Android: Highlight an item from List on setSelecto

问题:

I have a ListView & listselector.xml. Initially I set the item using setSeletion(position). But with this code the item doesn't get highlighted. It gets highlighted only when I click on an item.

        ArrayAdapter<String> ad = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, listItems);
    timeListView = (ListView) findViewById(R.id.listList);
    timeListView.setAdapter(ad);
    timeListView.setOnItemClickListener(this);      
    timeListView.setSelector(R.drawable.listselector);
    timeListView.setSelection(toSelectPos);

     ============================= 
     XML      
     <ListView android:id="@+id/listList" android:layout_width="match_parent"    android:layout_height="wrap_content"  android:dividerHeight="1dp" >

listselector.xml code

     <?xml version="1.0" encoding="UTF-8"?>
     <!-- listselector.xml  -->
     <selector xmlns:android="http://schemas.android.com/apk/res/android">  
<!-- Selected -->
<item android:state_focused="true" android:state_selected="false"
        android:drawable="@drawable/focused"/>

<!-- Pressed -->
<item android:state_selected="true" android:state_focused="false"
        android:drawable="@drawable/selected" />     
      </selector>

The above code highlights full listview, I only want to highlight(change bg color) of the item. For that I believe I will have to create another xml for the item and set selector properties for the item & not list as done above. Correct me if am wrong.

The point is, in anyway only the selected item on click and on setSelection should be changed. With the above code, it doesn't change on setSelection, how to make that happen.

I looked in other Qs, but couldn't find the point I am looking for, so pls don't mark it as a duplicate for other Qs.

Thanks

回答1:

As you probably already have seen in some answers here on stack-overflow, you can not put a View selected because it is implemented so that the User Interface has to be always in touch mode as you can see here However, there are some workarounds That you can do.

You can set your ListView onItemClick with the following listener:

    OnItemClickListener itemClickListener = new OnItemClickListener() {

public void onItemClick(AdapterView<?> arg0, View v, int pos, long id) {

    if (v == lastSelectedView) {

    v.setBackgroundResource(0);
    lastSelectedView = null;

    } else if (v != lastSelectedView) {



    if (lastSelectedView != null)

        lastSelectedView
            .setBackgroundColor(android.R.color.transparent);

    lastSelectedView = v;

    v.setBackgroundDrawable(v.getContext().getResources()
        .getDrawable(R.drawable.some_row_background));
    }
}

};

In this you will colour the lisview item as want. However there is a catch. The recycling of views will mark another view if you scroll down or up. You can "deselect" the view on scroll or you can find a way to tag the view.

Best regards

回答2:

I am not sure that whether this is right way or not but below solution i find from support-v4 examples's fragment demo.

Make check-able custom layout & use this layout for your list's row

public class CheckableLayout extends LinearLayout implements Checkable {
    private boolean mChecked;

    public CheckableLayout (Context context) {
        super(context);
    }

    public CheckableLayout (Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public void setChecked(boolean checked) {
        mChecked = checked;
        // set the custom background image/color
        setBackgroundResource(checked ? R.drawable.category_item_row_selected
                : R.drawable.custom_category_item_row);
    }

    public boolean isChecked() {
        return mChecked;
    }

    public void toggle() {
        setChecked(!mChecked);
    }

}

Define your listview as single choice mode like YOUR_LISTVIEW.setChoiceMode(ListView.CHOICE_MODE_SINGLE);

on click of row(inside OnItemClickListener) you have to set that row as checked like YOUR_LISTVIEW.setItemChecked(index, true);

Thats it