我正在尝试让我的应用程序显示我在数据库中设置的表中的信息。据我所知，数据库设置正确并且代码正确，但我不知道是什么导致了错误。我将发布所有代码，看看这里是否有人可以帮助我解决问题。
进度类:
public class WorkoutProgress extends ListActivity {
private DataBaseHelper datasource;
TextView goal;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,WindowManager.LayoutParams.FLAG_FULLSCREEN);
setContentView(R.layout.progress);
goal = (TextView)findViewById(R.id.goal);
datasource = new DataBaseHelper(this);
datasource.open();
fillData();
datasource.close();
}
private void fillData() {
Cursor c = datasource.getAllActs();
startManagingCursor(c);
String[] from = new String[] {DataBaseHelper.KEY_DATE,
DataBaseHelper.KEY_STEPS,DataBaseHelper.KEY_CALs };
int[] to = { R.id.code, R.id.Days, R.id.BMI };
SimpleCursorAdapter notes = new SimpleCursorAdapter (this, R.layout.notes_row, c, from, to);
setListAdapter(notes);
}
}
数据库助手:
public class DataBaseHelper
{
public static final String KEY_ROWID = "_id";
public static final String KEY_GOAL = "goal";
public static final String KEY_Current = "cweight";
public static final String KEY_Target = "nweight";
public static final String KEY_ROWID2 = "_id";
public static final String KEY_DATE = "date";
public static final String KEY_STEPS = "steps";
public static final String KEY_CALs = "calories";
public static final String KEY_CALID = "_id";
public static final String KEY_TOTALCALS = "totalcals";
private static final String TAG = "DBAdapter";
private static final String DATABASE_NAME = "workout";
private static final String DATABASE_TABLE = "goals";
private static final String DATATABLE = "acts";
private static final String CALTABLE = "cals";
private static final int DATABASE_VERSION = 1;
private static final String DATABASE_CREATE =
"create table goals (_id integer primary key autoincrement, "
+ "goal text not null, cweight number not null, "
+ "nweight number not null);";
private static final String DATABASE_CREATE2 =
"create table acts (_id integer primary key autoincrement, "
+ "date text not null, steps text not null, "
+ "calories number not null);"
private final Context context;
private DatabaseHelper DBHelper;
private SQLiteDatabase db;
public DataBaseHelper(Context ctx)
{
this.context = ctx;
DBHelper = new DatabaseHelper(context);
}
private static class DatabaseHelper extends SQLiteOpenHelper
{
DatabaseHelper(Context context)
{
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
@Override
public void onCreate(SQLiteDatabase db)
{
db.execSQL(DATABASE_CREATE);
db.execSQL(DATABASE_CREATE2);
}
@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 titles");
onCreate(db);
}
}
public DataBaseHelper open() throws SQLException
{
db = DBHelper.getWritableDatabase();
return this;
}
public void close()
{
DBHelper.close();
}
public long insertTitle(String goal, int current, int target)
{
ContentValues initialValues = new ContentValues();
initialValues.put(KEY_GOAL, goal);
initialValues.put(KEY_Current, current);
initialValues.put(KEY_Target, target);
return db.insert(DATABASE_TABLE, null, initialValues);
}
public long insertActivity(String date, String steps, double Calories)
{
ContentValues initialValues = new ContentValues();
initialValues.put(KEY_DATE, date);
initialValues.put(KEY_STEPS, steps);
initialValues.put(KEY_CALs, Calories);
return db.insert(DATATABLE, null, initialValues);
}
public boolean deleteTitle(long rowId)
{
return db.delete(DATABASE_TABLE, KEY_ROWID +
"=" + rowId, null) > 0;
}
public void deleteFirst()
{
Cursor cursor = db.query(DATABASE_TABLE, null, null, null, null, null, null);
if(cursor.moveToFirst()) {
long rowId = cursor.getLong(cursor.getColumnIndex(KEY_ROWID));
db.delete(DATABASE_TABLE, KEY_ROWID + "=" + rowId, null);
}
}
public boolean deleteAct(long rowId)
{
return db.delete(DATATABLE, KEY_ROWID +
"=" + rowId, null) > 0;
}
//---retrieves all the titles---
public Cursor getAllGoals()
{
return db.query(DATABASE_TABLE, new String[] {
KEY_ROWID,
KEY_GOAL,
KEY_Current,
KEY_Target},
null,
null,
null,
null,
null);
}
public Cursor getAllActs()
{
return db.query(DATATABLE, new String[] {
KEY_ROWID2,
KEY_DATE,
KEY_STEPS,
KEY_CALs},
null,
null,
null,
null,
null);
}
//---retrieves a particular title---
public Cursor getGoal
(long rowId) throws SQLException
{
Cursor mCursor =
db.query(true, DATABASE_TABLE, new String[] {
KEY_ROWID,
KEY_GOAL,
KEY_Current,
KEY_Target
},
KEY_ROWID + "=" + rowId,
null,
null,
null,
null,
null);
if (mCursor != null) {
mCursor.moveToFirst();
}
return mCursor;
}
public Cursor getAct(long rowId) throws SQLException
{
Cursor mCursor =
db.query(true, DATATABLE, new String[] {
KEY_ROWID2,
KEY_DATE,
KEY_STEPS,
KEY_CALs
},
KEY_ROWID2 + "=" + rowId,
null,
null,
null,
null,
null);
if (mCursor != null) {
mCursor.moveToFirst();
