我遇到了一个问题，在我从列表中“轻扫”某项后，我无法让屏幕动态更新。这些对象已成功从数据库中删除，但由于屏幕永远不会更新，因此我可以继续滑动以解除并最终导致IndexOutOfBoundsException。
我已经尝试过.remove（）,. notifyDataSetChanged（）的每个组合，而我正试图调查其他选项。
你认为我的问题可能源于我填充List lstEvents的方式吗？ ...我正在使用lstEvents = db.getAllContacts（）;
主要活动反映工作代码
MainActivity
public class MainActivity extends ListActivity implements OnClickListener {
List<Event> lstEvents = new ArrayList<Event>();
EventAdapter adapter;
DatabaseHandler db;
// detail view
TextView tvTitle, tvTime, tvDate;
ImageView ivPic;
ImageButton add;
String title;
String date;
String time;
Context context;
static final int PICK_CONTACT_REQUEST = 0;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
// // get detail controls
tvTitle = (TextView) findViewById(R.id.textViewTitle);
tvDate = (TextView) findViewById(R.id.textViewDate);
tvTime = (TextView) findViewById(R.id.textViewTime);
ivPic = (ImageView) findViewById(R.id.imageView1);
add = (ImageButton) findViewById(R.id.add);
add.setOnClickListener(this);
// /////////////////////////////DATABASE/////////////////////////////////////////////
db = new DatabaseHandler(this);
// /////////////////////////////DATABASE/////////////////////////////////////////////
// ///////////////////////////////LISTVIEW////////////////////////////////////////
// Create the adapter to convert the array to views
adapter = new EventAdapter(this, lstEvents);
// attach adapter to a list view
ListView listView = getListView();
listView.setAdapter(adapter);
context = this;
SwipeDismissListViewTouchListener touchListener = new SwipeDismissListViewTouchListener(
listView,
new SwipeDismissListViewTouchListener.DismissCallbacks() {
// DatabaseHandler db = new DatabaseHandler(context);
// EventAdapter adapter = new EventAdapter(context,
// lstEvents);
@Override
public boolean canDismiss(int position) {
return true;
}
@Override
public void onDismiss(ListView listView,
int[] reverseSortedPositions) {
for (int position : reverseSortedPositions) {
Event event = adapter.getItem(position);
adapter.remove(event);
db.deleteEvent(event);
for (Event ev : db.getAllContacts()) {
String log = "Id: " + ev.get_Id() + " ,Title: "
+ ev.get_title() + " ,Date: " + ev.get_date()
+ " ,RESOURCEID: " + ev.get_image();
// Writing Contacts to log
Log.e("````````````````ON DISMISS`````````````` ", log);
}
}
adapter.notifyDataSetChanged();
}
});
listView.setOnTouchListener(touchListener);
// Setting this scroll listener is required to ensure that during
// // ListView scrolling,
// // we don't look for swipes.
listView.setOnScrollListener(touchListener.makeScrollListener());
lstEvents = db.getAllContacts();
adapter.clear();
adapter.addAll(lstEvents);
adapter.notifyDataSetChanged();
for (Event ev : db.getAllContacts()) {
String log = "Id: " + ev.get_Id() + " ,Title: "
+ ev.get_title() + " ,Date: " + ev.get_date()
+ " ,RESOURCEID: " + ev.get_image();
// Writing Contacts to log
Log.e("++++++++++++++++ONCREATE+++++++++++++++ ", log);
}
}
// @Override
protected void onResume() {
// TODO Auto-generated method stub
super.onResume();
adapter.clear();
lstEvents = db.getAllContacts();
adapter.addAll(lstEvents);
adapter.notifyDataSetChanged();
for (Event ev : db.getAllContacts()) {
String log = "Id: " + ev.get_Id() + " ,Title: "
+ ev.get_title() + " ,Date: " + ev.get_date()
+ " ,RESOURCEID: " + ev.get_image();
// Writing Contacts to log
Log.e("++++++++++++++++ONRESUME+++++++++++++++ ", log);
}
}
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
switch (v.getId()) {
case R.id.add:
Intent intent = new Intent(this, CreateActivity.class);
startActivityForResult(intent, 100);
break;
}
}
@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
// attach adapter to a list view
ListView listView = getListView();
listView.setAdapter(adapter);
if (requestCode == 100) {
if (resultCode == RESULT_OK) {
Bundle b = data.getExtras();
title = b.getString("TITLE");
time = b.getString("TIME");
date = b.getString("DATE");
Bitmap bitmap = b.getParcelable("BITMAP");
// ///CONVERTING A BITMAP TO A BYTE[]
byte[] image = null;
ByteArrayOutputStream bos = new ByteArrayOutputStream();
bitmap.compress(Bitmap.CompressFormat.PNG, 100, bos);
image = bos.toByteArray();
// ///////
// /////////////////////////////DATABASE/////////////////////////////////////////////
/**
* CRUD OPERATIONS
*/
Log.e("Insert: ", "Inserting ..");
db.addEvent(new Event((int) Math.floor(Math.random() * 101),
title, time, date, image));
// Reading all contacts
Log.e("Reading: ", "Reading all contacts..");
lstEvents = db.getAllContacts();
adapter.clear();
adapter.addAll(lstEvents);
adapter.notifyDataSetChanged();
// logging all events
for (Event ev : db.getAllContacts()) {
String log = "Id: " + ev.get_Id() + " ,Title: "
+ ev.get_title() + " ,Date: " + ev.get_date()
+ " ,RESOURCEID: " + ev.get_image();
// Writing Contacts to log
Log.e("-----------------ON ACTIVITY RESULT-------------- ", log);
}
// /////////////////////////////DATABASE/////////////////////////////////////////////
}
}
}
}
EventAdapter
public class EventAdapter extends ArrayAdapter<Event> {
// View lookup cache
private static class ViewHolder {
//adding drawable to imageview
ImageView img;
TextView title;
TextView time;
TextView date;
}
public EventAdapter(Context context, List<Event> objects) {
super(context, R.layout.date_detail, objects);
// TODO Auto-generated constructor stub
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
// Get the data item for this position
Event event = getItem(position);
// Check if an existing view is being reused, otherwise inflate the view
ViewHolder viewHolder;
if (convertView == null) {
viewHolder = new ViewHolder();
LayoutInflater inflater = LayoutInflater.from(getContext());
convertView = inflater.inflate(R.layout.date_detail, parent, false);
viewHolder.title = (TextView) convertView
.findViewById(R.id.textViewTitle);
viewHolder.time = (TextView) convertView
.findViewById(R.id.textViewTime);
viewHolder.date = (TextView) convertView
.findViewById(R.id.textViewDate);
//adding drawable to imageview
viewHolder.img = (ImageView) convertView
.findViewById(R.id.imageView1);
convertView.setTag(viewHolder);
} else {
viewHolder = (ViewHolder) convertView.getTag();
}
// Populate the data into the template view using the data object
viewHolder.title.setText(event._title);
viewHolder.time.setText(event._time);
viewHolder.date.setText(event._date);
//convert from byte array to bitmap
Bitmap bitmap = convertByteArrayToBitmap(event._image);
// CONVERT BITMAP TO DRAWABLE
viewHolder.img.setImageBitmap(bitmap);
// Return the completed view to render on screen
return convertView;
}
public static Bitmap convertByteArrayToBitmap(
byte[] byteArrayToBeCOnvertedIntoBitMap)
{
Bitmap bitmap = BitmapFactory.decodeByteArray(
byteArrayToBeCOnvertedIntoBitMap, 0,
byteArrayToBeCOnvertedIntoBitMap.length);
return bitmap;
}
}
DATABASE HANDLER
public DatabaseHandler(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
@Override
public void onCreate(SQLiteDatabase db) {
// TODO Auto-generated method stub
String CREATE_EVENTS_TABLE = "CREATE TABLE " + TABLE_EVENTS + "("
+ KEY_ID + " INTEGER," + KEY_TITLE + " TEXT,"
+ KEY_TIME + " TEXT," + KEY_DATE + " TEXT," + KEY_IMAGE + " BLOB" + ")";
db.execSQL(CREATE_EVENTS_TABLE);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// Drop older table if existed
db.execSQL("DROP TABLE IF EXISTS " + TABLE_EVENTS);
// Create tables again
onCreate(db);
}
/**
* All CRUD(Create, Read, Update, Delete) Operations
*/
//adding an event (NEEDS TO ADD DRAWABLE)
public void addEvent(Event event) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(KEY_ID, event.get_Id()); //Event ID
values.put(KEY_TITLE, event.get_title()); // Event Title
values.put(KEY_TIME, event.get_time()); // Event Time
values.put(KEY_DATE, event.get_date()); // Event Date
values.put(KEY_IMAGE, event.get_image()); // Event RESOURCEID
// Inserting Row
db.insert(TABLE_EVENTS, null, values);
db.close(); // Closing database connection
}
// Getting single contact
public Event getEvent(int id) {
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.query(TABLE_EVENTS, new String[] { KEY_ID,
KEY_TITLE, KEY_TIME, KEY_DATE, KEY_IMAGE }, KEY_ID + "=?",
new String[] { String.valueOf(id) }, null, null, null, null);
if (cursor != null)
cursor.moveToFirst();
Event event = new Event(Integer.parseInt(cursor.getString(0)),
cursor.getString(1), cursor.getString(2), cursor.getString(3), cursor.getBlob(4));
// return contact
return event;
}
// Getting All Contacts
public List<Event> getAllContacts() {
List<Event> eventList = new ArrayList<Event>();
// Select All Query
String selectQuery = "SELECT * FROM " + TABLE_EVENTS;
SQLiteDatabase db = this.getWritableDatabase();
Cursor cursor = db.rawQuery(selectQuery, null);
// looping through all rows and adding to list
if (cursor.moveToFirst()) {
do {
Event event = new Event();
event.set_Id(Integer.parseInt(cursor.getString(0)));
event.set_title(cursor.getString(1));
event.set_time(cursor.getString(2));
event.set_date(cursor.getString(3));
event.set_image(cursor.getBlob(4));
eventList.add(event);
} while (cursor.moveToNext());
}
// return contact list
return eventList;
}
// Getting event Count
public int getEventsCount() {
String countQuery = "SELECT * FROM " + TABLE_EVENTS;
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.rawQuery(countQuery, null);
cursor.close();
// return count
return cursor.getCount();
}
// Updating single contact
public int updateEvent(Event event) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(KEY_TITLE, event.get_title());
values.put(KEY_TIME, event.get_time());
values.put(KEY_DATE, event.get_date());
// updating row
return db.update(TABLE_EVENTS, values, KEY_ID + " = ?",
new String[] { String.valueOf(event.get_Id()) });
}
// Deleting single contact
public void deleteEvent(Event event) {
SQLiteDatabase db = this.getWritableDatabase();
db.delete(TABLE_EVENTS, KEY_ID + " = ?",
new String[] { String.valueOf(event.get_Id()) });
db.close();
}
答案 0 :(得分：1)
问题是您要定义第二个 adapter变量，此处
SwipeDismissListViewTouchListener touchListener = new SwipeDismissListViewTouchListener(listView,
new SwipeDismissListViewTouchListener.DismissCallbacks()
{
DatabaseHandler db = new DatabaseHandler(context);
EventAdapter adapter = new EventAdapter(context, lstEvents); // <--
ListView绑定到“旧”适配器。通过更改lstEvents的内容，您基本上可以更改“true”适配器的后备阵列，而无需通知更改。
修复方法是删除这些实例，然后使用它来删除：
Event evt = adapter.getItem(position);
db.deleteEvent(evt); // to delete from the DB
adapter.remove(evt); // to remove from the adapter
这应该有用（ArrayAdapter.remove()自动调用notifyDataSetChanged()）。不要同时删除adapter 和 lstEvents，因为这些实际上指的是相同的数据。