我正在开发的应用中有一个GridView。我想通过拖放重新排序GridView中的项目。我在ListView上找到了很多帮助,但是在GridView上找不到什么相关的内容。我想实现类似这个启动器应用程序的行为 http://www.youtube.com/watch?v=u5LISE8BU_E&t=5m30s。有任何想法吗?
我正在开发的应用中有一个GridView。我想通过拖放重新排序GridView中的项目。我在ListView上找到了很多帮助,但是在GridView上找不到什么相关的内容。我想实现类似这个启动器应用程序的行为 http://www.youtube.com/watch?v=u5LISE8BU_E&t=5m30s。有任何想法吗?
grid = (GridView) findViewById(R.id.grid);
grid.setAdapter(new DragGridAdapter(items, getActivity()));
....
grid.setOnTouchListener(new View.OnTouchListener() {
@Override
public boolean onTouch(View v, MotionEvent event) {
if (event.getAction() == MotionEvent.ACTION_DOWN) {
GridView parent = (GridView) v;
int x = (int) event.getX();
int y = (int) event.getY();
int position = parent.pointToPosition(x, y);
if (position > AdapterView.INVALID_POSITION) {
int count = parent.getChildCount();
for (int i = 0; i < count; i++) {
View curr = parent.getChildAt(i);
curr.setOnDragListener(new View.OnDragListener() {
@Override
public boolean onDrag(View v, DragEvent event) {
boolean result = true;
int action = event.getAction();
switch (action) {
case DragEvent.ACTION_DRAG_STARTED:
break;
case DragEvent.ACTION_DRAG_LOCATION:
break;
case DragEvent.ACTION_DRAG_ENTERED:
v.setBackgroundResource(R.drawable.shape_image_view_small_gallery_selected);
break;
case DragEvent.ACTION_DRAG_EXITED:
v.setBackgroundResource(R.drawable.shape_image_view_small_gallery_unselected);
break;
case DragEvent.ACTION_DROP:
if (event.getLocalState() == v) {
result = false;
} else {
View droped = (View) event.getLocalState();
GridItem dropItem = ((DragGridItemHolder) droped.getTag()).item;
GridView parent = (GridView) droped.getParent();
DragGridAdapter adapter = (DragGridAdapter) parent.getAdapter();
List<GridItem> items = adapter.getItems();
View target = v;
GridItem targetItem = ((DragGridItemHolder) target.getTag()).item;
int index = items.indexOf(targetItem);
items.remove(dropItem);
items.add(index, dropItem);
adapter.notifyDataSetChanged();
}
break;
case DragEvent.ACTION_DRAG_ENDED:
v.setBackgroundResource(R.drawable.shape_image_view_small_gallery_unselected);
break;
default:
result = false;
break;
}
return result;
}
});
}
int relativePosition = position - parent.getFirstVisiblePosition();
View target = (View) parent.getChildAt(relativePosition);
DragGridItemHolder holder = (DragGridItemHolder) target.getTag();
GridItem currentItem = holder.item;
String text = currentItem.getFile().getAbsolutePath();
ClipData data = ClipData.newPlainText("DragData", text);
target.startDrag(data, new View.DragShadowBuilder(target), target, 0);
}
}
return false;
和DragGridAdapter
public class DragGridAdapter extends BaseAdapter{
private Context context;
private List<GridItem> items;
public DragGridAdapter(List<GridItem> items, Context context){
this.context = context;
this.items = items;
}
@Override
public int getCount() {
return items.size();
}
@Override
public Object getItem(int position) {
return items.get(position);
}
@Override
public long getItemId(int position) {
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
DragGridItemHolder holder;
if (convertView == null) {
holder = new DragGridItemHolder();
ImageView img = new ImageView(context);
holder.image = img;
convertView = img;
convertView.setTag(holder);
} else {
holder = (DragGridItemHolder) convertView.getTag();
}
holder.item = items.get(position);
holder.image.setImageBitmap(items.get(position).getBitmap());
return convertView;
}
public List<GridItem> getItems() {
return items;
}
我希望这对你有所帮助
我对拖放网格视图的版本进行了改进,Github链接:https://github.com/askerov/DynamicGrid。
它扩展了原始GridView,支持拖放以重新排序项目,在拖动到屏幕外时自动滚动。它在3.0+ API上完全可用,但在2.2和2.3上有限制(没有动画效果)。
看一下thquinn的DraggableGridView,这是针对Android 2.2(API级别8)开发的。 希望能对某些人有所帮助 :)
public class DragableLinearLayout extends LinearLayout {
public DragableLinearLayout(Context context, AttributeSet attrs,
int defStyle) {
super(context, attrs, defStyle);
}
public DragableLinearLayout(Context context, AttributeSet attrs) {
super(context, attrs);
}
public DragableLinearLayout(Context context) {
super(context);
}
@Override
public boolean onDragEvent(DragEvent event) {
//in wich grid item am I?
GridView parent = (GridView) getParent();
Object item = parent.getAdapter().getItem(
parent.getPositionForView(this));
//if you need the database id of your item...
Cursor cur = (Cursor) item;
long l_id = cur.getLong(cur.getColumnIndex("youritemid"));
switch (event.getAction()) {
case DragEvent.ACTION_DRAG_STARTED:
return true;
case DragEvent.ACTION_DRAG_ENTERED:
setBackgroundColor(Color.GREEN);
invalidate();
return true;
case DragEvent.ACTION_DRAG_EXITED:
setBackgroundColor(Color.WHITE);
invalidate();
return false;
case DragEvent.ACTION_DROP:
ClipData cd = event.getClipData();
long l_id_start = Long.valueOf(cd.getItemAt(0).getText()
.toString());
//
Toast.makeText(getContext(), "DROP FROM " + l_id_start
+ " TO " + l_id, Toast.LENGTH_LONG);
//do your stuff
........
//the db requery will be on the onDragEvent.drop of the container
//see the listener
return false;
case DragEvent.ACTION_DRAG_ENDED:
setBackgroundColor(Color.WHITE);
invalidate();
//
return false;
}
return true;
}
}
private View.OnDragListener listenerOnDragEvent = new View.OnDragListener() {
public boolean onDrag(View v, DragEvent event) {
// Defines a variable to store the action type for the incoming
// event
final int action = event.getAction();
switch (action) {
case DragEvent.ACTION_DROP:
// REQUERY
updateDbView();
return false;
// break;
}
return true;
}
};
可能 PagedDragDropGrid 项目是您需要的:https://github.com/mrKlar/PagedDragDropGrid
它提供了自定义的 ViewGroup
(类似于 GridView),具有平滑重新排序的功能(与您视频中的完全相同)。可能需要进行一些自定义,但这是值得的。
希望能对您有所帮助。
最近我发现了一个解决方案,它的作者在这里花费了相当长的时间 http://blahti.wordpress.com/2012/03/03/improved-drag-drop-for-gridview/。之前有4篇相关的博客文章更详细地解释了其中的原理。