Question

我正在尝试在CursorAdapter中显示来自SQLite数据库的数据。我使用Cursor直接将ListView插入public static final String ID="_id"; public Cursor feching_Data(){ String[] columns = {ID,USER_NAME,USER_PASSWORD}; db = dbHelper.getWritableDatabase(); Cursor cursor = db.query(TABLE_NAME, columns,null,null,null,null,null); return cursor; }但由于某种原因我总是遇到异常。这是我修改过的DBadapter活动：

SimpleCursorAdapter

我在这里设置public static final String ID="_id"; String[] from = {logindatabase_adapter.USER_NAME,logindatabase_adapter.USER_PASSWORD}; int[] to = {R.id.txt_username,R.id.txt_pasword}; Cursor cursor = logindatabase_adapter.feching_Data(); cursoradapter = new SimpleCursorAdapter(DatabaseListView.this, R.layout.listcell, cursor, from, to); database_results.setAdapter(cursoradapter);：

FATAL EXCEPTION: main
   Process: com.developer.milanandroid, PID: 5109
   java.lang.IllegalArgumentException: column '_id' does not exist
    at android.database.AbstractCursor.getColumnIndexOrThrow(AbstractCursor.java:303)
    at android.widget.CursorAdapter.init(CursorAdapter.java:172)
    at android.widget.CursorAdapter.<init>(CursorAdapter.java:120)
    at android.widget.ResourceCursorAdapter.<init>(ResourceCursorAdapter.java:52)
    at android.widget.SimpleCursorAdapter.<init>(SimpleCursorAdapter.java:78)
    at com.developer.milanandroid.DatabaseListView$1.onClick(DatabaseListView.java:50)
    at android.view.View.performClick(View.java:4438)
    at android.view.View.onKeyUp(View.java:8241)
    at android.widget.TextView.onKeyUp(TextView.java:5682)
    at android.view.KeyEvent.dispatch(KeyEvent.java:2664)
    at android.view.View.dispatchKeyEvent(View.java:7665)
    at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1408)
    at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1408)
    at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1408)
    at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1408)
    at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1408)
    at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchKeyEvent(PhoneWindow.java:2035)
    at com.android.internal.policy.impl.PhoneWindow.superDispatchKeyEvent(PhoneWindow.java:1505)
    at android.app.Activity.dispatchKeyEvent(Activity.java:2418)
    at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchKeyEvent(PhoneWindow.java:1962)
    at android.view.ViewRootImpl$ViewPostImeInputStage.processKeyEvent(ViewRootImpl.java:3852)
    at android.view.ViewRootImpl$ViewPostImeInputStage.onProcess(ViewRootImpl.java:3826)
    at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:3399)
    at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:3449)
    at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:3418)
    at android.view.ViewRootImpl$AsyncInputStage.forward(ViewRootImpl.java:3525)
    at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:3426)
    at android.view.ViewRootImpl$AsyncInputStage.apply(ViewRootImpl.java:3582)
    at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:3399)
    at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:3449)
    at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:3418)
    at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:3426)
    at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:3399)
    at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:3449)
    at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:3418)
    at android.view.ViewRootImpl$AsyncInputStage.forward(ViewRootImpl.java:3558)
    at android.view.ViewRootImpl$ImeInputStage.onFinishedInputEvent(ViewRootImpl.java:3718)
    at android.view.inputmethod.InputMethodManager$PendingEvent.run(InputMethodManager.java:2010)
    at android.view.inputmethod.InputMethodManager.invokeFinishedInputEventCallback(InputMethodManager.java:1704)
    at android.view.inputmethod.InputMethodManager.finishedInputEvent(InputMethodManager.java:1695)
    at android.view.inputmethod.InputMethodManager$ImeInputEventSender.onInputEventFinished(InputMethodManager.java:1987)
    at android.view.InputEventSender.dispatchInputEventFinished(InputEventSender.java:141)
    at android.os.MessageQueue.nativePollOnce(Native Method)
    at android.os.MessageQueue.next(MessageQueue.java:138)
    at android.os.Looper.loop(Looper.java:123)
    at android.app.ActivityThread.main(ActivityThread.java:5017)
    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:779)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
    at dalvik.system.NativeStart.main(Native Method)

这是我得到的例外：

<strong>Server Time&nbsp;:&nbsp;&nbsp;</strong><label id="timelable"></label>

Answer 1

只要看一下logcat，就会在第二行解释错误的来源：

java.lang.IllegalArgumentException: column '_id' does not exist.

您的表格没有_id列，但CursorAdapter要求存在_id列（如文档right here中所述）。

您的案例中的解决方案很简单：您已经拥有了一个id列，但它被称为ID。将其重命名为_id，一切都应该正常工作！

_{请注意，您可能需要重新安装应用以更改列和/或表格才能生效！}

Answer 2

在查询中，您可以选择_id作为ID

，而不是重命名为_id。

已在SO中回答。

如何创建列表视图包含来自android中的sqlite的数据

2 个答案: