我之前也问过类似的问题，但不确定如何措辞。从那以后，我看了一些教程，对我的问题有了更多的了解。我正在尝试将数据库中的信息显示到列表视图中，但无法弄清楚如何使其工作。任何帮助将是巨大的。
这是我的数据库适配器类：
public class DBAdapter {
public static final String KEY_ROWID = "id";
public static final String KEY_TITLE = "title";
public static final String KEY_WORKOUTDATE = "workoutDate";
public static final String KEY_EXERCISE_NOTES = "notes";
private static final String TAG = "WorkoutDBAdapter";
private DatabaseHelper mDBHelper;
private SQLiteDatabase mdb;
private static final String DATABASE_NAME = "WorkoutDB";
private static final String DATABASE_TABLE = "workouts";
private static final int DATABASE_VERSION = 1;
private final Context mCtx;
private static final String DATABASE_CREATE =
"create table if not exists workouts " +
"(id integer primary key autoincrement, " +
"title VARCHAR not null, " +
"workoutDate date, " +
"notes VARCHAR );";
private static class DatabaseHelper extends SQLiteOpenHelper {
DatabaseHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
@Override
public void onCreate(SQLiteDatabase db) {
Log.w(TAG, DATABASE_CREATE);
db.execSQL(DATABASE_CREATE);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
Log.w(TAG, "Upgrading database from version " + oldVersion + " to "
+ newVersion + ", which will destroy all old data");
db.execSQL("DROP TABLE IF EXISTS workouts");
onCreate(db);
}
}
public DBAdapter(Context ctx) {
this.mCtx = ctx;
}
public DBAdapter open() throws SQLException {
mDBHelper = new DatabaseHelper(mCtx);
mdb = mDBHelper.getWritableDatabase();
return this;
}
public void close() {
if (mDBHelper != null) {
mDBHelper.close();
}
}
//---retrieves all the records---
public Cursor getAllRecords() {
Cursor mCursor = mdb.query(DATABASE_TABLE, new String[]{KEY_ROWID, KEY_TITLE,
KEY_WORKOUTDATE, KEY_EXERCISE_NOTES}, null, null, null, null, null);
if (mCursor != null) {
mCursor.moveToFirst();
}
return mCursor;
}
}
这是我的AndroidListViewCursorAdaptorActivity类：
public class AndroidListViewCursorAdaptorActivity extends Activity {
private DBAdapter dbHelper;
private SimpleCursorAdapter dataAdapter;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.workouts);
dbHelper = new DBAdapter(this);
dbHelper.open();
//Generate ListView from SQLite Database
displayListView();
}
private void displayListView() {
Cursor cursor = dbHelper.getAllRecords();
// The desired columns to be bound
String[] columns = new String[] {
DBAdapter.KEY_TITLE,
DBAdapter.KEY_WORKOUTDATE,
DBAdapter.KEY_EXERCISE_NOTES,
};
// the XML defined views which the data will be bound to
int[] to = new int[] {
R.id.title,
R.id.workoutDate,
R.id.workoutDetails,
};
// create the adapter using the cursor pointing to the desired data
//as well as the layout information
dataAdapter = new SimpleCursorAdapter(
this, R.layout.workout_info,
cursor,
columns,
to,
0);
ListView listView = (ListView) findViewById(R.id.listView1);
// Assign adapter to ListView
listView.setAdapter(dataAdapter);
};
}
这是xml文件，用于保存数据应放置的位置（我认为我不是100％确信这是否是正确的方法）
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:padding="6dip" >
<TextView
android:id="@+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:text="Title: "
android:textAppearance="?android:attr/textAppearanceMedium" />
<TextView
android:id="@+id/textView2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/textView1"
android:layout_below="@+id/textView1"
android:text="WorkoutDate: "
android:textAppearance="?android:attr/textAppearanceMedium" />
<TextView
android:id="@+id/textView3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/textView2"
android:layout_below="@+id/textView2"
android:text="Workout Details"
android:textAppearance="?android:attr/textAppearanceMedium" />
<TextView
android:id="@+id/workoutDetails"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="TextView"
android:layout_alignBottom="@+id/textView3"
android:layout_centerHorizontal="true" />
