1. 拉起系统分享功能

1.1 在清单文件AndroidManifest.xml中声明

<manifest>
    <application>
        ...
        <provider
            android:name="androidx.core.content.FileProvider"
            android:authorities="包名.fileprovider"
            android:exported="false"
            android:grantUriPermissions="true">
            <meta-data
                android:name="android.support.FILE_PROVIDER_PATHS"
                android:resource="@xml/file_paths" />
        </provider>
        ...
    </application>
</manifest>

1.2 在res/xml/目录下创建一个file_paths.xml文件，用于指定你想要共享的文件路径

<paths xmlns:android="http://schemas.android.com/apk/res/android">
    <external-path name="external_files" path="." />
</paths>

1.3 编码

根据分享的内容不同判断shareType的值

String shareType = "text/plain";//文本
String shareType = "video/mp4";//视频
String shareType = "image/jpeg";//照片


Intent sendIntent = new Intent();
sendIntent.setAction(Intent.ACTION_SEND);
sendIntent.setType(shareType);

if() {
    //分享的是文本
   sendIntent.putExtra(Intent.EXTRA_TEXT, "分享的文本");
} else {
  //分享的是照片视频等文件时
  File file = new File(filePath);
  
  //注意此处的包名.fileprovider 要和清单文件中的保持一致
  Uri videoUri = FileProvider.getUriForFile(this, "包名.fileprovider", file);
  
  sendIntent.putExtra(Intent.EXTRA_STREAM, videoUri);
   // 添加权限标志
  sendIntent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
}

Intent chooser = Intent.createChooser(sendIntent, "选择分享方式");
if (sendIntent.resolveActivity(getPackageManager()) != null) {
    startActivity(chooser);
}

常见文件的mimeType

{".3gp", "video/3gpp"}, 
{".apk", "application/vnd.android.package-archive"},
{".asf", "video/x-ms-asf"}, 
{".avi", "video/x-msvideo"}, 
{".bin", "application/octet-stream"}, 
{".bmp", "image/bmp"}, 
{".c", "text/plain"},
{".class", "application/octet-stream"},
{".conf", "text/plain"},
{".cpp", "text/plain"},
{".doc", "application/msword"},
{".exe", "application/octet-stream"}, 
{".gif", "image/gif"}, 
{".gtar", "application/x-gtar"},
{".gz", "application/x-gzip"}, 
{".h", "text/plain"},
{".htm", "text/html"},
{".html", "text/html"}, 
{".jar", "application/java-archive"}, 
{".java", "text/plain"}, 
{".jpeg", "image/jpeg"}, 
{".jpg", "image/jpeg"}, 
{".js", "application/x-javascript"}, 
{".log", "text/plain"}, 
{".m3u", "audio/x-mpegurl"}, 
{".m4a", "audio/mp4a-latm"}, 
{".m4b", "audio/mp4a-latm"},
{".m4p", "audio/mp4a-latm"}, 
{".m4u", "video/vnd.mpegurl"}, 
{".m4v", "video/x-m4v"}, 
{".mov", "video/quicktime"}, 
{".mp2", "audio/x-mpeg"}, 
{".mp3", "audio/x-mpeg"}, 
{".mp4", "video/mp4"},
{".mpc", "application/vnd.mpohun.certificate"}, 
{".mpe", "video/mpeg"}, 
{".mpeg", "video/mpeg"}, 
{".mpg", "video/mpeg"}, 
{".mpg4", "video/mp4"}, 
{".mpga", "audio/mpeg"}, 
{".msg", "application/vnd.ms-outlook"}, 
{".ogg", "audio/ogg"}, 
{".pdf", "application/pdf"}, 
{".png", "image/png"}, 
{".pps", "application/vnd.ms-powerpoint"}, 
{".ppt", "application/vnd.ms-powerpoint"}, 
{".prop", "text/plain"}, 
{".rar", "application/x-rar-compressed"}, 
{".rc", "text/plain"}, 
{".rmvb", "audio/x-pn-realaudio"}, 
{".rtf", "application/rtf"}, 
{".sh", "text/plain"}, 
{".tar", "application/x-tar"}, 
{".tgz", "application/x-compressed"}, 
{".txt", "text/plain"}, 
{".wav", "audio/x-wav"}, 
{".wma", "audio/x-ms-wma"}, 
{".wmv", "audio/x-ms-wmv"}, 
{".wps", "application/vnd.ms-works"},
{".xml", "text/xml"}, 
{".xml", "text/plain"}, 
{".z", "application/x-compress"}, 
{".zip", "application/zip"},
{"", "*/*"} 

2. 拉起系统邮箱

Intent intent = new Intent(Intent.ACTION_SENDTO);
//指定一个空的收件人地址
intent.setData(Uri.parse("mailto:"));
//指定电子邮件的收件人地址
//intent.setData(Uri.parse("mailto:00@qq.com"));

this.startActivity(intent);