我已经完成了没有崩溃的应用程序，但是我在logcat中遇到了这些错误。当我回到第一个活动并从列表视图中选择项目时，它们会出现。我试图关闭游标和数据库。 出了什么问题？
09-25 09:13:07.609: I/dalvikvm(1013): threadid=3: reacting to signal 3
09-25 09:13:07.759: I/dalvikvm(1013): Wrote stack traces to '/data/anr/traces.txt'
09-25 09:13:08.089: I/dalvikvm(1013): threadid=3: reacting to signal 3
09-25 09:13:08.160: I/dalvikvm(1013): Wrote stack traces to '/data/anr/traces.txt'
09-25 09:13:08.579: I/dalvikvm(1013): threadid=3: reacting to signal 3
09-25 09:13:08.629: I/dalvikvm(1013): Wrote stack traces to '/data/anr/traces.txt'
09-25 09:13:23.170: D/dalvikvm(1013): GC_CONCURRENT freed 516K, 6% free 10848K/11463K, paused 27ms+14ms
09-25 09:13:23.209: E/SQLiteDatabase(1013): close() was never explicitly called on database '/data/data/hr.punctum.LociranjePonudaProizvoda/databases/proizvodidb'
09-25 09:13:23.209: E/SQLiteDatabase(1013): android.database.sqlite.DatabaseObjectNotClosedException: Application did not close the cursor or database object that was opened here
09-25 09:13:23.209: E/SQLiteDatabase(1013): at android.database.sqlite.SQLiteDatabase.<init>(SQLiteDatabase.java:1943)
09-25 09:13:23.209: E/SQLiteDatabase(1013): at android.database.sqlite.SQLiteDatabase.openDatabase(SQLiteDatabase.java:1007)
09-25 09:13:23.209: E/SQLiteDatabase(1013): at android.database.sqlite.SQLiteDatabase.openDatabase(SQLiteDatabase.java:986)
09-25 09:13:23.209: E/SQLiteDatabase(1013): at android.database.sqlite.SQLiteDatabase.openOrCreateDatabase(SQLiteDatabase.java:1051)
09-25 09:13:23.209: E/SQLiteDatabase(1013): at android.app.ContextImpl.openOrCreateDatabase(ContextImpl.java:770)
09-25 09:13:23.209: E/SQLiteDatabase(1013): at android.content.ContextWrapper.openOrCreateDatabase(ContextWrapper.java:221)
09-25 09:13:23.209: E/SQLiteDatabase(1013): at android.database.sqlite.SQLiteOpenHelper.getWritableDatabase(SQLiteOpenHelper.java:157)
09-25 09:13:23.209: E/SQLiteDatabase(1013): at hr.punctum.LociranjePonudaProizvoda.ListaProizvoda.onCreate(ListaProizvoda.java:27)
09-25 09:13:23.209: E/SQLiteDatabase(1013): at android.app.Activity.performCreate(Activity.java:4465)
09-25 09:13:23.209: E/SQLiteDatabase(1013): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1049)
09-25 09:13:23.209: E/SQLiteDatabase(1013): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1920)
09-25 09:13:23.209: E/SQLiteDatabase(1013): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1981)
09-25 09:13:23.209: E/SQLiteDatabase(1013): at android.app.ActivityThread.access$600(ActivityThread.java:123)
09-25 09:13:23.209: E/SQLiteDatabase(1013): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1147)
09-25 09:13:23.209: E/SQLiteDatabase(1013): at android.os.Handler.dispatchMessage(Handler.java:99)
09-25 09:13:23.209: E/SQLiteDatabase(1013): at android.os.Looper.loop(Looper.java:137)
09-25 09:13:23.209: E/SQLiteDatabase(1013): at android.app.ActivityThread.main(ActivityThread.java:4424)
09-25 09:13:23.209: E/SQLiteDatabase(1013): at java.lang.reflect.Method.invokeNative(Native Method)
09-25 09:13:23.209: E/SQLiteDatabase(1013): at java.lang.reflect.Method.invoke(Method.java:511)
09-25 09:13:23.209: E/SQLiteDatabase(1013): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
09-25 09:13:23.209: E/SQLiteDatabase(1013): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
09-25 09:13:23.209: E/SQLiteDatabase(1013): at dalvik.system.NativeStart.main(Native Method)
09-25 09:13:23.230: E/System(1013): Uncaught exception thrown by finalizer
09-25 09:13:23.261: E/System(1013): java.lang.IllegalStateException: Don't have database lock!
09-25 09:13:23.261: E/System(1013): at android.database.sqlite.SQLiteDatabase.verifyLockOwner(SQLiteDatabase.java:2090)
09-25 09:13:23.261: E/System(1013): at android.database.sqlite.SQLiteDatabase$1.entryRemoved(SQLiteDatabase.java:2182)
09-25 09:13:23.261: E/System(1013): at android.database.sqlite.SQLiteDatabase$1.entryRemoved(SQLiteDatabase.java:2178)
09-25 09:13:23.261: E/System(1013): at android.util.LruCache.trimToSize(LruCache.java:197)
09-25 09:13:23.261: E/System(1013): at android.util.LruCache.evictAll(LruCache.java:285)
09-25 09:13:23.261: E/System(1013): at android.database.sqlite.SQLiteDatabase.deallocCachedSqlStatements(SQLiteDatabase.java:2143)
09-25 09:13:23.261: E/System(1013): at android.database.sqlite.SQLiteDatabase.closeClosable(SQLiteDatabase.java:1126)
09-25 09:13:23.261: E/System(1013): at android.database.sqlite.SQLiteDatabase.finalize(SQLiteDatabase.java:1914)
09-25 09:13:23.261: E/System(1013): at java.lang.Daemons$FinalizerDaemon.doFinalize(Daemons.java:182)
09-25 09:13:23.261: E/System(1013): at java.lang.Daemons$FinalizerDaemon.run(Daemons.java:168)
09-25 09:13:23.261: E/System(1013): at java.lang.Thread.run(Thread.java:856)
09-25 09:13:23.390: I/dalvikvm(1013): threadid=3: reacting to signal 3
09-25 09:13:23.409: I/dalvikvm(1013): Wrote stack traces to '/data/anr/traces.txt'
DatabaseHelper.java
package hr.punctum.LociranjePonudaProizvoda;
public class DatabaseHelper extends SQLiteOpenHelper {
public static final String DATABASE_NAME = "proizvodidb";
public DatabaseHelper(Context context) {
super(context, DATABASE_NAME, null, 1);
}
@Override
public void onCreate(SQLiteDatabase db) {
String sql = "CREATE TABLE IF NOT EXISTS proizvodi (" +
"_id INTEGER PRIMARY KEY AUTOINCREMENT, " +
"naziv TEXT, " +
"tvrtka TEXT, " +
"cijena TEXT, " +
"kategorija TEXT, " +
"telefonTvrtke TEXT, " +
"adresaTvrtke TEXT, " +
"latitude INTEGER, " +
"longitude INTEGER)";
db.execSQL(sql);
ContentValues values = new ContentValues();
values.put("naziv", "Canon 5D mark III");
values.put("tvrtka", "M-Computers");
values.put("cijena", "27257kn");
values.put("kategorija", "fotoaparati");
values.put("telefonTvrtke", "01/3707800");
values.put("adresaTvrtke", "Cankareva 3, Zagreb");
values.put("latitude", 45813029);
values.put("longitude", 15977894);
db.insert("proizvodi", "tvrtka", values);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.execSQL("DROP TABLE IF EXISTS proizvodi");
onCreate(db);
db.close();
}
ListaProizvoda.java
package hr.punctum.LociranjePonudaProizvoda;
public class ListaProizvoda extends ListActivity {
protected EditText searchText;
protected SQLiteDatabase db;
protected Cursor cursor;
protected ListAdapter adapter;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
db = (new DatabaseHelper(this)).getWritableDatabase();
searchText = (EditText) findViewById (R.id.searchText);
}
@SuppressWarnings("deprecation")
public void search(View view) {
cursor = db.rawQuery("SELECT _id, naziv, tvrtka, cijena FROM proizvodi WHERE naziv LIKE ?",
new String[]{searchText.getText().toString() + "%"});
adapter = new SimpleCursorAdapter(this,R.layout.proizvodi_list_artikl,cursor,new String[] {"naziv", "tvrtka", "cijena"},new int[] {R.id.naziv, R.id.tvrtka, R.id.cijena});
