How to change the position of opened spinner?

For dropdown Spinner mode you can use this:

mSortingSpinner.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
    @Override
    public void onGlobalLayout() {
        mSortingSpinner.setDropDownVerticalOffset(
                mSortingSpinner.getDropDownVerticalOffset() + mSortingSpinner.getHeight());
        if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.JELLY_BEAN) {
            mSortingSpinner.getViewTreeObserver().removeOnGlobalLayoutListener(this);
        } else {
            mSortingSpinner.getViewTreeObserver().removeGlobalOnLayoutListener(this);
        }
    }
});

This set vertical offset of dropdown by spinner height.

Declare the spinner mode as a dropdown:

android:spinnerMode="dropdown"

then use the vertical offset to close the gap:

android:dropDownVerticalOffset="-15dp"

Spinner Android Documentation

You have to extend Spinner and change the location of AlertDialog (spinner when clicked acts as alertDialog).

Code (does a bit more than just position, it also sets background for opened spinner):

public class CustomSpinner extends Spinner {

private AlertDialog mPopup;

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

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

public CustomSpinner(Context context, AttributeSet attrs, int defStyle) {
    super(context, attrs, defStyle);
}

@Override
protected void onAttachedToWindow() {
    super.onAttachedToWindow();
}

@Override
protected void onDetachedFromWindow() {
    super.onDetachedFromWindow();

    if (mPopup != null && mPopup.isShowing()) {
        mPopup.dismiss();
        mPopup = null;
    }
}


//when clicked alertDialog is made
@Override
public boolean performClick() {
    Context context = getContext();

    AlertDialog.Builder builder = new AlertDialog.Builder(context);
    CharSequence prompt = getPrompt();
    if (prompt != null) {
        builder.setTitle(prompt);
    }



    mPopup = builder.setSingleChoiceItems(
            new DropDownAdapter(getAdapter()),
            getSelectedItemPosition(), this).show();

    WindowManager.LayoutParams WMLP = mPopup.getWindow().getAttributes();

            //width and height must be set to anything other than WRAP_CONTENT!
    WMLP.x = 0; // x position
    WMLP.y = 50; // y position
    WMLP.height =390 ; //LayoutParams.WRAP_CONTEN
    WMLP.width = 315;
    WMLP.horizontalMargin = 0; 
    WMLP.verticalMargin = 0;

    mPopup.getWindow().setAttributes(WMLP);



    //ListView.getDefaultSize(size, measureSpec)
    ListView listView = mPopup.getListView();
    //listView.set
    // Remove divider between rows
    listView.setDivider(null);

    // Set custom background
    listView.setBackgroundResource(R.drawable.drop);

    // Remove background from all (grand)parent's
    ViewParent parent = listView.getParent();
    while (parent != null && parent instanceof View) {
        ((View) parent).setBackgroundDrawable(null);

        parent = parent.getParent();
    }

    return true;
}

@Override
public void onClick(DialogInterface dialog, int which) {
    setSelection(which);
    dialog.dismiss();
    mPopup = null;
}


 * <p>Wrapper class for an Adapter. Transforms the embedded Adapter instance
 * into a ListAdapter.</p>
 */
private static class DropDownAdapter implements ListAdapter, SpinnerAdapter {
    private SpinnerAdapter mAdapter;

    /**
     * <p>Creates a new ListAddapter wrapper for the specified adapter.</p>
     *
     * @param adapter the Adapter to transform into a ListAdapter
     */
    public DropDownAdapter(SpinnerAdapter adapter) {
        this.mAdapter = adapter;
    }

    public int getCount() {
        return mAdapter == null ? 0 : mAdapter.getCount();
    }

    public Object getItem(int position) {
        return mAdapter == null ? null : mAdapter.getItem(position);
    }

    public long getItemId(int position) {
        return mAdapter == null ? -1 : mAdapter.getItemId(position);
    }

    public View getView(int position, View convertView, ViewGroup parent) {
        return getDropDownView(position, convertView, parent);
    }

    public View getDropDownView(int position, View convertView, ViewGroup parent) {
        return mAdapter == null ? null :
                mAdapter.getDropDownView(position, convertView, parent);
    }

    public boolean hasStableIds() {
        return mAdapter != null && mAdapter.hasStableIds();
    }

    public void registerDataSetObserver(DataSetObserver observer) {
        if (mAdapter != null) {
            mAdapter.registerDataSetObserver(observer);
        }
    }

    public void unregisterDataSetObserver(DataSetObserver observer) {
        if (mAdapter != null) {
            mAdapter.unregisterDataSetObserver(observer);
        }
    }

    /**
     * <p>Always returns false.</p>
     *
     * @return false
     */
    public boolean areAllItemsEnabled() {
        return true;
    }

    /**
     * <p>Always returns false.</p>
     *
     * @return false
     */
    public boolean isEnabled(int position) {
        return true;
    }

    public int getItemViewType(int position) {
        return 0;
    }

    public int getViewTypeCount() {
        return 1;
    }

    public boolean isEmpty() {
        return getCount() == 0;
    }

   }
   }

Then you just gotta insert it to your layout with "yourPackage.CustomSpinner" element like:

<yourPackage.CustomSpinner 
     android:layout_height="wrap_content"
     android:id="@+id/spinner" 
     android:layout_width="fill_parent">
</yourPackage.CustomSpinner>