我的数据库有问题。
当应用程序启动时，如果表不存在，它应该使用表创建数据库，但应用程序在启动后立即崩溃。当我在打开 logcat 后关闭数据库时，告诉我“我想打开一个已经关闭的对象”，而当我不关闭数据库时，我收到错误“getReadableDatabase called recursively”。我不知道我应该做什么。有时它可以工作，但是当我卸载应用程序并再次安装它们时，错误出现了。
没有关闭的错误:
02-20 11:50:06.980: E/AndroidRuntime(15375): FATAL EXCEPTION: main
02-20 11:50:06.980: E/AndroidRuntime(15375): java.lang.RuntimeException: Unable to start activity ComponentInfo{de.vertretungsplan2/de.vertretungsplan2.Main}: java.lang.IllegalStateException: getDatabase called recursively
02-20 11:50:06.980: E/AndroidRuntime(15375): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2339)
02-20 11:50:06.980: E/AndroidRuntime(15375): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2389)
02-20 11:50:06.980: E/AndroidRuntime(15375): at android.app.ActivityThread.access$600(ActivityThread.java:153)
02-20 11:50:06.980: E/AndroidRuntime(15375): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1269)
02-20 11:50:06.980: E/AndroidRuntime(15375): at android.os.Handler.dispatchMessage(Handler.java:99)
02-20 11:50:06.980: E/AndroidRuntime(15375): at android.os.Looper.loop(Looper.java:137)
02-20 11:50:06.980: E/AndroidRuntime(15375): at android.app.ActivityThread.main(ActivityThread.java:5289)
02-20 11:50:06.980: E/AndroidRuntime(15375): at java.lang.reflect.Method.invokeNative(Native Method)
02-20 11:50:06.980: E/AndroidRuntime(15375): at java.lang.reflect.Method.invoke(Method.java:525)
02-20 11:50:06.980: E/AndroidRuntime(15375): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:739)
02-20 11:50:06.980: E/AndroidRuntime(15375): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:555)
02-20 11:50:06.980: E/AndroidRuntime(15375): at dalvik.system.NativeStart.main(Native Method)
02-20 11:50:06.980: E/AndroidRuntime(15375): Caused by: java.lang.IllegalStateException: getDatabase called recursively
02-20 11:50:06.980: E/AndroidRuntime(15375): at android.database.sqlite.SQLiteOpenHelper.getDatabaseLocked(SQLiteOpenHelper.java:204)
02-20 11:50:06.980: E/AndroidRuntime(15375): at android.database.sqlite.SQLiteOpenHelper.getWritableDatabase(SQLiteOpenHelper.java:164)
02-20 11:50:06.980: E/AndroidRuntime(15375): at de.vertretungsplan2.helper.DBHandler.insertPW(DBHandler.java:89)
02-20 11:50:06.980: E/AndroidRuntime(15375): at de.vertretungsplan2.helper.DBHandler.onCreate(DBHandler.java:46)
02-20 11:50:06.980: E/AndroidRuntime(15375): at android.database.sqlite.SQLiteOpenHelper.getDatabaseLocked(SQLiteOpenHelper.java:252)
02-20 11:50:06.980: E/AndroidRuntime(15375): at android.database.sqlite.SQLiteOpenHelper.getWritableDatabase(SQLiteOpenHelper.java:164)
02-20 11:50:06.980: E/AndroidRuntime(15375): at de.vertretungsplan2.Main.onCreate(Main.java:42)
02-20 11:50:06.980: E/AndroidRuntime(15375): at android.app.Activity.performCreate(Activity.java:5133)
02-20 11:50:06.980: E/AndroidRuntime(15375): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
02-20 11:50:06.980: E/AndroidRuntime(15375): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2293)
02-20 11:50:06.980: E/AndroidRuntime(15375): ... 11 more
关闭错误:
02-20 11:57:47.880: E/AndroidRuntime(15853): FATAL EXCEPTION: main
02-20 11:57:47.880: E/AndroidRuntime(15853): java.lang.RuntimeException: Unable to start activity ComponentInfo{de.vertretungsplan2/de.vertretungsplan2.Main}: java.lang.IllegalStateException: attempt to re-open an already-closed object: SQLiteDatabase: /data/data/de.vertretungsplan2/databases/settings
02-20 11:57:47.880: E/AndroidRuntime(15853): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2339)
02-20 11:57:47.880: E/AndroidRuntime(15853): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2389)
02-20 11:57:47.880: E/AndroidRuntime(15853): at android.app.ActivityThread.access$600(ActivityThread.java:153)
02-20 11:57:47.880: E/AndroidRuntime(15853): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1269)
02-20 11:57:47.880: E/AndroidRuntime(15853): at android.os.Handler.dispatchMessage(Handler.java:99)
02-20 11:57:47.880: E/AndroidRuntime(15853): at android.os.Looper.loop(Looper.java:137)
02-20 11:57:47.880: E/AndroidRuntime(15853): at android.app.ActivityThread.main(ActivityThread.java:5289)
02-20 11:57:47.880: E/AndroidRuntime(15853): at java.lang.reflect.Method.invokeNative(Native Method)
02-20 11:57:47.880: E/AndroidRuntime(15853): at java.lang.reflect.Method.invoke(Method.java:525)
02-20 11:57:47.880: E/AndroidRuntime(15853): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:739)
02-20 11:57:47.880: E/AndroidRuntime(15853): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:555)
02-20 11:57:47.880: E/AndroidRuntime(15853): at dalvik.system.NativeStart.main(Native Method)
02-20 11:57:47.880: E/AndroidRuntime(15853): Caused by: java.lang.IllegalStateException: attempt to re-open an already-closed object: SQLiteDatabase: /data/data/de.vertretungsplan2/databases/settings
02-20 11:57:47.880: E/AndroidRuntime(15853): at android.database.sqlite.SQLiteClosable.acquireReference(SQLiteClosable.java:55)
02-20 11:57:47.880: E/AndroidRuntime(15853): at android.database.sqlite.SQLiteDatabase.endTransaction(SQLiteDatabase.java:520)
02-20 11:57:47.880: E/AndroidRuntime(15853): at android.database.sqlite.SQLiteOpenHelper.getDatabaseLocked(SQLiteOpenHelper.java:263)
02-20 11:57:47.880: E/AndroidRuntime(15853): at android.database.sqlite.SQLiteOpenHelper.getWritableDatabase(SQLiteOpenHelper.java:164)
02-20 11:57:47.880: E/AndroidRuntime(15853): at de.vertretungsplan2.Main.onCreate(Main.java:42)
02-20 11:57:47.880: E/AndroidRuntime(15853): at android.app.Activity.performCreate(Activity.java:5133)
02-20 11:57:47.880: E/AndroidRuntime(15853): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
02-20 11:57:47.880: E/AndroidRuntime(15853): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2293)
02-20 11:57:47.880: E/AndroidRuntime(15853): ... 11 more
这是我的数据库处理程序:
package de.vertretungsplan2.helper;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteException;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;
public class DBHandler extends SQLiteOpenHelper {
private static final String TAG = "DBHandler";
//Attributes of Database
private static final int DATABASE_VERSION = 1;
private static final String DATABASE_NAME = "settings";
//Attributes of table "PASSWORD"
private static final String TABLE_NAME_PW = "password";
private static final String PASSWORD_ID ="id";
private static final String PASSWORD_NAME = "password";
//Attributes of table "KURS"
private static final String TABLE_NAME_KURS = "kurs";
private static final String KURS_ID = "id";
private static final String KURS_NAME ="kurs";
//Operations
private static final String DROP_PW_TABLE = "DROP TABLE IF EXISTS " + TABLE_NAME_PW;
private static final String DROP_KURS_TABLE = "DROP TABLE IF EXISTS " + TABLE_NAME_KURS;
//Attributes of DBHandler
public DBHandler(Context context){
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
@Override
public void onCreate(SQLiteDatabase db) {
Log.i(TAG,"db aktion start, DBHandler-onCreate");
/*
if(db == null || !db.isOpen()) {
db = getWritableDatabase();
}*/
createTables(db);
insertPW("-1");
insertKurs("-1");
db.close();
Log.i(TAG,"db aktion stop, DBHandler-onCreate");
}
private void createTables(SQLiteDatabase db){
Log.i(TAG,"db aktion start, DBHandler-createTables");
String CREATE_PW_TABLE = "CREATE TABLE IF NOT EXISTS " + TABLE_NAME_PW +" (" + PASSWORD_ID + " INTEGER PRIMARY KEY AUTOINCREMENT, " + PASSWORD_NAME + " TEXT);";
String CREATE_KURS_TABLE = "CREATE TABLE IF NOT EXISTS " + TABLE_NAME_KURS +" (" + KURS_ID + " INTEGER PRIMARY KEY AUTOINCREMENT, " + KURS_NAME + " TEXT);";
if(db == null || !db.isOpen()) {
db = getWritableDatabase();
}
db.execSQL(CREATE_PW_TABLE);
Log.i(TAG,"db aktion start, nach PW Table erzeugen");
db.execSQL(CREATE_KURS_TABLE);
Log.i(TAG,"db aktion start, nach Kurs Table erzeugen");
db.close();
Log.i(TAG,"db aktion stop, DBHandler-createTables");
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
Log.i(TAG,"db aktion start, DBHandler-onUpgrade");
Log.w(TAG,"Upgrade der Datenbank von Version " + oldVersion
+ " zu " + newVersion + "; alle Daten werden gelöscht");
db.execSQL(DROP_PW_TABLE);
Log.i(TAG,"db aktion start, OnUpgrade nach Drop PW Table");
db.execSQL(DROP_KURS_TABLE);
Log.i(TAG,"db aktion start, OnUpgrade nach Drop kurs Table");
db.close();
Log.i(TAG,"db aktion start, OnUpgrade nach close db");
onCreate(db);
Log.i(TAG,"db aktion stop, DBHandler-onUpgrade");
}
public void insertPW(String PW){
Log.i(TAG,"db aktion start, DBHandler-insertPW");
long rowId = -1;
try{
SQLiteDatabase db = null;
if(db == null || !db.isOpen()) {
db = getWritableDatabase();
}
ContentValues values = new ContentValues();
values.put(PASSWORD_NAME, PW);
rowId = db.insert(TABLE_NAME_PW, null, values);
db.close();
}catch (SQLiteException e){
Log.e(TAG,"insert()",e);
}finally{
Log.d(TAG, "insert(): rowId=" + rowId);
Log.i(TAG,"db aktion stop, DBHandler-insertPW");
}
}
public void insertKurs(String Kurs){
Log.i(TAG,"db aktion start, DBHandler-insertKurs");
long rowId = -1;
try{
SQLiteDatabase db = null;
if(db == null || !db.isOpen()) {
db = getWritableDatabase();
}
ContentValues values = new ContentValues();
values.put(KURS_NAME, Kurs);
rowId = db.insert(TABLE_NAME_KURS, null, values);
db.close();
}catch (SQLiteException e){
Log.e(TAG,"insert()",e);
}finally{
Log.d(TAG, "insert(): rowId=" + rowId);
Log.i(TAG,"db aktion stop, DBHandler-insertKurs");
}
}
public String getPW(){
Log.i(TAG,"db aktion start, DBHandler-getPW");
SQLiteDatabase db = null;
if(db == null || !db.isOpen()) {
db = getReadableDatabase();
}
Cursor cursor = db.query(TABLE_NAME_PW, new String[] {PASSWORD_ID, PASSWORD_NAME},null,null,null,null,null);
for(int i=0; i<cursor.getCount();i++){
cursor.moveToNext();
}
Log.i(TAG,"db aktion stop, DBHandler-getPW");
db.close();
return cursor.getString(1);
}
public String getKurs(){
Log.i(TAG,"db aktion start, DBHandler-getKurs");
SQLiteDatabase db = null;
if(db == null || !db.isOpen()) {
db = getReadableDatabase();
}
Cursor cursor = db.query(TABLE_NAME_KURS, new String[] {KURS_ID, KURS_NAME},null,null,null,null, null);
for(int i=0; i<cursor.getCount();i++){
cursor.moveToNext();
}
db.close();
Log.i(TAG,"db aktion stop, DBHandler-getKurs");
return cursor.getString(1);
}
public int getPWCount(){
Log.i(TAG,"db aktion start, DBHandler-getPWCount");
String query = "SELECT * FROM " + TABLE_NAME_PW;
SQLiteDatabase db = null;
if(db == null || !db.isOpen()) {
db = getReadableDatabase();
}
Cursor cursor = db.rawQuery(query,null);
Log.i(TAG,"db aktion stop, DBHandler-getPWCount");
db.close();
return cursor.getCount();
}
public int getKursCount(){
Log.i(TAG,"db aktion start, DBHandler-getKursCount");
String query = "SELECT * FROM " + TABLE_NAME_KURS;
SQLiteDatabase db = null;
if(db == null || !db.isOpen()) {
db = getReadableDatabase();
}
Cursor cursor = db.rawQuery(query,null);
Log.i(TAG,"db aktion stop, DBHandler-getKursCount");
db.close();
return cursor.getCount();
}
}
我使用此日志找出错误出现的位置，但它对我没有帮助。
谢谢你的帮助。
最佳答案
当数据库文件不存在时调用 getWritableDatabase() 会导致调用打开助手 onCreate()。
作为参数传递给 onCreate() 的 db 是正在打开的数据库。您应该使用它进行初始化，而不是像在 insertPW() 和其他方法中那样再次调用 getWritableDatabase()。 db == null || !db.isOpen() 条件没有帮助，因为您刚刚将本地 db 变量初始化为 null。
关于递归调用Android sqlite getdatabase，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/21905864/