Android 11：发送带有自动附加文件的电子邮件

如何解决Android 11：发送带有自动附加文件的电子邮件

我想要使用已经生成的文本、主题、收件人和附件打开和发送电子邮件应用程序，它适用于 android sdk 版本 29 (android 10) 及更低版本。但是从 Android 11 开始，在外部或内部存储中写入文件有限制，还有另一个限制是不允许从应用程序文件目录自动附加文件。 以前我是从应用存储复制到内部或外部存储来附加文件，有什么解决方案吗？

完成 android:requestLegacyExternalStorage="true"

public static void sendMail(Context context) throws IOException {
        Context appContext = context.getApplicationContext();

        File logFile = FileUtils.createFile(context.getFilesDir().getAbsolutePath(),"testFile.txt","Test");

        File logsDirectory = new File(FileUtils.getStorageDirectory(appContext),"files");
        logsDirectory.mkdirs();

        File destFile = new File(logsDirectory,"log.txt");

        InputStream in = new FileInputStream(logFile);
        boolean copied = FileUtils.copyToFile(in,destFile);

        Uri logPath = Uri.fromFile(destFile);

        Intent emailIntent = new Intent(Intent.ACTION_SENDTO);
        emailIntent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
        emailIntent.addFlags(Intent.FLAG_GRANT_WRITE_URI_PERMISSION);
        // set the type to 'email'
        emailIntent.setData(Uri.parse("mailto:"));
        String[] to = {"[e-mail]"};
        String subject = "Test log";
        String body =
                "Hello";
        emailIntent.putExtra(Intent.EXTRA_SUBJECT,subject);
        emailIntent.putExtra(Intent.EXTRA_EMAIL,to);
        emailIntent.putExtra(android.content.Intent.EXTRA_TEXT,body);
        // the attachment
        emailIntent.putExtra(Intent.EXTRA_STREAM,logPath);

        context.startActivity(Intent.createChooser(emailIntent,"Send email..."));
    } 

public class FileUtils {
    
        public static String getExtensionFromFileName(String fileName) {
        if (fileName == null) return null;

        String extension = null;
        int i = fileName.lastIndexOf('.');
        if (i > 0) {
            extension = fileName.substring(i + 1);
        }
        return extension;
    }

    /**
     * Copy data from a source stream to destFile. Return true if succeed,return false if failed.
     */
    public static boolean copyToFile(InputStream inputStream,File destFile) {
        if (inputStream == null || destFile == null) return false;
        try {
            try (OutputStream out = new FileOutputStream(destFile)) {
                byte[] buffer = new byte[4096];
                int bytesRead;
                while ((bytesRead = inputStream.read(buffer)) >= 0) {
                    out.write(buffer,bytesRead);
                }
            }
            return true;
        } catch (IOException e) {
            Log.e("[File Utils]","copyToFile exception: " + e);

        }
        return false;
    }


    public static String getStorageDirectory(Context mContext) {
        String storageDir =
                Environment.getExternalStorageDirectory().getAbsolutePath()
                        + "/"
                        + mContext.getString(R.string.app_name);
        File file = new File(storageDir);
        mContext.getExternalMediaDirs();

        if (!file.isDirectory() || !file.exists()) {


        }
        return storageDir;
    }

    public static File createFile(String directory,String fileName,String textToAttach)
    {
        File logFile = new File(directory  + "/" + fileName);
        if (!logFile.exists())
        {
            try
            {
                logFile.createNewFile();
            }
            catch (IOException e)
            {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
        try
        {
            //BufferedWriter for performance,true to set append to file flag
            BufferedWriter buf = new BufferedWriter(new FileWriter(logFile,true));
            buf.append(textToAttach);
            buf.newLine();
            buf.close();
        }
        catch (IOException e)
        {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return logFile;
    }
}

解决方法

我已经使用了 FileProvider 和选择器，这是针对多个文件

public static void sendMail(Context context) {
        Context appContext = context.getApplicationContext();
        final String authority = appContext.getPackageName() + ".FileProvider";
        String[] to = {"[e-mail]"};
        String subject = "subject";
        String body = "body";
        
        ArrayList<File> logFiles = getLogFile(context);

        if (logFiles.size() == 0) {
            Toast.makeText(
                            context,context.getString(R.string.toast_send_failed_no_file_found),Toast.LENGTH_LONG)
                    .show();
            return;
        }
        // has to be an ArrayList

        ArrayList<Uri> logPaths = new ArrayList<>();
        for (File file : logFiles) {
            if (file.exists()) {
                logPaths.add(FileProvider.getUriForFile(appContext,authority,file));
            }
        }

        Intent emailSelectorIntent = new Intent(Intent.ACTION_SENDTO);
        emailSelectorIntent.setDataAndType(Uri.parse("mailto:"),"plain/text");

        final Intent emailIntent = new Intent(Intent.ACTION_SEND_MULTIPLE);
        // emailIntent.setType("plain/text");
        emailIntent.addFlags(
                Intent.FLAG_GRANT_READ_URI_PERMISSION | Intent.FLAG_GRANT_WRITE_URI_PERMISSION);

        emailIntent.putExtra(Intent.EXTRA_EMAIL,to);
        emailIntent.putExtra(Intent.EXTRA_SUBJECT,subject);
        emailIntent.putExtra(Intent.EXTRA_TEXT,body);
        emailIntent.putParcelableArrayListExtra(Intent.EXTRA_STREAM,logPaths);
        emailIntent.setSelector(emailSelectorIntent);

        context.startActivity(Intent.createChooser(emailIntent,"Send Logs"));
    }