Change between alternative layouts without recreating activity

Question

Initially I had a single layout for my activity and used the following attributes to avoid re-creating the activity and thus sending a new request to the database on screen rotation:

ConfigurationChanges = ConfigChanges.Orientation | ConfigChanges.ScreenSize

Later I decided to use an alternative layout for landscape mode. The problem was my app never switched to that alternative layout because of the above mentioned attributes. So, I removed them, and it started switching between landspace/portrait layout, but now I'm facing the same issue that the activity sends a new request to the DB on each recreate.

How can I use alternative layouts and avoid the activity being recreated?

    protected override void OnCreate(Bundle savedInstanceState)
            {
                AllLinesFromBatch = new List<WhseActivLine>();
                Orders = new List<WhseActivHeader>();

                base.OnCreate(savedInstanceState);
                SetContentView(Resource.Layout.NextOrder);

                var backBtn = FindViewById<Button>(Resource.Id.buttonBack);
                backBtn.Click += BackBtn_Click;

                var startBtn = FindViewById<Button>(Resource.Id.buttonStart);
                startBtn.Enabled = false;
                startBtn.Click += StartBtn_Click;

                notificationsArea = FindViewById<TextView>(Resource.Id.notificationsNextorder);
                notificationsArea.Text = string.Empty;

                var dsHeaders = Utility.WsHueckmann.GetDataWhseActivHeaders(PickActivity.CheckedZonesList.ToArray(), LoginActivity.User);

....other code.....
            }

In the above code the line

var dsHeaders = Utility.WsHueckmann.GetDataWhseActivHeaders(PickActivity.CheckedZonesList.ToArray(), LoginActivity.User)

is where the call to DB takes place.

Did you try to manage things in onConfigurationChanged method? — MeLean, Jan 14 '18 at 17:32
@MeLine can you be more specific? How should onConfigurationChanged look like in my case? Sorry, but I've never used that method before — bigb055, Jan 14 '18 at 17:40

Pouya Heydari · Accepted Answer · 2018-01-14T17:45:35.680

2

if problem is only the DB request ,I think the easiest way is making an Application global variable , and do something like this in your activity :

if (globalDsHeaders == null){
var dsHeaders = Utility.WsHueckmann.GetDataWhseActivHeaders(PickActivity.CheckedZonesList.ToArray(), LoginActivity.User)
globalDsHeaders = dsHeaders
}
else {
dsHeaders = globalDsHeader
}
....

let me know if this is helpful or not.

edited Jan 14 '18 at 17:45

answered Jan 14 '18 at 17:32

Pouya Heydari

2,496
26
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globalDsHeaders should survive on orientation changes – MeLean Jan 14 '18 at 17:33
@MeLine sure. it can be defined in Application class. – Pouya Heydari Jan 14 '18 at 17:35
I managed to solve the problem by following both your advices. I'm marking this as answer because it came first. – bigb055 Jan 14 '18 at 18:29

MeLean · Answer 2 · 2018-01-14T17:54:39.013

1

I don get full picture of what you are trying to do but I think you should override the onConfigurationChanged of your launcher activity as described here

Here you can find an answer, how to use different resources for different screen orientation

edited Jan 14 '18 at 17:54

answered Jan 14 '18 at 17:46

MeLean

3,092
6
29
43

Ok, but how do I change to the alternative layout inside onConfigurationChanged? – bigb055 Jan 14 '18 at 17:50
I think I get it but my two layouts have the exact same name "**NextOrder.axml**" just the folders are different. It won't work by simly calling `SetContentView(Resource.Layout.NextOrder)` cause it does not know which one to use. Or am I wrong? – bigb055 Jan 14 '18 at 18:03

Change between alternative layouts without recreating activity

2 Answers2