Question

有点卡在这里。我可以删除列表视图中的项目，但是也无法从数据库中删除它：

我的listview类：

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

        final VorgangDataSource dataSource = new VorgangDataSource(this);

        Log.d(TAG,"Die Datenquelle wird geöffnet!");
        dataSource.open();

        final List<vorgangsdaten> vorgangsdatenList = dataSource.getAllVorgangsDaten();

        final ArrayAdapter<vorgangsdaten> VorgangArrayAdapter = new ArrayAdapter<>(
                this,
                R.layout.mylistlayout,
                vorgangsdatenList
        );

        final ListView lv = (ListView)findViewById(R.id.listView);
        lv.setAdapter(VorgangArrayAdapter);
        lv.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
            @Override
            public boolean onItemLongClick(AdapterView<?> parent, View view, int position, long id) {

                int pos = position;
                long i = id;
                vorgangsdatenList.remove(pos);
                dataSource.deleteRow(i);
                VorgangArrayAdapter.notifyDataSetChanged();

                return false;
            }
        });
        dataSource.close();



        //ActionBar Costumization
        android.support.v7.app.ActionBar ab = getSupportActionBar();
        ab.setIcon(R.drawable.search1);
        ab.setDisplayShowHomeEnabled(true);
        ab.setDisplayUseLogoEnabled(true);
    }
}

deleterow-方法：

public void deleteRow(long id){
        String s_id;
        s_id = String.valueOf(id);
        database.delete(VorgangDbHelper.TABLE_VORGAENGE_LIST,VorgangDbHelper.COLUMN_ID + "="+s_id,null);
    }

来自vorgangdbhelper的

表行：

  public static final String TABLE_VORGAENGE_LIST = "vorgaenge_list";

    public static final String COLUMN_ID = "_id";

我的deleteRow给了我一个d`oh。那么我做错了什么？

编辑：ErrorMessage

05-29 21:43:55.829 7725-7725/com.example/AndroidRuntime: FATAL EXCEPTION: main
                                                                              Process: com.example PID: 7725
                                                                              java.lang.IllegalStateException: attempt to re-open an already-closed object: SQLiteDatabase: /data/data/com.example/databases/vorgaenge_list.db
                                                                                  at android.database.sqlite.SQLiteClosable.acquireReference(SQLiteClosable.java:55)
                                                                                  at android.database.sqlite.SQLiteDatabase.delete(SQLiteDatabase.java:1613)
                                                                                  at com.example.VorgangDataSource.deleteRow(VorgangDataSource.java:75)
                                                                                  at com.example.anzeigen$1.onItemLongClick(anzeigen.java:71)
                                                                                  at android.widget.AbsListView.performLongPress(AbsListView.java:3659)
                                                                                  at android.widget.AbsListView$CheckForLongPress.run(AbsListView.java:3601)
                                                                                  at android.os.Handler.handleCallback(Handler.java:733)
                                                                                  at android.os.Handler.dispatchMessage(Handler.java:95)
                                                                                  at android.os.Looper.loop(Looper.java:146)
                                                                                  at android.app.ActivityThread.main(ActivityThread.java:5679)
                                                                                  at java.lang.reflect.Method.invokeNative(Native Method)
                                                                                  at java.lang.reflect.Method.invoke(Method.java:515)
                                                                                  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1291)
                                                                                  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1107)
                                                                                  at dalvik.system.NativeStart.main(Native Method)

SOLUTION：

deleteRow-方法：

public void deleteRow(long id){
        String s_id;
        s_id = String.valueOf(id);

        database.delete(VorgangDbHelper.TABLE_VORGAENGE_LIST,VorgangDbHelper.COLUMN_ID + " = ?", new String[] { s_id });
    }

Answer 1

请尝试在dataSource.close()方法中移动行onDestroy()。问题是您在onCreate()。

中关闭了数据库

并将删除方法更新为： database.delete(VorgangDbHelper.TABLE_VORGAENGE_LIST,VorgangDbHelper.COLUMN_ID + " = ?", new String[] { s_id });

Android删除项目列表视图和数据库

1 个答案: