android - 向 RelativeLayout 动态添加按钮无法正常工作

Question

我的目标是根据数据库中“项目”的数量向 RelativeLayout 添加一些按钮(在 4 列网格中)。当我第一次学习如何向 RelativeLayout 添加按钮时，我刚刚创建了 6 个静态按钮并按以下方式添加它们(ItemButton 是扩展 Button 的简单类):

private void loadItemButtons2(){
    itemButtonLayout = (RelativeLayout)findViewById(R.id.itemButtonLayout);
    itemButtonLayout.removeAllViews();
    ArrayList<Item> items = db.getAllActiveItems();
    ItemButton b1, b2, b3, b4, b5, b6;
    b1 = new ItemButton(this, items.get(0));
    b2 = new ItemButton(this, items.get(1));
    b3 = new ItemButton(this, items.get(2));
    b4 = new ItemButton(this, items.get(3));
    b5 = new ItemButton(this, items.get(4));
    b6 = new ItemButton(this, items.get(5));

    RelativeLayout.LayoutParams params1 = (RelativeLayout.LayoutParams)b1.getLayoutParams();
    params1.addRule(RelativeLayout.ALIGN_PARENT_START);
    b1.setId(111);
    b1.setLayoutParams(params1);

    RelativeLayout.LayoutParams params2 = (RelativeLayout.LayoutParams)b2.getLayoutParams();
    params2.addRule(RelativeLayout.RIGHT_OF, 111);
    b2.setId(222);
    b2.setLayoutParams(params2);

    RelativeLayout.LayoutParams params3 = (RelativeLayout.LayoutParams)b3.getLayoutParams();
    params3.addRule(RelativeLayout.RIGHT_OF, 222);
    b3.setId(333);
    b3.setLayoutParams(params3);

    RelativeLayout.LayoutParams params4 = (RelativeLayout.LayoutParams)b4.getLayoutParams();
    params4.addRule(RelativeLayout.RIGHT_OF, 333);
    b4.setId(444);
    b4.setLayoutParams(params4);

    RelativeLayout.LayoutParams params5 = (RelativeLayout.LayoutParams)b5.getLayoutParams();
    params5.addRule(RelativeLayout.ALIGN_PARENT_START);
    params5.addRule(RelativeLayout.BELOW, 111);
    b5.setId(555);
    b5.setLayoutParams(params5);

    RelativeLayout.LayoutParams params6 = (RelativeLayout.LayoutParams)b6.getLayoutParams();
    params6.addRule(RelativeLayout.RIGHT_OF, 555);
    params6.addRule(RelativeLayout.BELOW, 222);
    b6.setId(666);
    b6.setLayoutParams(params6);

    itemButtonLayout.addView(b1);
    itemButtonLayout.addView(b2);
    itemButtonLayout.addView(b3);
    itemButtonLayout.addView(b4);
    itemButtonLayout.addView(b5);
    itemButtonLayout.addView(b6);
}

这给了我一个完美的结果:

但这是我想出的动态解决方案，在我看来它似乎在做完全相同的事情，但结果却非常不稳定:

private void loadItemButtons(){
    itemButtonLayout = (RelativeLayout)findViewById(R.id.itemButtonLayout);
    itemButtonLayout.removeAllViews();
    ArrayList<Item> items = db.getAllActiveItems();
    int colCount = 0;
    int rowCount = 0;
    int i = 0;

    while(i < items.size()-1){
        ItemButton newItemButton = new ItemButton(this, items.get(i));
        RelativeLayout.LayoutParams layoutParams = (RelativeLayout.LayoutParams)newItemButton.getLayoutParams();
        newItemButton.setId(i);

        if(colCount == 0){
            layoutParams.addRule(RelativeLayout.ALIGN_PARENT_START);
        }else if(colCount == 1){
            layoutParams.addRule(RelativeLayout.RIGHT_OF, i-1);
        }else if(colCount == 2){
            layoutParams.addRule(RelativeLayout.RIGHT_OF, i-1);
        }else if(colCount == 3){
            layoutParams.addRule(RelativeLayout.RIGHT_OF, i-1);
        }

        //If we are in any row except the top row, place in reference to the button above it
        if(rowCount != 0){
            layoutParams.addRule(RelativeLayout.BELOW, i-4);
        }

        newItemButton.setLayoutParams(layoutParams);
        itemButtonLayout.addView(newItemButton);

        if(colCount == 3){
            colCount = 0;
            rowCount += 1;
        }else{
            colCount += 1;
        }

        i++;
    }
}

有人能看出我做错了什么或与第一个例子不同吗？？？非常感谢任何建议!

Answer 1

您失败的原因是您使用的 ID。 Android 将“保留”ID 用于应用的一般内容区域等内容。

使用您的代码，我能够将 1000 添加到每个 ID 并生成预期结果。

请注意下面我的清理:

private void loadItemButtons(){
    itemButtonLayout = (RelativeLayout)findViewById(R.id.itemButtonLayout);
    itemButtonLayout.removeAllViews();
    List<String> items = itemList;
    int colCount = 0;
    int rowCount = 0;

    // # of items per column
    int colSpan = 4;

    final int itemListSize = itemList.size();
    for (int i = 0; i < itemListSize; i++) {
        int id = 1000 + i;
        ItemButton newItemButton = new ItemButton(this, items.get(i));
        RelativeLayout.LayoutParams layoutParams = new RelativeLayout.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT);
        newItemButton.setId(id);

        if(colCount == 0)
            layoutParams.addRule(RelativeLayout.ALIGN_PARENT_START);
        else
            layoutParams.addRule(RelativeLayout.RIGHT_OF, id-1);


        //If we are in any row except the top row, place in reference to the button above it
        if(rowCount != 0)
            layoutParams.addRule(RelativeLayout.BELOW, id-colSpan);

        newItemButton.setLayoutParams(layoutParams);
        itemButtonLayout.addView(newItemButton);

        if(colCount == colSpan - 1)
            rowCount += 1;

        colCount = (colCount + 1) % colSpan;
    }
}

此外，正如我在对原始帖子的评论中提到的，您确实应该为此使用 gridview，这就是它的构建目的。

我可以用干草叉挖一个洞，但我敢打赌铲子会更好。