我想实现一个布局，我可以拖动图像并将其拖放到另一个类似于android启动器的屏幕，我们可以将应用程序图标放在一组水平滚动的屏幕上。我不知道如何开始和从哪里开始。我正在考虑实现一个比屏幕大的布局，然后在用户触摸图像时立即开始自动滚动。丢弃图像的位置将被修复。任何参考或更好的方法来实现这个？
答案 0 :(得分：0)
注意：我假设您正在使用gridView.setOnItemLongClickListener()用于startDrag（）等。请在Android网站上提及。
答案 1 :(得分：0)
我刚刚写了这个:(它暂时工作）
只在ViewPager上添加addLragListener。您不需要在gridviews上添加DragListener。
获取Drop在目标网格上的位置。
跟踪源GridView和Target Gridview并使用它来获取其适配器。
然后在适配器之间操作Drop。
public void setDragListener() {
pager = getViewPager();
dragListener = new View.OnDragListener() {
GridViewAdapter sourceAdapter = null;
GridViewAdapter targetAdapter = null;
int currentOffset = 0;
@Override
public boolean onDrag(View v, DragEvent event) {
int currentX = -1;
int currentY = -1;
switch (event.getAction()) {
case DragEvent.ACTION_DRAG_STARTED:
if (!pager.isFakeDragging()) {
pager.beginFakeDrag();
}
break;
case DragEvent.ACTION_DRAG_ENTERED:
pager.setCurrentItem(pager.getCurrentItem());
currentOffset = (int) (event.getX());
if (!pager.isFakeDragging()) {
pager.beginFakeDrag();
}
break;
case DragEvent.ACTION_DRAG_EXITED:
break;
case DragEvent.ACTION_DRAG_LOCATION:
if (pager != null) {
if (!pager.isFakeDragging()) {
pager.beginFakeDrag();
}
if (pager.isFakeDragging()) {
int maxWidth = pager.getWidth() * pager.getCount();
int offset = (int) (event.getX());
int scrollX = getScrollX();
int dragBy = (int) -1 * (offset - currentOffset);
currentOffset = offset;
pager.fakeDragBy(dragBy * pager.getCount());
int scrolledPage = (int) (offset + scrollX) / pager.getWidth();
if (pager.getCurrentItem() != scrolledPage) {
pager.setCurrentItem(Math.abs(scrolledPage));
}
}
}
break;
case DragEvent.ACTION_DRAG_ENDED:
if (pager.isFakeDragging()) {
pager.endFakeDrag();
}
break;
case DragEvent.ACTION_DROP:
if (pager.isFakeDragging()) {
pager.endFakeDrag();
}
currentX = (int) event.getX();
currentY = (int) event.getY();
// u can use meta data and other info which u passed when longPress
// u can set sourcePage and sourcePosition in meta data.
metaMove = event.getLocalState();
sourceAdapter = // get Source Gridviews adapter
targetAdapter = // get Target GridViews Adapter ie current Page's gridviews adapter.
GridView g = // get The gridview current Page gridview
if (g != null) {
int position = g.pointToPosition(currentX + (getScrollX() - (pager.getWidth() * pager.getCurrentItem())), currentY);
metaMove.targetPosition = position;
metaMove.targetPage = currentPage;
getActivity().runOnUiThread(new Runnable() {
@Override
public void run() {
// u can move from source to target by inset and remove.
// use some broadcast function to reset if page does not have any item left while moving. Ur logic here.
move(sourceAdapter, targetAdapter, metaMove);
}
});
}
break;
default:
break;
}
return true;
}
};
pager.setOnDragListener(dragListener);
}
public int getScrollX() {
int maxWidth = pager.getWidth() * pager.getCount();
int scrollX = pager.getScrollX();
if (pager.getScrollX() < 0) {
scrollX = maxWidth + scrollX - pager.getWidth();
} else if (pager.getScrollX() == 0) {
if (pager.getCurrentItem() == (pager.getCount() - 1)) {
scrollX = maxWidth + scrollX - pager.getWidth();
}
}
return scrollX;
}
Use following onLongPress on your sourceGrid:
metaMove.sourcePage = // sourcePage;
metaMove.sourcePosition = position;
metaMove.targetPosition = -1; // to be set on drop
metaMove.targetPage = -1 // to be set on drop;
boolean dragStarted = view.startDrag(null,
myShadow,
metaMove,
0
);
public void setDragListener() {
pager = getViewPager();
dragListener = new View.OnDragListener() {
GridViewAdapter sourceAdapter = null;
GridViewAdapter targetAdapter = null;
int currentOffset = 0;
@Override
public boolean onDrag(View v, DragEvent event) {
int currentX = -1;
int currentY = -1;
switch (event.getAction()) {
case DragEvent.ACTION_DRAG_STARTED:
if (!pager.isFakeDragging()) {
pager.beginFakeDrag();
}
break;
case DragEvent.ACTION_DRAG_ENTERED:
pager.setCurrentItem(pager.getCurrentItem());
currentOffset = (int) (event.getX());
if (!pager.isFakeDragging()) {
pager.beginFakeDrag();
}
break;
case DragEvent.ACTION_DRAG_EXITED:
break;
case DragEvent.ACTION_DRAG_LOCATION:
if (pager != null) {
if (!pager.isFakeDragging()) {
pager.beginFakeDrag();
}
if (pager.isFakeDragging()) {
int maxWidth = pager.getWidth() * pager.getCount();
int offset = (int) (event.getX());
int scrollX = getScrollX();
int dragBy = (int) -1 * (offset - currentOffset);
currentOffset = offset;
pager.fakeDragBy(dragBy * pager.getCount());
int scrolledPage = (int) (offset + scrollX) / pager.getWidth();
if (pager.getCurrentItem() != scrolledPage) {
pager.setCurrentItem(Math.abs(scrolledPage));
}
}
}
break;
case DragEvent.ACTION_DRAG_ENDED:
if (pager.isFakeDragging()) {
pager.endFakeDrag();
}
break;
case DragEvent.ACTION_DROP:
if (pager.isFakeDragging()) {
pager.endFakeDrag();
}
currentX = (int) event.getX();
currentY = (int) event.getY();
// u can use meta data and other info which u passed when longPress
// u can set sourcePage and sourcePosition in meta data.
metaMove = event.getLocalState();
sourceAdapter = // get Source Gridviews adapter
targetAdapter = // get Target GridViews Adapter ie current Page's gridviews adapter.
GridView g = // get The gridview current Page gridview
if (g != null) {
int position = g.pointToPosition(currentX + (getScrollX() - (pager.getWidth() * pager.getCurrentItem())), currentY);
metaMove.targetPosition = position;
metaMove.targetPage = currentPage;
getActivity().runOnUiThread(new Runnable() {
@Override
public void run() {
// u can move from source to target by inset and remove.
// use some broadcast function to reset if page does not have any item left while moving. Ur logic here.
move(sourceAdapter, targetAdapter, metaMove);
}
});
}
break;
default:
break;
}
return true;
}
};
pager.setOnDragListener(dragListener);
}
public int getScrollX() {
int maxWidth = pager.getWidth() * pager.getCount();
int scrollX = pager.getScrollX();
if (pager.getScrollX() < 0) {
scrollX = maxWidth + scrollX - pager.getWidth();
} else if (pager.getScrollX() == 0) {
if (pager.getCurrentItem() == (pager.getCount() - 1)) {
scrollX = maxWidth + scrollX - pager.getWidth();
}
}
return scrollX;
}