Question

我想使用Android读取和写入资产中的SQLite数据库但我没有知道我为什么会收到错误。我将发布以下所有内容：

首先，我的DatabaseHelper.java文件：

var updatedProgress: Float = 0
// update progress

DispatchQueue.main.async {
    progressView.progress = updatedProgress
}

我还在我的Manifest文件中添加了这两个：

import android.content.Context;
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;

/**
 * Created by Koorosh on 1/6/2017.
 */

public class DatabaseHelper extends SQLiteOpenHelper {


    String DB_PATH = null;
    private static String DB_NAME = "mydatabase";
    private SQLiteDatabase myDataBase;
    private final Context myContext;

    public DatabaseHelper(Context context) {
        super(context, DB_NAME, null, 10);
        this.myContext = context;
        this.DB_PATH = myContext.getFilesDir().getPath().toString() + "/" + "databases/";
        Log.e("Path 1", DB_PATH);
    }


    public void createDataBase() throws IOException {
        boolean dbExist = checkDataBase();
        if (dbExist) {
        } 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();

            }
    }


}

这里我在主活动中调用我的db helper类：

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />

这是数据库文件：

https://ufile.io/4e23c

注意

我应该提一下，在DB_NAME中，我尝试了“mydatabase.db”和“mydatabase”，但它再次无效。
我正在手机上编程，其语言环境是波斯语（波斯语）。这是我的问题吗？（因为我在数据库中添加了英文元数据）

这是我的错误日志：

        DatabaseHelper myDbHelper = new DatabaseHelper(MainActivity.this);
        try {
            myDbHelper.createDataBase();
        } catch (IOException ioe) {
            throw new Error("Unable to create database");
        }
        try {
            myDbHelper.openDataBase();
        } catch (SQLException sqle) {
            throw sqle;
        }

提前谢谢。

Android SQLite资产复制错误

0 个答案: