liffshare_intent.kt

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)

        setContentView(R.layout.activity_main)

        if (intent?.action == Intent.ACTION_SEND) {
            var url = intent.getStringExtra(Intent.EXTRA_TEXT) ?: ""
            handleSendText(url) // Handle text being sent
        }
    }

    private fun handleSendText(url: String) {
        // 要開啟的 LIFF App link
        var liffUrl = "https://liff.line.me/1654950578-67erzKdm"
        // 將欲分享的 url 加在其後面當成 query parameter
        liffUrl += "?url=" + URLEncoder.encode(sharedUrl)
        val webIntent = Intent(Intent.ACTION_VIEW, Uri.parse(liffUrl))
        // 將 Intent 丟給系統處理，它會幫忙把 LINE App 打開，並開啟 LIFF App
        startActivity(webIntent)
        // 關閉這個 Activity，並將自己從 Task 中移除
        finishAndRemoveTask()
    }