Question

请我尝试从预加载的数据库创建登录。但我在复制数据库时遇到问题。以下是我的调试错误：

E / AndroidRuntime：致命异常：主要过程：com.babbangona.preloadedtestingagain，PID：11863 java.lang.Error：复制数据库时出错在com.babbangona.preloadedtestingagain.DBHandler.createDatabase（DBHandler.java:42） at com.babbangona.preloadedtestingagain.DBcopyActivity $ 1.onClick（DBcopyActivity.java:28）在android.view.View.performClick（View.java:6199）在android.view.View $ PerformClick.run（View.java:23235）在android.os.Handler.handleCallback（Handler.java:836）在android.os.Handler.dispatchMessage（Handler.java:103）在android.os.Looper.loop（Looper.java:203）在android.app.ActivityThread.main（ActivityThread.java:6251） at java.lang.reflect.Method.invoke（Native Method）在com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run（ZygoteInit.java:1073）在com.android.internal.os.ZygoteInit.main（ZygoteInit.java:934）我/艺术：输入while循环。我/艺术：输入while循环。断开了目标VM，地址：'localhost：8600'，transport：'socket'

我的DBHandler java文件：

import android.content.Context;
import android.database.Cursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteException;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;

import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

public class DBHandler extends SQLiteOpenHelper{

    String DB_PATH = null;
    private static String DB_NAME = "rehoboth.db";
    private SQLiteDatabase myDatabase;
    private final Context myContext;

    public DBHandler(Context context){
        super(context, DB_NAME, null, 2);
        this.myContext = context;
        this.DB_PATH = "/data/data" + context.getPackageName() + "/databases/";
        Log.e("Path 1", DB_PATH);
    }

    public void createDatabase() throws IOException {
        boolean dbExist = checkDatabase();
        if(dbExist){
           /* openDatabase();
            int cVersion = myDatabase.getVersion();
            if(cVersion != 2){
                onUpgrade(myDatabase, myDatabase.getVersion(),2);
                close();
            }*/
        }else{
            this.getReadableDatabase();
            try{
                copyDatabase();
            }catch (IOException e){
                throw new Error("Error copying database");
            }
        }
    }

    private boolean checkDatabase(){
        SQLiteDatabase checkDB = null;
        try{
            String myPath = DB_PATH + DB_NAME;
            checkDB = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);
        }catch(SQLiteException e){
        }
        if(checkDB != null){
            checkDB.close();
        }
        return checkDB != null ? true : false;
    }


    private void copyDatabase() throws IOException{
        InputStream myInput = myContext.getAssets().open(DB_NAME);
        String outFileName = DB_PATH + DB_NAME;
        OutputStream myOutput = new FileOutputStream(outFileName);
        byte[] buffer = new byte[10];
        int length;
        while((length = myInput.read(buffer)) > 0) {
            myOutput.write(buffer, 0, length);
        }
        myOutput.flush();
        myOutput.close();
        myInput.close();
    }

    public void openDatabase() throws SQLException{
        String myPath = DB_PATH + DB_NAME;
        myDatabase = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);
        }

    @Override
    public synchronized void close(){
        if(myDatabase != null)
            myDatabase.close();
        super.close();
    }

    @Override
    public void onCreate(SQLiteDatabase db){

    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion){
       if(newVersion > oldVersion)
           try{
               copyDatabase();
           }catch (IOException e){
               e.printStackTrace();
           }
    }

    public Cursor query(String table, String[] columns, String selection, String[] selectionArgs, String groupBy, String having, String orderBy){
        return myDatabase.query("rehoboth", null, null, null, null, null, null);
    }
}

我的主要活动：

import android.app.Activity;
import android.database.Cursor;
import android.database.SQLException;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;

import java.io.IOException;

public class DBcopyActivity extends Activity {

    Cursor c = null;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_dbcopy);

        ((Button) findViewById(R.id.button1)).setOnClickListener(new View.OnClickListener(){
            @Override
            public void onClick(View v){
                DBHandler myDbHelper = new DBHandler(DBcopyActivity.this);
                try{
                    myDbHelper.createDatabase();
                }catch(IOException ioe){
                    throw new Error("Unable to create database");
                }try{
                    myDbHelper.openDatabase();
                }catch(SQLException sqle){
                    throw sqle;
                }
                Toast.makeText(DBcopyActivity.this, "Successfully Imported", Toast.LENGTH_SHORT).show();
                c = myDbHelper.query("rehoboth", null, null, null, null, null, null);
                if(c.moveToFirst()){
                    do{
                        Toast.makeText(DBcopyActivity.this,
                                "_id: " + c.getString(0) + "\n" +
                                "NAME: " + c.getString(1) + "\n" +
                                        "PASSWORD: " + c.getString(2),
                                Toast.LENGTH_LONG).show();
                    }while (c.moveToNext());
                }

            }
        });
    }
}

使用sqlite的预加载数据库复制数据库时出错

0 个答案: