一列GridView图像

Question

我不知道如何在网格顶部对齐图片

有我的ImageAdaptater.java代码：

public class ImageAdapter extends BaseAdapter {

private Context mContext;
File[] files;
public ImageAdapter(Context c) {
    mContext = c;

    File dir = new File(Environment.getExternalStorageDirectory() + File.separator + "Favorite" + File.separator + "Pictures");
    files = dir.listFiles();

}
public int getCount() {
    return files.length;
}
public Object getItem(int position) {
    return files[position].getAbsolutePath();
}
public long getItemId(int position) {
    return position;
}

public View getView(int position, View convertView, ViewGroup parent) {

    ImageView imageView;

    if (convertView == null) {
        imageView = new ImageView(mContext);
    } else {
        imageView = (ImageView) convertView;
    }

    imageView.setImageURI(Uri.parse(files[position].getAbsolutePath()));
    return imageView;

}

}

我的布局：

<GridView
    android:id="@+id/dinamicGrid"
    android:stretchMode="columnWidth"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:horizontalSpacing="0dp"
    android:numColumns="1"
    android:scaleType="fitStart"/>

有结果...

为什么在ImageView之前会有很大的空白，该如何删除呢？

谢谢