如何检测应用程序是否已安装超过一天？

Question

What is the simplest way to detect if my app has been installed for more than a day? I'd like to use Kotlin.

Pseudo-code:

if(appInstalledForMoreThanADay)
{
    print("this app has been installed on this device for more than 1 day")
}

Answer 1

You can get the actual install time through context.getPackageManager() and grabbing the PackageInfo

public long firstInstallTime

The time at which the app was first installed. Units are as per System#currentTimeMillis()

There's lastUpdateTime too if you're into that

Answer 2

As Henry mentioned, You can use shared preferences to save the date of installation, and then every time the app starts check if the current date is one day bigger than the saved date. It should look something like this:

class MainActivity : AppCompatActivity()
{
    companion object
    {
        const val INSTALLATION_DATE_KEY = "INSTALLATION_DATE_KEY"
        const val MILLIS_IN_ONE_DAY = 86_400_000L;
    }

    override fun onCreate(savedInstanceState: Bundle?)
    {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        val sharedPref = getPreferences(Context.MODE_PRIVATE) ?: return

        val installationTime = sharedPref.getLong(INSTALLATION_DATE_KEY, -1L)

        if (installationTime == -1L) // app run for first time
        {
            with(sharedPref.edit()) {
                val time = System.currentTimeMillis()
                Log.d("MyTag", "First run. Time = $time")
                putLong(INSTALLATION_DATE_KEY, time)
                commit()
            }
        }
        else
        {
            if (System.currentTimeMillis() - MILLIS_IN_ONE_DAY >= installationTime)
            {
                Log.d("MyTag", "App installed more than one day ago")
            }
            else
            {
                Log.d("MyTag", "App installed less than one day ago")
            }
        }
    }
}

PS. It won't be "installation" time but "first-run time". So when the user installs the app and runs it for the first time after 2 days it won't work.