How to instantiate a Gridview or a Listview for the same Activity?

Question

In my app I am presenting a list of items. I would like in certain situations to be presented with a ListView and others like GridView. Situations are:

1. Smartphone(Portrait) - ListView
2. Smartphone(Landscape) and Tablet - GridView

Question

How could I check each situation and correctly instantiate the object in Activity?

OBS: The xml part is already done, with the folders in the correct way.

Answer 1

You should work with screen sizes. The most common way I learned was to use a Resource with a Boolean is property (you can put whatever name you want, isGrid, for example), usually use isTablet.

First, you must create a values folder for each qualifier you have of layout. For example, if you have layout-land, layout-large-land, layout-xlarge then you should also have the values-land, values-large-land and values-xlarge folders.

Then you should create within each of the values folders a bool.xml file with the following content:

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <bool name="isGrid">false</bool>
</resources>

The value true or false changes according to the existence of gridView, if there is a gridView you must put true, otherwise false.

Now in Activity calling gridView or Listview you add the following code:

private boolean isGrid(){
    return getResources().getBoolean(R.bool.isGrid);
}

Now in the onCreate method of the same Activity you must have a code with the following:

if(this.isGrid()){
    //crie uma gridView
}
else{
    //crie uma listView
}

Answer 2

If it is necessary to check the orientation, you can use:

getResources().getConfiguration().orientation

which may be one of the following:

ORIENTATION_LANDSCAPE 
ORIENTATION_PORTRAIT

and to check if the screen is large(Tablet) you can try to catch the inches(diagonals) of the device:

public static Double getPolegadas(Activity activity) {

    DisplayMetrics metrics = new DisplayMetrics();
    WindowManager wm = (WindowManager) activity.getSystemService(Context.WINDOW_SERVICE);
    wm.getDefaultDisplay().getMetrics(metrics);

    final int largura = metrics.widthPixels;
    final int altura = metrics.heightPixels;
    final double diagonal = Math.sqrt((largura * largura) + (altura * altura));

    polegadas = diagonal / metrics.densityDpi;

    return polegadas;
}

Then for Tablet, you would check if it is bigger than 6.5, for example:

if (polegadas >= 6.5)

I hope I’ve helped!

Answer 3

I received the reply in another forum where I also asked and I received as an answer a great solution, I will copy here because it can help someone else in the future. I applied it to my app and it worked.

Suppose the XML containing the ListView or the GridView be called layout.xml. So:

• in the briefcase layout, there must be a layout.xml with ListView.
• in the briefcase layout-land and layout-large should there be a layout.xml with GridView.

With this done, Android will already inflate the layout.xml correct in doing:

setContentView(R.layout.layout);

As both Listview and Gridview are children of Abslistview, do the following:

AbsListView listOrGrid = 
    (AbsListView) findViewById(R.id.id_do_grid_e_list); 

Written by Lucas at GUJ(I hope there are no problems in quoting another forum)