Question

我已使用该代码在SD卡下创建文件夹。但该文件夹永远不会创建。我已添加了uses-permission 机器人：名称=＆＃34; android.permission.WRITE_EXTERNAL_STORAGE＆＃34;表现出来。

 File folder = new File(Environment.getExternalStorageDirectory().toString()+"/Images");
       folder.mkdirs();


       if(folder.exists()){
           Toast.makeText(getApplicationContext(),"exists",Toast.LENGTH_LONG).show();
       }else{

           Toast.makeText(getApplicationContext()," not exists",Toast.LENGTH_LONG).show();
       }

Answer 1

你还应该添加：

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

Answer 2

File directory = new File(pathname);
                if (directory != null && !directory.exists()
                        && !directory.mkdirs()) {
                    try {
                        throw new IOException("Cannot create dir "
                                + directory.getAbsolutePath());
                    } catch (IOException e) {

                        e.printStackTrace();
                    }
                }

Answer 3

尝试添加此代码以调试您是否可以实际写入外部存储：

Log.d("MyActivity", "Can write: " + Environment.getExternalStorageDirectory().canWrite());

并验证mkdirs的结果：

boolean result = folder.mkdirs();
Log.d("MyActivity", "mkdirs: " + result);

Answer 4

试试这个并检查Log的流程 - ＆gt;

      //First check if the sd card is mounted or not      
         if (android.os.Environment.getExternalStorageState().equals(android.os.Environment.MEDIA_MOUNTED))

                {
                   // sd card mounted
                   Log.d("SDCard", "SDcard is present");
                }  

                File folder = new File(Environment.getExternalStorageDirectory() + File.separator +"Images/");
             if(!folder.exists())

              {
                folder.mkdirs();
                Log.d("SDcard", "Folder created");
              }   
            else
         {
                Log.d("SDCard", "Folder already exists");
         }       
     }

Answer 5

问题解决了！我在清单的错误部分添加了块。它应该在该部分之前或之后。

在Android Studio中简单创建SDCARD下的文件夹

5 个答案: