1.ContentProvider定义

这里通过一个实际的例子来说明ContentProvider（内容提供者）是什么，作用是什么

短信应用要访问通讯录应用中的数据，是不能直接访问的，应用通讯录的中的数据是属于通讯录app数据库中的数据，无法直接访问

通讯录应用使用ContentProvider将数据库表数据操作（增删改查）暴露给其他应用（包括本身）访问

其他应用通过ContentResolver来调用ContentProvider方法

ContentResolver和ContentProvider之间是通过URI交流

作用

进程间 进行数据交互 & 共享，即跨进程通信

2.Url

统一资源标识符,唯一标识 ContentProvider & 其中的数据,外界进程通过 URI 找到对应的ContentProvider & 其中的数据，再进行数据操作

以联系人Contacts的Uri为例，其结构如下所示：

  • schema: Android中固定为content://。
  • authority: 用于唯一标识一个ContentProvider。
  • path: ContentProvider中数据表的表名。
  • id: 数据表中数据的标识，可选字段。

注意：

// 设置URI
Uri uri = Uri.parse("content://com.demo.provider/User/1")
// 上述URI指向的资源是：名为 `com.demo.provider`的`ContentProvider` 中表名 为`User` 中的 `id`为1的数据

// 特别注意：URI模式存在匹配通配符* & ＃

// *：匹配任意长度的任何有效字符的字符串
// 以下的URI 表示 匹配provider的任何内容
content://com.example.app.provider/*
// ＃：匹配任意长度的数字字符的字符串
// 以下的URI 表示 匹配provider中的table表的所有行
content://com.example.app.provider/table/#

3.MIME数据类型

3.1概述

指定某个扩展名的文件用某种应用程序来打开,当该扩展名文件被访问的时候，浏览器会自动使用指定应用程序来打开。多用于指定一些客户端自定义的文件名，以及一些媒体文件打开方式。
如指定.html文件采用text应用程序打开、指定.pdf文件采用flash应用程序打开

格式前面为后缀名，后面为对应的MIME型

（例如： ".apk", "application/vnd.android.package-archive" 表示。.apk对应的是application/vnd.android.package-archive）

3.2具体使用

ContentProvider根据 URI 返回MIME类型

ContentProvider.geType(uri) ；

3.3MIME类型组成

每种MIME类型 由2部分组成 = 类型 + 子类型

MIME类型是 一个 包含2部分的字符串

text / html
// 类型 = text、子类型 = htmltext/css
text/xml
application/pdf

3.4MIME类型形式

MIME类型有2种形式：


// 形式1：单条记录
vnd.android.demo.item/自定义
// 形式2：多条记录（集合）
vnd.android.demo.dir/自定义 // 注：// 1. vnd：表示父类型和子类型具有非标准的、特定的形式。// 2. 父类型已固定好（即不能更改），只能区别是单条还是多条记录// 3. 子类型可自定义

实例

<-- 单条记录 -->// 单个记录的MIME类型vnd.android.cursor.item/vnd.yourcompanyname.contenttype // 若一个Uri如下content://com.example.transportationprovider/trains/122   // 则ContentProvider会通过ContentProvider.geType(url)返回以下MIME类型vnd.android.cursor.item/vnd.example.rail<-- 多条记录 -->// 多个记录的MIME类型vnd.android.cursor.dir/vnd.yourcompanyname.contenttype // 若一个Uri如下content://com.example.transportationprovider/trains // 则ContentProvider会通过ContentProvider.geType(url)返回以下MIME类型vnd.android.cursor.dir/vnd.example.rail

