Android 使用GridLayoutManager在RecyclerView中拖放项目
我想要达到的目标: 有一个带有GridLayoutManager的RecyclerView,它支持拖放,并在拖动时重新排列项目 旁注:第一次用拖放开发任何东西 关于如何使用ListView实现此功能,有很多主题,例如: 然而,这些示例通常有很多代码,创建拖动视图的位图,感觉使用Android 使用GridLayoutManager在RecyclerView中拖放项目,android,drag-and-drop,android-recyclerview,gridlayoutmanager,Android,Drag And Drop,Android Recyclerview,Gridlayoutmanager,我想要达到的目标: 有一个带有GridLayoutManager的RecyclerView,它支持拖放,并在拖动时重新排列项目 旁注:第一次用拖放开发任何东西 关于如何使用ListView实现此功能,有很多主题,例如: 然而,这些示例通常有很多代码,创建拖动视图的位图,感觉使用view.startDrag(…)和带有notifyItemAdded(),notifyItemMoved()和notifyItemRemoved()的RecycleView应该可以获得相同的结果因为它们提供了重新排列动画
view.startDrag(…)
和带有notifyItemAdded()
,notifyItemMoved()
和notifyItemRemoved()的RecycleView应该可以获得相同的结果
因为它们提供了重新排列动画
因此,我玩了一些游戏,得出了以下结论:
final CardAdapter adapter = new CardAdapter(list);
adapter.setHasStableIds(true);
adapter.setListener(new CardAdapter.OnLongClickListener() {
@Override
public void onLongClick(View view) {
ClipData data = ClipData.newPlainText("","");
View.DragShadowBuilder builder = new View.DragShadowBuilder(view);
final int pos = mRecyclerView.getChildAdapterPosition(view);
final Goal item = list.remove(pos);
mRecyclerView.setOnDragListener(new View.OnDragListener() {
int prevPos = pos;
@Override
public boolean onDrag(View view, DragEvent dragEvent) {
final int action = dragEvent.getAction();
switch(action) {
case DragEvent.ACTION_DRAG_LOCATION:
View onTopOf = mRecyclerView.findChildViewUnder(dragEvent.getX(), dragEvent.getY());
int i = mRecyclerView.getChildAdapterPosition(onTopOf);
list.add(i, list.remove(prevPos));
adapter.notifyItemMoved(prevPos, i);
prevPos = i;
break;
case DragEvent.ACTION_DROP:
View underView = mRecyclerView.findChildViewUnder(dragEvent.getX(), dragEvent.getY());
int underPos = mRecyclerView.getChildAdapterPosition(underView);
list.add(underPos, item);
adapter.notifyItemInserted(underPos);
adapter.notifyDataSetChanged();
break;
}
return true;
}
});
view.startDrag(data, builder, view, 0);
}
});
mRecyclerView.setAdapter(adapter);
这段代码是一种工作,我得到了交换,但非常不稳定/不稳定,有时当它刷新整个网格时,会重新排列到原始顺序或随机的位置。无论如何,上面的代码只是我的第一次快速尝试,我真正感兴趣的是,是否有一些标准/最佳实践方法可以使用ReyclerView进行拖放操作,或者正确的解决方法是否仍然与ListView多年来使用的方法相同?实际上有更好的方法来实现这一点。您可以使用一些
RecyclerView
的“伴生”类:
,即
一个实用程序类,用于向RecyclerView添加swipe以关闭和拖放支持
还有它的
ItemTouchHelper与应用程序之间的合同
有关更多详细信息,请查看他们的文档。这是我的数据库重新排序解决方案:
ItemTouchHelper.SimpleCallback simpleItemTouchCallback = new ItemTouchHelper.SimpleCallback(ItemTouchHelper.UP | ItemTouchHelper.DOWN, ItemTouchHelper.LEFT | ItemTouchHelper.RIGHT) {
@Override
public boolean onMove(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, RecyclerView.ViewHolder target) {
final int fromPosition = viewHolder.getAdapterPosition();
final int toPosition = target.getAdapterPosition();
if (fromPosition < toPosition) {
for (int i = fromPosition; i < toPosition; i++) {
Collections.swap(mAdapter.getCapitolos(), i, i + 1);
}
} else {
for (int i = fromPosition; i > toPosition; i--) {
Collections.swap(mAdapter.getCapitolos(), i, i - 1);
}
}
mAdapter.notifyItemMoved(fromPosition, toPosition);
return true;
}
@Override
public void onSwiped(RecyclerView.ViewHolder viewHolder, int swipeDir) {
MyViewHolder svH = (MyViewHolder ) viewHolder;
int index = mAdapter.getCapitolos().indexOf(svH.currentItem);
mAdapter.getCapitolos().remove(svH.currentItem);
mAdapter.notifyItemRemoved(index);
if (emptyView != null) {
if (mAdapter.getCapitolos().size() > 0) {
emptyView.setVisibility(TextView.GONE);
} else {
emptyView.setVisibility(TextView.VISIBLE);
}
}
}
@Override
public void clearView(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) {
super.clearView(recyclerView, viewHolder);
reorderData();
}
};
ItemTouchHelper itemTouchHelper = new ItemTouchHelper(simpleItemTouchCallback);
itemTouchHelper.attachToRecyclerView(recList);
ItemTouchHelper.SimpleCallback simpleItemTouchCallback=新建ItemTouchHelper.SimpleCallback(ItemTouchHelper.UP | ItemTouchHelper.DOWN,ItemTouchHelper.LEFT | ItemTouchHelper.RIGHT){
@凌驾
公共布尔onMove(RecyclerView RecyclerView、RecyclerView.ViewHolder ViewHolder、RecyclerView.ViewHolder目标){
final int fromPosition=viewHolder.getAdapterPosition();
final int-toPosition=target.getAdapterPosition();
如果(从位置<位置){
for(inti=fromPosition;itoPosition;i--){
swap(mAdapter.getCapitolos(),i,i-1);
}
}
mAdapter.notifyItemMoved(从位置、位置);
返回true;
}
@凌驾
公共空间(RecyclerView.ViewHolder ViewHolder,int swipeDir){
MyViewHolder svH=(MyViewHolder)viewHolder;
int index=mAdapter.getCapitolos().indexOf(svH.currentItem);
mAdapter.getCapitolos().remove(svH.currentItem);
mAdapter.notifyItemRemoved(索引);
if(emptyView!=null){
如果(mAdapter.getCapitolos().size()>0){
emptyView.setVisibility(TextView.GONE);
}否则{
emptyView.setVisibility(TextView.VISIBLE);
}
}
}
@凌驾
公共无效clearView(RecyclerView RecyclerView,RecyclerView.ViewHolder视图持有人){
super.clearView(recyclerView,viewHolder);
reorderData();
}
};
ItemTouchHelper ItemTouchHelper=新的ItemTouchHelper(simpleItemTouchCallback);
itemTouchHelper.attachToRecyclerView(重新列表);
有一个支持函数可以使用AsyncTask:
private void reorderData() {
AsyncTask<String, Void, Spanned> task = new AsyncTask<String, Void, Spanned>() {
@Override
protected Spanned doInBackground(String... strings) {
dbService.deleteAllData();
for (int i = mAdapter.getCapitolos().size() - 1; i >= 0; i--) {
Segnalibro s = mAdapter.getCapitolos().get(i);
dbService.saveData(s.getIdCapitolo(), s.getVersetto());
}
return null;
}
@Override
protected void onPostExecute(Spanned spanned) {
}
};
task.execute();
}
private void reorderData(){
AsyncTask任务=新建AsyncTask(){
@凌驾
受保护的跨距doInBackground(字符串…字符串){
dbService.deleteAllData();
对于(int i=mAdapter.getCapitolos().size()-1;i>=0;i--){
segnalibros=mAdapter.getCapitolos().get(i);
saveData(s.getIdCapitolo(),s.getVersetto());
}
返回null;
}
@凌驾
受保护的void onPostExecute(已跨越){
}
};
task.execute();
}
我发现这很有用。看一看 在这里,我在Kotlin()中制作了一个完整的示例,如果您愿意,可以启用swipe来消除它。下面是它的全部代码:
build.gradle
implementation 'androidx.appcompat:appcompat:1.1.0-rc01'
implementation 'androidx.core:core-ktx:1.2.0-alpha02'
implementation 'androidx.constraintlayout:constraintlayout:2.0.0-beta2'
implementation 'com.google.android.material:material:1.1.0-alpha08'
implementation 'androidx.recyclerview:recyclerview:1.1.0-beta01'
grid\u item.xml
<TextView
android:id="@+id/textView" xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent" android:layout_height="100dp" android:gravity="center"/>
<androidx.recyclerview.widget.RecyclerView
android:id="@+id/recyclerView" tools:listitem="@layout/grid_item" xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent" android:layout_height="match_parent"
android:orientation="vertical" app:spanCount="3" app:layoutManager="androidx.recyclerview.widget.GridLayoutManager"/>
活动\u main.xml
<TextView
android:id="@+id/textView" xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent" android:layout_height="100dp" android:gravity="center"/>
<androidx.recyclerview.widget.RecyclerView
android:id="@+id/recyclerView" tools:listitem="@layout/grid_item" xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent" android:layout_height="match_parent"
android:orientation="vertical" app:spanCount="3" app:layoutManager="androidx.recyclerview.widget.GridLayoutManager"/>
清单
<manifest package="com.sample.recyclerviewdraganddroptest" xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools">
<application
android:allowBackup="true" android:icon="@mipmap/ic_launcher" android:label="@string/app_name"
android:roundIcon="@mipmap/ic_launcher_round" android:supportsRtl="true"
android:theme="@style/AppTheme.NoActionBar" tools:ignore="AllowBackup,GoogleAppIndexingWarning">
<activity
android:name=".MainActivity" android:label="@string/app_name" android:theme="@style/AppTheme.NoActionBar">
<intent-filter>
<action android:name="android.intent.action.MAIN"/>
<category android:name="android.intent.category.LAUNCHER"/>
</intent-filter>
</activity>
</application>
</manifest>
class MainActivity : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
val items = ArrayList<Int>(100)
for (i in 0 until 100)
items.add(i)
recyclerView.adapter = object : RecyclerView.Adapter<RecyclerView.ViewHolder>() {
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): RecyclerView.ViewHolder {
return object : RecyclerView.ViewHolder(LayoutInflater.from(parent.context).inflate(R.layout.grid_item, parent, false)) {}
}
override fun getItemCount() = items.size
override fun onBindViewHolder(holder: RecyclerView.ViewHolder, position: Int) {
val data = items[position]
holder.itemView.setBackgroundColor(if (data % 2 == 0) 0xffff0000.toInt() else 0xff00ff00.toInt())
holder.itemView.textView.text = "item $data"
}
}
val itemTouchHelper = ItemTouchHelper(object : ItemTouchHelper.Callback() {
override fun isLongPressDragEnabled() = true
override fun isItemViewSwipeEnabled() = false
override fun getMovementFlags(recyclerView: RecyclerView, viewHolder: RecyclerView.ViewHolder): Int {
val dragFlags = ItemTouchHelper.UP or ItemTouchHelper.DOWN or ItemTouchHelper.LEFT or ItemTouchHelper.RIGHT
val swipeFlags = if (isItemViewSwipeEnabled) ItemTouchHelper.START or ItemTouchHelper.END else 0
return makeMovementFlags(dragFlags, swipeFlags)
}
override fun onMove(recyclerView: RecyclerView, viewHolder: RecyclerView.ViewHolder, target: RecyclerView.ViewHolder): Boolean {
if (viewHolder.itemViewType != target.itemViewType)
return false
val fromPosition = viewHolder.adapterPosition
val toPosition = target.adapterPosition
val item = items.removeAt(fromPosition)
items.add(toPosition, item)
recyclerView.adapter!!.notifyItemMoved(fromPosition, toPosition)
return true
}
override fun onSwiped(viewHolder: RecyclerView.ViewHolder, direction: Int) {
val position = viewHolder.adapterPosition
items.remove(position)
recyclerView.adapter!!.notifyItemRemoved(position)
}
})
itemTouchHelper.attachToRecyclerView(recyclerView)
}
}
MainActivity.kt
<manifest package="com.sample.recyclerviewdraganddroptest" xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools">
