为什么Android Studio的Java中的文件列表数组为空？

我正在使用Android Studio和Java

我已经编写了一个方法（即deleteWithExtension）来从设备内存中删除文件。此方法正在添加一些测试文件，并尝试获取这些文件的列表

但问题是，由于数组theFiles[]返回null，代码永远不会进入for循环。正如您所看到的，代码从示例文件添加过程开始，因此不应为空。我还可以在Android Studio的设备文件浏览器中看到这些示例文件

public static void CreateFile(Context mContext, String fileName, String textToBeWritten) {
    try {
        File dosya = new File(mContext.getFilesDir() + fileName);
        dosya.createNewFile();

        FileWriter fw = new FileWriter(dosya);
        BufferedWriter yazici = new BufferedWriter(fw);
        yazici.write(textToBeWritten);
        yazici.flush();
        yazici.close();
    } catch (Exception e) {
        e.printStackTrace();
    }
}

public static void deleteWithExtension(Context mContext, String extension) {
    //First let's add a few sample files with same extension.
    CreateFile(mContext,"SampleFile1.smp","anything1");
    CreateFile(mContext,"SampleFile2.smp","anything2");
    CreateFile(mContext,"SampleFile3.smp","anything3");
    CreateFile(mContext,"SampleFile4.smp","anything4");
    CreateFile(mContext,"SampleFile5.smp","anything5");

    //Now, 5 sample files have been added. Let get them and put in an array.
    File dir = mContext.getFilesDir();
    final String[] theFiles = dir.list();
    for (final String file : theFiles) {    
        //do something here....
        int aa=9;
        //The code never goes into here, because array theFiles is always null but 5 sample files was added at first.
    }
}

替换CreateFile（）方法，如下所示。我希望我能帮助你

public static void CreateFile(Context mContext, String fileName, String textToBeWritten) {
        try {
            File dosya = new File(mContext.getFilesDir() + File.separator + fileName);
            dosya.createNewFile();
    
            FileWriter fw = new FileWriter(dosya);
            BufferedWriter yazici = new BufferedWriter(fw);
            yazici.write(textToBeWritten);
            yazici.flush();
            yazici.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

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非常感谢你。你确实帮了我很多。这解决了我的问题。