创建分享

创建Intent并指定Action为Intent.ACTION_SEND。

val shareIntent = Intent(Intent.ACTION_SEND)

指定需要发送的内容和类型。

//传输文件 采用流的方式

intent.putExtra(Intent.EXTRA_STREAM,Uri.fromFile(File(fileUrl))

intent.type = "*/*"

发送隐式意图，打开系统分享选择器。

context.startActivity(shareIntent)

获取文件类型(MimeType)

文件分享时一般都要设置好文件类型，默认指定类型为*/*，已默认类型进行分享时有些App不支持这种类型，会导致我们分享失败，最好的方式是预先根据文件路径设置好文件类型。

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"},

{"", "*/*"}

方式一：通过 ContentResolver 查询 Android 系统提供的 ContentProvider 获取(方便但不稳定)

当 targetSdkVersion >= 24 时，

使用 Uri.fromFile(File file) 获取文件 URI 会报android.os.FileUriExposedException 异常

获取文件的 url

val shareFile = File(shareFilePath)

val fileUri = Uri.fromFile(shareFile)

获取系统的提供的 ContentResolver

val contentResolver = context!!.contentResolver

获取文件MimeType，如 image/png

val fileMimeType = contentResolver.getType(fileUri)

获取文件Type，如 txt

val mime = MimeTypeMap.getSingleton()

val fileType = mime.getExtensionFromMimeType(fileMimeType)

方式二：解析文件信息，通过匹配识别判断：

识别文件后缀，根据后缀名来判断文件类型。

获取文件头信息，转成十六进制字符串后判断文件类型。

object FileUtil {

/**

* 根据文件后缀回去MIME类型

*

* @param file file

* @return string

*/

public fun getMIMEType(file: File): String {

var type = "*/*"

val fName = file.name

//获取后缀名前的分隔符"."在fName中的位置。

val dotIndex = fName.lastIndexOf(".")

if (dotIndex < 0) {

return type

}

/* 获取文件的后缀名*/

val end = fName.substring(dotIndex, fName.length).toLowerCase()

if (TextUtils.isEmpty(end)) {

return type

}

//在MIME和文件类型的匹配表中找到对应的MIME类型。

for (i in MIME_MapTable.indices) {

if (end == MIME_MapTable[i][0]) {

type = MIME_MapTable[i][1]

break

}

}

return type

}

private val MIME_MapTable = arrayOf(

// {后缀名，MIME类型}

arrayOf(".3gp", "video/3gpp"),

arrayOf(".apk", "application/vnd.android.package-archive"),

arrayOf(".asf", "video/x-ms-asf"),

arrayOf(".avi", "video/x-msvideo"),

arrayOf(".bin", "application/octet-stream"),

arrayOf(".bmp", "image/bmp"),

arrayOf(".c", "text/plain"),

arrayOf(".class", "application/octet-stream"),

arrayOf(".conf", "text/plain"),

arrayOf(".cpp", "text/plain"),

arrayOf(".doc", "application/msword"),

arrayOf(".docx", "application/vnd.openxmlformats-officedocument.wordprocessingml.document"),

arrayOf(".xls", "application/vnd.ms-excel"),

arrayOf(".xlsx", "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet"),

arrayOf(".exe", "application/octet-stream"),

arrayOf(".gif", "image/gif"),

arrayOf(".gtar", "application/x-gtar"),

arrayOf(".gz", "application/x-gzip"),

arrayOf(".h", "text/plain"),

arrayOf(".htm", "text/html"),

arrayOf(".html", "text/html"),

arrayOf(".jar", "application/java-archive"),

arrayOf(".java", "text/plain"),

arrayOf(".jpeg", "image/jpeg"),

arrayOf(".jpg", "image/jpeg"), arrayOf(".js", "application/x-javascript"), arrayOf(".log", "text/plain"),

arrayOf(".m3u", "audio/x-mpegurl"), arrayOf(".m4a", "audio/mp4a-latm"), arrayOf(".m4b", "audio/mp4a-latm"),

arrayOf(".m4p", "audio/mp4a-latm"), arrayOf(".m4u", "video/vnd.mpegurl"), arrayOf(".m4v", "video/x-m4v"), arrayOf(".mov", "video/quicktime"),

arrayOf(".mp2", "audio/x-mpeg"), arrayOf(".mp3", "audio/x-mpeg"), arrayOf(".mp4", "video/mp4"),

arrayOf(".mpc", "application/vnd.mpohun.certificate"), arrayOf(".mpe", "video/mpeg"), arrayOf(".mpeg", "video/mpeg"),

arrayOf(".mpg", "video/mpeg"), arrayOf(".mpg4", "video/mp4"), arrayOf(".mpga", "audio/mpeg"), arrayOf(".msg", "application/vnd.ms-outlook"),

arrayOf(".ogg", "audio/ogg"),

arrayOf(".pdf", "application/pdf"), arrayOf(".png", "image/png"), arrayOf(".pps", "application/vnd.ms-powerpoint"),

arrayOf(".ppt", "application/vnd.ms-powerpoint"), arrayOf(".pptx", "application/vnd.openxmlformats-officedocument.presentationml.presentation"),

arrayOf(".prop", "text/plain"),

arrayOf(".rc", "text/plain"), arrayOf(".rmvb", "audio/x-pn-realaudio"), arrayOf(".rtf", "application/rtf"),

arrayOf(".sh", "text/plain"),

arrayOf(".tar", "application/x-tar"), arrayOf(".tgz", "application/x-compressed"), arrayOf(".txt", "text/plain"),

arrayOf(".wav", "audio/x-wav"),

arrayOf(".wma", "audio/x-ms-wma"), arrayOf(".wmv", "audio/x-ms-wmv"), arrayOf(".wps", "application/vnd.ms-works"),

arrayOf(".xml", "text/plain"), arrayOf(".z", "application/x-compress"), arrayOf(".zip", "application/x-zip-compressed"), arrayOf("", "*/*"))

}