每当我按下继续按钮删除任务时，它都会显示以下错误并关闭应用程序[重复]。
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异常。
E / androidRuntime: FATAL EXCEPTION: main
Process: com.example.justdoit, PID: 11200
java.lang.ArrayIndexOutOfBoundsException: length = 11; index = -1
at java.util.ArrayList.get(ArrayList.java: 439)
at com.example.justdoit.DashboardActivity$DashboardAdapter$2$1$1.onClick(DashboardActivity.java: 173)
at androidx.appcompat.app.AlertController$ButtonHandler.handleMessage(AlertController.java: 167)
at android.os.Handler.dispatchMessage(Handler.java: 106)
at android.os.Looper.loop(Looper.java: 164)
at android.app.ActivityThread.main(ActivityThread.java: 6494)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java: 438)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java: 807)
代码：
public class DashboardActivity extends AppCompatActivity {
DBHandler dbHandler;
DashboardActivity activity;
Toolbar dashboard_toolbar;
RecyclerView rv_dashboard;
FloatingActionButton fab_dashboard;
@Override protected void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_dashboard);
dashboard_toolbar=findViewById(R.id.dashboard_toolbar);
rv_dashboard=findViewById(R.id.rv_dashboard);
fab_dashboard=findViewById(R.id.fab_dashboard);
getSupportActionBar(dashboard_toolbar);
setTitle("Dashboard");
activity=this;
dbHandler=new DBHandler(activity);
rv_dashboard.setLayoutManager(new LinearLayoutManager(activity));
fab_dashboard.setOnClickListener(new View.OnClickListener() {
@Override public void onClick(View v) {
AlertDialog.Builder dialog=new AlertDialog.Builder(activity);
dialog.setTitle("Add ToDo");
View view=getLayoutInflater().inflate(R.layout.dialog_dashboard, null);
final EditText toDoName=view.findViewById(R.id.ev_todo);
dialog.setView(view);
dialog.setPositiveButton("Add", new DialogInterface.OnClickListener() {
@Override public void onClick(DialogInterface dialogInterface, int i) {
if (toDoName.getText().toString().length() > 0) {
ToDo toDo=new ToDo();
toDo.setName(toDoName.getText().toString());
dbHandler.addToDo(toDo);
refreshList();
}
}
}
);
dialog.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
@Override public void onClick(DialogInterface dialogInterface, int i) {}
}
);
dialog.show();
}
}
);
}
private void getSupportActionBar(Toolbar dashboard_toolbar) {}
@Override protected void onResume() {
refreshList();
super.onResume();
}
public void updateToDo(final ToDo toDo) {
AlertDialog.Builder dialog=new AlertDialog.Builder(activity);
dialog.setTitle("Update ToDo");
View view=getLayoutInflater().inflate(R.layout.dialog_dashboard, null);
final EditText toDoName=view.findViewById(R.id.ev_todo);
toDoName.setText(toDo.getName());
dialog.setView(view);
dialog.setPositiveButton("Update", new DialogInterface.OnClickListener() {
@Override public void onClick(DialogInterface dialogInterface, int i) {
if (toDoName.getText().toString().length() > 0) {
toDo.setName(toDoName.getText().toString());
dbHandler.updateToDo(toDo);
refreshList();
}
}
}
);
dialog.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
@Override public void onClick(DialogInterface dialogInterface, int i) {}
}
);
dialog.show();
}
public void refreshList() {
rv_dashboard.setAdapter(new DashboardAdapter(activity, dbHandler.getToDos()));
}
class DashboardAdapter extends RecyclerView.Adapter < DashboardAdapter.ViewHolder> {
ArrayList < ToDo>list;
DashboardActivity activity;
DashboardAdapter(DashboardActivity activity, ArrayList < ToDo > list) {
this.list=list;
this.activity=activity;
Log.d("DashboardAdapter", "DashboardAdapter");
Log.d("DashboardAdapter", "list : " + list.size());
}
@Override public ViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int i) {
return new ViewHolder(LayoutInflater.from(activity).inflate(R.layout.rv_child_dashboard, viewGroup, false));
}
@Override public void onBindViewHolder(@NonNull final ViewHolder holder, final int i) {
holder.toDoName.setText(list.get(i).getName());
holder.toDoName.setOnClickListener(new View.OnClickListener() {
@Override public void onClick(View view) {
Intent intent=new Intent(activity, ItemActivity.class);
intent.putExtra(INTENT_TODO_ID, list.get(i).getId());
intent.putExtra(INTENT_TODO_NAME, list.get(i).getName());
activity.startActivity(intent);
}
}
);
holder.menu.setOnClickListener(new View.OnClickListener() {
@Override public void onClick(View view) {
PopupMenu popup=new PopupMenu(activity, holder.menu);
popup.inflate(R.menu.dashboard_child);
popup.setOnMenuItemClickListener(new PopupMenu.OnMenuItemClickListener() {
@Override public boolean onMenuItemClick(MenuItem menuItem) {
switch (menuItem.getItemId()) {
case R.id.menu_edit: {
activity.updateToDo(list.get(i));
break;
}
case R.id.menu_delete: {
AlertDialog.Builder dialog=new AlertDialog.Builder(activity);
dialog.setTitle("Are you sure");
dialog.setMessage("Do you want to delete this task ?");
dialog.setPositiveButton("Continue", new DialogInterface.OnClickListener() {
@Override public void onClick(DialogInterface dialogInterface, int i) {
activity.dbHandler.deleteToDo(list.get(i).getId());
activity.refreshList();
}
}
);
dialog.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
@Override public void onClick(DialogInterface dialogInterface, int i) {}
}
);
dialog.show();
}
case R.id.menu_mark_as_completed: {
activity.dbHandler.updateToDoItemCompletedStatus(list.get(i).getId(), true);
break;
}
case R.id.menu_reset: {
activity.dbHandler.updateToDoItemCompletedStatus(list.get(i).getId(), false);
break;
}
}
return true;
}
}
);
popup.show();
}
}
);
}
@Override public int getItemCount() {
return list.size();
}
class ViewHolder extends RecyclerView.ViewHolder {
TextView toDoName;
ImageView menu;
ViewHolder(View v) {
super(v);
toDoName=v.findViewById(R.id.tv_todo_name);
menu=v.findViewById(R.id.iv_menu);
}
}
}
}
***DBHandler:*** public class DBHandler extends SQLiteOpenHelper {
public DBHandler(Context context) {
super(context, DB_NAME, null, DB_VERSION);
}
@Override public void onCreate(SQLiteDatabase db) {
String createToDoTable=" CREATE TABLE "+TABLE_TODO+" ("+COL_ID+" integer PRIMARY KEY AUTOINCREMENT,"+COL_CREATED_AT+" datetime DEFAULT CURRENT_TIMESTAMP,"+COL_NAME+" varchar)";
String createToDoItemTable=" CREATE TABLE "+TABLE_TODO_ITEM+" ("+COL_ID+" integer PRIMARY KEY AUTOINCREMENT,"+COL_CREATED_AT+" datetime DEFAULT CURRENT_TIMESTAMP,"+COL_TODO_ID+" integer,"+COL_ITEM_NAME+" varchar,"+COL_IS_COMPLETED+" integer)";
db.execSQL(createToDoTable);
db.execSQL(createToDoItemTable);
}
@Override public void onUpgrade(SQLiteDatabase sqLiteDatabase, int i, int i1) {}
boolean addToDo(ToDo todo) {
SQLiteDatabase db=getWritableDatabase();
ContentValues cv=new ContentValues();
cv.put(COL_NAME, todo.getName());
long result=db.insert(TABLE_TODO, null, cv);
return result !=-1;
}
void updateToDo(ToDo todo) {
SQLiteDatabase db=getWritableDatabase();
ContentValues cv=new ContentValues();
cv.put(COL_NAME, todo.getName());
db.update(TABLE_TODO, cv, COL_ID + "=?", new String[] {
String.valueOf(todo.getId())
}
);
}
void deleteToDo(Long todoId) {
SQLiteDatabase db=getWritableDatabase();
db.delete(TABLE_TODO_ITEM, COL_TODO_ID + "=?", new String[] {
String.valueOf(todoId)
}
);
db.delete(TABLE_TODO, COL_ID + "=?", new String[] {
String.valueOf(todoId)
}
);
}
void updateToDoItemCompletedStatus(Long todoId, Boolean isCompleted) {
SQLiteDatabase db=getWritableDatabase();
Cursor queryResult=db.rawQuery(" SELECT * FROM " + TABLE_TODO_ITEM +" WHERE " + COL_TODO_ID + "="+ todoId, null);
if (queryResult.moveToFirst()) {
do {
ToDoItem item=new ToDoItem();
item.setId(queryResult.getLong(queryResult.getColumnIndex(COL_ID)));
item.setToDoId(queryResult.getLong(queryResult.getColumnIndex(COL_TODO_ID)));
item.setItemName(queryResult.getString(queryResult.getColumnIndex(COL_ITEM_NAME)));
item.setCompleted(isCompleted);
updateToDoItem(item);
}
while (queryResult.moveToNext());
}
queryResult.close();
}
public void updateToDoItem(ToDoItem item) {
SQLiteDatabase db=getWritableDatabase();
ContentValues cv=new ContentValues();
cv.put(COL_ITEM_NAME, item.getItemName());
cv.put(COL_TODO_ID, item.getToDoId());
cv.put(COL_IS_COMPLETED, item.isCompleted());
db.update(TABLE_TODO_ITEM, cv, COL_ID + "=?", new String [] {
String.valueOf(item.getId())
}
);
}
ArrayList<ToDo>getToDos() {
ArrayList<ToDo>result=new ArrayList<>();
SQLiteDatabase db=getReadableDatabase();
Cursor queryResult=db.rawQuery(" SELECT * from " + TABLE_TODO, null);
if(queryResult.moveToFirst()) {
do {
ToDo todo=new ToDo();
todo.setId(queryResult.getLong(queryResult.getColumnIndex(COL_ID)));
todo.setName(queryResult.getString(queryResult.getColumnIndex(COL_NAME)));
result.add(todo);
}
while(queryResult.moveToNext());
}
queryResult.close();
return result;
}
public boolean addToDoItem(ToDoItem item) {
SQLiteDatabase db=getWritableDatabase();
ContentValues cv=new ContentValues();
cv.put(COL_ITEM_NAME, item.getItemName());
cv.put(COL_TODO_ID, item.getToDoId());
cv.put(COL_IS_COMPLETED, item.isCompleted());
long result=db.insert(TABLE_TODO_ITEM, null, cv);
return result!=-1;
}
public void deleteToDoItem(long itemId) {
SQLiteDatabase db=getWritableDatabase();
db.delete(TABLE_TODO_ITEM, COL_ID + "=?", new String[] {
String.valueOf(itemId)
}
);
}
public ArrayList<ToDoItem>getToDoItems(long todoId) {
ArrayList<ToDoItem>result=new ArrayList<>();
SQLiteDatabase db=getReadableDatabase();
Cursor queryResult=db.rawQuery("SELECT * FROM " + TABLE_TODO_ITEM + " WHERE " + COL_TODO_ID + "=" + todoId, null);
if (queryResult.moveToFirst()) {
do {
ToDoItem item=new ToDoItem();
item.setId(queryResult.getLong(queryResult.getColumnIndex(COL_ID)));
item.setToDoId(queryResult.getLong(queryResult.getColumnIndex(COL_TODO_ID)));
item.setItemName(queryResult.getString(queryResult.getColumnIndex(COL_ITEM_NAME)));
item.setCompleted(queryResult.getInt(queryResult.getColumnIndex(COL_IS_COMPLETED))==1);
result.add(item);
}
while (queryResult.moveToNext());
}
queryResult.close();
return result;
}
}
这是我一直得到的错误，当我试图从列表中删除一个任务时，应用程序在按下继续按钮从列表中删除任务后立即关闭。我需要怎么做才能解决这个问题？
另外，我在列表中添加的项目之间的空间相当大，我怎么也要改变它？
答案
我在 仪表盘适配器 请检查更新后的适配器代码。
class DashboardAdapter extends RecyclerView.Adapter < DashboardAdapter.ViewHolder> {
ArrayList < ToDo>list;
DashboardActivity activity;
DashboardAdapter(DashboardActivity activity, ArrayList < ToDo > list) {
this.list=list;
this.activity=activity;
Log.d("DashboardAdapter", "DashboardAdapter");
Log.d("DashboardAdapter", "list : " + list.size());
}
@Override public ViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int i) {
return new ViewHolder(LayoutInflater.from(activity).inflate(R.layout.rv_child_dashboard, viewGroup, false));
}
@Override public void onBindViewHolder(@NonNull final ViewHolder holder, final int i) {
ToDo todoModel=list.get(i);//added this line
holder.toDoName.setText(list.get(i).getName());
holder.toDoName.setOnClickListener(new View.OnClickListener() {
@Override public void onClick(View view) {
Intent intent=new Intent(activity, ItemActivity.class);
intent.putExtra(INTENT_TODO_ID, list.get(i).getId());
intent.putExtra(INTENT_TODO_NAME, list.get(i).getName());
activity.startActivity(intent);
}
}
);
holder.menu.setOnClickListener(new View.OnClickListener() {
@Override public void onClick(View view) {
PopupMenu popup=new PopupMenu(activity, holder.menu);
popup.inflate(R.menu.dashboard_child);
popup.setOnMenuItemClickListener(new PopupMenu.OnMenuItemClickListener() {
@Override public boolean onMenuItemClick(MenuItem menuItem) {
switch (menuItem.getItemId()) {
case R.id.menu_edit: {
activity.updateToDo(list.get(i));
break;
}
case R.id.menu_delete: {
AlertDialog.Builder dialog=new AlertDialog.Builder(activity);
dialog.setTitle("Are you sure");
dialog.setMessage("Do you want to delete this task ?");
dialog.setPositiveButton("Continue", new DialogInterface.OnClickListener() {
@Override public void onClick(DialogInterface dialogInterface, int i) {
activity.dbHandler.deleteToDo(todoModel.getId());
activity.refreshList();
}
}
);
dialog.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
@Override public void onClick(DialogInterface dialogInterface, int i) {}
}
);
dialog.show();
}
case R.id.menu_mark_as_completed: {
activity.dbHandler.updateToDoItemCompletedStatus(list.get(i).getId(), true);
break;
}
case R.id.menu_reset: {
activity.dbHandler.updateToDoItemCompletedStatus(list.get(i).getId(), false);
break;
}
}
return true;
}
}
);
popup.show();
}
}
);
}
@Override public int getItemCount() {
return list.size();
}
class ViewHolder extends RecyclerView.ViewHolder {
TextView toDoName;
ImageView menu;
ViewHolder(View v) {
super(v);
toDoName=v.findViewById(R.id.tv_todo_name);
menu=v.findViewById(R.id.iv_menu);
}
}
}
}
另一答案
请你把你的代码中439行是什么？是那一行吗。
@Override public void onClick(DialogInterface dialogInterface, int i) {
activity.dbHandler.deleteToDo(list.get(i).getId()); // <- this one?
activity.refreshList();
}
如果是，那么原因是 i 这里指的是 onClick(DialogInterface dialogInterface, int i) 而不是 onBindViewHolder(@NonNull final ViewHolder holder, final int i) 了。
愿将你的参数重命名为更有意义的名字，帮助你更好地理解代码。
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