android - ExpandableListView - 父项及其子项周围的边界

Question

我有一个使用 ExpandableListView 的 View ，它周围和适配器中都有大量逻辑。例如，它看起来像这样

我需要用不同的皮肤显示相同的 View ，隐藏展开/折叠并且在父项及其子项周围有一个边框，就像这样

我看到属性为整个控件或仅父控件或单个子控件设置了边框，但没有在父控件及其子控件周围设置边框。

有没有人做过这样的事情？除了不使用 Expandablelistview 并重新创建 View 之外，我还能实现边框吗？

编辑 1:

Here is a gist有我正在尝试做的模板。

编辑 2:

我有一个解决方案，可以玩父子边界，

setting parent to            ┎─┒ 

and all-but-last children to ┃ ┃

and last child to            ┖─┚

Here is the gist for the solution I have so far

我仍然对更好的解决方案持开放态度，并且会为任何比我的解决方案更简单的东西提供赏金。

Answer 1

编辑 所以我向 ExpandableListView 添加了 ItemDecoration 功能，它的工作原理与 RecyclerView 非常相似' s ItemDecoration，这里是代码:

子类化 ExpandableListView

public class ExpandableListViewItemDecoration extends ExpandableListView {
private List<ItemDecorationListView> itemDecorations = new ArrayList<>(1);

/* ... */

public void addItemDecoration(ItemDecorationListView item){
    itemDecorations.add(item);
}

@Override
public void draw(Canvas canvas) {
    super.draw(canvas);
    final int count = itemDecorations.size();
    for (int i = 0; i < count; i++) {
        itemDecorations.get(i).onDrawOver(canvas, this);
    }
}

元素装饰 ListView :

public abstract class ItemDecorationListView {

    public void onDrawOver(Canvas c, ListView parent) {
    }
}

ItemDecorator:

public class ItemDecoratorBorderListView extends ItemDecorationListView {

private final Paint paint = new Paint();
private final int size;

public ItemDecoratorBorderListView(int size, @ColorInt int color) {
    this.size = size;
    paint.setColor(color);
    paint.setStrokeWidth(size);
    paint.setStyle(Paint.Style.STROKE);
}

public static final String TAG = ItemDecoratorBorderListView.class.getSimpleName();

@Override
public void onDrawOver(Canvas c, ListView parent) {
    super.onDrawOver(c, parent);
    int childCount = parent.getChildCount();
    for (int i = 0; i < childCount; i++) {
        View child = parent.getChildAt(i);
        if (isHeader(child, parent, i)) {
            for (int j = i + 1; j < childCount; j++) {
                View childEnd = parent.getChildAt(j);
                boolean end = isHeader(childEnd, parent, i) || j == childCount - 1;
                if (end) {
                    if (BuildConfig.DEBUG) { Log.d(TAG, String.format(Locale.ENGLISH, "Draw called i: %d, j: %d", i, j)); }
                    childEnd = parent.getChildAt(j - 1);
                    if (j == childCount - 1) { childEnd = parent.getChildAt(j); }
                    float top = child.getTop() + child.getTranslationY() + size + child.getPaddingTop();
                    float bottom = childEnd.getBottom() + childEnd.getTranslationY() - size - childEnd
                            .getPaddingBottom();

                    float right = child.getRight() + child.getTranslationX() - size - child.getPaddingRight();
                    float left = child.getLeft() + child.getTranslationX() + size + child.getPaddingLeft();
                    c.drawRect(left, top, right, bottom, paint);
                    i = j - 1;
                    break;
                }
            }
        }
    }
}

public boolean isHeader(View child, ListView parent, int position) {
    //You need to set an Id for your layout
    return child.getId() == R.id.header;
}

只需将它添加到您的ExpandableListView:

expandableList.addItemDecoration(new ItemDecoratorBorderListView(
            getResources().getDimensionPixelSize(R.dimen.stroke_size),
            Color.GRAY
    ));

旧答案:

这是一个使用 RecyclerView 和 ItemDecoration 的实现，在知道你被遗留代码困住之前我已经写了这个解决方案，所以我还是分享这个.

元素装饰:

public class ItemDecoratorBorder extends RecyclerView.ItemDecoration {

private final Paint paint = new Paint();
private final int size;

public ItemDecoratorBorder(int size, @ColorInt int color) {
    this.size = size;
    paint.setColor(color);
    paint.setStrokeWidth(size);
    paint.setStyle(Paint.Style.STROKE);
}

public static final String TAG = ItemDecoratorBorder.class.getSimpleName();

@Override
public void onDrawOver(Canvas c, RecyclerView parent, RecyclerView.State state) {
    super.onDrawOver(c, parent, state);
    if (parent.getLayoutManager() == null) { return; }
    int childCount = parent.getChildCount();
    RecyclerView.LayoutManager lm = parent.getLayoutManager();
    for (int i = 0; i < childCount; i++) {
        View child = parent.getChildAt(i);
        if (isHeader(child, parent)) {
            for (int j = i + 1; j < childCount; j++) {
                View childEnd = parent.getChildAt(j);
                boolean end = isHeader(childEnd, parent) || j == childCount - 1;
                if (end) {
                    if (BuildConfig.DEBUG) { Log.d(TAG, String.format(Locale.ENGLISH, "Draw called i: %d, j: %d", i, j)); }
                    childEnd = parent.getChildAt(j - 1);
                    if (j == childCount - 1) {
                        childEnd = parent.getChildAt(j);
                    }
                    float top = child.getTop() + child.getTranslationY() + size + child.getPaddingTop();
                    float bottom = lm.getDecoratedBottom(childEnd) + childEnd.getTranslationY() - size - childEnd.getPaddingBottom();

                    float right = lm.getDecoratedRight(child) + child.getTranslationX() - size - child.getPaddingRight();
                    float left = lm.getDecoratedLeft(child) + child.getTranslationX() + size + child.getPaddingLeft();
                    c.drawRect(left, top, right, bottom, paint);
                    i = j - 1;
                    break;
                }
            }
        }
    }
}

public boolean isHeader(View child, RecyclerView parent) {
    int viewType = parent.getLayoutManager().getItemViewType(child);
    return viewType == R.layout.layout_header;
}

我正在使用 View 类型查找组的开始和结束位置，并在开始和结束位置周围绘制一个矩形。

代码可在 my github repo 获得