java - 安卓写入sdcard

Question

我无法写入 SDCARD。我无法创建目录或文件，我缺少什么我在 list 中有这个

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

这在我的代码中

btnSave.setOnClickListener(new View.OnClickListener() 
        {
            public void onClick(View arg0) 
            {   
                // Create a directory; all ancestor directories must exist
                    boolean success = (new File("/sdcard/Methods/")).mkdirs();
                //create file   
                    try{
                    File myFile = new File("/sdcard/Methods/Method 1 Square.xml");
                    File file = myFile;
                        // Create file if it does not exist
                        boolean success1 = file.createNewFile();}   
                    catch (IOException e) 
                        {}
                //write to file
                    try {
                        BufferedWriter out = new BufferedWriter(new FileWriter("/sdcard/Methods/Method 1 Square.xml"));
                        out.write ("<?xml version=\"1.0\"?>");
                        out.write ("<?mso-application progid=\"Excel.Sheet\"?>");
                        out.write ("Workbook xmlns=\"urn:schemas-microsoft-com:office:spreadsheet\"");
                        out.close();
                    } // end try
                    catch (IOException e) 
                    {
                    } // end catch

            } // end public

        }); // end SAVE Button

Answer 1

第一件事:

只需检查“success”变量，它是否真的返回true。

第二件事:

因为您已经对/sdcard 进行了硬编码，所以我建议您使用以下方法获取目录:Environment.getExternalStorageDirectory() 因为在某些设备中，sd 卡根目录是/mnt/sdcard 所以上面的方法获取根目录。

第三件事:

首先要检查SD卡是否挂载。

示例:

File sdCard = Environment.getExternalStorageDirectory();
File dir = new File (sdcard.getAbsolutePath() + "/dir/subdir");  // in your case, just give /Methods

dir.mkdirs();
File file = new File(dir, "filename");  // in your case, just give "Method 1 Square.xml"

FileOutputStream f = new FileOutputStream(file);