可拖放的回收器视图wrap_content
可拖放的回收器视图wrap_content
提问于 2015-04-07 14:37:35
我正在尝试创建一个待办事项列表，就像"google keep“android应用程序一样。基本上，我需要一个滚动布局与2个列表:一个选中的项目，和一个未选中的项目。未选中的列表应该有一个选项来拖放项目，以便更改它们的位置。我唯一的问题是我不能在recyclerview中使用width=wrap_content，当我尝试拖放时，我发现的layoutManager实现会导致应用程序崩溃。
对于拖放，我使用this library.
我的布局：
<ScrollView
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fillViewport="true"
tools:context="views.fragments.ItemsFragment">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
<AutoCompleteTextView
android:id="@+id/fragment_items_atv_name"
android:layout_width="0dp"
android:layout_weight="1"
android:layout_height="wrap_content" />
<Button
android:id="@+id/fragment_items_btn_add"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:padding="8dp"
android:text="@string/add" />
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<android.support.v7.widget.RecyclerView
android:id="@+id/fragment_items_lv_unchecked_list"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
<android.support.v7.widget.RecyclerView
android:id="@+id/fragment_items_lv_checked_list"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
<TextView
android:id="@+id/fragment_items_tv_empty"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:text="Empty list"
android:visibility="gone" />
</LinearLayout>
</LinearLayout>
</ScrollView>我使用的布局管理器
public class MyLinearLayoutManager extends LinearLayoutManager {
public MyLinearLayoutManager(Context context) {
super(context, VERTICAL, false);
}
private int[] mMeasuredDimension = new int[2];
@Override
public void onMeasure(RecyclerView.Recycler recycler, RecyclerView.State state,
int widthSpec, int heightSpec) {
final int widthMode = View.MeasureSpec.getMode(widthSpec);
final int heightMode = View.MeasureSpec.getMode(heightSpec);
final int widthSize = View.MeasureSpec.getSize(widthSpec);
final int heightSize = View.MeasureSpec.getSize(heightSpec);
int width = 0;
int height = 0;
for (int i = 0; i < getItemCount(); i++) {
measureScrapChild(recycler, i,
View.MeasureSpec.makeMeasureSpec(i, View.MeasureSpec.UNSPECIFIED),
View.MeasureSpec.makeMeasureSpec(i, View.MeasureSpec.UNSPECIFIED),
mMeasuredDimension);
if (getOrientation() == HORIZONTAL) {
width = width + mMeasuredDimension[0];
if (i == 0) {
height = mMeasuredDimension[1];
}
} else {
height = height + mMeasuredDimension[1];
if (i == 0) {
width = mMeasuredDimension[0];
}
}
}
switch (widthMode) {
case View.MeasureSpec.EXACTLY:
width = widthSize;
case View.MeasureSpec.AT_MOST:
case View.MeasureSpec.UNSPECIFIED:
}
switch (heightMode) {
case View.MeasureSpec.EXACTLY:
height = heightSize;
case View.MeasureSpec.AT_MOST:
case View.MeasureSpec.UNSPECIFIED:
}
setMeasuredDimension(width, height);
}
private void measureScrapChild(RecyclerView.Recycler recycler, int position, int widthSpec,
int heightSpec, int[] measuredDimension) {
View view = recycler.getViewForPosition(position);
if (view != null) {
RecyclerView.LayoutParams p = (RecyclerView.LayoutParams) view.getLayoutParams();
int childWidthSpec = ViewGroup.getChildMeasureSpec(widthSpec,
getPaddingLeft() + getPaddingRight(), p.width);
int childHeightSpec = ViewGroup.getChildMeasureSpec(heightSpec,
getPaddingTop() + getPaddingBottom(), p.height);
view.measure(childWidthSpec, childHeightSpec);
measuredDimension[0] = view.getMeasuredWidth() + p.leftMargin + p.rightMargin;
measuredDimension[1] = view.getMeasuredHeight() + p.bottomMargin + p.topMargin;
recycler.recycleView(view);
}
}
}回答 1
Stack Overflow用户
发布于 2016-03-21 17:16:30
您可以在supportv7中使用ItemTouchHelper，并实现简单的回调，如下所示：
mSimpleCallback = new ItemTouchHelper.SimpleCallback(
ItemTouchHelper.LEFT|ItemTouchHelper.RIGHT|ItemTouchHelper.UP|ItemTouchHelper.DOWN, 0) {
@Override
public boolean onMove(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, RecyclerView.ViewHolder target) {
int fromPosition = viewHolder.getAdapterPosition();//得到拖动ViewHolder的position
int toPosition = target.getAdapterPosition();//得到目标ViewHolder的position
List<NHUser.DescriptionEntity> datas = mItemAdapter.getData();
if (fromPosition < toPosition) {
//分别把中间所有的item的位置重新交换
for (int i = fromPosition; i < toPosition; i++) {
Collections.swap(datas, i, i + 1);
}
} else {
for (int i = fromPosition; i > toPosition; i--) {
Collections.swap(datas, i, i - 1);
}
}
mItemAdapter.notifyItemMoved(fromPosition, toPosition);
return true;
}
@Override
public void onSwiped(RecyclerView.ViewHolder viewHolder, int direction) {
}
};页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/29485306
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