Question

我试图在设备磁盘上创建一个db文件（SQLite） - 一切正常，没有例外 - 但是文件没有创建。

添加了这些权限

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

代码：

public class DbHandler extends SQLiteOpenHelper {

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

private static final String PersistenceFolder = Environment.getExternalStorageDirectory() + File.separator + "MyApp" + File.separator;
private static final String  PersistenceFilePath = PersistenceFolder + DATABASE_NAME;


public DbHandler(Context context) {
    super(context, PersistenceFilePath, null, DATABASE_VERSION);
}



@Override
public void onCreate(SQLiteDatabase db) {

    createTable1();
    createTable2();
}

private void createTable1(){
    // create table 1 with no exception
}

private void createTable2(){
    // create table 2 with no exception
}
}

Answer 1

好吧让我们这么简单下面的代码决定我是否有SD卡如果不是我们使用内部存储但它获取路径然后将该PATH传递给创建数据库的DBHelper我将发布代码以先获取PATH然后DBHelper代码

    public void onAvail() {

    String state = Environment.getExternalStorageState();

    if (state.equals(Environment.MEDIA_MOUNTED) && (!state.equals(Environment.MEDIA_MOUNTED_READ_ONLY))) {

        File removable = ContextCompat.getExternalFilesDirs(this, null)[1];
        THE_PATH = String.valueOf(removable) + "/Documents/";

        //System.out.println("ALL TRUE ==> " + THE_PATH);

    } else {// if (state.equals(Environment.MEDIA_MOUNTED_READ_ONLY)) {
        THE_PATH = "";
        //System.out.println("ALL FALSE ==> "+ THE_PATH);
    }
}

创建DB的部分DBHelper代码

public class DBHelper扩展了SQLiteOpenHelper {

public static final String DB_NAME = THE_PATH +"PassWord";
//public static final String DB_NAME = "PassWord";
// Code Above for Internal Storage ONLY
public static final Integer DB_VERSION = 1;

无法在设备上创建db文件（特定路径上的db文件）（附加代码）

1 个答案: