Android 使用基于领域的适配器进行RecyclerView拖放
我是Android新手,但在阅读了一些教程后,我成功地编写了一个简单的应用程序,通过扩展Android 使用基于领域的适配器进行RecyclerView拖放,android,android-recyclerview,realm,Android,Android Recyclerview,Realm,我是Android新手,但在阅读了一些教程后,我成功地编写了一个简单的应用程序,通过扩展realmrecyclererviewadapter,使用recyclererview和领域数据 我知道默认的动画师需要稳定的id,所以我为我的实体添加了一个唯一的id。除了拖放之外,所有操作似乎都很正常(滑动以删除、添加、所有领域操作)。嗯,这意味着数据和ui保持一致,但动画看起来很奇怪,我只能将项目向下移动一个位置。 一幅画抵得上千言万语,所以它就在这里: 我想我还需要粘贴代码。我尽量把它缩短 publ
realmrecyclererviewadapter
,使用recyclererview
和领域数据
我知道默认的动画师需要稳定的id,所以我为我的实体添加了一个唯一的id。除了拖放之外,所有操作似乎都很正常(滑动以删除、添加、所有领域操作)。嗯,这意味着数据和ui保持一致,但动画看起来很奇怪,我只能将项目向下移动一个位置。一幅画抵得上千言万语,所以它就在这里:
我想我还需要粘贴代码。我尽量把它缩短
public class MainActivity extends AppCompatActivity implements OnStartDragListener {
private ItemTouchHelper touchHelper;
private Realm realm;
private TestRecyclerViewAdapter adapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
// Irrelevant init stuff stripped
RecyclerView recyclerView = (RecyclerView) findViewById(R.id.recycler_view);
recyclerView.setHasFixedSize(true);
recyclerView.setLayoutManager(new LinearLayoutManager(this));
recyclerView.addItemDecoration(new DividerItemDecoration(this, DividerItemDecoration.VERTICAL));
adapter = new TestRecyclerViewAdapter(this, realm.where(Item.class)
.findAll()
.sort(Item.INDEX));
recyclerView.setAdapter(adapter);
ItemTouchHelper.Callback callback = new ItemTouchHelperCallback(adapter);
touchHelper = new ItemTouchHelper(callback);
touchHelper.attachToRecyclerView(recyclerView);
}
@Override
public void onStartDrag(RecyclerView.ViewHolder viewHolder) {
touchHelper.startDrag(viewHolder);
}
// not sure how this method should be implemented
public void moveItem(Item item, final int fromPosition, final int toPosition) {
final int index = item.index;
realm.executeTransaction(new Realm.Transaction() {
@Override
public void execute(Realm realm) {
Item item = realm.where(Item.class).equalTo(Item.INDEX, index).findFirst();
if (fromPosition < toPosition) {
RealmResults<Item> results = realm.where(Item.class)
.greaterThan(Item.INDEX, fromPosition)
.lessThanOrEqualTo(Item.INDEX, toPosition)
.findAll();
for (int i = 0; i < results.size(); i++) {
results.get(i).index -= 1;
}
} else {
RealmResults<Item> results = realm.where(Item.class)
.greaterThanOrEqualTo(Item.INDEX, toPosition)
.lessThan(Item.INDEX, fromPosition)
.findAll();
for (int i = 0; i < results.size(); i++) {
results.get(i).index += 1;
}
}
item.index = toPosition;
}
});
}
@Override
protected void onDestroy() {
super.onDestroy();
realm.close();
}
}
我为发布这么多的代码感到内疚…您的问题源于这样一个事实,即
RealmRecyclServiceAdapter
注册了一个RealmChangeListener
,它调用适配器.notifyDataSetChanged()
,它覆盖了所有RecyclerView动画
一种可能的解决方法是使用常规的RecycleServiceAdapter,当您使用UI线程事务处理领域的元素时,您可以
类TestRecycleServiceAdapter扩展了RecycleView.Adapter{
@凌驾
公共布尔onItemMove(int-fromPosition,int-toPosition){
activity.moveItem(getData().get(fromPosition)、fromPosition、TopoPosition);//我接受了你的建议,但我做的有点不同。我使用了常规的
RecycleServiceAdapter
并将领域操作移到了适配器上,到目前为止,它还在工作。
public class Item extends RealmObject {
public static final String INDEX = "index";
public static final String TEXT = "text";
public static final String ID = "id";
@PrimaryKey
public long id;
@Index
public int index;
public String text;
}
interface OnStartDragListener {
void onStartDrag(RecyclerView.ViewHolder viewHolder);
}
class TestRecyclerViewAdapter extends RealmRecyclerViewAdapter<Item,
TestRecyclerViewAdapter.EditInfoViewHolder> implements ItemTouchHelperAdapter {
private final static String TAG = TestRecyclerViewAdapter.class.getName();
private final MainActivity activity;