<application
android:allowBackup="true" android:icon="@mipmap/ic_launcher" android:label="@string/app_name"
android:roundIcon="@mipmap/ic_launcher_round" android:supportsRtl="true"
android:theme="@style/AppTheme.NoActionBar" tools:ignore="AllowBackup,GoogleAppIndexingWarning">
<activity
android:name=".MainActivity" android:label="@string/app_name" android:theme="@style/AppTheme.NoActionBar">
<intent-filter>
<action android:name="android.intent.action.MAIN"/>
<category android:name="android.intent.category.LAUNCHER"/>
</intent-filter>
</activity>
</application>
</manifest>
class MainActivity : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
val items = ArrayList<Int>(100)
for (i in 0 until 100)
items.add(i)
recyclerView.adapter = object : RecyclerView.Adapter<RecyclerView.ViewHolder>() {
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): RecyclerView.ViewHolder {
return object : RecyclerView.ViewHolder(LayoutInflater.from(parent.context).inflate(R.layout.grid_item, parent, false)) {}
}
override fun getItemCount() = items.size
override fun onBindViewHolder(holder: RecyclerView.ViewHolder, position: Int) {
val data = items[position]
holder.itemView.setBackgroundColor(if (data % 2 == 0) 0xffff0000.toInt() else 0xff00ff00.toInt())
holder.itemView.textView.text = "item $data"
}
}
val itemTouchHelper = ItemTouchHelper(object : ItemTouchHelper.Callback() {
override fun isLongPressDragEnabled() = true
override fun isItemViewSwipeEnabled() = false
override fun getMovementFlags(recyclerView: RecyclerView, viewHolder: RecyclerView.ViewHolder): Int {
val dragFlags = ItemTouchHelper.UP or ItemTouchHelper.DOWN or ItemTouchHelper.LEFT or ItemTouchHelper.RIGHT
val swipeFlags = if (isItemViewSwipeEnabled) ItemTouchHelper.START or ItemTouchHelper.END else 0
return makeMovementFlags(dragFlags, swipeFlags)
}
override fun onMove(recyclerView: RecyclerView, viewHolder: RecyclerView.ViewHolder, target: RecyclerView.ViewHolder): Boolean {
if (viewHolder.itemViewType != target.itemViewType)
return false
val fromPosition = viewHolder.adapterPosition
val toPosition = target.adapterPosition
val item = items.removeAt(fromPosition)
items.add(toPosition, item)
recyclerView.adapter!!.notifyItemMoved(fromPosition, toPosition)
return true
}
override fun onSwiped(viewHolder: RecyclerView.ViewHolder, direction: Int) {
val position = viewHolder.adapterPosition
items.remove(position)
recyclerView.adapter!!.notifyItemRemoved(position)
}
})
itemTouchHelper.attachToRecyclerView(recyclerView)
}
}
class MainActivity:AppCompatActivity(){
重写创建时的乐趣(savedInstanceState:Bundle?){
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
val项目=阵列列表(100)
对于(i在0到100之间)
项目.添加(i)
recyclerView.adapter=对象:recyclerView.adapter(){
override fun onCreateViewHolder(父级:ViewGroup,viewType:Int):RecyclerView.ViewHolder{
返回对象:RecyclerView.ViewHolder(LayoutInflater.from(parent.context).inflate(R.layout.grid_item,parent,false)){}
}
重写getItemCount()=items.size
覆盖onBindViewHolder(holder:RecyclerView.ViewHolder,位置:Int){
val数据=项目[位置]
holder.itemView.setBackgroundColor(如果(数据%2==0)0xffff0000.toInt()或0xff00ff00.toInt())
holder.itemView.textView.text=“item$data”
}
}
val itemTouchHelper=itemTouchHelper(对象:itemTouchHelper.Callback(){
override fun isLongPressDragEnabled()=真
override fun IsItemViewSwipEnabled()=false
覆盖f