错误：无法打开数据库'/storage/emulated/0/database//db.sqlite'

Question

尝试创建数据库，运行时出现此错误：Failed to open database '/storage/emulated/0/database//db.sqlite'

public class G extends Application {
    public static Context context;
    public static String Sdk_Dir= Environment.getExternalStorageDirectory().getAbsolutePath();
    public static String App_Dir=Sdk_Dir+"/database/";
    public  SQLiteDatabase database;

    @Override
    public void onCreate() {
        super.onCreate();
        context=getApplicationContext();
        File file=new File(App_Dir);
        file.mkdirs();
        if (file.exists() && !file.isDirectory()) {
            Toast.makeText(context, "error", Toast.LENGTH_SHORT).show();
        }
        database=SQLiteDatabase.openOrCreateDatabase(App_Dir+"/db.sqlite",null);
    }
}

Answer 1

不要像这样忘记 Manifest 文件中的权限

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

Answer 2

“App_Dir”和“db.sqlite”之间有两个斜线，删除一个。