Monday, August 31, 2015

Android ListViews and Updating the Backend Data

I wanted to spend at least one more post to try to put my app in a finished state so there was a lot of time spent on both backend code and getting my skills list to display properly.

My first thought was to use a ListView to display all of my skills, it seemed logical. It was a of items, numbers and a checkbox. Time to brush off what I learned from custom spinner items. Creating adapters for your ListView is actually pretty standard as a lot of the time the default elements are going to not provide what you need.

The first step was to at least get my ListView organized and all my skills displayed. I already had all the hookups in place thanks to my work last week with implementing ViewPager. The first step was to create a new LayoutView, which housed my ListView. I then used a default ArrayAdapter to just grab a placeholder list of strings.


        public override View OnCreateView (LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
        {
            var root = inflater.Inflate (Resource.Layout.fragment_charsheet_skills, container, false);
            ListView view = root.FindViewById<ListView> (Resource.Id.skillsList);
            var skills = ((CharacterSheetActivity)this.Activity).CharacterInformation.Skills;
           view.Adapter = new ArrayAdapter<string> (this.Activity,Android.Resource.Layout.SimpleListItem1, skills);

            return root;

        }


 Pretty straight forward, and shows at least a starting point:
 

We have a successful ListView! Now to add the Custom Adapter. In this case, I want to display not only the name, but the ability mod score, whether or not the character is trained, and then the final value. (Mod + Proficiency)

The adapter is set up and in order. The first challenge I ran into was getting my items to not clump together. RelativeLayout was not really an option here, so a little searching I discovered one effective option was to use the "Weight" tag to give each item equal weight within the control. 

 





<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="horizontal"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:padding="5dp">
    <TextView
        android:id="@+id/skillName"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Placeholder"
        android:layout_weight="1" />
    <TextView
        android:id="@+id/modValue"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:text="+3" />
    <CheckBox
        android:id="@+id/isTrained"
        android:layout_width="32.0dp"
        android:layout_height="wrap_content"
        android:layout_weight="1" />
    <TextView
        android:id="@+id/totalValue"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:text="+5" />
</LinearLayout>


In theory that worked well, but then I realized I had a problem once I got the final result running.


Looks Perfect
Maybe I need to think this through...
As the weights are row specific, it does not help align each column. Once again, for implementation and times sake I decided to call that "good enough" for now. 

The next step was to work on my back end code. As can be seen in the above, I am hard coding all of my values, and no hookup event for the proficiency checkbox. This actually required a lot of back end work, which was good to revisit and clean up the data.

 Now, I will preface by saying I do not admit this code will be the best. I'm playing more of the functional over proper card here. As a side project it will regularly be a work in progress. 

I created both a Skill and SkillsList class on my back end. The reason for the latter is it gave me a collection that I could house some of the more static concepts like what skills have what ability mods, and a fully populated list of all possible names. Again, not proud of it, but its functional. Then, at launch all possible skills are preloaded based on starting stats. This gives me all my initial conditions that I access as accessor methods. (Loading data I will revisit at a later point).

From an input standpoint the two big changes I needed to make sure happened were 

a) update final values as proficiency was enabled
b) update mods when ability scores are changed.

For the first, I did an inline set of code, pretty straight forward.


proficient.CheckedChange += (object sender, CompoundButton.CheckedChangeEventArgs e) =>  
{ 
    CharacterSheet sheet = ((CharacterSheetActivity)_context).CharacterInformation; 
    
sheet.Skills[position].IsProficient = e.IsChecked;
    skillMod.Text = sheet.Skills [position].TotalValue + ""; 
}


On the flip side, with all of my Attribute code, I added this line:

character.UpdateSkills (Attributes.AttributeName.STR);

Which is essentially calling an update method within my SkillsList:

public void UpdateSkillMod (Attributes.AttributeName type, int mod)
{
    foreach(Skill skill in _skills)
    {                
        if(skill.ModType == type)
        {
            skill.ModValue = mod;
        }
    }
}


This is simply an enumeration through all skills that updates the ModValue of the associated type. That gets us to our final version, which we will hold with for now.

On the back end I also did a lot of cleanup for better preparation for when I need to load character data. At this point I am going to call the Android version of the app in a good spot and now move to get an iOS skin running with this.

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