Android 10及以上版本中，如何以编程方式判断应用能否启动Activity？

Great question! Let's break this down clearly—since Android 10 rolled out strict background activity launch rules, it's tricky that the system doesn't throw an exception when blocking a launch, only logging that "ActivityTaskManager: Background activity start" message. Here's how you can handle this programmatically:

Why no exception is thrown #

First, it's key to understand: Android doesn't throw errors when blocking background activity starts. It just silently prevents the launch and logs that message. So you can't rely on try/catch blocks to detect this scenario.

Programming ways to check if you can start an Activity #

1. Use the official API (Android 12+, API 31) #

Android 12 added a direct, reliable method to check if your app can start an activity from the background:

// Kotlin example
val activityManager = context.getSystemService(Context.ACTIVITY_SERVICE) as ActivityManager
val targetPackage = "com.your.target.package" // Use your app's package or the target's
val canStartActivity = activityManager.canStartActivityFromBackground(
    context,
    targetPackage,
    0 // Adjust flags as needed for your use case
)

This method returns true if the system allows the activity start, accounting for all background restrictions and exemptions automatically.

2. For Android 10/11 (API 29-30) #

Since the above API doesn't exist here, you'll need to manually verify two core conditions:

a. Check if your app is in the foreground

If your app has a visible activity or is running a foreground service, you can safely start activities. Here's a robust way to check foreground status:

fun isAppInForeground(context: Context): Boolean {
    val activityManager = context.getSystemService(Context.ACTIVITY_SERVICE) as ActivityManager
    
    // Quick check via running processes (simpler but less precise)
    activityManager.runningAppProcesses?.forEach { processInfo ->
        if (processInfo.processName == context.packageName && 
            processInfo.importance == ActivityManager.RunningAppProcessInfo.IMPORTANCE_FOREGROUND) {
            return true
        }
    }
    
    // More accurate check with UsageStatsManager (requires permission)
    val usageStatsManager = context.getSystemService(Context.USAGE_STATS_SERVICE) as UsageStatsManager
    val currentTime = System.currentTimeMillis()
    val usageStats = usageStatsManager.queryUsageStats(
        UsageStatsManager.INTERVAL_DAILY,
        currentTime - 60000, // Check the last 1 minute of usage
        currentTime
    )
    
    usageStats?.sortedByDescending { it.lastTimeUsed }?.forEach { stats ->
        if (stats.packageName == context.packageName) {
            return stats.isForeground
        }
    }
    
    return false
}

Note: Using UsageStatsManager requires the android.permission.PACKAGE_USAGE_STATS permission, and users need to enable it manually in Settings > Apps > Special access > Usage access.

b. Check if your app qualifies for an exemption

Even in the background, some exemptions let you start activities. Common ones include:

• Your app is running a foreground service
• The user recently interacted with your app (e.g., tapped a notification, used a shortcut)
• Your app is a device owner or profile owner

To check for an active foreground service:

fun hasActiveForegroundService(context: Context): Boolean {
    val activityManager = context.getSystemService(Context.ACTIVITY_SERVICE) as ActivityManager
    return activityManager.getRunningServices(Int.MAX_VALUE).any { serviceInfo ->
        serviceInfo.service.packageName == context.packageName && serviceInfo.foreground
    }
}

For user interaction exemptions, track these events yourself (e.g., save a timestamp when a user taps your notification, then check if that timestamp is within the system's grace period—usually 5-10 minutes).

Recommended workflow #

Putting it all together:

• If isAppInForeground(context) is true: Start the activity directly.
• Else if hasActiveForegroundService(context) is true: Start the activity directly.
• Else if you have proof of recent user interaction (e.g., within the last 5 minutes): You can attempt to start the activity (it’s likely allowed, though not guaranteed).
• Otherwise: Show a notification to let the user tap and launch the activity manually.

内容的提问来源于stack exchange，提问作者Arnaud