将 Listview 项目拖放到另一个项目中
Drag drop Listview item into another item
我有一个包含不同项目类型的列表视图：header，文件夹和文件如下：
现在我想实现拖动文件项并将其放入文件夹项并获取源和目标 position.I不想像某些拖动排序那样在拖动时更改目标位置（重新排列）列表视图库。
有什么建议可以入手吗？
将您的 ListView 切换为 RecyclerView 将使事情变得容易得多。
您可以在 Styling Android and the whole code here.
上找到整篇文章
此代码使用 OnItemTouchListener 来检测何时应拖动项目。在 RecyclerView 上方有一个 ImageView，其中包含正在移动的项目图像以廉价地对其进行动画处理。
OnItemTouckListener (DragController.java):
public class DragController implements RecyclerView.OnItemTouchListener {
private RecyclerView recyclerView;
private ImageView overlay;
private final GestureDetectorCompat gestureDetector;
private boolean isDragging = false;
public DragController(RecyclerView recyclerView, ImageView overlay) {
this.recyclerView = recyclerView;
this.overlay = overlay;
GestureDetector.SimpleOnGestureListener longClickGestureListener = new GestureDetector.SimpleOnGestureListener() {
@Override
public void onLongPress(MotionEvent e) {
super.onLongPress(e);
isDragging = true;
dragStart(e.getX(), e.getY());
}
};
this.gestureDetector = new GestureDetectorCompat(recyclerView.getContext(), longClickGestureListener);
}
@Override
public boolean onInterceptTouchEvent(RecyclerView rv, MotionEvent e) {
if (isDragging) {
return true;
}
gestureDetector.onTouchEvent(e);
return false;
}
@Override
public void onTouchEvent(RecyclerView rv, MotionEvent e) {
int x = (int) e.getX();
int y = (int) e.getY();
View view = recyclerView.findChildViewUnder(x, y);
if (e.getAction() == MotionEvent.ACTION_UP) {
dragEnd(view);
isDragging = false;
} else {
drag(y, view);
}
}
开始和结束拖动（DragController.java）：
private boolean isFirst = true;
private static final int ANIMATION_DURATION = 100;
private int draggingItem = -1;
private float startY = 0f;
private Rect startBounds = null;
private void dragStart(float x, float y) {
View draggingView = recyclerView.findChildViewUnder(x, y);
View first = recyclerView.getChildAt(0);
isFirst = draggingView == first;
startY = (y - draggingView.getTop());
paintViewToOverlay(draggingView);
overlay.setTranslationY(y - startY);
draggingView.setVisibility(View.INVISIBLE);
draggingItem = recyclerView.indexOfChild(draggingView);
startBounds = new Rect(draggingView.getLeft(), draggingView.getTop(), draggingView.getRight(), draggingView.getBottom());
}
private void drag(int y, View view) {
overlay.setTranslationY(y - startY);
}
private void dragEnd(View view) {
overlay.setImageBitmap(null);
view.setVisibility(View.VISIBLE);
view.setTranslationY(overlay.getTranslationY() - view.getTop());
view.animate().translationY(0f).setDuration(ANIMATION_DURATION).start();
}
private void paintViewToOverlay(View view) {
Bitmap bitmap = Bitmap.createBitmap(view.getWidth(), view.getHeight(), Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(bitmap);
view.draw(canvas);
overlay.setImageBitmap(bitmap);
overlay.setTop(0);
}
代码是Mark Allison on StylingAndroid.
写的
编辑：
But I don't know how to get the position of item when dragging is end
答案位于 part 7 样式 Android。
View view = recyclerView.findChildViewUnder(0, y);
And how can I disable drag on Folder and Header item? Just allow dragging File item?