startManagingCursor(cursor);
setListAdapter(adapter);
}
public void onListItemClick(ListView parent, View view, int position, long id) {
Intent intent = new Intent(getApplicationContext(), DetaljiProizvoda.class);
Cursor cursor = (Cursor) adapter.getItem(position);
intent.putExtra("PROIZVODI_ID", cursor.getInt(cursor.getColumnIndex("_id")));
startActivity(intent);
}
}
DetaljiProizvoda.java
package hr.punctum.LociranjePonudaProizvoda;
public class DetaljiProizvoda extends Activity {
protected TextView naziv;
protected TextView kategorija;
protected TextView tvrtka;
protected TextView telefonTvrtke;
protected TextView adresaTvrtke;
protected int proizvodId;
protected Cursor cursor;
protected ListAdapter adapter;
protected SQLiteDatabase db;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.detalji_proizvoda);
proizvodId = getIntent().getIntExtra("PROIZVODI_ID", 0);
db = (new DatabaseHelper(this)).getWritableDatabase();
cursor = db.rawQuery("SELECT proizv._id, proizv.naziv, proizv.tvrtka, proizv.cijena, proizv.kategorija, proizv.telefonTvrtke, proizv.adresaTvrtke, proizv.latitude, proizv.longitude FROM proizvodi proizv LEFT OUTER JOIN proizvodi mgr ON proizv._id = mgr._id WHERE proizv._id = ?",
new String[]{""+proizvodId});
if (cursor.getCount() == 1)
{
cursor.moveToFirst();
naziv = (TextView) findViewById(R.id.naziv);
naziv.setText(cursor.getString(cursor.getColumnIndex("naziv")));
kategorija = (TextView) findViewById(R.id.kategorija);
kategorija.setText(cursor.getString(cursor.getColumnIndex("kategorija")));
tvrtka = (TextView) findViewById(R.id.tvrtka);
tvrtka.setText(cursor.getString(cursor.getColumnIndex("tvrtka")));
telefonTvrtke = (TextView) findViewById(R.id.telefonTvrtke);
telefonTvrtke.setText(cursor.getString(cursor.getColumnIndex("telefonTvrtke")));
adresaTvrtke = (TextView) findViewById(R.id.adresaTvrtke);
adresaTvrtke.setText(cursor.getString(cursor.getColumnIndex("adresaTvrtke")));
}
}
public void changeActivity(View view) {
Intent intent = new Intent(getApplicationContext(), GMapsActivity.class);
intent.putExtra("PROIZVODI_ID", cursor.getColumnIndex("_id"));
intent.putExtra("PROIZVODI_LATITUDE", cursor.getInt(cursor.getColumnIndex("latitude")));
intent.putExtra("PROIZVODI_LONGITUDE", cursor.getInt(cursor.getColumnIndex("longitude")));
startActivity(intent);
cursor.close();
db.close();
}
}
答案 0 :(得分：3)
按活动的onStop()或onDestroy()方法关闭数据库。
答案 1 :(得分：1)
你应该忘记database.close()。请在您的案例中验证所有 database.open（），并在成功运行后关闭数据库。
答案 2 :(得分：1)
最好将DatabaseHelper变成单例并在应用程序的生命周期内保持打开状态： -
DatabaseHelper helper = DatabaseHelper.getInstance();
这是一种常见的方法，因为您永远不必显式关闭数据库，并且由于Android是单用户环境，因此无需经常打开和关闭数据库。
ContentProvider实现作为单例持久化，并且通常在提供者onCreate（...）中创建SqliteOpenHelper的字段实例，您可以在此处查看它的示例http://developer.android.com/guide/topics/providers/content-provider-creating.html
因此，无论您决定管理数据库生命周期，请考虑在某处保留单个实例以避免遇到麻烦，尤其是当您开始在线程中使用它时。
答案 3 :(得分：0)
在活动的onDestroy
protected void onDestroy()
{
super.onDestroy();
if (db != null)
{
db.close();
}
}
并在datahelper类中添加close方法
public void close() {
// NOTE: openHelper must now be a member of CallDataHelper;
// you currently have it as a local in your constructor
if (openHelper != null) {
openHelper.close();
}
}