Question

这个问题已经被人们提出但是经历了很多人的步骤我仍然无法解决问题，我的应用程序在模拟器上工作正常，但在真实设备上并没有提供以下内容2例外，第一个例外是第二个例外的主要来源，我猜有一些许可问题。我添加了

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

到清单文件，但我得到了相同的结果。我的数据库非常简单，只有一个表。另外我添加了“android_metadata”表并将我的其他表的id字段编辑为“_id”。我确信我的数据库存在于assets文件夹中。

任何帮助都将不胜感激。

第一个例外

02-24 12:58:10.067: E/SQLiteAssetHelper(7107): Couldn't open Shajra for writing (will try read-only):
02-24 12:58:10.067: E/SQLiteAssetHelper(7107): com.readystatesoftware.sqliteasset.SQLiteAssetHelper$SQLiteAssetException: Missing databases/Shajra file (or .zip, .gz archive) in assets, or target folder not writable
02-24 12:58:10.067: E/SQLiteAssetHelper(7107):  at android.content.res.AssetManager.openAsset(Native Method)
02-24 12:58:10.067: E/SQLiteAssetHelper(7107):  at android.content.res.AssetManager.open(AssetManager.java:325)
02-24 12:58:10.067: E/SQLiteAssetHelper(7107):  at android.content.res.AssetManager.open(AssetManager.java:299)
02-24 12:58:10.067: E/SQLiteAssetHelper(7107):  at com.readystatesoftware.sqliteasset.SQLiteAssetHelper.copyDatabaseFromAssets(SQLiteAssetHelper.java:436)
02-24 12:58:10.067: E/SQLiteAssetHelper(7107):  at com.readystatesoftware.sqliteasset.SQLiteAssetHelper.createOrOpenDatabase(SQLiteAssetHelper.java:400)
02-24 12:58:10.067: E/SQLiteAssetHelper(7107):  at com.readystatesoftware.sqliteasset.SQLiteAssetHelper.getWritableDatabase(SQLiteAssetHelper.java:176)
02-24 12:58:10.067: E/SQLiteAssetHelper(7107):  at com.readystatesoftware.sqliteasset.SQLiteAssetHelper.getReadableDatabase(SQLiteAssetHelper.java:254)
02-24 12:58:10.067: E/SQLiteAssetHelper(7107):  at com.nannandotcom.MainActivity.onCreate(MainActivity.java:27)
02-24 12:58:10.067: E/SQLiteAssetHelper(7107):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1072)
02-24 12:58:10.067: E/SQLiteAssetHelper(7107):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1836)
02-24 12:58:10.067: E/SQLiteAssetHelper(7107):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1893)
02-24 12:58:10.067: E/SQLiteAssetHelper(7107):  at android.app.ActivityThread.access$1500(ActivityThread.java:135)
02-24 12:58:10.067: E/SQLiteAssetHelper(7107):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1054)
02-24 12:58:10.067: E/SQLiteAssetHelper(7107):  at android.os.Handler.dispatchMessage(Handler.java:99)
02-24 12:58:10.067: E/SQLiteAssetHelper(7107):  at android.os.Looper.loop(Looper.java:150)
02-24 12:58:10.067: E/SQLiteAssetHelper(7107):  at android.app.ActivityThread.main(ActivityThread.java:4389)
02-24 12:58:10.067: E/SQLiteAssetHelper(7107):  at java.lang.reflect.Method.invokeNative(Native Method)
02-24 12:58:10.067: E/SQLiteAssetHelper(7107):  at java.lang.reflect.Method.invoke(Method.java:507)
02-24 12:58:10.067: E/SQLiteAssetHelper(7107):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:849)
02-24 12:58:10.067: E/SQLiteAssetHelper(7107):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:607)
02-24 12:58:10.067: E/SQLiteAssetHelper(7107):  at dalvik.system.NativeStart.main(Native Method)

第二个例外

02-24 12:58:10.077: E/Database(7107): dbopen(): sqlite3_open_v2("/data/data/com.example.nannandotcom/databases/Shajra", &handle, 1, NULL) failed
02-24 12:58:10.077: E/Database(7107): dbopen(): errno = 2, error message = No such file or directory
02-24 12:58:10.077: D/AndroidRuntime(7107): Shutting down VM
02-24 12:58:10.077: W/dalvikvm(7107): threadid=1: thread exiting with uncaught exception (group=0x4011f5a0)
02-24 12:58:10.108: E/AndroidRuntime(7107): FATAL EXCEPTION: main
02-24 12:58:10.108: E/AndroidRuntime(7107): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.nannandotcom/com.nannandotcom.MainActivity}: android.database.sqlite.SQLiteException: unable to open database file
02-24 12:58:10.108: E/AndroidRuntime(7107):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1872)
02-24 12:58:10.108: E/AndroidRuntime(7107):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1893)
02-24 12:58:10.108: E/AndroidRuntime(7107):     at android.app.ActivityThread.access$1500(ActivityThread.java:135)
02-24 12:58:10.108: E/AndroidRuntime(7107):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1054)
02-24 12:58:10.108: E/AndroidRuntime(7107):     at android.os.Handler.dispatchMessage(Handler.java:99)
02-24 12:58:10.108: E/AndroidRuntime(7107):     at android.os.Looper.loop(Looper.java:150)
02-24 12:58:10.108: E/AndroidRuntime(7107):     at android.app.ActivityThread.main(ActivityThread.java:4389)
02-24 12:58:10.108: E/AndroidRuntime(7107):     at java.lang.reflect.Method.invokeNative(Native Method)
02-24 12:58:10.108: E/AndroidRuntime(7107):     at java.lang.reflect.Method.invoke(Method.java:507)
02-24 12:58:10.108: E/AndroidRuntime(7107):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:849)
02-24 12:58:10.108: E/AndroidRuntime(7107):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:607)
02-24 12:58:10.108: E/AndroidRuntime(7107):     at dalvik.system.NativeStart.main(Native Method)
02-24 12:58:10.108: E/AndroidRuntime(7107): Caused by: android.database.sqlite.SQLiteException: unable to open database file
02-24 12:58:10.108: E/AndroidRuntime(7107):     at android.database.sqlite.SQLiteDatabase.dbopen(Native Method)
02-24 12:58:10.108: E/AndroidRuntime(7107):     at android.database.sqlite.SQLiteDatabase.<init>(SQLiteDatabase.java:1962)
02-24 12:58:10.108: E/AndroidRuntime(7107):     at android.database.sqlite.SQLiteDatabase.openDatabase(SQLiteDatabase.java:906)
02-24 12:58:10.108: E/AndroidRuntime(7107):     at com.readystatesoftware.sqliteasset.SQLiteAssetHelper.getReadableDatabase(SQLiteAssetHelper.java:264)
02-24 12:58:10.108: E/AndroidRuntime(7107):     at com.nannandotcom.MainActivity.onCreate(MainActivity.java:27)
02-24 12:58:10.108: E/AndroidRuntime(7107):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1072)
02-24 12:58:10.108: E/AndroidRuntime(7107):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1836)
02-24 12:58:10.108: E/AndroidRuntime(7107):     ... 11 more

DatabaseHelper

package com.nannandotcom;

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

import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;

import com.nannandotcom.model.ProfileBean;
import com.readystatesoftware.sqliteasset.SQLiteAssetHelper;

public class DatabaseHelper extends SQLiteAssetHelper {

    private static final String DATABASE_NAME = "Shajra";
    private static final int DATABASE_VERSION = 1;

    private Context context;

    public DatabaseHelper(Context context) {
        super(context, DATABASE_NAME, null, DATABASE_VERSION);
        this.context = context;
    }

    public void copyDatabase() throws IOException{
    //  SQLiteDatabase checkDB = SQLiteDatabase.openDatabase(context.getAssets().+(DATABASE_NAME), null, SQLiteDatabase.OPEN_READONLY);
    //  checkDB.close();
    InputStream myInput = context.getAssets().open(DATABASE_NAME);      
    String outFileName =  "/data/data/"+ context.getPackageName() + "/databases/" + DATABASE_NAME;     
    OutputStream myOutput = new FileOutputStream(outFileName);

    byte[] buffer = new byte[1024];
    int length;
    while ((length = myInput.read(buffer))>0){
        myOutput.write(buffer, 0, length);
    }

    myOutput.flush();
    myOutput.close();
    myInput.close();
    }

    public ProfileBean getProfileBean(SQLiteDatabase database,int id){
        ProfileBean profileBean = new ProfileBean();
        try {
            Cursor c = database.query("Profiles",
                    new String[]{"_id","Name","Qualification","WorkingAt","LivesAt","MaritalStatus","NumberOfChildren",
                    "Telephone","Email","Picture","MarriedTo","Father","Mother","DOB","Gender"},
                    "_id=?",
                    new String[]{Integer.toString(id)},null, null, null);
            if (c != null ) {
                if  (c.moveToFirst()) {
                    do {

