how to set image width height based on screen size in gridview

Question

I want to show 3x3 sized gridview. I want to set the height and width based on device size. I am taking reference from this link.

MainActivity-

public class MainActivity extends Activity {

   @Override
   protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);

      GridView gridview = (GridView) findViewById(R.id.gridview);
      gridview.setAdapter(new ImageAdapter(this));
   }

   @Override
   public boolean onCreateOptionsMenu(Menu menu) {
      getMenuInflater().inflate(R.menu.main, menu);
      return true;
   }

}

activity_main-

<?xml version="1.0" encoding="utf-8"?>
<GridView xmlns:android="http://schemas.android.com/apk/res/android" 
   android:id="@+id/gridview"
   android:layout_width="fill_parent" 
   android:layout_height="fill_parent"
   android:columnWidth="90dp"
   android:numColumns="auto_fit"
   android:verticalSpacing="10dp"
   android:horizontalSpacing="10dp"
   android:stretchMode="columnWidth"
   android:gravity="center"
/>

Edit-

Like first getting screen height and width then each item height and width 1/3 of the value of screen height and width I am getting.

Answer 1

Do not use screen size, in a multi-windows context this method is invalid. If your grid is a 3x3 items size fixed, so use custom layout ViewGroup like this: (and set RelativeLayout items content)

public class MainActivity extends Activity {

    @Override
    protected void onCreate(Bundle state) {
        setContentView(new ViewGroup(this) {
            private RelativeLayout[] items = new RelativeLayout[9];
            private int width, height, itemWidth, itemHeight;
            {
                Random r = new Random();
                for (int i = 0; i < 9; i++) {
                    items[i] = new RelativeLayout(getContext());
                    float[] hsv = new float[] {360 * r.nextFloat(), .50f, .75f};
                    items[i].setBackgroundColor(Color.HSVToColor(hsv));
                    addView(items[i]);

                    // UPDATE ////////////////////////////////////
                    ImageView image = new ImageView(getContext());
                    switch (i) {
                    case 0: // top left
                    case 1: // top center
                    case 2: // top right
                    case 3: // center left
                    case 4: // center center
                    case 5: // center right
                    case 6: // bottom left
                    case 7: // bottom center
                    case 8: // bottom right
                        image.setImageResource(R.drawable.ic_launcher);
                        break;
                    }
                    image.setScaleType(ScaleType.FIT_XY);
                    image.setLayoutParams(new RelativeLayout.LayoutParams(
                            RelativeLayout.LayoutParams.MATCH_PARENT,
                            RelativeLayout.LayoutParams.MATCH_PARENT
                    ));
                    items[i].addView(image);
                    //////////////////////////////////////////////
                }
            }
            @Override
            protected void onMeasure(int wMS, int hMS) {
                width = MeasureSpec.getSize(wMS);
                height = MeasureSpec.getSize(hMS);
                itemWidth = width / 3;
                itemHeight = height / 3;
                wMS = MeasureSpec.makeMeasureSpec(itemWidth, MeasureSpec.EXACTLY);
                hMS = MeasureSpec.makeMeasureSpec(itemHeight, MeasureSpec.EXACTLY);
                measureChildren(wMS, hMS);
                setMeasuredDimension(width, height);
            }
            @Override
            protected void onLayout(boolean changed, int l, int t, int r, int b) {
                for (int i = 0; i < 9; i++) {
                    l = itemWidth * (i % 3);
                    t = itemHeight * (i / 3);
                    r = l + itemWidth;
                    b = t + itemHeight;
                    items[i].layout(l, t, r, b);
                }
            }
        });
        super.onCreate(state);
    }

}

---

EDIT : see my update in code, you have simply to add your images to the items containers. With this method, no XML layout file needed because you manage content and size yourself.

Result :

---

EDIT : the minimalist way:

public class MainActivity extends Activity {

    @Override
    protected void onCreate(Bundle state) {
        setContentView(new ViewGroup(this) {
            private static final int SIZE_X = 3;
            private static final int SIZE_Y = 3;
            private ImageView[] items = new ImageView[SIZE_X * SIZE_Y];
            private int itemWidth, itemHeight;
            {
                setBackgroundColor(Color.DKGRAY);
                for (int i = 0; i < items.length; i++) {
                    items[i] = new ImageView(getContext());
                    items[i].setScaleType(ScaleType.CENTER);
                    items[i].setImageResource(R.drawable.ic_launcher);
                    addView(items[i]);
                }
            }
            @Override
            protected void onMeasure(int wMS, int hMS) {
                int width = MeasureSpec.getSize(wMS);
                int height = MeasureSpec.getSize(hMS);
                itemWidth = width / SIZE_X;
                itemHeight = height / SIZE_Y;
                wMS = MeasureSpec.makeMeasureSpec(itemWidth, MeasureSpec.EXACTLY);
                hMS = MeasureSpec.makeMeasureSpec(itemHeight, MeasureSpec.EXACTLY);
                measureChildren(wMS, hMS);
                setMeasuredDimension(width, height);
            }
            @Override
            protected void onLayout(boolean changed, int l, int t, int r, int b) {
                for (int i = 0; i < items.length; i++) {
                    l = itemWidth * (i % SIZE_X);
                    t = itemHeight * (i / SIZE_X);
                    r = l + itemWidth;
                    b = t + itemHeight;
                    items[i].layout(l, t, r, b);
                }
            }
        });
        super.onCreate(state);
    }

}

Result :

---

@ Kanwaljit Singh:

In MainActivity items creation loop:

final int id = i;
items[i].setOnClickListener(new OnClickListener() {
    @Override
    public void onClick(View v) {
        startActivity(new Intent(getContext(), NextActivity.class).putExtra("id", id));
    }
});

In NextActivity:

int id = getIntent().getIntExtra("id", -1);