在Android上无法设置负边距

Question

我正在我的android应用中创建ImageView的列表，并为每个列表设置了负边距。 我正在使用它来将dp转换为像素：

public int dpToPixel(float dp) {
    DisplayMetrics displayMetrics = this.getResources().getDisplayMetrics();
    return (int)((dp * displayMetrics.density) + 0.5);
}

列表是这样的：

List<GridLayout> columnNLinesGrid = new ArrayList<GridLayout>();
List<ImageView> columnLines = new ArrayList<ImageView>();

for (int i = 1; i <= rowLayoutsCount; i++) {

    columnNLinesGrid.add(new GridLayout(this));
    GridLayout.LayoutParams colGridParam = new GridLayout.LayoutParams();
    colGridParam.setMargins(0,0,0,0);
    colGridParam.topMargin = dpToPixel(-10);
    columnNLinesGrid.get(i - 1).setLayoutParams(colGridParam);
    columnNLinesGrid.get(i - 1).setColumnCount(columnLayoutsCount);
    linearLayouts.get(i - 1).addView(columnNLinesGrid.get(i - 1));

    for (int j = 1; j <= columnLayoutsCount; j++) {
         columnLines.add(new ImageView(this));
         GridLayout.LayoutParams lineParam = new GridLayout.LayoutParams();
         lineParam.rowSpec = GridLayout.spec(0);
         lineParam.columnSpec = GridLayout.spec(j - 1);
         if(j-1>0){
             lineParam.leftMargin = (int) dpToPixel(23);
         } else{
             lineParam.leftMargin = 0;
         }
         lineParam.width = GridLayout.LayoutParams.WRAP_CONTENT;
         lineParam.height = (int) dpToPixel(35);
         columnLines.get(colLinesCount).setLayoutParams(lineParam);
         columnLines.get(colLinesCount).setImageResource(R.drawable.linevert);
         columnNLinesGrid.get(i - 1).addView(columnLines.get(colLinesCount));
         colLinesCount++;
    }
}

似乎colGridParam.topMargin = dpToPixel(-10)无效。在其他一些情况下，我尝试使用负边距，但没有一个起作用。