Question

我是学生并且第一次学习android并尝试使用SQLite制作测验应用程序它在模拟器上正常工作但在Android移动设备上崩溃

每当我尝试时，我都无法理解这个问题安装测验通过复制它的.apk它安装在android上电话，但每当我点击按钮显示问题它崩溃

这是我的db帮助程序类。

package com.example.quiz;

    import java.util.ArrayList;
    import java.util.HashMap;
    import java.util.List;

    import android.content.ContentValues;
    import android.content.Context;
    import android.database.Cursor;
    import android.database.sqlite.SQLiteDatabase;
    import android.database.sqlite.SQLiteDatabase.CursorFactory;
    import android.database.sqlite.SQLiteOpenHelper;
    import android.util.Log;
    import android.widget.Toast;

    public class dbhelper extends SQLiteOpenHelper {
        private final static String  DATABASE_NAME="questio.db";
        private final static int  DATABASE_VERSION=2;
        private final static String  Android="quiz1";

        private final static String  php="quiz2";

        private final static String  ID="id";
        private final static String  score="score";


        private final static String  Question="question";
        private final static String  answer="ans";
        private final static String  op1="opa";
        private final static String  op2="opb";
        private final static String  op3="opc";

        public static final String SQL_Create="create table " +Android+"("+ID+" INTEGER PRIMARY KEY AUTOINCREMENT, "+Question+" TEXT NOT NULL, "+answer+" TEXT,"+op1+" TEXT, "+op2+" TEXT, "+op3+" TEXT"+")";
        public static final String SQL_Create2="create table " +php+"("+ID+" INTEGER PRIMARY KEY AUTOINCREMENT, "+Question+" TEXT NOT NULL, "+answer+" TEXT,"+op1+" TEXT, "+op2+" TEXT, "+op3+" TEXT"+")";







        SQLiteDatabase db1;
        public dbhelper(Context context) {
            super(context, DATABASE_NAME, null, DATABASE_VERSION);
            // TODO Auto-generated constructor stub
        }

        @Override
        public void onCreate(SQLiteDatabase db) {

            db.execSQL(SQL_Create);
            db.execSQL(SQL_Create2);

            db1=db;
            db.close();


            // TODO Auto-generated method stub

        }

onUpgrade方法的所有语句都被注释掉了表中插入的问题不会丢失。

@Override
        public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {





        //db.execSQL("drop table if exists"+Android);

            //db.execSQL("drop table "+php);


            //db.execSQL("drop table if exist"+TableName);
            //onCreate(db);

            // TODO Auto-generated method stubS

        }
        public void insertIntoTable(String str1,String str2,String str3,String str5,String str4)
        {
             db1=getWritableDatabase();

            ContentValues values=new ContentValues();
            values.put(Question, str1);
            values.put(answer, str2);
            values.put(op1, str3);
            values.put(op2, str5);
            values.put(op3, str4);
            db1.insert(Android, null, values);

        }
        public void insertIntoTable2(String str1,String str2,String str3,String str4,String str5)
        {
            SQLiteDatabase db=getWritableDatabase();

            ContentValues values=new ContentValues();
            values.put(Question, str1);
            values.put(answer, str2);
            values.put(op1, str3);
            values.put(op2, str5);
            values.put(op3, str4);
            db1.insert(php, null, values);

        }




        public List<Question> getAllQuestions() {
            List<Question> quesList = new ArrayList<Question>();
            // Select All Query
            String selectQuery = "SELECT * FROM " +Android;
        //String del="delete from "+Android+ " where ID=16";
            SQLiteDatabase db2=this.getReadableDatabase();
            //db2.execSQL(del);
        Log.d("chk", selectQuery);
            Cursor cursor = db2.rawQuery(selectQuery, null);
            // looping through all rows and adding to list
            if (cursor.moveToFirst()) {
                do {
                    Question quest = new Question();
                    quest.setID(cursor.getInt(0));
                    quest.setQUESTION(cursor.getString(1));
                    Log.d("quest", quest.getQUESTION());
                    quest.setANSWER(cursor.getString(2));
                    quest.setOPTA(cursor.getString(3));
                    quest.setOPTB(cursor.getString(5));
                    quest.setOPTC(cursor.getString(4));
                    quesList.add(quest);
                } while (cursor.moveToNext());
            }
            // return quest list
            return quesList;
        }

        public int rowcount()
        {
            int row=0;
            String selectQuery = "SELECT  * FROM " + Android;
            SQLiteDatabase db = this.getWritableDatabase();
            Cursor cursor = db.rawQuery(selectQuery, null);
            row=cursor.getCount();
            return row;
        }


    }

Answer 1

对于任何崩溃，请参阅logcat以获取有关查找问题的有用信息。始终在您的问题中包含堆栈跟踪。有关详情，请参阅Unfortunately MyApp has stopped. How can I solve this?。

在代码中，请勿在传递给您的帮助者close()的{{1}}上致电SQLiteDatabase。

为什么它＆＃34;工作＆＃34;在模拟器上是可能的，因为如果数据库文件已经存在（使用早期版本的代码设置），则不会调用onCreate()回调。它只在刚刚创建数据库文件时调用。如果您发现崩溃，则会发生崩溃，例如在模拟器上卸载您的应用程序或清除其数据。有关详情，请参阅When is SQLiteOpenHelper onCreate() / onUpgrade() run?。

使用SQLite数据库制作的测验应用程序，在模拟器上运行但在实际设备上崩溃

1 个答案: