以编程方式从应用程序的资产文件夹复制数据库文件

Question

我搜索了很多关于这个问题。我的手机没有根。我想以编程方式从我的应用程序的资产文件夹复制数据库文件到我的Android设备的/system/usr。这样我就可以从那里访问数据库文件并检查我的应用程序的用户是否能够升级数据库。我知道我必须在以下代码中更改'outFileName'和' outputStream '，但我不完全确定如何在以下代码中指定/system/usr的输出路径:

copyDBfromassetstodevicedrive.setOnClickListener(new View.OnClickListener() {
            public void onClick(View view) {
                try {
                    // Open your local db as the input stream
                    InputStream myInput = myContext.getAssets().open("myDB.db");
                    // Path to the just created empty db
                    String outFileName = "/data/data/your app package name/databases/database file name";
                    OutputStream myOutput = new FileOutputStream(outFileName);
                    // transfer bytes from the inputfile to the outputfile
                    byte[] buffer = new byte[1024];
                    int length;
                    while ((length = myInput.read(buffer)) > 0) 
                     {
                         myOutput.write(buffer, 0, length);
                     }
                    // Close the streams
                    myOutput.flush();
                    myOutput.close();
                    myInput.close();
                    } 
                    catch (Exception e) 
                    {
                    Log.e("error", e.toString());
                    }
            }
          });

谢谢你的建议。

Answer 1

这是不可能的，除非您的设备是根。但是我不明白你为什么要这样做。如果你能说出你想做什么，也许这里有人能帮你找到解决办法。

Answer 2

private static String DB_PATH = Environment.getDataDirectory()+"/data/package-name/databases/";
private void copyDataBase() throws IOException
{

    // Open your local db as the input stream
    InputStream myInput = myContext.getAssets().open(DB_NAME);
    // Path to the just created empty d inb
    String outFileName = DB_PATH + DB_NAME;
    // Open the empty db as the output stream
    OutputStream myOutput = new FileOutputStream(outFileName);
    // transfer bytes from the inputfile to the outputfile
    byte[] buffer = new byte[1024];
    int length;
    while ((length = myInput.read(buffer)) > 0) 
    {
        myOutput.write(buffer, 0, length);
    }
    // Close the streams
    myOutput.flush();
    myOutput.close();
    myInput.close();
    //Copy successful
    outFileName = DB_PATH + DB_SUCCESS;
    myOutput = new FileOutputStream(outFileName);
    myOutput.write(1);
    myOutput.flush();
    myOutput.close();
}