http://www.androidguys.com/2008/11/07/rotational-forces-part-two/
On Aug 14, 12:12 am, Indicator Veritatis <mej1...@yahoo.com> wrote:
> The advice to read and memorize the online docs on lifecycle is good.
> But memorization will be somewhat elusive. While you are waiting for
> that elusive satori to bloom, remember one point: there is never a
> good reason to do TCP/IP in the main thread, which in Android, is also
> the UI thread. (or what did you mean by "global thread-based class?)
> You really must move it to another thread. Mostly likely, you will
> want that other thread to run in a Service, which itself will run in
> the background (in both senses of the word: it will have no UI and
> will be a thread separate from and ultimately subordinate to the main
> thread).
>
> Now for some answers:
>
> 1) you don't. That's not your job. The system has the last word.
> 2) I have no idea why you thought onResume() was the way to do this.
> But how you really DO do this depends entirely on your implementation
> of how Preferences are entered. But you didn't tell us this, though
> you did suggest it strongly in the words "Preference Activity".
>
> Well, actually, I do have one idea why you thought that, but it would
> be a mistake: perhaps you thought that you could count on onResume()
> invocation implying that the user had finished entering the
> preferences. But you cannot: lots of things cause onResume() to be
> called. OTOH, if the PreferenceActivity is started via startActivity()
> called from the main Activity, then when the user presses Back (during
> the PreferenceActivity), the system calls finish() on the
> PreferenceActivity, making the main Activity once more the top of the
> stack: the system will display it, calling onResume(), when it gets
> around to it.
>
> Are you really using a PreferenceActivity to read/set the preferences?
> If so, the safe thing to do is always read the settings back in from
> the XML whenever your main/first Activity reaches onResume(). This is
> guaranteed to follow onCreate() and onStart(). This means that your
> default preferences have to make sense.
>
> Now if that is too much computation for you, then before you try to
> get clever and cut down on inflation (reading the XML), you really
> will have to know the Activity lifecycle much better. Wait for that
> satori. Then you can move on to more 'advanced' ideas such as using an
> Application object to store global state.
>
> On Aug 12, 11:32 am, TheWanz <jameswans...@gmail.com> wrote:
>
>
>
>
>
>
>
> > I would like to know the best practice approach to accomplishing this
> > in Android:
>
> > Main Activity: Contains 1 textview, 1 opens menu and 1 global thread-
> > based class. The global thread-based class that opens a socket and
> > reads in data via TCP/IP, and sends thread-safe notification to the
> > main activity so that it can update its textview. This class is
> > developed and works well when it is called from the main activity's
> > onCreate method.
> > Preferences Activity: This activity allows the user to choose options
> > for host and TCP/IP.
>
> > Here are my questions:
> > 1. How do I keep my global class from being destroyed when the onPause
> > is called? Every time I rotate the phone or enter the preferences
> > activity, the object is trashed.
> > 2. How do I capture the event that the user has entered preferences
> > and it is time to start my global class? I have tried onResume, but
> > there is ambiguity between when the app is loaded and when the
> > preferences screen was exited.
>
> > Thanks in advance...
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