誰かが助けることができますか。私はアプリを作成していて、これまでのところ私のデータはデータベースに正常に保存されていますが、空白の値を送信でき、データベースに正常に保存されるため、notnullはまったく機能していないようです。また、「close（）がデータベースで明示的に呼び出されることはありません」というデータベースエラーが発生します。
package com.example.tasksystemapp;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.HashSet;
import java.util.Set;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteException;
import android.database.sqlite.SQLiteOpenHelper;
public class MyDatabaseHelper extends SQLiteOpenHelper {
//singleton/ single instance reference of database instance
private static MyDatabaseHelper _dbHelper;
//The Android's default system path of your application database.
//private static String DB_PATH = "/data/data/YOUR_PACKAGE/";
private static String DB_PATH = "/data/data/com.example.tasksystemapp/";
//database name
private static String DB_NAME = "tasksystem.db";
//database version
private static int VERSION=1;
private final Context _context;
public MyDatabaseHelper(Context context)
{
super(context, DB_NAME, null, VERSION);
this._context = context;
}
public static MyDatabaseHelper getInstance(Context context)
{
if(_dbHelper == null)
{
_dbHelper = new MyDatabaseHelper(context);
}
return _dbHelper;
}
public String createDataBase() throws IOException
{
boolean dbExist = checkDataBase();
if(dbExist)
{
//do nothing - database already exist
}else{
this.getReadableDatabase();
try {
copyDataBase();
} catch (IOException e) {
return (e.getMessage());
}
}
return "database copied";
}
private boolean checkDataBase()
{
SQLiteDatabase checkDB = null;
try
{
String myPath = DB_PATH + DB_NAME;
checkDB = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);
}catch(SQLiteException e)
{
//database does't exist yet.
}
if(checkDB != null)
{
checkDB.close();
}
return checkDB != null ? true : false;
}
public void copyDataBase() throws IOException
{
//Open your local db as the input stream
InputStream myInput = _context.getAssets().open(DB_NAME);
// Path to the just created empty db
String outFileName = DB_PATH + DB_NAME;
//Open the empty db as the output stream
OutputStream myOutput = new FileOutputStream(outFileName);
//transfer bytes from the inputfile to the outputfile
byte[] buffer = new byte[1024];
int length;
while ((length = myInput.read(buffer))>0)
{
myOutput.write(buffer, 0, length);
}
//Close the streams
myOutput.flush();
myOutput.close();
myInput.close();
}
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL("CREATE TABLE Contact (_id INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL, " +
"lastname TEXT NOT NULL, firstname TEXT NOT NULL, email TEXT, " +
"phone TEXT, address TEXT, city TEXT, postcode TEXT);");
db.execSQL("CREATE TABLE Action (_id INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL, " +
"Actiondescription TEXT);");
db.execSQL("CREATE TABLE Autoreminder (_id INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL, " +
"Autoreminderdescription TEXT, Autoremindate TEXT, Autoremintime TEXT);");
db.execSQL("CREATE TABLE Priority (_id INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL, " +
"Actionid INTEGER);");
db.execSQL("CREATE TABLE Task (_id INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL, " +
"Description TEXT NOT NULL, Priority TEXT, Duedate TEXT, Duetime TEXT " +
"Completed INTEGER);");
db.execSQL("CREATE TABLE User (_id TEXT PRIMARY KEY NOT NULL, " +
"password TEXT NOT NULL, name TEXT NOT NULL, phoneno INTEGER);");
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
}
}