<TextView
android:id="@+id/workoutDate"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="TextView"
android:layout_alignBottom="@+id/textView2"
android:layout_alignLeft="@+id/workoutDetails"
android:layout_alignStart="@+id/workoutDetails" />
<TextView
android:id="@+id/title"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="TextView"
android:layout_alignParentTop="true"
android:layout_alignLeft="@+id/workoutDetails"
android:layout_alignStart="@+id/workoutDetails" />
使用listview1继承锻炼XML
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent" android:layout_height="fill_parent"
android:orientation="vertical">
<TextView android:layout_width="fill_parent"
android:layout_height="wrap_content" android:padding="10dp"
android:text="@string/some_text" android:textSize="20sp" />
<EditText android:id="@+id/myFilter" android:layout_width="match_parent"
android:layout_height="wrap_content" android:ems="10"
android:hint="@string/some_hint">
<requestFocus />
</EditText>
<ListView android:id="@+id/listView1" android:layout_width="fill_parent"
android:layout_height="fill_parent" />
这是堆栈跟踪。我收到新的错误消息？
04-30 08:05:52.741 2565-2565/course.labs.todomanager E/AndroidRuntime: FATAL EXCEPTION: main
Process: course.labs.todomanager, PID: 2565
java.lang.RuntimeException: Unable to start activity ComponentInfo{course.labs.todomanager/course.labs.todomanager.AndroidListViewCursorAdaptorActivity}: android.database.sqlite.SQLiteException: no such column: _id (code 1): , while compiling: SELECT _id, title, workoutDate, notes FROM workouts
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2325)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2387)
at android.app.ActivityThread.access$800(ActivityThread.java:151)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1303)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5254)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)
Caused by: android.database.sqlite.SQLiteException: no such column: _id (code 1): , while compiling: SELECT _id, title, workoutDate, notes FROM workouts
at android.database.sqlite.SQLiteConnection.nativePrepareStatement(Native Method)
at android.database.sqlite.SQLiteConnection.acquirePreparedStatement(SQLiteConnection.java:889)
at android.database.sqlite.SQLiteConnection.prepare(SQLiteConnection.java:500)
at android.database.sqlite.SQLiteSession.prepare(SQLiteSession.java:588)
at android.database.sqlite.SQLiteProgram.<init>(SQLiteProgram.java:58)
at android.database.sqlite.SQLiteQuery.<init>(SQLiteQuery.java:37)
at android.database.sqlite.SQLiteDirectCursorDriver.query(SQLiteDirectCursorDriver.java:44)
at android.database.sqlite.SQLiteDatabase.rawQueryWithFactory(SQLiteDatabase.java:1316)
at android.database.sqlite.SQLiteDatabase.queryWithFactory(SQLiteDatabase.java:1163)
at android.database.sqlite.SQLiteDatabase.query(SQLiteDatabase.java:1034)
at android.database.sqlite.SQLiteDatabase.query(SQLiteDatabase.java:1202)
at course.labs.todomanager.DBAdapter.getAllRecords(DBAdapter.java:91)
at course.labs.todomanager.AndroidListViewCursorAdaptorActivity.displayListView(AndroidListViewCursorAdaptorActivity.java:43)
at course.labs.todomanager.AndroidListViewCursorAdaptorActivity.onCreate(AndroidListViewCursorAdaptorActivity.java:36)
at android.app.Activity.performCreate(Activity.java:5990)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1106)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2278)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2387)
at android.app.ActivityThread.access$800(ActivityThread.java:151)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1303)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5254)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)
我没有在您的代码中看到任何错误，您是否尝试过重新安装应用程序？这样您的SQL更改将被重新验证。
注意：我的回答是基于当前的EDIT以及对当前评论的响应。
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