我是 Android 开发的初学者——也很抱歉我的英语不好，这不是我的母语。（：好的，所以。我正在尝试实现一个在三个选项卡之间滑动的应用程序，其中一个选项卡中有一个数据库 - 它必须显示在 ListView 中。我的代码远非正确，我正在尝试找出每个错误，只要他们自己显示。成功，因为......现在。当我运行应用程序时，似乎......没有这样的表。接下来，我的代码：
SQLDBase.java：
public class SQLDBase {
public static final String KEY_ROWID = "_id";
public static final String KEY_NAME = "name";
public static final String KEY_TIMER = "time";
public static final String KEY_DISTANCE = "kms";
public static final String KEY_HR = "heart_rate";
public static final String KEY_CAL = "kcals";
private static final String DATABASE_NAME = "SESSION";
private static final int DATABASE_VERSION = 42;
private static final String DATABASE_READABLE = "rdInfos";
private static final String DATABASE_WRITEABLE = "wrtInfos";
private DBHelper mHelper;
private final Context mContext;
private SQLiteDatabase mDatabase;
public static class DBHelper extends SQLiteOpenHelper {
public DBHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
@Override
//Set up database here
public void onCreate(SQLiteDatabase db) {
db.execSQL("CREATE TABLE " + DATABASE_READABLE + " (" +
//Column name Type of variable
KEY_ROWID + " INTEGER PRIMARY KEY AUTOINCREMENT, " +
// KEY_NAME + " TEXT NOT NULL, " +
KEY_TIMER + " TEXT NOT NULL, " +
KEY_DISTANCE + " TEXT NOT NULL, " +
KEY_HR + " TEXT NOT NULL);"
);
db.execSQL("CREATE TABLE " + DATABASE_WRITEABLE + " (" +
KEY_ROWID + " INTEGER PRIMARY KEY AUTOINCREMENT, " +
// KEY_NAME + " TEXT NOT NULL, " +
KEY_TIMER + " TEXT NOT NULL, " +
KEY_DISTANCE + " TEXT NOT NULL, " +
KEY_HR + " TEXT NOT NULL);"
);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.execSQL("DROP TABLE IF EXISTS " + DATABASE_READABLE);
db.execSQL("DROP IF TABLE EXISTS " + DATABASE_WRITEABLE);
onCreate(db);
}
}
public SQLDBase(Context c) {
mContext = c;
}
public SQLDBase open() throws SQLException {
//Set up the helper with the context
mHelper = new DBHelper(mContext);
//Open the database with our helper
mDatabase = mHelper.getWritableDatabase();
return this;
}
public long createEntry(String timer, String distance, String hr, String kcals) {
ContentValues cv = new ContentValues();
cv.put(KEY_TIMER, timer);
cv.put(KEY_DISTANCE, distance);
cv.put(KEY_HR, hr);
cv.put(KEY_CAL, kcals);
return mDatabase.insert(DATABASE_WRITEABLE, null, cv);
}
public int deleteAll(){
return mDatabase.delete(DATABASE_NAME, null, null);
}
public Cursor queueAll(){
String[] columns = new String[]{KEY_ROWID, KEY_TIMER, KEY_DISTANCE, KEY_HR, KEY_ROWID};
Cursor cursor = mDatabase.query(DATABASE_NAME, columns,
null, null, null, null, null);
return cursor;
}
}
日记.java
public class Diary extends ListFragment implements LoaderManager.LoaderCallbacks<Cursor>{
private SQLDBase db;
private LoaderManager.LoaderCallbacks<Cursor> mCallbacks;
private SimpleCursorAdapter mAdapter;
SearchView mSearchView;
String mCurFilter;
private Context mContext;
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.tab_2, container, false);
ButterKnife.inject(this, view);
return view;
}
public void onViewCreated(View view, Bundle savedInstanceState) {
setEmptyText("No entries.");
db = new SQLDBase(getActivity());
db.open();
Log.i("", "Database in diary opened.");
Cursor cursor = db.queueAll();
mAdapter = new SimpleCursorAdapter(getActivity(), android.R.layout.simple_list_item_2,null,
new String[] {SQLDBase.KEY_TIMER, SQLDBase.KEY_DISTANCE,SQLDBase.KEY_HR, SQLDBase.KEY_CAL,},
new int[] {android.R.id.text1, android.R.id.text2}, 0);
setListAdapter(mAdapter);
setListShown(false);
getLoaderManager().initLoader(0, null, this);
}
public static class MySearchView extends SearchView {
public MySearchView(Context context) {
super(context);
}
public void onActionViewCollapsed() {
setQuery("", false);
super.onActionViewCollapsed();
}
}
public boolean onClose() {
if (!TextUtils.isEmpty(mSearchView.getQuery())) {
mSearchView.setQuery(null, true);
}
return true;
}
@Override
public void onListItemClick(ListView l, View v, int position, long id) {
// Insert desired behavior here.
