java - 查看/写入数据库 SQLite 时出现致命异常？

Question

当我运行模拟器并尝试开始读取或查看数据库时出现错误。

请查看本页底部的我的 logcat!

我有一个数据库 Activity 、一个 SQLView Activity 和一个 SQLite Activity 。

数据库 Activity 是运行数据库，SQLView Activity 是查看数据库，最后一个，我的 SQLite Activity 是写入数据库。

我使用 SQLiteAssetHelper，我的 .rar 文件位于我的 assets/databases/Voedsel.rar 中。

这是我的 Activity :

我的数据库 Activity :

package com.jacob.eindproject;

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.database.sqlite.SQLiteDatabase.CursorFactory;

import java.sql.*;

import com.readystatesoftware.sqliteasset.SQLiteAssetHelper;

public class Database extends SQLiteAssetHelper {

    public static final String KEY_PRODUCT = "Product";
    public static final String KEY_EENHEID = "Eenheid";
    public static final String KEY_KCAL = "Kcal";

    private static final String DATABASE_NAME = "Voedsel";
    private static final String DATABASE_TABLE = "Voeding";
    private static final int DATABASE_VERSION = 1;

    private DbHelper ourHelper;
    private Context Context;
    private SQLiteDatabase ourDatabase;

    private static class DbHelper extends SQLiteAssetHelper{

        public DbHelper(Context context) {
            super(context, DATABASE_NAME, context.getExternalFilesDir(null).getAbsolutePath(), null, DATABASE_VERSION);
            // TODO Auto-generated constructor stub
        }

    }

        @Override
        public void onUpgrade(SQLiteDatabase Voedsel, int oldVersion, int newVersion) {
            Voedsel.execSQL("DROP TABLE IF EXISTS " + DATABASE_TABLE);
            onCreate(Voedsel);
        }



    public Database(Context context){
        super(context, DATABASE_NAME, null, DATABASE_VERSION);
    }

    public Database open() throws SQLException{
        ourHelper = new DbHelper(Context);
        ourDatabase = ourHelper.getWritableDatabase();
        return this;        
    }

    public void close() {

    ourHelper.close();
}



    public long createEntry(String product, String kcal, String eenheid) {
        ContentValues cv = new ContentValues();
        cv.put(KEY_PRODUCT, product);
        cv.put(KEY_EENHEID, eenheid);
        cv.put(KEY_KCAL, kcal);
        return ourDatabase.insert(DATABASE_TABLE, null, cv);

    }

    public String getData() {
        // TODO Auto-generated method stub
        String[] columns = new String[]{ KEY_PRODUCT, KEY_EENHEID, KEY_KCAL};
        Cursor c = ourDatabase.query(DATABASE_TABLE, columns, null, null, null, null, null);
        String result = "";

        int iProduct = c.getColumnIndex(KEY_PRODUCT);
        int iEenheid = c.getColumnIndex(KEY_EENHEID);
        int iKcal = c.getColumnIndex(KEY_KCAL);

        for (c.moveToFirst(); !c.isAfterLast(); c.moveToNext()){
            result = result + c.getString(iProduct) + " " + c.getString(iEenheid) + " " + c.getString(iKcal) + "\n";


        }

        return result;
    }

    public void close(Database database) {
        // TODO Auto-generated method stub

    }



}

我的 SQLite Activity :

public class SQLite extends Activity implements View.OnClickListener {

    Button sqlUpdate, sqlView;
    EditText sqlVoeding, sqlKcal, sqlEenheid;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.sqllite);
        sqlUpdate = (Button) findViewById(R.id.bSQLUpdate);
        sqlVoeding = (EditText) findViewById(R.id.etSQLVoeding);
        sqlEenheid = (EditText) findViewById(R.id.etSQLEenheid);
        sqlKcal = (EditText) findViewById(R.id.etSQLKcal);

        sqlView = (Button) findViewById(R.id.bSQLopenView);
        sqlView.setOnClickListener((android.view.View.OnClickListener) this);
        sqlUpdate.setOnClickListener((android.view.View.OnClickListener) this);
    }

    public void onClick(View arg0) {
        switch (arg0.getId()) {
        case R.id.bSQLUpdate:


            boolean didItWork = true;
            try{            
            String voeding = sqlVoeding.getText().toString();
            String Kcal = sqlKcal.getText().toString();
            String eenheid = sqlEenheid.getText().toString();

            Database entry = new Database(SQLite.this);
            entry.open();
            entry.createEntry(voeding, Kcal, eenheid);
            entry.close();

            }catch (Exception e ){
                didItWork = false;

            }finally{
                if (didItWork){
                    Dialog d = new Dialog(this);
                    d.setTitle("Heak Yeay");
                    TextView tv = new TextView(this);
                    tv.setText("Succes");
                    d.setContentView(tv);
                    d.show();
            }
        }

            break;
        case R.id.bSQLopenView:
            Intent i = new Intent(this, SQLView.class);
            startActivity(i);


        }
        }

    public void onClick(DialogInterface arg0, int arg1) {
        // TODO Auto-generated method stub

    }

    }

以及 SQLView Activity :

public class SQLView extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.sqlview);
        TextView tv = (TextView) findViewById(R.id.tvSQLinfo);
        Database info = new Database(this);
        info.open();
        String data = info.getData();
        info.close();
        tv.setText(data);
    }
}

这是我单击 SQLView Activity 时出现的 logcat 错误:

    12-16 14:28:26.883: E/AndroidRuntime(1170): FATAL EXCEPTION: main
    12-16 14:28:26.883: E/AndroidRuntime(1170): java.lang.NoClassDefFoundError: com.jacob.eindproject.Database
    12-16 14:28:26.883: E/AndroidRuntime(1170):     at com.jacob.eindproject.SQLView.onCreate(SQLView.java:14)
    12-16 14:28:26.883: E/AndroidRuntime(1170):     at android.app.Activity.performCreate(Activity.java:5133)
    12-16 14:28:26.883: E/AndroidRuntime(1170):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
    12-16 14:28:26.883: E/AndroidRuntime(1170):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2175)
    12-16 14:28:26.883: E/AndroidRuntime(1170):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2261)
    12-16 14:28:26.883: E/AndroidRuntime(1170):     at android.app.ActivityThread.access$600(ActivityThread.java:141)
    12-16 14:28:26.883: E/AndroidRuntime(1170):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256)
    12-16 14:28:26.883: E/AndroidRuntime(1170):     at android.os.Handler.dispatchMessage(Handler.java:99)
    12-16 14:28:26.883: E/AndroidRuntime(1170):     at android.os.Looper.loop(Looper.java:137)
    12-16 14:28:26.883: E/AndroidRuntime(1170):     at android.app.ActivityThread.main(ActivityThread.java:5103)
    12-16 14:28:26.883: E/AndroidRuntime(1170):     at java.lang.reflect.Method.invokeNative(Native Method)
    12-16 14:28:26.883: E/AndroidRuntime(1170):     at java.lang.reflect.Method.invoke(Method.java:525)
    12-16 14:28:26.883: E/AndroidRuntime(1170):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
    12-16 14:28:26.883: E/AndroidRuntime(1170):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
    12-16 14:28:26.883: E/AndroidRuntime(1170):     at dalvik.system.NativeStart.main(Native Method)

这是我点击“写入” Activity 时出现的错误:

12-16 14:27:35.913: E/AndroidRuntime(999): FATAL EXCEPTION: main
12-16 14:27:35.913: E/AndroidRuntime(999): java.lang.NoClassDefFoundError: com.jacob.eindproject.Database
12-16 14:27:35.913: E/AndroidRuntime(999):  at com.jacob.eindproject.SQLite.onClick(SQLite.java:45)
12-16 14:27:35.913: E/AndroidRuntime(999):  at android.view.View.performClick(View.java:4240)
12-16 14:27:35.913: E/AndroidRuntime(999):  at android.view.View$PerformClick.run(View.java:17721)
12-16 14:27:35.913: E/AndroidRuntime(999):  at android.os.Handler.handleCallback(Handler.java:730)
12-16 14:27:35.913: E/AndroidRuntime(999):  at android.os.Handler.dispatchMessage(Handler.java:92)
12-16 14:27:35.913: E/AndroidRuntime(999):  at android.os.Looper.loop(Looper.java:137)
12-16 14:27:35.913: E/AndroidRuntime(999):  at android.app.ActivityThread.main(ActivityThread.java:5103)
12-16 14:27:35.913: E/AndroidRuntime(999):  at java.lang.reflect.Method.invokeNative(Native Method)
12-16 14:27:35.913: E/AndroidRuntime(999):  at java.lang.reflect.Method.invoke(Method.java:525)
12-16 14:27:35.913: E/AndroidRuntime(999):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
12-16 14:27:35.913: E/AndroidRuntime(999):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
12-16 14:27:35.913: E/AndroidRuntime(999):  at dalvik.system.NativeStart.main(Native Method)

希望有人可以帮助我解决我的错误。预先感谢大家抽出宝贵的时间。

雅各布。

Answer 1

我认为您没有正确地将 SQLiteAssetHelper 库添加到您的项目中。您必须确保项目的构建路径正确，并且选择所有引用的库。

右键单击您的项目并选择“属性”

点击“Android”

确保选择了 SQLiteAssetHelper 库