Java 如何通过电子邮件发送文本文件作为附件-Android？

我在网上看到了许多代码，但它们似乎都遇到了问题

使用以下功能创建并保存文件：

    private static String filename = "eulerY.txt" ;

    private void saveData() {

      

        FileOutputStream fos_FILE_eulerY = null;

        String message = "hello";
        try {
            fos_FILE_eulerY = openFileOutput(filename , MODE_PRIVATE);
            fos_FILE_eulerY.write(message.getBytes());
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (fos_FILE_eulerY != null) {
                try {
                    fos_FILE_eulerY.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }


        // export data
        sendEmail ();
    }

但是，在运行下面的代码发送文件时，我一直遇到问题

ClipData.Item.getUri

正如建议的那样，使用此链接中的所有答案”https://stackoverflow.com/questions/48117511/exposed-beyond-app-through-clipdata-item-geturi，打开Gmail时，会显示“无法附加文件”

---

如果有任何方法发送此文件，我将不胜感激。

如果您的

targetSdkVersion>=24

，则我们必须使用

FileProvider

类来访问特定的文件或文件夹，以便其他应用程序可以访问这些文件或文件夹

第1步： 在

AndroidManifest.xml

文件中添加以下代码

        <provider
        android:name="androidx.core.content.FileProvider"
        android:authorities="${applicationId}.provider"
        android:exported="false"
        android:grantUriPermissions="true">
        <meta-data
            android:name="android.support.FILE_PROVIDER_PATHS"
            android:resource="@xml/file_paths" />
    </provider>

步骤3 现在，您可以将文件保存在您的

包.private

文件夹中，并将保存在该文件夹中的

文件uri

共享给其他应用程序，例如

gmail

应用程序作为

附件。现在，您的方法如下所示：

    private void saveData() {
    String filename = "eulerY.txt" ;
    //FileOutputStream fos_FILE_eulerY = null;
    File externalFilesDirectory = this.getExternalFilesDir(Environment.DIRECTORY_DOCUMENTS);
    File textFile = new File(externalFilesDirectory,filename);
    String message = "hello";
    try {
        //fos_FILE_eulerY = openFileOutput(textFile.getAbsolutePath() , MODE_PRIVATE);
        //fos_FILE_eulerY.write(message.getBytes());
        FileWriter writer = new FileWriter(textFile);
        writer.append(message);
        writer.flush();
        writer.close();
    } catch (FileNotFoundException e) {
        e.printStackTrace();
    } catch (Exception e){
        e.getLocalizedMessage();
    }


    // export data
    sendEmail (textFile);
}

    private void sendEmail (File file){
    //File filelocation = new File(Environment.getExternalStorageDirectory().getAbsolutePath(), filename);
    //Uri path = Uri.fromFile(filelocation);
    //FileProvider.getUriForFile(it, "${it.packageName}.provider", file)
    Uri fileUri = FileProvider.getUriForFile(this,getPackageName()+".provider",file);
    Intent emailIntent = new Intent(Intent.ACTION_SEND);
    emailIntent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
    // set the type to 'email'
    emailIntent .setType("vnd.android.cursor.dir/email");
    String[] to = {"asd@gmail.com"};
    emailIntent .putExtra(Intent.EXTRA_EMAIL, to);
    // the attachment
    emailIntent .putExtra(Intent.EXTRA_STREAM, fileUri);
    // the mail subject
    emailIntent .putExtra(Intent.EXTRA_SUBJECT, "Subject");
    startActivity(Intent.createChooser(emailIntent , "Send email..."));
}

非常感谢你。我对你感激不尽：）
<paths>
    <external-path name="external_files" path="."/>
</paths>

    private void saveData() {
    String filename = "eulerY.txt" ;
    //FileOutputStream fos_FILE_eulerY = null;
    File externalFilesDirectory = this.getExternalFilesDir(Environment.DIRECTORY_DOCUMENTS);
    File textFile = new File(externalFilesDirectory,filename);
    String message = "hello";
    try {
        //fos_FILE_eulerY = openFileOutput(textFile.getAbsolutePath() , MODE_PRIVATE);
        //fos_FILE_eulerY.write(message.getBytes());
        FileWriter writer = new FileWriter(textFile);
        writer.append(message);
        writer.flush();
        writer.close();
    } catch (FileNotFoundException e) {
        e.printStackTrace();
    } catch (Exception e){
        e.getLocalizedMessage();
    }


    // export data
    sendEmail (textFile);
}

    private void sendEmail (File file){
    //File filelocation = new File(Environment.getExternalStorageDirectory().getAbsolutePath(), filename);
    //Uri path = Uri.fromFile(filelocation);
    //FileProvider.getUriForFile(it, "${it.packageName}.provider", file)
    Uri fileUri = FileProvider.getUriForFile(this,getPackageName()+".provider",file);
    Intent emailIntent = new Intent(Intent.ACTION_SEND);
    emailIntent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
    // set the type to 'email'
    emailIntent .setType("vnd.android.cursor.dir/email");
    String[] to = {"asd@gmail.com"};
    emailIntent .putExtra(Intent.EXTRA_EMAIL, to);
    // the attachment
    emailIntent .putExtra(Intent.EXTRA_STREAM, fileUri);
    // the mail subject
    emailIntent .putExtra(Intent.EXTRA_SUBJECT, "Subject");
    startActivity(Intent.createChooser(emailIntent , "Send email..."));
}