java - Android ListView 与 SimpleCursorAdapter - CursorIndexOutOfBoundsException 错误

标签 java android sqlite listview cursor

我在 AcitivityA 中有一个 ListView，它使用名为 RecipeAdapter 的自定义 SimpleCursorAdapter 进行填充。适配器保存来自 SQLite

的数据

ListView 顶部有一个 EditText View ，用于在用户搜索菜谱时过滤 ListView 。当用户单击已过滤的 ListView 中的某个项目时，ActivityB 启动。

这一切都很完美。但是，当用户按下后退按钮恢复 ActivityB 时，我收到以下错误。

java.lang.RuntimeException: Unable to resume activity {ttj.android.quorn/ttj.android.quorn.RecipeActivity}: 
java.lang.IllegalStateException: trying to requery an already closed cursor  android.database.sqlite.SQLiteCursor@418ae5d8

为了解决这个问题，我修改了 onResume():

...
c = db.getCursor(); 
adapter.changeCursor(c);

到

....
Cursor cursor = db.getCursor(); 
adapter.changeCursor(cursor);

然后我得到以下异常。在 Logcat 中，问题出现在 DBHelper 中的 getId() 方法。我在这个方法中添加了c.moveToFirst()，但这仍然不能解决问题。

FATAL EXCEPTION: main
android.database.CursorIndexOutOfBoundsException: Index -1 requested, with a size of 70
at android.database.AbstractCursor.checkPosition(AbstractCursor.java:400)
at android.database.AbstractWindowedCursor.checkPosition(AbstractWindowedCursor.java:136)
at android.database.AbstractWindowedCursor.getString(AbstractWindowedCursor.java:50)
at ttj.android.quorn.DBHelper.getId(DBHelper.java:224)
at ttj.android.quorn.RecipeActivity$RecipeHolder.populateFrom(RecipeActivity.java:650)
at ttj.android.quorn.RecipeActivity$RecipeAdapter.bindView(RecipeActivity.java:572)
at android.support.v4.widget.CursorAdapter.getView(CursorAdapter.java:256)
at android.widget.AbsListView.obtainView(AbsListView.java:2214)
at android.widget.ListView.makeAndAddView(ListView.java:1774)
at android.widget.ListView.fillDown(ListView.java:672)
at android.widget.ListView.fillFromTop(ListView.java:732)
at android.widget.ListView.layoutChildren(ListView.java:1611)
at android.widget.AbsListView.onLayout(AbsListView.java:2044)
at android.view.View.layout(View.java:11418)
at android.view.ViewGroup.layout(ViewGroup.java:4224)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1628)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1486)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1399)
at android.view.View.layout(View.java:11418)
at android.view.ViewGroup.layout(ViewGroup.java:4224)
at android.widget.FrameLayout.onLayout(FrameLayout.java:431)
at android.view.View.layout(View.java:11418)
at android.view.ViewGroup.layout(ViewGroup.java:4224)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1628)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1486)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1399)
at android.view.View.layout(View.java:11418)
at android.view.ViewGroup.layout(ViewGroup.java:4224)
at android.widget.FrameLayout.onLayout(FrameLayout.java:431)
at android.view.View.layout(View.java:11418)
at android.view.ViewGroup.layout(ViewGroup.java:4224)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1628)
at android.view.ViewRootImpl.handleMessage(ViewRootImpl.java:2585)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:4507)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:790)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:557)
at dalvik.system.NativeStart.main(Native Method)

谁能帮我解决我的问题吗？

这是我的代码:

在 onCreate 中，cursor 使用 c.getCursor 填充 ListView，并且当用户筛选时ListView 通过 EditText，使用 c.getFilterCursor。

public class RecipeActivity extends SherlockListActivity {

private DBHelper db = null;
private Cursor c = null;
private RecipeAdapter adapter = null;
ListView listContent;   
private EditText filterText = null;

@SuppressWarnings("deprecation")
@Override
public void onCreate(Bundle savedInstanceState) {
    try {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.filter_list);

        filterText = (EditText) findViewById(R.id.search_box);
        filterText.addTextChangedListener(filterTextWatcher);

        ListView listContent = getListView();

        db = new DBHelper(this);
        db.createDataBase();
        db.openDataBase();

        c = db.getCursor();         

        adapter = new RecipeAdapter(c);

        listContent.setAdapter(adapter);

        adapter.setFilterQueryProvider(new FilterQueryProvider() {
            public Cursor runQuery(CharSequence constraint) {
                // Search for states whose names begin with the specified letters.
                c = db.getFilterCursor(constraint);
                return c;
            }
        });

        startManagingCursor(c);


    } catch (IOException e) {
        e.printStackTrace();
    }
}

@Override
protected void onDestroy() {
    super.onDestroy();
    filterText.removeTextChangedListener(filterTextWatcher);
    db.close();
}


@SuppressWarnings("deprecation")
@Override
protected void onResume() {
    super.onResume();

    Cursor cursor = db.getCursor(); 
    adapter.changeCursor(cursor);

}


@Override
protected void onPause() {
    super.onPause();

    adapter.notifyDataSetInvalidated();
    adapter.changeCursor(null);

}




    private TextWatcher filterTextWatcher = new TextWatcher() {

    public void afterTextChanged(Editable s) {
    }

    public void beforeTextChanged(CharSequence s, int start, int count,
            int after) {
    }

    public void onTextChanged(CharSequence s, int start, int before,
            int count) {

        adapter.getFilter().filter(s);


    }

};

RecipeAdapter 内部类

class RecipeAdapter extends CursorAdapter {

    @SuppressWarnings("deprecation")
    public RecipeAdapter(Cursor c) {
        super(RecipeActivity.this, c);
    }

    public void bindView(View row, Context arg1, Cursor arg2) {
        RecipeHolder holder = (RecipeHolder) row.getTag();
        holder.populateFrom(c, db);

    }

    public View newView(Context arg0, Cursor arg1, ViewGroup arg2) {
        LayoutInflater inflater = getLayoutInflater();
        View row = inflater.inflate(R.layout.reciperow, arg2, false);
        RecipeHolder holder = new RecipeHolder(row);
        row.setTag(holder);

        return (row);
    }


static class RecipeHolder {
    public TextView id = null;
    private TextView name = null;
    private TextView desc = null;
    private TextView preptime = null;
    private TextView cooktime = null;
    private TextView serves = null;
    private TextView calories = null;
    private TextView fat = null;
    private TextView fav = null;

    RecipeHolder(View row) {
        id = (TextView) row.findViewById(R.id.id);
        name = (TextView) row.findViewById(R.id.recipe);
        desc = (TextView) row.findViewById(R.id.desc);
        preptime = (TextView) row.findViewById(R.id.preptime);
        cooktime = (TextView) row.findViewById(R.id.cooktime);
        serves = (TextView) row.findViewById(R.id.serving);
        calories = (TextView) row.findViewById(R.id.calories);
        fat = (TextView) row.findViewById(R.id.fat);
        fav = (TextView) row.findViewById(R.id.fav);
    }


    void populateFrom(Cursor c, DBHelper r) {
        id.setText(r.getId(c));
        name.setText(r.getRecipe(c));
        name.setTextColor(Color.parseColor("#CCf27c22"));
        desc.setText(r.getDesc(c));
        preptime.setText(r.getPrepTime(c) + ". ");
        cooktime.setText(r.getCookTime(c) + " mins");
        serves.setText(r.getServes(c));
        calories.setText(r.getCalories(c));
        fat.setText(r.getFat(c));
        fav.setText(r.getFav(c));

DBHelper类

public Cursor getCursor() {
    SQLiteQueryBuilder queryBuilder = new SQLiteQueryBuilder();
    queryBuilder.setTables(DATABASE_TABLE);

    String[] columns = new String[] { KEY_ROWID, RECIPE, DESC, PREPTIME,
            COOKTIME, SERVES, CALORIES, FAT, CATEGORY, FAV };

    Cursor myCursor = queryBuilder.query(myDataBase, columns, null, null,
            null, null, RECIPE + " ASC");

    return myCursor;
}


public Cursor getFilterCursor(CharSequence constraint) {
    SQLiteQueryBuilder queryBuilder = new SQLiteQueryBuilder();
    queryBuilder.setTables(DATABASE_TABLE);

    String[] columns = new String[] { KEY_ROWID, RECIPE, DESC, PREPTIME,
            COOKTIME, SERVES, CALORIES, FAT, CATEGORY, FAV };

    if (constraint == null || constraint.length() == 0) {
        // Return the full list
        return queryBuilder.query(myDataBase, columns, null, null, null,
                null, RECIPE + " ASC");
    } else {
        String value = "%" + constraint.toString() + "%";

        return myDataBase.query(DATABASE_TABLE, columns, "RECIPE like ? ",
                new String[] { value }, null, null, null);
    }
}

public String getId(Cursor c) {
               c.moveToFirst();
    return (c.getString(0));
}

public String getRecipe(Cursor c) {
    return (c.getString(1));
}

public String getDesc(Cursor c) {
    return (c.getString(2));
}

public String getPrepTime(Cursor c) {
    return (c.getString(3));
}

public String getCookTime(Cursor c) {
    return (c.getString(4));
}

public String getServes(Cursor c) {
    return (c.getString(5));
}

public String getCalories(Cursor c) {
    return (c.getString(6));
}

public String getFat(Cursor c) {
    return (c.getString(7));
}

public String getCategory(Cursor c) {
    return (c.getString(8));
}

public String getFav(Cursor c) {
    return (c.getString(9));
}

最佳答案 

@SuppressWarnings("deprecation")

不好。您应该摆脱弃用而不是隐藏它:)

startManagingCursor(c);

不要那样做。这可能导致对已经关闭的游标进行重新查询。只需删除该行即可。

    adapter.setFilterQueryProvider(new FilterQueryProvider() {
        public Cursor runQuery(CharSequence constraint) {
            // Search for states whose names begin with the specified letters.
            c = db.getFilterCursor(constraint);
            return c;
        }
    });

不要在这里覆盖您的c。只需 return db.getFilterCursor(constraint); 就可以了。 其他可能产生积极影响的事情

@SuppressWarnings("deprecation")
public RecipeAdapter(Cursor c) {
    super(RecipeActivity.this, c);
}

public RecipeAdapter(Cursor c) {
    // no requeries and no observer required if you change the cursor yourself
    super(RecipeActivity.this, c, 0)
}

下一篇:

adapter.notifyDataSetInvalidated();
adapter.changeCursor(null);

// change to
adapter.changeCursor(null);
adapter.notifyDataSetChanged(); // maybe without this

据我了解，文档 notifyDataSetInvalidated() 意味着数据随后无效(“一旦调用此适配器就不再有效，不应报告进一步的数据集更改。” )并且您需要创建一个新的适配器实例。但不确定。只需执行 notifyDataSetChanged() 就可以了。甚至可能出现这样的情况:执行 adapter.changeCursor() 已经隐式执行更改通知。

P.S.:不需要c.MoveToFirst()。 CursorAdapter 会将光标移动到所需的位置。

关于java - Android ListView 与 SimpleCursorAdapter - CursorIndexOutOfBoundsException 错误，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/11909363/

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