ok Dianne, then,
Class MySingleton
{
static List<> myList;
}
//This activity is singleTop
Class MyActivity
{
onCreate(Bundle)
{
initStaticList(); //say the init size is 2
}
//Now suppose in between some other activity add 2 more objects in
myList
map()
{
int size = MySingleton.myList.size();
}
}
When I run this scenario using singleTask/singleInstance root
activity, I always get size 2.
But when I run this activity standalone, I get the desired result as
4.
I am not saying it is because of singleTask or singleTop, but this is
what is happening.
Is there something I am doing wrong here? Please suggest something!
On Sep 6, 11:24 pm, Dianne Hackborn <[email protected]> wrote:
> Sorry I can't understand what you are doing enough to help. If you have a
> static variable holding a singleton, it will hold whatever the last value
> you put into it is (until your process gets killed, and then of course the
> next time it is restarted it will be re-initialized to its default value).
> There is nothing about activities or anything else in Android that has an
> impact on this fundamental behavior.
>
>
>
> On Sun, Sep 6, 2009 at 3:48 AM, indra <[email protected]> wrote:
>
> > Hi,
> > Here I come across a strange problem. I am using a static list (say
> > myList) in a Singleton class, which I use in a activity (say
> > myActivity) which is run by a singleTask root activity (rootActivty).
> > But when i try to access myList in the myActivity, I do not get a
> > refreshed version of that myList, instead I get the value one which I
> > first time accessed in myActivity.
> > Strangle when I run this myActivity standalone I get correct values of
> > myList each time.
> > Please help me out.
> > Thanks and Regards
> > Indra
>
> > On Aug 25, 9:46 pm, Dianne Hackborn <[email protected]> wrote:
> > > Please read the documentation. As I said in my original post, this is
> > for
> > > when your activity gets killed while it is in the background. When you
> > > press back, the default implementation is to finish() the activity so
> > there
> > > is no longer any instance data.
>
> > > On Tue, Aug 25, 2009 at 6:57 AM, sdphil <[email protected]>
> > wrote:
>
> > > > hm... okay, so I check for null in my onCreate() method.
>
> > > > public void onCreate(Bundle savedInstanceData) {
> > > > if (savedInstanceData == null) {
> > > > // do everything I did before.
> > > > // show splash screen
> > > > super.onCreate(savedInstanceState);
> > > > }
> > > > }
>
> > > > However, now if I'm in my app, I click on "home", and then click on
> > > > the icon again, it behaves as expected, it simply brings the app back
> > > > in the expected state. If I hit "back" and then click on the icon
> > > > again, it behaves like I launched a brand new app - shows the splash
> > > > screen, etc...
>
> > > > On Aug 24, 11:24 pm, Dianne Hackborn <[email protected]> wrote:
> > > > > The simple fact that it is non-null tells you. And you can have
> > placed
> > > > > anything else you want in there in onSaveInstanceState() for whatever
> > > > other
> > > > > data you want to retain. See here:
>
> > > > >http://developer.android.com/guide/topics/fundamentals.html#actlife
>
> > > > > and here:
>
> > > > >http://developer.android.com/reference/android/app/Activity.html
>
> > > > > On Mon, Aug 24, 2009 at 10:51 PM, sdphil <[email protected]
>
> > > > wrote:
>
> > > > > > "You can use the state passed in to onCreate() to determine whether
> > > > > > you are starting for the first time or not."
>
> > > > > > How do I do that?
>
> > > > > > I'm looking at onCreate --
>
> > > > > > public void onCreate(Bundle savedInstanceState) {
>
> > > > > > and I look at savedInstanceState, nothing jumps out at me...
>
> > > > > > On Aug 24, 10:39 pm, Dianne Hackborn <[email protected]> wrote:
> > > > > > > If you just want pressing back to not close the activity, just
> > catch
> > > > the
> > > > > > > BACK key and call Activity.moveTaskToBack() instead of letting it
> > do
> > > > the
> > > > > > > default behavior (of calling finish()).
>
> > > > > > > There is no need to use launchMode nor alwaysRetainTaskState.
>
> > > > > > > However, you DO need to deal with the normal lifecycle behavior
> > -- in
> > > > > > > particular, when you are in the background, regardless of how
> > this
> > > > > > happened,
> > > > > > > the system is free to kill your process, so when the user next
> > > > returns to
> > > > > > > your app a new instance of your activity will be created. You
> > can
> > > > use
> > > > > > the
> > > > > > > state passed in to onCreate() to determine whether you are
> > starting
> > > > for
> > > > > > the
> > > > > > > first time or not.
>
> > > > > > > Also, a "quit" menu on an android application is not normal,
> > > > expected,
> > > > > > nor
> > > > > > > desired. Please don't do it; there is no need. I think you will
> > > > have a
> > > > > > > much better time if you try to design your app to follow the kind
> > of
> > > > flow
> > > > > > > shown by the existing applications, rather than trying to make it
> > > > work
> > > > > > like
> > > > > > > a desktop application.
>
> > > > > > > For example: you could save your current state to persistent
> > storage
> > > > when
> > > > > > > the user leaves the app, and restore it when they return, so they
> > > > know
> > > > > > they
> > > > > > > will always come back to the same thing. If it makes for them to
> > > > > > actually
> > > > > > > throw away that state, you could have an option for them to reset
> > the
> > > > app
> > > > > > so
> > > > > > > they can decide to do that at the time they want, rather than
> > having
> > > > to
> > > > > > > decide earlier on to have this happen as a side-effect of some
> > > > unusual
> > > > > > > "quit" command.
>
> > > > > > > On Mon, Aug 24, 2009 at 10:16 PM, sdphil <
> > [email protected]
>
> > > > > > wrote:
>
> > > > > > > > I want my application to work like this:
>
> > > > > > > > 1. When the user launches the application, it starts up.
> > > > > > > > 2. When the user hits back, or home, the application is still
> > > > running
> > > > > > > > (although not visible).
> > > > > > > > 3. If the user hits "menu->quit" the application exits cleanly.
> > > > > > > > 4. If the user starts the application, hits "home" and selects
> > the
> > > > > > > > application icon *again*, I want it to bring up the existing
> > > > insance
> > > > > > > > of the application with whatever activity state it had before
> > it
> > > > left.
> > > > > > > > 5. I do not ever want more than one instance of my application
> > to
> > > > be
> > > > > > > > running (i.e. singleton).
> > > > > > > > 6. I always want to retain activity stack/state. when you come
> > > > back
> > > > > > > > into the application, it's like you never left.
>
> > > > > > > > <?xml version="1.0" encoding="utf-8"?>
> > > > > > > > <manifest xmlns:android="
> > > >http://schemas.android.com/apk/res/android";
> > > > > > > > package="com.company.gui"
> > > > > > > > android:versionCode="1"
> > > > > > > > android:versionName="1.0">
> > > > > > > > <application android:icon="@drawable/icon"
> > > > > > > > android:label="@string/app_name"
> > > > > > > > android:debuggable="true">
> > > > > > > > <activity android:name=".Main"
> > > > > > > > android:launchMode="singleTask"
> > > > > > > > android:alwaysRetainTaskState="true"
> > > > > > > > android:label="@string/app_name"
> > > > > > > > android:screenOrientation="portrait"
>
> > android:theme="@android:style/Theme.NoTitleBar">
> > > > > > > > <intent-filter>
> > > > > > > > <action
> > android:name="android.intent.action.MAIN" />
> > > > > > > > <category
> > > > > > > > android:name="android.intent.category.LAUNCHER" />
> > > > > > > > </intent-filter>
> > > > > > > > </activity>
>
> > > > > > > > <activity android:name=".SplashScreen"
> > > > > > > > android:label="@string/app_name">
> > > > > > > > </activity>
>
> > > > > > > > </application>
> > > > > > > > <uses-sdk android:minSdkVersion="3" />
> > > > > > > > <uses-permission
> > android:name="android.permission.INTERNET"></uses-
> > > > > > > > permission>
> > > > > > > > </manifest>
>
> > > > > > > > my main activity onCreate() looks like this:
>
> > > > > > > > startActivityForResult( new Intent(this,
> > > > SplashScreen.class),
> > > > > > > > SPLASH_REQUEST_ID );
> > > > > > > > new Thread() {
> > > > > > > > public void run() {
> > > > > > > > try {
> > > > > > > > Thread.sleep(4 * 1000);
>
> > > > > > > > // put initialization
> > stuff
> > > > > > here.
>
> > > > > > > > } catch (InterruptedException e)
> > {
> > > > > > > > e.printStackTrace();
> > > > > > > > }
> > > > > > > > finishActivity( SPLASH_REQUEST_ID );
> > > > > > > > }
> > > > > > > > }.start();
>
> > > > > > > > setContentView(R.layout.main);
>
> > > > > > > > If I leave the application by hitting home and then selecting
> > the
> > > > icon
> > > > > > > > again, it starts with the splash screen again!
>
> > > > > > > > any ideas on how to best fix this?
>
> > > > > > > > tia.
>
> > > > > > > --
> > > > > > > Dianne Hackborn
> > > > > > > Android framework engineer
> > > > > > > [email protected]
>
> > > > > > > Note: please don't send private questions to me, as I don't have
> > time
> > > > to
> > > > > > > provide private support, and so won't reply to such e-mails. All
> > > > such
> > > > > > > questions should be posted on public forums, where I and others
> > can
> > > > see
> > > > > > and
> > > > > > > answer them.
>
> > > > > --
> > > > > Dianne Hackborn
> > > > > Android framework engineer
> > > > > [email protected]
>
> > > > > Note: please don't send private questions to me, as I don't have time
> > to
> > > > > provide private support, and so won't reply to such e-mails. All
> > such
> > > > > questions should be posted on public forums, where I and others can
> > see
> > > > and
> > > > > answer them.
>
> > > --
> > > Dianne Hackborn
> > > Android framework engineer
> > > [email protected]
>
> > > Note: please don't send private questions to me, as I don't have time to
> > > provide private support, and so won't reply to such e-mails. All such
>
> ...
>
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