Change the background image of frame layout using Java

Question

I have a frame layout and want to change the background image/color depending on the current state of an array. I can change text depending on the array so understand how to do that but can't find a way to reference the layout.

I've initialised the frame layout (li) after the on create however when I try change the colour in the later method I get the error "Non-static field 'li' can not be referenced from a static context".

Any help appreciated

public class GridViewFragmentActivity extends FragmentActivity
{
    FrameLayout li;

    @Override
    protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        FrameLayout li =(FrameLayout) findViewById(R.id.framelayout);

        final DotsPageIndicator mPageIndicator;
        final GridViewPager mViewPager;

        final String[][] data =
                {
                { "Row 0, Col 0", "Row 0, Col 1", "Row 0, Col 2", "Row 0, Col 3" },
                { "Row 1, Col 0", "Row 1, Col 1", "Row 1, Col 2" },
                { "Row 2, Col 0", "Row 2, Col 1", "Row 2, Col 2" }
        };

        // Get UI references
        mPageIndicator = (DotsPageIndicator) findViewById(R.id.page_indicator);
        mViewPager = (GridViewPager) findViewById(R.id.pager);

        // Assigns an adapter to provide the content for this pager
        mViewPager.setAdapter(new GridPagerAdapter(getFragmentManager(), data));
        mPageIndicator.setPager(mViewPager);
    }



    private static final class GridPagerAdapter extends FragmentGridPagerAdapter {


        String[][] mData;

        private GridPagerAdapter(FragmentManager fm, String[][] data)
        {
            super(fm);
            mData = data;

        }

        @Override
        public Fragment getFragment(int row, int column)
        {
            String text = "CARD FRAGMENT";
            if (row == 2 && column == 1)
            {
                text = "SIT UP";
                li.setBackgroundColor(Color.parseColor("#FFFFFF"));
            }
            else
            {
                text = "PRESS UP";
                li.setBackgroundColor(Color.parseColor("#FF0000"));
            }
            return (CardFragment.create(text, mData[row][column]));
        }

        @Override
        public int getRowCount()
        {
            return mData.length;
        }

        @Override
        public int getColumnCount(int row)
        {
            return mData[row].length;
        }
    }
}

http://stackoverflow.com/questions/2559527/non-static-variable-cannot-be-referenced-from-a-static-context — yosriz, Feb 13 '17 at 17:49

mantas dziaugys · Accepted Answer · 2017-02-14T20:01:04.123

Pass layout via GridPagerAdapter constructor and save in a variable.

private static final class GridPagerAdapter extends FragmentGridPagerAdapter {


    private final FrameLayout li;
    String[][] mData;

    private GridPagerAdapter(FragmentManager fm, String[][] data, FrameLayout li)
    {
        super(fm);
        mData = data;
        this.li = li;
    }

    //... stuff
}

Then modify your onCreate method accordingly

@Override
protected void onCreate(Bundle savedInstanceState)
{
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    FrameLayout li =(FrameLayout) findViewById(R.id.framelayout);

    final DotsPageIndicator mPageIndicator;
    final GridViewPager mViewPager;

    final String[][] data =
            {
            { "Row 0, Col 0", "Row 0, Col 1", "Row 0, Col 2", "Row 0, Col 3" },
            { "Row 1, Col 0", "Row 1, Col 1", "Row 1, Col 2" },
            { "Row 2, Col 0", "Row 2, Col 1", "Row 2, Col 2" }
    };

    // Get UI references
    mPageIndicator = (DotsPageIndicator) findViewById(R.id.page_indicator);
    mViewPager = (GridViewPager) findViewById(R.id.pager);

    // Assigns an adapter to provide the content for this pager
    mViewPager.setAdapter(new GridPagerAdapter(getFragmentManager(), data, li));
    mPageIndicator.setPager(mViewPager);
}

Seems to work except I'm not getting an error on the mViewPager.setAdapter line as it is requiring 3 arguments due to the addition of FrameLayout li to the GridPageAdapter method. http://imgh.us/Screen_Shot_2017-02-13_at_19.54.42.jpg — James B, Feb 13 '17 at 20:02
replace mViewPager.setAdapter(new GridPagerAdapter(getFragmentManager(), data)); with mViewPager.setAdapter(new GridPagerAdapter(getFragmentManager(), data, li)); because you need to pass layout from activity to adapter. — mantas dziaugys, Feb 14 '17 at 08:17

Change the background image of frame layout using Java

1 Answers1