Log.i("FragmentComplexList", "Item clicked: " + id);
}
public Loader<Cursor> onCreateLoader(int id, Bundle args) {
// This is called when a new Loader needs to be created. This
// sample only has one Loader, so we don't care about the ID.
// First, pick the base URI to use depending on whether we are
// currently filtering.
Uri baseUri;
if (mCurFilter != null) {
baseUri = Uri.withAppendedPath(Uri.parse(SQLDBase.KEY_ROWID),
Uri.encode(mCurFilter));
} else {
baseUri = Uri.parse(SQLDBase.KEY_TIMER + " " + SQLDBase.KEY_DISTANCE + " " + SQLDBase.KEY_HR + " " + SQLDBase.KEY_CAL + " ");
}
// Now create and return a CursorLoader that will take care of
// creating a Cursor for the data being displayed.
String select = "((" + SQLDBase.KEY_TIMER + " NOTNULL) AND ("
+ SQLDBase.KEY_DISTANCE + " NOTNULL) AND ("
+ SQLDBase.KEY_HR + "NOTNULL) AND ("
+ SQLDBase.KEY_CAL + " NOTNULL ))";
return new CursorLoader(getActivity(), baseUri,
new String [] {SQLDBase.KEY_TIMER + " " + SQLDBase.KEY_DISTANCE + " " + SQLDBase.KEY_HR + " " + SQLDBase.KEY_CAL + " "}, select,
new String [] {SQLDBase.KEY_NAME}, null);
}
public void onLoadFinished(Loader<Cursor> loader, Cursor data) {
// Swap the new cursor in. (The framework will take care of closing the
// old cursor once we return.)
mAdapter.swapCursor(data);
// The list should now be shown.
if (isResumed()) {
setListShown(true);
} else {
setListShownNoAnimation(true);
}
}
public void onLoaderReset(Loader<Cursor> loader) {
// This is called when the last Cursor provided to onLoadFinished()
// above is about to be closed. We need to make sure we are no
// longer using it.
mAdapter.swapCursor(null);
}
}
我的日志猫
09-06 16:52:41.960 31324-31324/apheniti.prova E/AndroidRuntime﹕ FATAL EXCEPTION: main
android.database.sqlite.SQLiteException: no such table: SESSION (code 1): , while compiling: SELECT _id, time, kms, heart_rate, _id FROM SESSION
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:1314)
at android.database.sqlite.SQLiteDatabase.queryWithFactory(SQLiteDatabase.java:1161)
at android.database.sqlite.SQLiteDatabase.query(SQLiteDatabase.java:1032)
at android.database.sqlite.SQLiteDatabase.query(SQLiteDatabase.java:1200)
at apheniti.prova.SQLDBase.queueAll(SQLDBase.java:95)
at apheniti.prova.Diary.onViewCreated(Diary.java:46)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:973)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1138)
at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:740)
at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1501)
at android.support.v4.app.FragmentManagerImpl.executePendingTransactions(FragmentManager.java:490)
at android.support.v4.app.FragmentStatePagerAdapter.finishUpdate(FragmentStatePagerAdapter.java:163)
at android.support.v4.view.ViewPager.populate(ViewPager.java:1105)
at android.support.v4.view.ViewPager.populate(ViewPager.java:951)
at android.support.v4.view.ViewPager.onMeasure(ViewPager.java:1473)
at android.view.View.measure(View.java:15848)
at android.widget.RelativeLayout.measureChildHorizontal(RelativeLayout.java:728)
at android.widget.RelativeLayout.onMeasure(RelativeLayout.java:477)
at android.view.View.measure(View.java:15848)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5008)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
at android.support.v7.internal.widget.ContentFrameLayout.onMeasure(ContentFrameLayout.java:124)
at android.view.View.measure(View.java:15848)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5008)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1404)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:695)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:588)
at android.view.View.measure(View.java:15848)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5008)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
at android.view.View.measure(View.java:15848)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5008)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1404)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:695)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:588)
at android.view.View.measure(View.java:15848)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5008)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2189)
at android.view.View.measure(View.java:15848)
at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:1905)
at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1104)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1284)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1004)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5481)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:749)
at android.view.Choreographer.doCallbacks(Choreographer.java:562)
SQLDBase 的第 95 行：
Cursor cursor = mDatabase.query(DATABASE_NAME, columns,
null, null, null, null, null);
日记第 46 行：
Cursor cursor = db.queueAll();
谢谢你的帮助！