public TestRecyclerViewAdapter(@NonNull MainActivity activity, @Nullable
OrderedRealmCollection<Item> data) {
super(activity, data, true);
this.activity = activity;
setHasStableIds(true);
}
@Override
public long getItemId(int index) {
return getData().get(index).id;
}
@Override
public EditInfoViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = inflater.inflate(R.layout.item, parent, false);
return new EditInfoViewHolder(view);
}
@Override
public void onBindViewHolder(final EditInfoViewHolder holder, int position) {
Item obj = getData().get(position);
holder.data = obj;
holder.text.setText(obj.text);
holder.handle.setOnTouchListener(new View.OnTouchListener() {
@Override
public boolean onTouch(View v, MotionEvent event) {
if (MotionEventCompat.getActionMasked(event) == MotionEvent.ACTION_DOWN) {
activity.onStartDrag(holder);
}
return false;
}
});
}
@Override
public boolean onItemMove(int fromPosition, int toPosition) {
activity.moveItem(getData().get(fromPosition), fromPosition, toPosition);
notifyItemMoved(fromPosition, toPosition);
return true;
}
class EditInfoViewHolder extends RecyclerView.ViewHolder {
final TextView text;
final ImageView handle;
public Item data;
public EditInfoViewHolder(View itemView) {
super(itemView);
text = (TextView) itemView.findViewById(R.id.text);
handle = (ImageView) itemView.findViewById(R.id.handle);
}
}
}
interface ItemTouchHelperAdapter {
boolean onItemMove(int fromPosition, int toPosition);
}
class ItemTouchHelperCallback extends ItemTouchHelper.Callback {
private final ItemTouchHelperAdapter adapter;
public ItemTouchHelperCallback(ItemTouchHelperAdapter adapter) {
this.adapter = adapter;
}
@Override
public boolean isItemViewSwipeEnabled() {
return true;
}
@Override
public boolean isLongPressDragEnabled() {
return false;
}
@Override
public int getMovementFlags(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) {
int dragFlags = ItemTouchHelper.UP | ItemTouchHelper.DOWN;
int swipeFlags = 0;
return makeMovementFlags(dragFlags, swipeFlags);
}
@Override
public boolean onMove(RecyclerView recyclerView, RecyclerView.ViewHolder source, RecyclerView.ViewHolder target) {
if (source.getItemViewType() != target.getItemViewType()) {
return false;
}
adapter.onItemMove(source.getAdapterPosition(), target.getAdapterPosition());
return true;
}
@Override
public void onSwiped(RecyclerView.ViewHolder viewHolder, int direction) {
}
}
class TestRecyclerViewAdapter extends RecyclerView.Adapter<...> {
@Override
public boolean onItemMove(int fromPosition, int toPosition) {
activity.moveItem(getData().get(fromPosition), fromPosition, toPosition); // <-- refresh in there
notifyItemMoved(fromPosition, toPosition);
return true;
}
public void moveItem(Item item, final int fromPosition, final int toPosition) {
final int index = item.index;
realm.executeTransaction(new Realm.Transaction() {
@Override
public void execute(Realm realm) {
Item item = realm.where(Item.class).equalTo(Item.INDEX, index).findFirst();
if (fromPosition < toPosition) {
RealmResults<Item> results = realm.where(Item.class)
.greaterThan(Item.INDEX, fromPosition)
.lessThanOrEqualTo(Item.INDEX, toPosition)
.findAll();
for (int i = 0; i < results.size(); i++) {
results.get(i).index -= 1;
}
} else {
RealmResults<Item> results = realm.where(Item.class)
.greaterThanOrEqualTo(Item.INDEX, toPosition)
.lessThan(Item.INDEX, fromPosition)
.findAll();
for (int i = 0; i < results.size(); i++) {
results.get(i).index += 1;
}
}
item.index = toPosition;
}
});
RealmRefresh.refreshRealm(realm);
}