/User-Agent设置无关；
  • getLaunchingUrl()：只能获取启动URL，无法修改；
  • createTwaLauncher()：可跟踪TWA启动器创建过程，但无法自定义请求头；
  • launchTwa()：无直接控制请求头的能力；
  • getCustomTabsCallback()：实现了自定义CustomTabsCallback（MyQualityEnforcer），但无法向Web应用发送消息。

测试代码与日志 #

重写LauncherActivity的测试代码 #

@Override
protected void onCreate(Bundle savedInstanceState) {
    Intent i = super.getIntent();
    i.putExtra("my app", "company app 2");
    Bundle iExtras = i.getExtras();
    if (savedInstanceState == null) {
        Log.d(tag, "2.onCreate Intent.getExtras " + i.getExtras().toString());
        super.onCreate(iExtras);
    } else {
        Log.d(tag, "2.onCreate savedInstanceState " + savedInstanceState.toString());
        super.onCreate(savedInstanceState);
    }
    Log.d(tag, "2.onCreate launcher activity last line");
}

@Override
protected Uri getLaunchingUrl() {
    Log.d(tag, "4.getLaunchingUrl");
    // Get the original launch Url.
    Uri uri = super.getLaunchingUrl();
    Log.d(tag, "4.getLaunchingUrl Launching URL: " + uri);
    return uri;
}

@Override
protected TwaLauncher createTwaLauncher() {
    Log.d(tag, "5.createTwaLauncher twa launcher created");
    TwaLauncher l = super.createTwaLauncher();
    Log.d(tag, "5.createTwaLauncher twa launcher created " + l.getProviderPackage());
    return l;
}

@Override
protected void launchTwa() {
    Log.d(tag, "3.launchTwa main fn starting");
    super.launchTwa();
    Log.d(tag, "3.launchTwa executed");
}

@Override
protected CustomTabsCallback getCustomTabsCallback() {
    Log.d(tag, "6.CustomTabsCallback ");
    CustomTabsCallback q = new MyQualityEnforcer();
    Bundle b = new Bundle();
    b.putString("myapp", "company app");
    q.onMessageChannelReady(b);
    Log.d(tag, "6.CustomTabsCallback " + q.toString());
    return q;
}

自定义QualityEnforcer类 #

public class MyQualityEnforcer extends QualityEnforcer {

    private final String tag = "MyLauncherActivity";

    @Override
    public void onMessageChannelReady(Bundle extras) {
        // Handle the URL update event here
        Log.i(tag, "URL updated: " + extras.toString());
    }
}

日志输出 #

---------------------------- PROCESS STARTED (9972) for package com.company.app.twa ----------------------------
2024-01-10 16:29:56.370  9972-9972  MyLauncherActivity      com.company.app.twa               D  1. hello worldWed Jan 10 16:29:56 GMT+11:00 2024
2024-01-10 16:29:56.604  9972-9972  MyLauncherActivity      com.company.app.twa               D  2.onCreate Intent.getExtras Bundle[{my app=company app 2}]
2024-01-10 16:29:56.617  9972-9972  MyLauncherActivity      com.company.app.twa               D  3.launchTwa main fn starting
2024-01-10 16:29:56.621  9972-9972  MyLauncherActivity      com.company.app.twa               D  4.getLaunchingUrl
2024-01-10 16:29:56.622  9972-9972  MyLauncherActivity      com.company.app.twa               D  4.getLaunchingUrl Launching URL: https://amazing-domain.example.com/
2024-01-10 16:29:56.623  9972-9972  MyLauncherActivity      com.company.app.twa               D  5.createTwaLauncher twa launcher created
2024-01-10 16:29:56.639  9972-9972  MyLauncherActivity      com.company.app.twa               D  5.createTwaLauncher twa launcher created com.android.chrome
2024-01-10 16:29:56.639  9972-9972  MyLauncherActivity      com.company.app.twa               D  6.CustomTabsCallback 
2024-01-10 16:29:56.641  9972-9972  MyLauncherActivity      com.company.app.twa               I  URL updated: Bundle[{myapp=company app}]
2024-01-10 16:29:56.650  9972-9972  MyLauncherActivity      com.company.app.twa               D  6.CustomTabsCallback com.company.app.twa.MyQualityEnforcer@a6145b7
2024-01-10 16:29:57.339  9972-9972  MyLauncherActivity      com.company.app.twa               D  3.launchTwa executed
2024-01-10 16:29:57.347  9972-9972  MyLauncherActivity      com.company.app.twa               D  2.onCreate launcher activity last line

需求 #

寻求通过JavaScript检测Android设备是否运行在Trusted Web Activity中的有效方法。

内容的提问来源于stack exchange，提问作者Foyzul Karim