                    }while (c.moveToNext());
                } 
            }   
        }
        catch(Exception e){
            e.printStackTrace();
        }
        return profileBean;
    }
}

MainActivity

package com.nannandotcom;

import java.io.IOException;
import com.example.nannandotcom.R;

import android.os.Bundle;
import android.app.Activity;
import android.content.Intent;
import android.database.Cursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

public class MainActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        DatabaseHelper databaseHelper = new DatabaseHelper(this);
        SQLiteDatabase database = databaseHelper.getReadableDatabase();

        try {
            databaseHelper.copyDatabase();
    }   
        }catch(SQLException sqle){

            throw sqle;

        }
        }
        catch(Exception e){
            Log.e("MainActivity", e.getMessage());
            e.printStackTrace();
        }

        final EditText enterName = (EditText) findViewById(R.id.editText1);
        Button submit = (Button) findViewById(R.id.button1);
        submit.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                Intent mainActivityIntent = new   Intent(MainActivity.this, Welcome.class);
                mainActivityIntent.putExtra("userName", enterName.getText().toString());
                startActivity(mainActivityIntent);
            }
        });
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

}

Answer 1

我认为您在DATABASE_NAME中缺少数据库扩展名。

因此，请根据资产目录为特定DATABASE_NAME添加扩展名。

替换

private static final String DATABASE_NAME = "Shajra";

用

private static final String DATABASE_NAME = "Shajra.db";

或者

private static final String DATABASE_NAME = "Shajra.sqlite";

Answer 2

同样的问题困扰着我整夜，我的解决方案：

使用官方方式在Android Studio中创建“assets”文件夹：右键单击您的应用模块 - ＆gt;新的 - ＆gt;文件夹 - ＆gt;资产

Answer 3

Android Studio也可能在您不知情的情况下更改DATABASE_NAME ...

将db文件放在assets/databases子目录中。

然后一定要改变

private static final String DATABASE_NAME = "databases/mydb.db";

到

private static final String DATABASE_NAME = "mydb.db";

这是我的问题

Answer 4

哦，那是我的坏问题最后我找到了解决方案！

因此您应该重命名数据库文件，以小写字母开头然后

private static final String DATABASE_NAME = "mydata.db";
    private static final int DATABASE_VERSION = 1;

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

Answer 5

在我的情况下 SQLiteHelper 扩展 SQLiteOpenHelper ，然后我有一个自定义类，使用这个 SQLiteHelper 和接下来的3个方法（初始化，打开和关闭）。请看一下dbHelper.getWritableDatabase();方法。那可能就是你需要的那个。

private SQLiteDatabase database;
private SQLiteHelper dbHelper;

public CallHistoryDataSource(Context context) {
    dbHelper = new SQLiteHelper(context);
}

private void open() throws SQLException {
    database = dbHelper.getWritableDatabase();
}

private void close() {
    dbHelper.close();
}

Answer 6

当您将数据库复制到SD卡时，请使用这种方式分配路径。

String outFileName =  Environment.getExternalStorageDirectory() + "/databases/" + DATABASE_NAME;

只有当它成功时，如果您只想从数据库中读取记录，您需要致电databaseHelper.getReadableDatabase();或者如果您想阅读＆amp;写下你需要拨打databaseHelper.getWritableDatabase();

Answer 7

对我来说，它会抛出相同的错误，我解决了以下步骤

第1步：添加了权限

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

第2步：添加了运行时权限

if (ContextCompat.checkSelfPermission(MainActivity.this,
                Manifest.permission.READ_CONTACTS)
                != PackageManager.PERMISSION_GRANTED) {

            ActivityCompat.requestPermissions(MainActivity.this,
                    new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE},
                    101);
        }else {
            db=new DbUtils(MainActivity.this);
        }

步骤3：更改了Assets文件夹中的文件名，如下所述

private static final String DATABASE_NAME = "thirukkural.db";

资产文件夹中的文件名（导致错误）

旧文件名 thirukkural

NewFile名称 thirukkural.db

注意： 没有扩展程序的文件名

SQLiteAssetHelper：无法打开数据库进行写入（将尝试只读）

7 个答案: