应用程序在从回收视图中删除项目时崩溃

Question

在我的应用程序中，我在回收视图中显示了一个项目列表。我已经创建了两个功能，编辑和删除每个项目在回收视图。通过这个应用程序，用户可以创建一个任务列表，可以编辑项目，也可以从回收视图中删除该项目。现在，如果我点击编辑，它是完美的工作。但是，如果我单击delete选项，应用程序就会崩溃，在adaper类中，消息数组索引会出现异常。

这是我的适配器代码。我还在代码中提到了这一行，在这里我会看到应用程序崩溃。

编辑适配器类

public class TodoAdapter extends RealmRecyclerViewAdapter<TodoModel, TodoAdapter.TaskHolder> {
    public final static String INTENT_KEY_ID = "taskId";
    public final static String INTENT_KEY_POSITION = "position";
    public final static String DATE_FORMAT = "dd/MMM/yy";


    private Realm realm;

    public interface TaskListener {

    }

    private final TaskListener taskListener;
    private final Context context;

    public TodoAdapter(TaskListener taskListener, RealmResults<TodoModel> realmResults, Context context, Realm realm) {
        super(realmResults, true);
        this.taskListener = taskListener;
        this.context = context;
        this.realm = realm;
    }

    @Override
    public TaskHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        return new TaskHolder( LayoutInflater.from(parent.getContext()).inflate(R.layout.todo_row, parent, false));
    }

    @Override
    public void onBindViewHolder(TaskHolder holder, final int position) {

        final TodoModel task = getData().get(position);
        holder.taskTextView.setText(task.getName());
        holder.doneCheckBox.setChecked(task.isDone());
        holder.timeTextView.setText( task.getTime() );

        final SimpleDateFormat sdf = new SimpleDateFormat(DATE_FORMAT);

        final Date date = (task.getDate());
        if (sdf.format(date).equals(sdf.format(getDate(0))))
            holder.dateTextView.setText("Today");
        else if (sdf.format(date).equals(sdf.format(getDate(-1))))
            holder.dateTextView.setText("Yesterday");
        else if (sdf.format(date).equals(sdf.format(getDate(1))))
            holder.dateTextView.setText("Tomorrow");
        else if (date.getTime() < getDate(6).getTime()) {
            Calendar calendar = Calendar.getInstance();
            calendar.setTime(date);
            holder.dateTextView.setText( DateFormat.format("EEEE", calendar.getTime()).toString());
        } else
            holder.dateTextView.setText(sdf.format(task.getDate()));

        holder.cardView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent intent = new Intent(context, TodoAddActivity.class);
                intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
                intent.putExtra(INTENT_KEY_ID, getTask(position).getId());
                context.startActivity(intent);
            }
        });

        holder.doneCheckBox.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                TodoModel task = new TodoModel();
                task.setId(getTask(position).getId());
                task.setDate(getTask(position).getDate());
                task.setName(getTask(position).getName());
                task.setDone(((CheckBox) v).isChecked());
                updateTask(position, task);
            }
        });

        holder.deleteImageView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (getTask(position).isDone()) {
                    removeTask(position);
                    notifyDataSetChanged();
                    return;
                }
                AlertDialog.Builder alertDialog = new AlertDialog.Builder(context);
                alertDialog.setTitle("Confirm Delete?");
                alertDialog.setMessage("Do you want to delete the task you created?");
                alertDialog.setPositiveButton("YES", new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int which) {
                        dialog.cancel();
                        removeTask(position);
                    }
                });
                alertDialog.setNegativeButton("NO", new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int which) {
                        dialog.cancel();
                    }
                });
                alertDialog.show();
            }
        });
    }

    public class TaskHolder extends RecyclerView.ViewHolder {
        public CardView cardView;
        public TextView taskTextView;
        public TextView dateTextView;
        public TextView timeTextView;
        public ImageView deleteImageView;
        public CheckBox doneCheckBox;


        public TaskHolder(View itemView) {
            super(itemView);

            taskTextView = (TextView) itemView.findViewById( R.id.row_task_list_tv_name);
            dateTextView = (TextView) itemView.findViewById(R.id.row_task_list_tv_date);
            timeTextView=(TextView)itemView.findViewById( R.id.row_task_list_tv_time );
            deleteImageView = (ImageView) itemView.findViewById(R.id.row_task_list_iv_delete);
            doneCheckBox = (CheckBox) itemView.findViewById(R.id.row_task_list_cb_done);
            cardView = (CardView) itemView.findViewById(R.id.cardView);
        }
    }

    private Date getDate(int day) {
        Calendar calendar = Calendar.getInstance();
        calendar.add(Calendar.DATE, day);
        return calendar.getTime();
    }

    protected TodoModel getTask(int position) {
        return getData().get(position);
    }

    protected void updateTask(int position, TodoModel task) {
        realm.beginTransaction();
        TodoModel newTask = realm.where(TodoModel.class).equalTo("id", task.getId()).findFirst();
        newTask.setDate(task.getDate());
        newTask.setDone(task.isDone());
        newTask.setName(task.getName());
        realm.commitTransaction();
    }

    protected void removeTask(int position) {
        TodoModel newTask = realm.where(TodoModel.class).equalTo("id", getTask(position).getId()).findFirst();
        realm.beginTransaction();
        newTask.deleteFromRealm();
        realm.commitTransaction();
        notifyItemRemoved(position);
    }
   }

坠机报告

09-10 12:25:57.876 7332-7332/realmtest.com.to_do_list_test E/AndroidRuntime: FATAL EXCEPTION: main
                                                                         Process: realmtest.com.to_do_list_test, PID: 7332
                                                                         java.lang.ArrayIndexOutOfBoundsException: Out of range  in /Users/cm/Realm/realm-java/realm/realm-library/src/main/cpp/io_realm_internal_Collection.cpp line 133(requested: 1 valid: 1)
                                                                             at io.realm.internal.Collection.nativeGetRow(Native Method)
                                                                             at io.realm.internal.Collection.getUncheckedRow(Collection.java:386)
                                                                             at io.realm.OrderedRealmCollectionImpl.get(OrderedRealmCollectionImpl.java:106)
                                                                             at io.realm.RealmResults.get(RealmResults.java:53)
                                                                             at io.realm.OrderedRealmCollectionImpl.get(OrderedRealmCollectionImpl.java:19)
                                                                             at realmtest.com.to_do_list_test.activity.TodoAdapter.getTask(TodoAdapter.java:157)
                                                                             at realmtest.com.to_do_list_test.activity.TodoAdapter$3.onClick(TodoAdapter.java:106)
                                                                             at android.view.View.performClick(View.java:5610)
                                                                             at android.view.View$PerformClick.run(View.java:22265)
                                                                             at android.os.Handler.handleCallback(Handler.java:751)
                                                                             at android.os.Handler.dispatchMessage(Handler.java:95)
                                                                             at android.os.Looper.loop(Looper.java:154)
                                                                             at android.app.ActivityThread.main(ActivityThread.java:6077)
                                                                             at java.lang.reflect.Method.invoke(Native Method)
                                                                             at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:866)
                                                                             at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:756)

getData()的实现

@Nullable
public OrderedRealmCollection<T> getData() {
    return adapterData;
}

TaskActivity类

    public class TaskActivity extends AppCompatActivity implements TodoAdapter.TaskListener{

    private static final int ADD_TASK_REQUEST_CODE = 1000;
    private static final int EDIT_TASK_REQUEST_CODE = 1001;

    private Realm realm;

    private RecyclerView recyclerView;
    private TodoAdapter adapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.fragment_todo_layout);

        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        toolbar.setTitle("ToDo List");
        setSupportActionBar(toolbar);

        realm = Realm.getDefaultInstance();
        recyclerView =(RecyclerView)findViewById(R.id.activity_tasks_ll_task);

        setUpRecycler();

        // Variables

        // Views
        FloatingActionButton addFloatingActionButton = (FloatingActionButton) findViewById(R.id.activity_tasks_fab_add);
        //Listeners
        addFloatingActionButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                startActivityForResult(new Intent(getApplicationContext(), TodoAddActivity.class), ADD_TASK_REQUEST_CODE);
            }
        });
    }

    private void setAdapter() {
        adapter = new TodoAdapter(this, realm.where(TodoModel.class).findAll(),this,realm);
        recyclerView.setAdapter(adapter);
        adapter.notifyDataSetChanged();

    }

    private void setUpRecycler() {
        // use this setting to improve performance if you know that changes
        // in content do not change the layout size of the RecyclerView
        recyclerView.setHasFixedSize(true);
        // use a linear layout manager since the cards are vertically scrollable
        final LinearLayoutManager layoutManager = new LinearLayoutManager(this);
        layoutManager.setOrientation(LinearLayoutManager.VERTICAL);
        recyclerView.setLayoutManager(layoutManager);
        setAdapter();
    }
}

image1

image2

Answer 1

从if (getTask(position).isDone()) {中删除return语句，并将AlertDialog放在if的from子句中，如下所示。

holder.deleteImageView.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            if (getTask(position).isDone()) {
                removeTask(position);
                notifyDataSetChanged();

            }else {
                AlertDialog.Builder alertDialog = new AlertDialog.Builder(context);
                alertDialog.setTitle("Confirm Delete?");
                alertDialog.setMessage("Do you want to delete the task you created?");
                alertDialog.setPositiveButton("YES", new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int which) {
                       dialog.cancel();
                       removeTask(position);
                    }
                });
                alertDialog.setNegativeButton("NO", new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int which) {
                       dialog.cancel();
                    }
                });
                alertDialog.show();
            }
        }
});

Answer 2

删除条目后，您将更改适配器的列表，但没有通知适配器您已更改了列表的大小。因此，您必须告诉适配器列表的大小已经更改。

holder.deleteImageView.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {
        if (getTask(position).isDone()) { //Error for this line 
            removeTask(position);
            notifyDataSetChanged(); <-------------------Add this line to your code.
            return;
        }
        AlertDialog.Builder alertDialog = new AlertDialog.Builder(context);
        alertDialog.setTitle("Confirm Delete?");
        alertDialog.setMessage("Do you want to delete the task you created?");
        alertDialog.setPositiveButton("YES", new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog, int which) {
                dialog.cancel();
                removeTask(position);
            }
        });
        alertDialog.setNegativeButton("NO", new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog, int which) {
                dialog.cancel();
            }
        });
        alertDialog.show();
    }
});

每当您更改适配器列表的大小时，都必须通过调用函数notifyDataSetChanged().向适配器显式地告知适配器更改的情况。

Answer 3

可以使用notifyDataSetChanged()

但是，如果您想要显示动画以及更新列表中的项位置

在sequest中使用此代码

notifyItemRemoved(position)

MH:用于删除项并显示动画

notifyItemRangeChanged(position, ListSize);