这是之前在ListView类中使用divider和dividerHeight参数实现的一个例子:

<ListView
    android:id="@+id/activity_home_list_view"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:divider="@android:color/transparent"
    android:dividerHeight="8dp"/>

然而,在RecyclerView类中我没有看到这样的可能性。

<android.support.v7.widget.RecyclerView
    android:id="@+id/activity_home_recycler_view"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:scrollbars="vertical"/>

在这种情况下,是否可以定义边距和/或直接添加自定义分隔符视图到列表项的布局中,或者是否有更好的方法来实现我的目标?


当前回答

从谷歌搜索,添加这个ItemDecoration到你的RecyclerView:

public class DividerItemDecoration extends RecyclerView.ItemDecoration {

    private Drawable mDivider;
    private boolean mShowFirstDivider = false;
    private boolean mShowLastDivider = false;


    public DividerItemDecoration(Context context, AttributeSet attrs) {
        final TypedArray a = context
                .obtainStyledAttributes(attrs, new int[]{android.R.attr.listDivider});
        mDivider = a.getDrawable(0);
        a.recycle();
    }

    public DividerItemDecoration(Context context, AttributeSet attrs, boolean showFirstDivider,
                                 boolean showLastDivider) {
        this(context, attrs);
        mShowFirstDivider = showFirstDivider;
        mShowLastDivider = showLastDivider;
    }

    public DividerItemDecoration(Drawable divider) {
        mDivider = divider;
    }

    public DividerItemDecoration(Drawable divider, boolean showFirstDivider,
                                 boolean showLastDivider) {
        this(divider);
        mShowFirstDivider = showFirstDivider;
        mShowLastDivider = showLastDivider;
    }

    @Override
    public void getItemOffsets(Rect outRect, View view, RecyclerView parent,
                               RecyclerView.State state) {

        super.getItemOffsets(outRect, view, parent, state);
        if (mDivider == null) {
            return;
        }
        if (parent.getChildPosition(view) < 1) {
            return;
        }

        if (getOrientation(parent) == LinearLayoutManager.VERTICAL) {
            outRect.top = mDivider.getIntrinsicHeight();
        } else {
            outRect.left = mDivider.getIntrinsicWidth();
        }
    }

    @Override
    public void onDrawOver(Canvas c, RecyclerView parent, RecyclerView.State state) {
        if (mDivider == null) {
            super.onDrawOver(c, parent, state);
            return;
        }

        // Initialization needed to avoid compiler warning
        int left = 0, right = 0, top = 0, bottom = 0, size;
        int orientation = getOrientation(parent);
        int childCount = parent.getChildCount();

        if (orientation == LinearLayoutManager.VERTICAL) {
            size = mDivider.getIntrinsicHeight();
            left = parent.getPaddingLeft();
            right = parent.getWidth() - parent.getPaddingRight();
        } else { // Horizontal
            size = mDivider.getIntrinsicWidth();
            top = parent.getPaddingTop();
            bottom = parent.getHeight() - parent.getPaddingBottom();
        }

        for (int i = mShowFirstDivider ? 0 : 1; i < childCount; i++) {
            View child = parent.getChildAt(i);
            RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child.getLayoutParams();

            if (orientation == LinearLayoutManager.VERTICAL) {
                top = child.getTop() - params.topMargin;
                bottom = top + size;
            } else { // Horizontal
                left = child.getLeft() - params.leftMargin;
                right = left + size;
            }
            mDivider.setBounds(left, top, right, bottom);
            mDivider.draw(c);
        }

        // Show the last divider
        if (mShowLastDivider && childCount > 0) {
            View child = parent.getChildAt(childCount - 1);
            RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child.getLayoutParams();
            if (orientation == LinearLayoutManager.VERTICAL) {
                top = child.getBottom() + params.bottomMargin;
                bottom = top + size;
            } else { // hHorizontal
                left = child.getRight() + params.rightMargin;
                right = left + size;
            }
            mDivider.setBounds(left, top, right, bottom);
            mDivider.draw(c);
        }
    }

    private int getOrientation(RecyclerView parent) {
        if (parent.getLayoutManager() instanceof LinearLayoutManager) {
            LinearLayoutManager layoutManager = (LinearLayoutManager) parent.getLayoutManager();
            return layoutManager.getOrientation();
        } else {
            throw new IllegalStateException(
                "DividerItemDecoration can only be used with a LinearLayoutManager.");
        }
    }
}

其他回答

如果有人想为spaceBetween, paddingLeft, paddingTop, paddingRight和paddingBottom设置不同的值。

class ItemPaddingDecoration(
    private val spaceBetween: Int,
    private val paddingLeft: Int = spaceBetween,
    private val paddingTop: Int = spaceBetween,
    private val paddingRight: Int = spaceBetween,
    private val paddingBottom: Int = spaceBetween
) : RecyclerView.ItemDecoration() {

    override fun getItemOffsets(outRect: Rect, view: View, parent: RecyclerView, state: RecyclerView.State) {
        val position = parent.getChildAdapterPosition(view)
        val orientation = when (val layoutManager = parent.layoutManager) {
            is LinearLayoutManager -> {
                layoutManager.orientation
            }
            is GridLayoutManager -> {
                layoutManager.orientation
            }
            else -> {
                RecyclerView.HORIZONTAL
            }
        }
        if (orientation == RecyclerView.HORIZONTAL) {
            when {
                position == 0 -> {
                    outRect.set(paddingLeft, paddingTop, spaceBetween, paddingBottom)
                }
                position < parent.adapter!!.itemCount - 1 -> {
                    outRect.set(0, paddingTop, spaceBetween, paddingBottom)
                }
                else -> {
                    outRect.set(0, paddingTop, paddingRight, paddingBottom)
                }
            }
        } else {
            when {
                position == 0 -> {
                    outRect.set(paddingLeft, paddingTop, paddingRight, paddingBottom)
                }
                position < parent.adapter!!.itemCount - 1 -> {
                    outRect.set(paddingLeft, 0, paddingRight, spaceBetween)
                }
                else -> {
                    outRect.set(paddingLeft, 0, paddingRight, paddingBottom)
                }
            }
        }
    }
}

您可以通过编程方式轻松地添加它。

如果你的布局管理器是线性布局,那么你可以使用:

DividerItemDecoration是一个RecyclerView。ItemDecoration即可以 用作LinearLayoutManager项之间的分隔符。它支持 水平方向和垂直方向。

mDividerItemDecoration =
  new DividerItemDecoration(recyclerView.getContext(),
                            mLayoutManager.getOrientation());
recyclerView.addItemDecoration(mDividerItemDecoration);

public class CommonItemSpaceDecoration extends RecyclerView.ItemDecoration {

    private int mSpace = 0;
    private boolean mVerticalOrientation = true;

    public CommonItemSpaceDecoration(int space) {
        this.mSpace = space;
    }

    public CommonItemSpaceDecoration(int space, boolean verticalOrientation) {
        this.mSpace = space;
        this.mVerticalOrientation = verticalOrientation;
    }

    @Override
    public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
        outRect.top = SizeUtils.dp2px(view.getContext(), mSpace);
        if (mVerticalOrientation) {
            if (parent.getChildAdapterPosition(view) == 0) {
                outRect.set(0, SizeUtils.dp2px(view.getContext(), mSpace), 0, SizeUtils.dp2px(view.getContext(), mSpace));
            } else {
                outRect.set(0, 0, 0, SizeUtils.dp2px(view.getContext(), mSpace));
            }
        } else {
            if (parent.getChildAdapterPosition(view) == 0) {
                outRect.set(SizeUtils.dp2px(view.getContext(), mSpace), 0, 0, 0);
            } else {
                outRect.set(SizeUtils.dp2px(view.getContext(), mSpace), 0, SizeUtils.dp2px(view.getContext(), mSpace), 0);
            }
        }
    }
}

这将增加每个项目的顶部和底部(或左右)的空间。然后你可以将它设置为你的recyclerView。

recyclerView.addItemDecoration(new CommonItemSpaceDecoration(16));

文件SizeUtils.java

public class SizeUtils {
    public static int dp2px(Context context, float dpValue) {
        final float scale = context.getResources().getDisplayMetrics().density;
        return (int) (dpValue * scale + 0.5f);
    }
}

实现它自己的RecyclerView版本。ItemDecoration

public class SpacingItemDecoration extends RecyclerView.ItemDecoration {
    private int spacingPx;
    private boolean addStartSpacing;
    private boolean addEndSpacing;

    public SpacingItemDecoration(int spacingPx) {
        this(spacingPx, false, false);
    }

    public SpacingItemDecoration(int spacingPx, boolean addStartSpacing, boolean addEndSpacing) {
        this.spacingPx = spacingPx;
        this.addStartSpacing = addStartSpacing;
        this.addEndSpacing = addEndSpacing;
    }

    @Override
    public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
        super.getItemOffsets(outRect, view, parent, state);
        if (spacingPx <= 0) {
            return;
        }

        if (addStartSpacing && parent.getChildLayoutPosition(view) < 1 || parent.getChildLayoutPosition(view) >= 1) {
            if (getOrientation(parent) == LinearLayoutManager.VERTICAL) {
                outRect.top = spacingPx;
            } else {
                outRect.left = spacingPx;
            }
        }

        if (addEndSpacing && parent.getChildAdapterPosition(view) == getTotalItemCount(parent) - 1) {
            if (getOrientation(parent) == LinearLayoutManager.VERTICAL) {
                outRect.bottom = spacingPx;
            } else {
                outRect.right = spacingPx;
            }
        }
    }

    private int getTotalItemCount(RecyclerView parent) {
        return parent.getAdapter().getItemCount();
    }

    private int getOrientation(RecyclerView parent) {
        if (parent.getLayoutManager() instanceof LinearLayoutManager) {
            return ((LinearLayoutManager) parent.getLayoutManager()).getOrientation();
        } else {
            throw new IllegalStateException("SpacingItemDecoration can only be used with a LinearLayoutManager.");
        }
    }
}

其中一种方法是同时使用cardview和recycler视图。我们可以很容易地添加一个效果,比如分隔线。 示例:使用RecyclerView创建动态列表 另一种方法是将视图作为分隔符添加到回收器视图的list_item_layout中。 <视图 android: id =“@ + id / view1” android: layout_width = " match_parent " android: layout_height = " 1 dp " android:背景= " @color / colorAccent " / >