如何在 android 中创建包含来自 sqlite 的数据的列表视图

Question

我正在尝试在 ListView 中显示来自 SQLite 数据库的数据。我使用 CursorAdapter 直接将 Cursor 插入 ListView 但出于某种原因，我总是遇到异常。这是我修改后的 DBadapter activity:

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;

        }

这里我设置SimpleCursorAdapter:

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);

这是我遇到的异常：

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.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)

Answer 1

只要看看 logcat，错误的来源就在第二行中解释：

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

您的 table 没有 _id 列，但 CursorAdapter 需要存在 _id 列（如文档 right here 中所述).

您的解决方案很简单：您已经有一个 id 列，但它被称为 ID。将其重命名为 _id，一切正常！

_{请注意，您可能需要重新安装您的应用才能使 and/or table 列的更改生效！}

Answer 2

而不是重命名为 _id 另一种方法是，在查询中你可以 select ID as _id

它已经在 SO 中回答了。

Android: column '_id' does not exist
Android column '_id' does not exist?
About “_id” field in Android SQLite

如何在 android 中创建包含来自 sqlite 的数据的列表视图

How to create a list view contains data from sqlite in android

sqlite

android

android-cursoradapter