在android/java中調用createNewFile()時，為什么會出現：java.io.IOException: No such file or directory

Question

我們嘗試通過獲取路徑、創建新目錄然后在該目錄中創建文件來在 android 中創建文件，但在運行時出現錯誤。 這是代碼：

private File createTestFile() throws IOException {
    String rootPath = Environment.getExternalStorageDirectory().getAbsolutePath() + "/RNDAlexaData/";
    Log.d("rootpath", rootPath);
    File root = new File(rootPath);
    if (!root.exists()) {
        root.mkdirs();
    }
    File f = new File(rootPath + "test.pcm");
    if (f.exists()) {
        f.delete();
    }
    f.createNewFile();
  
    FileOutputStream out = new FileOutputStream(f);

    out.flush();
    out.close();

    return f;
}

Output 來自 android：

D/rootpath: /storage/emulated/0/RNDAlexaData/
D/Response error: java.io.IOException: No such file or directory
W/System.err: java.io.IOException: No such file or directory
        at java.io.UnixFileSystem.createFileExclusively0(Native Method)
        at java.io.UnixFileSystem.createFileExclusively(UnixFileSystem.java:317)
        at java.io.File.createNewFile(File.java:1008)
        at aut.rnd.alexa.ui.account.AccountFragment$TokenListener.createTestFile(AccountFragment.java:318)

Android Manifest 具有以下權限：

<uses-permission android:name="android.permission.INTERNET"/>
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" android:maxSdkVersion="18"/>
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>

Answer 1

在谷歌搜索和評論中的@blackapps 和@Andreas 的幫助下修復了我自己的問題。

Environment.getExternalStorageDirectory()已棄用，請改用mContext.getExternalFilesDir(null).getAbsolutePath() 。

private File createTestFile() throws IOException {
    File dataFolder = new File(mContext.getExternalFilesDir(null).getAbsolutePath(), "RNDAlexaData");
    Log.d("parent", dataFolder.getParent());

    if (!dataFolder.exists()) {
        Log.d("mkdir_success", "Succesfully created directory: " + dataFolder.mkdirs());
    }
    else {
        Log.d("fileexists", "true");
    }

    File testMediaFile = new File(dataFolder, "test.pcm");
    if (testMediaFile.exists()) {
        testMediaFile.delete();
    }
    Log.d("media_file", "successfully created: " + testMediaFile.createNewFile());

    FileOutputStream out = new FileOutputStream(testMediaFile);
    // TODO
    out.flush();
    out.close();

    return testMediaFile;
}