我使用这段代码通过直接启动默认的邮件应用程序撰写部分来发送邮件。

    Intent i = new Intent(Intent.ACTION_SENDTO);
    i.setType("message/rfc822"); 
    i.setData(Uri.parse("mailto:"));
    i.putExtra(Intent.EXTRA_EMAIL  , new String[]{"test@gmail.com"});
    i.putExtra(Intent.EXTRA_SUBJECT, "Subject");
    i.putExtra(Intent.EXTRA_TEXT   , "body of email");
    try {
        startActivity(Intent.createChooser(i, "Send mail..."));
    } catch (android.content.ActivityNotFoundException ex) {
        Toast.makeText(this, "There are no email clients installed.", Toast.LENGTH_SHORT).show();
    }

解决方案很简单:android文档解释了这一点。

(https://developer.android.com/guide/components/intents-common.html邮件)

最重要的是标志:它是ACTION_SENDTO，而不是ACTION_SEND

另一条重要的线是

intent.setData(Uri.parse("mailto:")); ***// only email apps should handle this***

顺便说一下，如果你发送一个空的Extra，末尾的if()将不起作用，应用程序将无法启动电子邮件客户端。

根据Android文档。如果你想确保你的意图只被电子邮件应用程序处理(而不是其他短信或社交应用程序)，那么使用ACTION_SENDTO动作并包括“mailto:”数据方案。例如:

public void composeEmail(String[] addresses, String subject) {
    Intent intent = new Intent(Intent.ACTION_SENDTO);
    intent.setData(Uri.parse("mailto:")); // only email apps should handle this
    intent.putExtra(Intent.EXTRA_EMAIL, addresses);
    intent.putExtra(Intent.EXTRA_SUBJECT, subject);
    if (intent.resolveActivity(getPackageManager()) != null) {
        startActivity(intent);
    }
}

这个函数首先直接意图gmail发送电子邮件，如果gmail没有找到，然后提升意图选择器。我在许多商业应用程序中使用了这个功能，它工作得很好。希望对你有所帮助:

public static void sentEmail(Context mContext, String[] addresses, String subject, String body) {

    try {
        Intent sendIntentGmail = new Intent(Intent.ACTION_VIEW);
        sendIntentGmail.setType("plain/text");
        sendIntentGmail.setData(Uri.parse(TextUtils.join(",", addresses)));
        sendIntentGmail.setClassName("com.google.android.gm", "com.google.android.gm.ComposeActivityGmail");
        sendIntentGmail.putExtra(Intent.EXTRA_EMAIL, addresses);
        if (subject != null) sendIntentGmail.putExtra(Intent.EXTRA_SUBJECT, subject);
        if (body != null) sendIntentGmail.putExtra(Intent.EXTRA_TEXT, body);
        mContext.startActivity(sendIntentGmail);
    } catch (Exception e) {
        //When Gmail App is not installed or disable
        Intent sendIntentIfGmailFail = new Intent(Intent.ACTION_SEND);
        sendIntentIfGmailFail.setType("*/*");
        sendIntentIfGmailFail.putExtra(Intent.EXTRA_EMAIL, addresses);
        if (subject != null) sendIntentIfGmailFail.putExtra(Intent.EXTRA_SUBJECT, subject);
        if (body != null) sendIntentIfGmailFail.putExtra(Intent.EXTRA_TEXT, body);
        if (sendIntentIfGmailFail.resolveActivity(mContext.getPackageManager()) != null) {
            mContext.startActivity(sendIntentIfGmailFail);
        }
    }
}

简单，试试这个

 public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    buttonSend = (Button) findViewById(R.id.buttonSend);
    textTo = (EditText) findViewById(R.id.editTextTo);
    textSubject = (EditText) findViewById(R.id.editTextSubject);
    textMessage = (EditText) findViewById(R.id.editTextMessage);

    buttonSend.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View v) {

            String to = textTo.getText().toString();
            String subject = textSubject.getText().toString();
            String message = textMessage.getText().toString();

            Intent email = new Intent(Intent.ACTION_SEND);
            email.putExtra(Intent.EXTRA_EMAIL, new String[] { to });
            // email.putExtra(Intent.EXTRA_CC, new String[]{ to});
            // email.putExtra(Intent.EXTRA_BCC, new String[]{to});
            email.putExtra(Intent.EXTRA_SUBJECT, subject);
            email.putExtra(Intent.EXTRA_TEXT, message);

            // need this to prompts email client only
            email.setType("message/rfc822");

            startActivity(Intent.createChooser(email, "Choose an Email client :"));

        }
    });
}

下面的代码可以在Android 10及更高的设备上运行。它还设置了主题、正文和收件人(To)。

val uri = Uri.parse("mailto:$EMAIL")
                .buildUpon()
                .appendQueryParameter("subject", "App Feedback")
                .appendQueryParameter("body", "Body Text")
                .appendQueryParameter("to", EMAIL)
                .build()

            val emailIntent = Intent(Intent.ACTION_SENDTO, uri)

            startActivity(Intent.createChooser(emailIntent, "Select app"))

我是这么做的。很好很简单。

String emailUrl = "mailto:email@example.com?subject=Subject Text&body=Body Text";
        Intent request = new Intent(Intent.ACTION_VIEW);
        request.setData(Uri.parse(emailUrl));
        startActivity(request);