使用. settype ("message/rfc822")或ACTION_SEND的策略似乎也适用于非电子邮件客户端的应用程序，如Android Beam和蓝牙。

使用ACTION_SENDTO和mailto: URI似乎工作得很好，并且在开发人员文档中推荐使用。但是，如果你在官方模拟器上这样做，并且没有设置任何电子邮件帐户(或者没有任何邮件客户端)，你会得到以下错误:

不支持的操作 目前不支持该操作。

如下图所示:

结果是模拟器将意图解析为一个名为com.android.fallback的活动。Fallback，它显示上面的消息。显然这是故意的。

如果你想让你的应用在官方模拟器上也能正常运行，你可以在发送邮件之前检查一下:

private void sendEmail() {
    Intent intent = new Intent(Intent.ACTION_SENDTO)
        .setData(new Uri.Builder().scheme("mailto").build())
        .putExtra(Intent.EXTRA_EMAIL, new String[]{ "John Smith <johnsmith@yourdomain.com>" })
        .putExtra(Intent.EXTRA_SUBJECT, "Email subject")
        .putExtra(Intent.EXTRA_TEXT, "Email body")
    ;

    ComponentName emailApp = intent.resolveActivity(getPackageManager());
    ComponentName unsupportedAction = ComponentName.unflattenFromString("com.android.fallback/.Fallback");
    if (emailApp != null && !emailApp.equals(unsupportedAction))
        try {
            // Needed to customise the chooser dialog title since it might default to "Share with"
            // Note that the chooser will still be skipped if only one app is matched
            Intent chooser = Intent.createChooser(intent, "Send email with");
            startActivity(chooser);
            return;
        }
        catch (ActivityNotFoundException ignored) {
        }

    Toast
        .makeText(this, "Couldn't find an email app and account", Toast.LENGTH_LONG)
        .show();
}

在开发人员文档中找到更多信息。

使用. settype ("message/rfc822")或者选择器会显示所有(许多)支持发送意图的应用程序。

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);
        }
    }
}

/**
 * Will start the chosen Email app
 *
 * @param context    current component context.
 * @param emails     Emails you would like to send to.
 * @param subject    The subject that will be used in the Email app.
 * @param forceGmail True - if you want to open Gmail app, False otherwise. If the Gmail
 *                   app is not installed on this device a chooser will be shown.
 */
public static void sendEmail(Context context, String[] emails, String subject, boolean forceGmail) {

    Intent i = new Intent(Intent.ACTION_SENDTO);
    i.setData(Uri.parse("mailto:"));
    i.putExtra(Intent.EXTRA_EMAIL, emails);
    i.putExtra(Intent.EXTRA_SUBJECT, subject);
    if (forceGmail && isPackageInstalled(context, "com.google.android.gm")) {
        i.setPackage("com.google.android.gm");
        i.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
        context.startActivity(i);
    } else {
        try {
            context.startActivity(Intent.createChooser(i, "Send mail..."));
        } catch (ActivityNotFoundException e) {
            Toast.makeText(context, "No email app is installed on your device...", Toast.LENGTH_SHORT).show();
        }
    }
}

/**
 * Check if the given app is installed on this devuice.
 *
 * @param context     current component context.
 * @param packageName The package name you would like to check.
 * @return True if this package exist, otherwise False.
 */
public static boolean isPackageInstalled(@NonNull Context context, @NonNull String packageName) {
    PackageManager pm = context.getPackageManager();
    if (pm != null) {
        try {
            pm.getPackageInfo(packageName, 0);
            return true;
        } catch (PackageManager.NameNotFoundException e) {
            e.printStackTrace();
        }
    }
    return false;
}

我很久以前就一直在用这个，看起来不错，没有非电子邮件应用程序显示。这是发送电子邮件意图的另一种方式:

Intent intent = new Intent(Intent.ACTION_SENDTO); // it's not ACTION_SEND
intent.putExtra(Intent.EXTRA_SUBJECT, "Subject of email");
intent.putExtra(Intent.EXTRA_TEXT, "Body of email");
intent.setData(Uri.parse("mailto:default@example.com")); // or just "mailto:" for blank
intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK); // this will make such that when user returns to your app, your app is displayed, instead of the email app.
startActivity(intent);

我在我的应用程序中使用下面的代码。这显示准确的电子邮件客户端应用程序，如Gmail。

    Intent contactIntent = new Intent(Intent.ACTION_SENDTO, Uri.fromParts("mailto", getString(R.string.email_to), null));
    contactIntent.putExtra(Intent.EXTRA_SUBJECT, getString(R.string.email_subject));
    startActivity(Intent.createChooser(contactIntent, getString(R.string.email_chooser)));