I have been looking at the source code. I'm looking in particular at
TabActivity/TabHost/TabWidget and how it works. I'm looking at
setCurrentTab() in TabHost, which from my experience is sufficient in
"closing" an activity, and trying to understand everything that's
going on. Notes below.
I need to understand better how localActivityManager fits into the
code.
public void setCurrentTab(int index) {
if (index < 0 || index >= mTabSpecs.size()) {
return;
}
if (index == mCurrentTab) {
return;
}
// using the IntentContentStrategy, this merely sets the view
visibility to View.GONE
if (mCurrentTab != -1) {
mTabSpecs.get(mCurrentTab).mContentStrategy.tabClosed();
}
//set focus on the current tab
mCurrentTab = index;
final TabHost.TabSpec spec = mTabSpecs.get(index);
mTabWidget.focusCurrentTab(mCurrentTab);
// getContentView() starts the activity if null, and sets the
view to visible
mCurrentView = spec.mContentStrategy.getContentView();
if (mCurrentView.getParent() == null) {
mTabContent
.addView(
mCurrentView,
new ViewGroup.LayoutParams(
ViewGroup.LayoutParams.FILL_PARENT,
ViewGroup.LayoutParams.FILL_PARENT));
}
if (!mTabWidget.hasFocus()) {
mCurrentView.requestFocus();
}
invokeOnTabChangeListener();
}
***
I commented on the code that I have traced through. From what I see,
setCurrentTab() will change the previous window's view to View.GONE,
and the current view to View.VISIBLE. I've tried this in my
ActivityGroup code and it's not surprisingly not enough.
If someone can point me more specifically to where the activity is
actually "disabled" within this code (or where the
localActivityManager is called), that would help me tremendously.
Or, if someone could show me a way in which tabs can be made
unselectable/unscrollable in a TabActivity, that would help out
equally. The fact that I was always able to switch tabs with the
trackball, even when TabWidget's selectable and focusable values are
false, is the entire reason why I am using ActivityGroup instead.
On Feb 10, 1:50 pm, "Justin (Google Employee)" <[email protected]>
wrote:
> The answer is that its complicated. You need to switch not only the
> View, but the entity that the system considers to be active. As Dianne
> suggests android.app.LocalActivityManager is where I'd
> start,http://android.git.kernel.org/?p=platform/frameworks/base.git;a=blob;...
> . A lot of the heavy lifting is done here, but there's also
> android.widget.TabHost and android.app.ActivityGroup (which TabHost
> extends), and android.app.ActivityThread.
>
> Cheers,
> Justin
> Android Team @ Google
>
> On Feb 10, 1:36 pm, Dianne Hackborn <[email protected]> wrote:
>
> > Well it doesn't use a ViewFlipper. :} I suggest looking at the code.
>
> > On Tue, Feb 10, 2009 at 11:43 AM, kingkung <[email protected]> wrote:
>
> > > I'm trying to implement my own ActivityGroup to mimic TabActivity
> > > (without tabs) but I'm having trouble "closing" activities. My
> > > ActivityGroup has a ViewFlipper, each housing a separate activity's
> > > window. When I attempt to switch "activities" I call
> > > ViewFlipper.setDisplayedChild() on the view of choice.
>
> > > However, when I scroll up and down in the view of choice, the OTHER
> > > non-visible activities' views are responding to these actions, so it
> > > seems like I'm not successfully "switching" the activity fully.
>
> > > When I use a TabActivity to run this code, this doesn't happen; when I
> > > scroll up and down in one activity, I don't see any event firing from
> > > any of the other activities.
>
> > > I'm wondering... what does TabActivity do to handle these activities
> > > as separate, individual entities?
>
> > --
> > 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. All such questions should be posted on public
> > forums, where I and others can see and answer them.
--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google
Groups "Android Developers" group.
To post to this group, send email to [email protected]
To unsubscribe from this group, send email to
[email protected]
For more options, visit this group at
http://groups.google.com/group/android-developers?hl=en
-~----------~----~----~----~------~----~------~--~---