您可以使用多个 ViewType（文件、文件夹和 header）来执行此操作。然后你可以在DragController中使用getItemViewType只对文件开始移动。
使用RecyclerView和ItemTouchHelper.SimpleCallback。
您可以在 activity:
中这样设置
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_list); // Your layout with RecyclerView
RecyclerView itemRecyclerView = findViewById(R.id.itemRecyclerView);
LinearLayoutManager itemLayoutManager = new LinearLayoutManager(this);
itemRecyclerView.setLayoutManager(itemLayoutManager);
itemAdapter = new ItemAdapter(); // Your adapter which extends RecyclerView.Adapter
itemRecyclerView.setAdapter(itemAdapter);
itemRecyclerView.setHasFixedSize(true);
itemDragAndDropCallback = new ItemDragAndDropCallback(this, itemRecyclerView);
// Your class which extends ItemTouchHelper.SimpleCallback
// It will be shown in the next code sample
new ItemTouchHelper(itemDragAndDropCallback)
.attachToRecyclerView(itemRecyclerView);
}
您可以使用 ItemTouchHelper.SimpleCallback 提供的项目拖动的默认功能。
以下class 将演示更改文件夹的背景颜色。项目将被放入该文件夹。
class ItemDragAndDropCallback extends ItemTouchHelper.SimpleCallback {
ItemDragAndDropCallback() {
// Choose drag and swipe directions
// Up and down is chosen for dragging
// Right and left is chosen for swiping
super(ItemTouchHelper.UP | ItemTouchHelper.DOWN, ItemTouchHelper.RIGHT | ItemTouchHelper.LEFT);
}
@Override
public boolean onMove(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, RecyclerView.ViewHolder target) {
// You can reorder items here
// Do nothing in your case
return true;
}
@Override
public void onSwiped(RecyclerView.ViewHolder viewHolder, int direction) {
// You can react for swiping items here
// Do nothing in your case
}
// An item will be dropped into this folder
private View folder;
@Override
public void onSelectedChanged(RecyclerView.ViewHolder viewHolder, int actionState) {
super.onSelectedChanged(viewHolder, actionState);
if (actionState == ItemTouchHelper.ACTION_STATE_DRAG) {
// Here you are notified that the drag operation began
if (folder != null) {
folder.setBackgroundResource(0); // Clear former folder background
}
} else if (actionState == ItemTouchHelper.ACTION_STATE_IDLE) {
// Here you are notified that the last operation ended
if (folder != null) {
// Set folder background to a color indicating
// that an item was dropped into it
folder.setBackgroundColor(
ContextCompat.getColor(
recyclerView.getContext(), android.R.color.holo_green_dark
)
);
}
}
}
@Override
public void onChildDraw(
Canvas c,
RecyclerView recyclerView,
RecyclerView.ViewHolder viewHolder,
float dX,
float dY,
int actionState,
boolean isCurrentlyActive
) {
if (actionState == ItemTouchHelper.ACTION_STATE_DRAG && isCurrentlyActive) {
// Here you are notified that the drag operation is in progress
if (folder != null) {
folder.setBackgroundResource(0); // Clear former folder background
}
float itemActualPosition = viewHolder.itemView.getTop() + dY;
// Find folder under dragged item
for (int i = 0; i < recyclerView.getChildCount(); i++) {
folder = recyclerView.getChildAt(i);
// Exclude dragged item from detection
if (!folder.equals(viewHolder.itemView)) {
// Accept folder which encloses item position
if (folder.getTop() < itemActualPosition && itemActualPosition < folder.getBottom()) {
// Set folder background to a color indicating
// that an item will be dropped into it upon release
folder.setBackgroundColor(
ContextCompat.getColor(
recyclerView.getContext(), android.R.color.holo_green_light
)
);
break;
}
}
}
}
super.onChildDraw(c, recyclerView, viewHolder, dX, dY, actionState, isCurrentlyActive);
}
}
当您将项目拖到文件夹上时，项目下方的文件夹背景将为浅绿色。
当您将项目放入文件夹时，其背景将为深绿色。
我有一个包含不同项目类型的列表视图：header，文件夹和文件如下：
现在我想实现拖动文件项并将其放入文件夹项并获取源和目标 position.I不想像某些拖动排序那样在拖动时更改目标位置（重新排列）列表视图库。
有什么建议可以入手吗？
将您的 ListView 切换为 RecyclerView 将使事情变得容易得多。
您可以在 Styling Android and the whole code here.
上找到整篇文章此代码使用 OnItemTouchListener 来检测何时应拖动项目。在 RecyclerView 上方有一个 ImageView，其中包含正在移动的项目图像以廉价地对其进行动画处理。
OnItemTouckListener (DragController.java):
public class DragController implements RecyclerView.OnItemTouchListener {
private RecyclerView recyclerView;
private ImageView overlay;
private final GestureDetectorCompat gestureDetector;
private boolean isDragging = false;
public DragController(RecyclerView recyclerView, ImageView overlay) {
this.recyclerView = recyclerView;
this.overlay = overlay;
GestureDetector.SimpleOnGestureListener longClickGestureListener = new GestureDetector.SimpleOnGestureListener() {
@Override
public void onLongPress(MotionEvent e) {
super.onLongPress(e);
isDragging = true;
dragStart(e.getX(), e.getY());
}
};
this.gestureDetector = new GestureDetectorCompat(recyclerView.getContext(), longClickGestureListener);
}
@Override
public boolean onInterceptTouchEvent(RecyclerView rv, MotionEvent e) {
if (isDragging) {
return true;
}
gestureDetector.onTouchEvent(e);
return false;
}
@Override
public void onTouchEvent(RecyclerView rv, MotionEvent e) {
int x = (int) e.getX();
int y = (int) e.getY();
View view = recyclerView.findChildViewUnder(x, y);
if (e.getAction() == MotionEvent.ACTION_UP) {
dragEnd(view);
isDragging = false;
} else {
drag(y, view);
}
}
开始和结束拖动（DragController.java）：
private boolean isFirst = true;
private static final int ANIMATION_DURATION = 100;
private int draggingItem = -1;
private float startY = 0f;
private Rect startBounds = null;
private void dragStart(float x, float y) {
View draggingView = recyclerView.findChildViewUnder(x, y);
View first = recyclerView.getChildAt(0);
isFirst = draggingView == first;
startY = (y - draggingView.getTop());
paintViewToOverlay(draggingView);
overlay.setTranslationY(y - startY);
draggingView.setVisibility(View.INVISIBLE);
draggingItem = recyclerView.indexOfChild(draggingView);
startBounds = new Rect(draggingView.getLeft(), draggingView.getTop(), draggingView.getRight(), draggingView.getBottom());
}
private void drag(int y, View view) {
overlay.setTranslationY(y - startY);
}
private void dragEnd(View view) {
overlay.setImageBitmap(null);
view.setVisibility(View.VISIBLE);
view.setTranslationY(overlay.getTranslationY() - view.getTop());
view.animate().translationY(0f).setDuration(ANIMATION_DURATION).start();
}
private void paintViewToOverlay(View view) {
Bitmap bitmap = Bitmap.createBitmap(view.getWidth(), view.getHeight(), Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(bitmap);
view.draw(canvas);
overlay.setImageBitmap(bitmap);
overlay.setTop(0);
}
代码是Mark Allison on StylingAndroid.
写的编辑：
But I don't know how to get the position of item when dragging is end
答案位于 part 7 样式 Android。
View view = recyclerView.findChildViewUnder(0, y);
And how can I disable drag on Folder and Header item? Just allow dragging File item?
您可以使用多个 ViewType（文件、文件夹和 header）来执行此操作。然后你可以在DragController中使用getItemViewType只对文件开始移动。
使用RecyclerView和ItemTouchHelper.SimpleCallback。
您可以在 activity:
中这样设置@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_list); // Your layout with RecyclerView
RecyclerView itemRecyclerView = findViewById(R.id.itemRecyclerView);
LinearLayoutManager itemLayoutManager = new LinearLayoutManager(this);
itemRecyclerView.setLayoutManager(itemLayoutManager);
itemAdapter = new ItemAdapter(); // Your adapter which extends RecyclerView.Adapter
itemRecyclerView.setAdapter(itemAdapter);
itemRecyclerView.setHasFixedSize(true);
itemDragAndDropCallback = new ItemDragAndDropCallback(this, itemRecyclerView);
// Your class which extends ItemTouchHelper.SimpleCallback
// It will be shown in the next code sample
new ItemTouchHelper(itemDragAndDropCallback)
.attachToRecyclerView(itemRecyclerView);
}
您可以使用 ItemTouchHelper.SimpleCallback 提供的项目拖动的默认功能。
以下class 将演示更改文件夹的背景颜色。项目将被放入该文件夹。
class ItemDragAndDropCallback extends ItemTouchHelper.SimpleCallback {
ItemDragAndDropCallback() {
// Choose drag and swipe directions
// Up and down is chosen for dragging
// Right and left is chosen for swiping
super(ItemTouchHelper.UP | ItemTouchHelper.DOWN, ItemTouchHelper.RIGHT | ItemTouchHelper.LEFT);
}
@Override
public boolean onMove(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, RecyclerView.ViewHolder target) {
// You can reorder items here
// Do nothing in your case
return true;
}
@Override
public void onSwiped(RecyclerView.ViewHolder viewHolder, int direction) {
// You can react for swiping items here
// Do nothing in your case
}
// An item will be dropped into this folder
private View folder;
@Override
public void onSelectedChanged(RecyclerView.ViewHolder viewHolder, int actionState) {
super.onSelectedChanged(viewHolder, actionState);
if (actionState == ItemTouchHelper.ACTION_STATE_DRAG) {
// Here you are notified that the drag operation began
if (folder != null) {
folder.setBackgroundResource(0); // Clear former folder background
}
} else if (actionState == ItemTouchHelper.ACTION_STATE_IDLE) {
// Here you are notified that the last operation ended
if (folder != null) {
// Set folder background to a color indicating
// that an item was dropped into it
folder.setBackgroundColor(
ContextCompat.getColor(
recyclerView.getContext(), android.R.color.holo_green_dark
)
);
}
}
}
@Override
public void onChildDraw(
Canvas c,
RecyclerView recyclerView,
RecyclerView.ViewHolder viewHolder,
float dX,
float dY,
int actionState,
boolean isCurrentlyActive
) {
if (actionState == ItemTouchHelper.ACTION_STATE_DRAG && isCurrentlyActive) {
// Here you are notified that the drag operation is in progress
if (folder != null) {
folder.setBackgroundResource(0); // Clear former folder background
}
float itemActualPosition = viewHolder.itemView.getTop() + dY;
// Find folder under dragged item
for (int i = 0; i < recyclerView.getChildCount(); i++) {
folder = recyclerView.getChildAt(i);
// Exclude dragged item from detection
if (!folder.equals(viewHolder.itemView)) {
// Accept folder which encloses item position
if (folder.getTop() < itemActualPosition && itemActualPosition < folder.getBottom()) {
// Set folder background to a color indicating
// that an item will be dropped into it upon release
folder.setBackgroundColor(
ContextCompat.getColor(
recyclerView.getContext(), android.R.color.holo_green_light
)
);
break;
}
}
}
}
super.onChildDraw(c, recyclerView, viewHolder, dX, dY, actionState, isCurrentlyActive);
}
}
当您将项目拖到文件夹上时，项目下方的文件夹背景将为浅绿色。 当您将项目放入文件夹时，其背景将为深绿色。