}
return mCursor;
}
public boolean updateAct(long rowId, String date,
String steps, String cals)
{
ContentValues args = new ContentValues();
args.put(KEY_DATE, date);
args.put(KEY_STEPS, steps);
args.put(KEY_CALs, cals);
return db.update(DATATABLE, args,
KEY_ROWID2 + "=" + rowId, null) > 0;
}
/*public boolean updateCals(long rowId, double cals)
{
ContentValues args = new ContentValues();
args.put(KEY_TOTALCALS, cals);
return db.update(CALTABLE, args,
KEY_CALID + "=" + rowId, null) > 0;
}*/
//---updates a title---
public boolean updateTitle(long rowId, String isbn,
String title, String publisher)
{
ContentValues args = new ContentValues();
args.put(KEY_GOAL, isbn);
args.put(KEY_Current, title);
args.put(KEY_Target, publisher);
return db.update(DATABASE_TABLE, args,
KEY_ROWID + "=" + rowId, null) > 0;
}
}
日志:
05-26 14:42:03.895: E/AndroidRuntime(345): FATAL EXCEPTION: main
05-26 14:42:03.895: E/AndroidRuntime(345): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.b00348312.workout/com.b00348312.workout.WorkoutProgress}: android.database.sqlite.SQLiteException: no such column: _id: , while compiling: SELECT _id, date, steps, calories FROM acts
05-26 14:42:03.895: E/AndroidRuntime(345): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663)
05-26 14:42:03.895: E/AndroidRuntime(345): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
05-26 14:42:03.895: E/AndroidRuntime(345): at android.app.ActivityThread.access$2300(ActivityThread.java:125)
05-26 14:42:03.895: E/AndroidRuntime(345): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
05-26 14:42:03.895: E/AndroidRuntime(345): at android.os.Handler.dispatchMessage(Handler.java:99)
05-26 14:42:03.895: E/AndroidRuntime(345): at android.os.Looper.loop(Looper.java:123)
05-26 14:42:03.895: E/AndroidRuntime(345): at android.app.ActivityThread.main(ActivityThread.java:4627)
05-26 14:42:03.895: E/AndroidRuntime(345): at java.lang.reflect.Method.invokeNative(Native Method)
05-26 14:42:03.895: E/AndroidRuntime(345): at java.lang.reflect.Method.invoke(Method.java:521)
05-26 14:42:03.895: E/AndroidRuntime(345): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
05-26 14:42:03.895: E/AndroidRuntime(345): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
05-26 14:42:03.895: E/AndroidRuntime(345): at dalvik.system.NativeStart.main(Native Method)
05-26 14:42:03.895: E/AndroidRuntime(345): Caused by: android.database.sqlite.SQLiteException: no such column: _id: , while compiling: SELECT _id, date, steps, calories FROM acts
05-26 14:42:03.895: E/AndroidRuntime(345): at android.database.sqlite.SQLiteCompiledSql.native_compile(Native Method)
05-26 14:42:03.895: E/AndroidRuntime(345): at android.database.sqlite.SQLiteCompiledSql.compile(SQLiteCompiledSql.java:91)
05-26 14:42:03.895: E/AndroidRuntime(345): at android.database.sqlite.SQLiteCompiledSql.<init>(SQLiteCompiledSql.java:64)
05-26 14:42:03.895: E/AndroidRuntime(345): at android.database.sqlite.SQLiteProgram.<init>(SQLiteProgram.java:80)
05-26 14:42:03.895: E/AndroidRuntime(345): at android.database.sqlite.SQLiteQuery.<init>(SQLiteQuery.java:46)
05-26 14:42:03.895: E/AndroidRuntime(345): at android.database.sqlite.SQLiteDirectCursorDriver.query(SQLiteDirectCursorDriver.java:42)
05-26 14:42:03.895: E/AndroidRuntime(345): at android.database.sqlite.SQLiteDatabase.rawQueryWithFactory(SQLiteDatabase.java:1345)
05-26 14:42:03.895: E/AndroidRuntime(345): at android.database.sqlite.SQLiteDatabase.queryWithFactory(SQLiteDatabase.java:1229)
05-26 14:42:03.895: E/AndroidRuntime(345): at android.database.sqlite.SQLiteDatabase.query(SQLiteDatabase.java:1184)
05-26 14:42:03.895: E/AndroidRuntime(345): at android.database.sqlite.SQLiteDatabase.query(SQLiteDatabase.java:1264)
05-26 14:42:03.895: E/AndroidRuntime(345): at com.b00348312.workout.DataBaseHelper.getAllActs(DataBaseHelper.java:168)
05-26 14:42:03.895: E/AndroidRuntime(345): at com.b00348312.workout.WorkoutProgress.fillData(WorkoutProgress.java:30)
05-26 14:42:03.895: E/AndroidRuntime(345): at com.b00348312.workout.WorkoutProgress.onCreate(WorkoutProgress.java:25)
05-26 14:42:03.895: E/AndroidRuntime(345): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
05-26 14:42:03.895: E/AndroidRuntime(345): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)
05-26 14:42:03.895: E/AndroidRuntime(345): ... 11 more
查看 logcat，它似乎告诉我我缺少列 "_id" 但我修改了数据库以包含此列，您可以在上面的数据库帮助程序代码中看到它。我错过了什么吗？
最佳答案
您可能已经修改了数据库以包含所需的列，但是直到再次调用方法 onCreate 或您在 onUpgrade 中实现更改后，此更改才会真正在数据库中实现 方法并修改数据库的版本。
尝试卸载应用程序，然后在模拟器/手机上再次安装该应用程序，以便再次调用 SQLiteOpenHelper 实现的 onCreate 方法。
关于android - 无法在 ListView 中显示数据库，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/10767189/