In this exercise, another OnDragListener (ItemOnDragListener) implemented for rowView of ListView items, such that we can actually drop on ListView items, and insert in the previous position.
MainActivity.java
package com.example.androidimageviewlist;
import java.util.ArrayList;
import java.util.List;
import android.support.v7.app.ActionBarActivity;
import android.text.method.ScrollingMovementMethod;
import android.app.Activity;
import android.content.ClipData;
import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.drawable.Drawable;
import android.os.Bundle;
import android.view.DragEvent;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.DragShadowBuilder;
import android.view.View.OnDragListener;
import android.view.View.OnLongClickListener;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.AdapterView.OnItemLongClickListener;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;
public class MainActivity extends ActionBarActivity {
//items stored in ListView
public class Item {
Drawable ItemDrawable;
String ItemString;
Item(Drawable drawable, String t){
ItemDrawable = drawable;
ItemString = t;
}
}
//objects passed in Drag and Drop operation
class PassObject{
View view;
Item item;
List<Item> srcList;
PassObject(View v, Item i, List<Item> s){
view = v;
item = i;
srcList = s;
}
}
static class ViewHolder {
ImageView icon;
TextView text;
}
public class ItemsListAdapter extends BaseAdapter {
private Context context;
private List<Item> list;
ItemsListAdapter(Context c, List<Item> l){
context = c;
list = l;
}
@Override
public int getCount() {
return list.size();
}
@Override
public Object getItem(int position) {
return list.get(position);
}
@Override
public long getItemId(int position) {
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
View rowView = convertView;
// reuse views
if (rowView == null) {
LayoutInflater inflater = ((Activity) context).getLayoutInflater();
rowView = inflater.inflate(R.layout.row, null);
ViewHolder viewHolder = new ViewHolder();
viewHolder.icon = (ImageView) rowView.findViewById(R.id.rowImageView);
viewHolder.text = (TextView) rowView.findViewById(R.id.rowTextView);
rowView.setTag(viewHolder);
}
ViewHolder holder = (ViewHolder) rowView.getTag();
holder.icon.setImageDrawable(list.get(position).ItemDrawable);
holder.text.setText(list.get(position).ItemString);
rowView.setOnDragListener(new ItemOnDragListener(list.get(position)));
return rowView;
}
public List<Item> getList(){
return list;
}
}
List<Item> items1, items2, items3;
ListView listView1, listView2, listView3;
ItemsListAdapter myItemsListAdapter1, myItemsListAdapter2, myItemsListAdapter3;
LinearLayoutListView area1, area2, area3;
TextView prompt;
//Used to resume original color in drop ended/exited
int resumeColor;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
listView1 = (ListView)findViewById(R.id.listview1);
listView2 = (ListView)findViewById(R.id.listview2);
listView3 = (ListView)findViewById(R.id.listview3);
area1 = (LinearLayoutListView)findViewById(R.id.pane1);
area2 = (LinearLayoutListView)findViewById(R.id.pane2);
area3 = (LinearLayoutListView)findViewById(R.id.pane3);
area1.setOnDragListener(myOnDragListener);
area2.setOnDragListener(myOnDragListener);
area3.setOnDragListener(myOnDragListener);
area1.setListView(listView1);
area2.setListView(listView2);
area3.setListView(listView3);
initItems();
myItemsListAdapter1 = new ItemsListAdapter(this, items1);
myItemsListAdapter2 = new ItemsListAdapter(this, items2);
myItemsListAdapter3 = new ItemsListAdapter(this, items3);
listView1.setAdapter(myItemsListAdapter1);
listView2.setAdapter(myItemsListAdapter2);
listView3.setAdapter(myItemsListAdapter3);
/*
//Auto scroll to end of ListView
listView1.setTranscriptMode(ListView.TRANSCRIPT_MODE_ALWAYS_SCROLL);
listView2.setTranscriptMode(ListView.TRANSCRIPT_MODE_ALWAYS_SCROLL);
listView3.setTranscriptMode(ListView.TRANSCRIPT_MODE_ALWAYS_SCROLL);
*/
listView1.setOnItemClickListener(listOnItemClickListener);
listView2.setOnItemClickListener(listOnItemClickListener);
listView3.setOnItemClickListener(listOnItemClickListener);
listView1.setOnItemLongClickListener(myOnItemLongClickListener);
listView2.setOnItemLongClickListener(myOnItemLongClickListener);
listView3.setOnItemLongClickListener(myOnItemLongClickListener);
prompt = (TextView) findViewById(R.id.prompt);
// make TextView scrollable
prompt.setMovementMethod(new ScrollingMovementMethod());
//clear prompt area if LongClick
prompt.setOnLongClickListener(new OnLongClickListener(){
@Override
public boolean onLongClick(View v) {
prompt.setText("");
return true;
}});
resumeColor = getResources().getColor(android.R.color.background_light);
}
OnItemLongClickListener myOnItemLongClickListener = new OnItemLongClickListener(){
@Override
public boolean onItemLongClick(AdapterView<?> parent, View view,
int position, long id) {
Item selectedItem = (Item)(parent.getItemAtPosition(position));
ItemsListAdapter associatedAdapter = (ItemsListAdapter)(parent.getAdapter());
List<Item> associatedList = associatedAdapter.getList();
PassObject passObj = new PassObject(view, selectedItem, associatedList);
ClipData data = ClipData.newPlainText("", "");
DragShadowBuilder shadowBuilder = new View.DragShadowBuilder(view);
view.startDrag(data, shadowBuilder, passObj, 0);
return true;
}
};
OnDragListener myOnDragListener = new OnDragListener() {
@Override
public boolean onDrag(View v, DragEvent event) {
String area;
if(v == area1){
area = "area1";
}else if(v == area2){
area = "area2";
}else if(v == area3){
area = "area3";
}else{
area = "unknown";
}
switch (event.getAction()) {
case DragEvent.ACTION_DRAG_STARTED:
prompt.append("ACTION_DRAG_STARTED: " + area + "\n");
break;
case DragEvent.ACTION_DRAG_ENTERED:
prompt.append("ACTION_DRAG_ENTERED: " + area + "\n");
break;
case DragEvent.ACTION_DRAG_EXITED:
prompt.append("ACTION_DRAG_EXITED: " + area + "\n");
break;
case DragEvent.ACTION_DROP:
prompt.append("ACTION_DROP: " + area + "\n");
PassObject passObj = (PassObject)event.getLocalState();
View view = passObj.view;
Item passedItem = passObj.item;
List<Item> srcList = passObj.srcList;
ListView oldParent = (ListView)view.getParent();
ItemsListAdapter srcAdapter = (ItemsListAdapter)(oldParent.getAdapter());
LinearLayoutListView newParent = (LinearLayoutListView)v;
ItemsListAdapter destAdapter = (ItemsListAdapter)(newParent.listView.getAdapter());
List<Item> destList = destAdapter.getList();
if(removeItemToList(srcList, passedItem)){
addItemToList(destList, passedItem);
}
srcAdapter.notifyDataSetChanged();
destAdapter.notifyDataSetChanged();
//smooth scroll to bottom
newParent.listView.smoothScrollToPosition(destAdapter.getCount()-1);
break;
case DragEvent.ACTION_DRAG_ENDED:
prompt.append("ACTION_DRAG_ENDED: " + area + "\n");
default:
break;
}
return true;
}
};
class ItemOnDragListener implements OnDragListener{
Item me;
ItemOnDragListener(Item i){
me = i;
}
@Override
public boolean onDrag(View v, DragEvent event) {
switch (event.getAction()) {
case DragEvent.ACTION_DRAG_STARTED:
prompt.append("Item ACTION_DRAG_STARTED: " + "\n");
break;
case DragEvent.ACTION_DRAG_ENTERED:
prompt.append("Item ACTION_DRAG_ENTERED: " + "\n");
v.setBackgroundColor(0x30000000);
break;
case DragEvent.ACTION_DRAG_EXITED:
prompt.append("Item ACTION_DRAG_EXITED: " + "\n");
v.setBackgroundColor(resumeColor);
break;
case DragEvent.ACTION_DROP:
prompt.append("Item ACTION_DROP: " + "\n");
PassObject passObj = (PassObject)event.getLocalState();
View view = passObj.view;
Item passedItem = passObj.item;
List<Item> srcList = passObj.srcList;
ListView oldParent = (ListView)view.getParent();
ItemsListAdapter srcAdapter = (ItemsListAdapter)(oldParent.getAdapter());
ListView newParent = (ListView)v.getParent();
ItemsListAdapter destAdapter = (ItemsListAdapter)(newParent.getAdapter());
List<Item> destList = destAdapter.getList();
int removeLocation = srcList.indexOf(passedItem);
int insertLocation = destList.indexOf(me);
/*
* If drag and drop on the same list, same position,
* ignore
*/
if(srcList != destList || removeLocation != insertLocation){
if(removeItemToList(srcList, passedItem)){
destList.add(insertLocation, passedItem);
}
srcAdapter.notifyDataSetChanged();
destAdapter.notifyDataSetChanged();
}
v.setBackgroundColor(resumeColor);
break;
case DragEvent.ACTION_DRAG_ENDED:
prompt.append("Item ACTION_DRAG_ENDED: " + "\n");
v.setBackgroundColor(resumeColor);
default:
break;
}
return true;
}
}
OnItemClickListener listOnItemClickListener = new OnItemClickListener(){
@Override
public void onItemClick(AdapterView<?> parent, View view, int position,
long id) {
Toast.makeText(MainActivity.this,
((Item)(parent.getItemAtPosition(position))).ItemString,
Toast.LENGTH_SHORT).show();
}
};
private void initItems(){
items1 = new ArrayList<Item>();
items2 = new ArrayList<Item>();
items3 = new ArrayList<Item>();
TypedArray arrayDrawable = getResources().obtainTypedArray(R.array.resicon);
TypedArray arrayText = getResources().obtainTypedArray(R.array.restext);
for(int i=0; i<arrayDrawable.length(); i++){
Drawable d = arrayDrawable.getDrawable(i);
String s = arrayText.getString(i);
Item item = new Item(d, s);
items1.add(item);
}
arrayDrawable.recycle();
arrayText.recycle();
}
private boolean removeItemToList(List<Item> l, Item it){
boolean result = l.remove(it);
return result;
}
private boolean addItemToList(List<Item> l, Item it){
boolean result = l.add(it);
return result;
}
}
LinearLayoutListView.java and the layout file, /res/layout/activity_main.xml, refer to last post.
/res/layout/row.xml and /res/values/arrays.xml, refer to previous post of "Custom ListView with ImageView".
To use Drag and Drop on your app, you have to modify AndroidManifest.xml to set android:minSdkVersion="11".
Download the files.Next:
- Drag and Drop between ListView and GridView
