java.io.FileNotFoundException：/ storage / emulated / 0 /

我写了下面的类,它一直给我文件没有异常错误.我搜索了很多并搜索了这个论坛,但没有一个是有效的.

请帮忙.

我的课..

public static void StoreData(String input) throws IOException {
    File Root = Environment.getExternalStorageDirectory();
    Log.d("hello",Root.getAbsolutePath());
    File Dir = new File(Root.getAbsoluteFile() + "/testfolder");
    if (!Dir.exists()) {
        Log.d("hello","doesn't exists "+Root.getAbsolutePath());
        Dir.mkdir();
    }

    File file = new File(Dir, "Contacts_Google_Sheets.txt");
    FileOutputStream fileoutputstream = new FileOutputStream(file);
    fileoutputstream.write(input.getBytes());
    fileoutputstream.close();
    Log.d("hello", "writing complete");
}

它不断发出以下错误：

W/System.err: java.io.FileNotFoundException: /storage/emulated/0/testfolder/Contacts_Google_Sheets.txt (No such file or directory)
W/System.err:     at java.io.FileOutputStream.open(Native Method)
W/System.err:     at java.io.FileOutputStream.<init>(FileOutputStream.java:221)
W/System.err:     at java.io.FileOutputStream.<init>(FileOutputStream.java:169)
W/System.err:     at com.therock.app3_contact_list_googlesheet_public.FileOperations.StoreData(FileOperations.java:55)
W/System.err:     at com.therock.app3_contact_list_googlesheet_public.GetDataAsyncTask.doInBackground(GetDataAsyncTask.java:64)
W/System.err:     at com.therock.app3_contact_list_googlesheet_public.GetDataAsyncTask.doInBackground(GetDataAsyncTask.java:33)
W/System.err:     at android.os.AsyncTask$2.call(AsyncTask.java:305)
W/System.err:     at java.util.concurrent.FutureTask.run(FutureTask.java:237)
W/System.err:     at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:243)
W/System.err:     at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1133)
W/System.err:     at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:607)
W/System.err:     at java.lang.Thread.run(Thread.java:761)
E/EGL_emulation: tid 3410: eglSurfaceAttrib(1174): error 0x3009 (EGL_BAD_MATCH)
W/OpenGLRenderer: Failed to set EGL_SWAP_BEHAVIOR on surface 0x8fe424c0, error=EGL_BAD_MATCH