Home » Android » java – Highlight Multiple Selected/Checked/Activated in ListView

java – Highlight Multiple Selected/Checked/Activated in ListView

Posted by: admin June 15, 2020 Leave a comment

Questions:

Wow, documentation is horrible when it comes to list item selection. All I need is to be able to select and highlight multiple items in a list. I’ve scoured the web and seen references to android:choiceMode="multipleChoice", which I’m guessing allows you to select multiple items. But where can I get the selected items in my Activity? And how come when I try to select multiple items using setSelection(position), the previously highlighted item disappears?

Google also describes in View.setActivated(boolean) that

Note that activation is not the same as selection. Selection is a transient property, representing the view (hierarchy) the user is currently interacting with. Activation is a longer-term state that the user can move views in and out of. For example, in a list view with single or multiple selection enabled, the views in the current selection set are activated. (Um, yeah, we are deeply sorry about the terminology here.)

So am I supposed to use activation instead of selection? This SO answer talks about how “activated” is just the post-HoneyComb version of “checked”. But if you’re supposed to use “activated” for multiple selection, whats the point of android:choiceMode="multipleChoice" in the first place?

How to&Answers:

So apparently I was led off the wrong track because I was supposed to be looking for highlighting “checked” items and not “selected” items. Thus, many answers told me to use the selector with my ListView layout using android:listSelector="@drawable/myselector, but what I really needed was to use the selector with my row layout. The solution is actually rather simple, I’ll post it below:

drawable/rowbackgroundselector.xml

<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:state_activated="true"
    android:drawable="@android:color/holo_green_light"/>
</selector>
  • note how you use “state_activated” to detect if an item is “checked”…

drawable/mylistrow.xml

<TextView xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@android:id/text1"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:gravity="center_vertical"
    android:background="@drawable/rowbackgroundselector"
    android:padding="10sp"
/>
  • using the selector for the row background

MainActivity.onListItemClick()

public void onListItemClick(ListView l, View v, int position, long id) {
    getListView().setItemChecked(pos, true);
}

Lastly, make sure your adapter is using your custom row layout

mAdapter = new ArrayAdapter<FileTag>(this.getActivity(),
    R.layout.mylistrow, mList);