How to treat HttpURLConnection when failed to connect to URL

Issue

When my database is running, everything is okey. But when is not running my mobile app always crash.

Error message:

Caused by: java.net.ConnectException: Failed to connect to /httpURL.

How to fix problem?

here is my code:

AsyncTaskHandleJson().execute(url)    

inner class AsyncTaskHandleJson : AsyncTask<String, String, String>() {
        override fun doInBackground(vararg url: String?): String {
            var text: String
            var connection = URL(url[0]).openConnection() as HttpURLConnection
            try {
                connection.connect()
                text = connection.inputStream.use { it.reader().use { reader -> reader.readText() } }
            } finally {
                connection.disconnect()
            }
            return text
        }

        override fun onPostExecute(result: String?) {
            super.onPostExecute(result)
            handleJson(result)
        }
    }

Solution

Since there is no catch block in your code, you are not catching any exceptions currently.

If you would like to handle the ConnectException, then you simply have to catch it:

override fun doInBackground(vararg url: String?): String {
    var text = ""
    var connection: HttpURLConnection? = null

    try {
        connection = URL(url[0]).openConnection() as HttpURLConnection
        connection.connect()
        text = connection.inputStream.use {
            it.reader().use { reader ->
                reader.readText()
            }
        }
    } catch (ce: ConnectException) {
        // ConnectionException occurred, do whatever you'd like
        ce.printStackTrace()
    } catch (e: Exception) {
        // some other Exception occurred
        e.printStackTrace()
    } finally {
        connection?.disconnect()
    }

    return text
}

Check out the Exceptions reference.

Answered By - earthw0rmjim