3.5MIME类型大全

import java.io.File;public class MimeTest {/*** MIME全部类型映射*/final static String[][] MIME_MapTable = {{ ".323", "text/h323" },{ ".3gp", "video/3gpp" },{ ".aab", "application/x-authoware-bin" },{ ".aam", "application/x-authoware-map" },{ ".aas", "application/x-authoware-seg" },{ ".acx", "application/internet-property-stream" },{ ".ai", "application/postscript" },{ ".aif", "audio/x-aiff" },{ ".aifc", "audio/x-aiff" },{ ".aiff", "audio/x-aiff" },{ ".als", "audio/X-Alpha5" },{ ".amc", "application/x-mpeg" },{ ".ani", "application/octet-stream" },{ ".apk", "application/vnd.android.package-archive" },{ ".asc", "text/plain" },{ ".asd", "application/astound" },{ ".asf", "video/x-ms-asf" },{ ".asn", "application/astound" },{ ".asp", "application/x-asap" },{ ".asr", "video/x-ms-asf" },{ ".asx", "video/x-ms-asf" },{ ".au", "audio/basic" },{ ".avb", "application/octet-stream" },{ ".avi", "video/x-msvideo" },{ ".awb", "audio/amr-wb" },{ ".axs", "application/olescript" },{ ".bas", "text/plain" },{ ".bcpio", "application/x-bcpio" },{ ".bin ", "application/octet-stream" },{ ".bld", "application/bld" },{ ".bld2", "application/bld2" },{ ".bmp", "image/bmp" },{ ".bpk", "application/octet-stream" },{ ".bz2", "application/x-bzip2" },{ ".c", "text/plain" },{ ".cal", "image/x-cals" },{ ".cat", "application/vnd.ms-pkiseccat" },{ ".ccn", "application/x-cnc" },{ ".cco", "application/x-cocoa" },{ ".cdf", "application/x-cdf" },{ ".cer", "application/x-x509-ca-cert" },{ ".cgi", "magnus-internal/cgi" },{ ".chat", "application/x-chat" },{ ".class", "application/octet-stream" },{ ".clp", "application/x-msclip" },{ ".cmx", "image/x-cmx" },{ ".co", "application/x-cult3d-object" },{ ".cod", "image/cis-cod" },{ ".conf", "text/plain" },{ ".cpio", "application/x-cpio" },{ ".cpp", "text/plain" },{ ".cpt", "application/mac-compactpro" },{ ".crd", "application/x-mscardfile" },{ ".crl", "application/pkix-crl" },{ ".crt", "application/x-x509-ca-cert" },{ ".csh", "application/x-csh" },{ ".csm", "chemical/x-csml" },{ ".csml", "chemical/x-csml" },{ ".css", "text/css" },{ ".cur", "application/octet-stream" },{ ".dcm", "x-lml/x-evm" },{ ".dcr", "application/x-director" },{ ".dcx", "image/x-dcx" },{ ".der", "application/x-x509-ca-cert" },{ ".dhtml", "text/html" },{ ".dir", "application/x-director" },{ ".dll", "application/x-msdownload" },{ ".dmg", "application/octet-stream" },{ ".dms", "application/octet-stream" },{ ".doc", "application/msword" },{ ".docx","application/vnd.openxmlformats-officedocument.wordprocessingml.document" },{ ".dot", "application/msword" },{ ".dvi", "application/x-dvi" },{ ".dwf", "drawing/x-dwf" },{ ".dwg", "application/x-autocad" },{ ".dxf", "application/x-autocad" },{ ".dxr", "application/x-director" },{ ".ebk", "application/x-expandedbook" },{ ".emb", "chemical/x-embl-dl-nucleotide" },{ ".embl", "chemical/x-embl-dl-nucleotide" },{ ".eps", "application/postscript" },{ ".epub", "application/epub+zip" },{ ".eri", "image/x-eri" },{ ".es", "audio/echospeech" },{ ".esl", "audio/echospeech" },{ ".etc", "application/x-earthtime" },{ ".etx", "text/x-setext" },{ ".evm", "x-lml/x-evm" },{ ".evy", "application/envoy" },{ ".exe", "application/octet-stream" },{ ".fh4", "image/x-freehand" },{ ".fh5", "image/x-freehand" },{ ".fhc", "image/x-freehand" },{ ".fif", "application/fractals" },{ ".flr", "x-world/x-vrml" },{ ".flv", "flv-application/octet-stream" },{ ".fm", "application/x-maker" },{ ".fpx", "image/x-fpx" },{ ".fvi", "video/isivideo" },{ ".gau", "chemical/x-gaussian-input" },{ ".gca", "application/x-gca-compressed" },{ ".gdb", "x-lml/x-gdb" },{ ".gif", "image/gif" },{ ".gps", "application/x-gps" },{ ".gtar", "application/x-gtar" },{ ".gz", "application/x-gzip" },{ ".h", "text/plain" },{ ".hdf", "application/x-hdf" },{ ".hdm", "text/x-hdml" },{ ".hdml", "text/x-hdml" },{ ".hlp", "application/winhlp" },{ ".hqx", "application/mac-binhex40" },{ ".hta", "application/hta" },{ ".htc", "text/x-component" },{ ".htm", "text/html" },{ ".html", "text/html" },{ ".hts", "text/html" },{ ".htt", "text/webviewhtml" },{ ".ice", "x-conference/x-cooltalk" },{ ".ico", "image/x-icon" },{ ".ief", "image/ief" },{ ".ifm", "image/gif" },{ ".ifs", "image/ifs" },{ ".iii", "application/x-iphone" },{ ".imy", "audio/melody" },{ ".ins", "application/x-internet-signup" },{ ".ips", "application/x-ipscript" },{ ".ipx", "application/x-ipix" },{ ".isp", "application/x-internet-signup" },{ ".it", "audio/x-mod" },{ ".itz", "audio/x-mod" },{ ".ivr", "i-world/i-vrml" },{ ".j2k", "image/j2k" },{ ".jad", "text/vnd.sun.j2me.app-descriptor" },{ ".jam", "application/x-jam" },{ ".jar", "application/java-archive" },{ ".java", "text/plain" },{ ".jfif", "image/pipeg" },{ ".jnlp", "application/x-java-jnlp-file" },{ ".jpe", "image/jpeg" },{ ".jpeg", "image/jpeg" },{ ".jpg", "image/jpeg" },{ ".jpz", "image/jpeg" },{ ".js", "application/x-javascript" },{ ".jwc", "application/jwc" },{ ".kjx", "application/x-kjx" },{ ".lak", "x-lml/x-lak" },{ ".latex", "application/x-latex" },{ ".lcc", "application/fastman" },{ ".lcl", "application/x-digitalloca" },{ ".lcr", "application/x-digitalloca" },{ ".lgh", "application/lgh" },{ ".lha", "application/octet-stream" },{ ".lml", "x-lml/x-lml" },{ ".lmlpack", "x-lml/x-lmlpack" },{ ".log", "text/plain" },{ ".lsf", "video/x-la-asf" },{ ".lsx", "video/x-la-asf" },{ ".lzh", "application/octet-stream" },{ ".m13", "application/x-msmediaview" },{ ".m14", "application/x-msmediaview" },{ ".m15", "audio/x-mod" },{ ".m3u", "audio/x-mpegurl" },{ ".m3url", "audio/x-mpegurl" },{ ".m4a", "audio/mp4a-latm" },{ ".m4b", "audio/mp4a-latm" },{ ".m4p", "audio/mp4a-latm" },{ ".m4u", "video/vnd.mpegurl" },{ ".m4v", "video/x-m4v" },{ ".ma1", "audio/ma1" },{ ".ma2", "audio/ma2" },{ ".ma3", "audio/ma3" },{ ".ma5", "audio/ma5" },{ ".man", "application/x-troff-man" },{ ".map", "magnus-internal/imagemap" },{ ".mbd", "application/mbedlet" },{ ".mct", "application/x-mascot" },{ ".mdb", "application/x-msaccess" },{ ".mdz", "audio/x-mod" },{ ".me", "application/x-troff-me" },{ ".mel", "text/x-vmel" },{ ".mht", "message/rfc822" },{ ".mhtml", "message/rfc822" },{ ".mi", "application/x-mif" },{ ".mid", "audio/mid" },{ ".midi", "audio/midi" },{ ".mif", "application/x-mif" },{ ".mil", "image/x-cals" },{ ".mio", "audio/x-mio" },{ ".mmf", "application/x-skt-lbs" },{ ".mng", "video/x-mng" },{ ".mny", "application/x-msmoney" },{ ".moc", "application/x-mocha" },{ ".mocha", "application/x-mocha" },{ ".mod", "audio/x-mod" },{ ".mof", "application/x-yumekara" },{ ".mol", "chemical/x-mdl-molfile" },{ ".mop", "chemical/x-mopac-input" },{ ".mov", "video/quicktime" },{ ".movie", "video/x-sgi-movie" },{ ".mp2", "video/mpeg" },{ ".mp3", "audio/mpeg" },{ ".mp4", "video/mp4" },{ ".mpa", "video/mpeg" },{ ".mpc", "application/vnd.mpohun.certificate" },{ ".mpe", "video/mpeg" },{ ".mpeg", "video/mpeg" },{ ".mpg", "video/mpeg" },{ ".mpg4", "video/mp4" },{ ".mpga", "audio/mpeg" },{ ".mpn", "application/vnd.mophun.application" },{ ".mpp", "application/vnd.ms-project" },{ ".mps", "application/x-mapserver" },{ ".mpv2", "video/mpeg" },{ ".mrl", "text/x-mrml" },{ ".mrm", "application/x-mrm" },{ ".ms", "application/x-troff-ms" },{ ".msg", "application/vnd.ms-outlook" },{ ".mts", "application/metastream" },{ ".mtx", "application/metastream" },{ ".mtz", "application/metastream" },{ ".mvb", "application/x-msmediaview" },{ ".mzv", "application/metastream" },{ ".nar", "application/zip" },{ ".nbmp", "image/nbmp" },{ ".nc", "application/x-netcdf" },{ ".ndb", "x-lml/x-ndb" },{ ".ndwn", "application/ndwn" },{ ".nif", "application/x-nif" },{ ".nmz", "application/x-scream" },{ ".nokia-op-logo", "image/vnd.nok-oplogo-color" },{ ".npx", "application/x-netfpx" },{ ".nsnd", "audio/nsnd" },{ ".nva", "application/x-neva1" },{ ".nws", "message/rfc822" },{ ".oda", "application/oda" },{ ".ogg", "audio/ogg" },{ ".oom", "application/x-AtlasMate-Plugin" },{ ".p10", "application/pkcs10" },{ ".p12", "application/x-pkcs12" },{ ".p7b", "application/x-pkcs7-certificates" },{ ".p7c", "application/x-pkcs7-mime" },{ ".p7m", "application/x-pkcs7-mime" },{ ".p7r", "application/x-pkcs7-certreqresp" },{ ".p7s", "application/x-pkcs7-signature" },{ ".pac", "audio/x-pac" },{ ".pae", "audio/x-epac" },{ ".pan", "application/x-pan" },{ ".pbm", "image/x-portable-bitmap" },{ ".pcx", "image/x-pcx" },{ ".pda", "image/x-pda" },{ ".pdb", "chemical/x-pdb" },{ ".pdf", "application/pdf" },{ ".pfr", "application/font-tdpfr" },{ ".pfx", "application/x-pkcs12" },{ ".pgm", "image/x-portable-graymap" },{ ".pict", "image/x-pict" },{ ".pko", "application/ynd.ms-pkipko" },{ ".pm", "application/x-perl" },{ ".pma", "application/x-perfmon" },{ ".pmc", "application/x-perfmon" },{ ".pmd", "application/x-pmd" },{ ".pml", "application/x-perfmon" },{ ".pmr", "application/x-perfmon" },{ ".pmw", "application/x-perfmon" },{ ".png", "image/png" },{ ".pnm", "image/x-portable-anymap" },{ ".pnz", "image/png" },{ ".pot,", "application/vnd.ms-powerpoint" },{ ".ppm", "image/x-portable-pixmap" },{ ".pps", "application/vnd.ms-powerpoint" },{ ".ppt", "application/vnd.ms-powerpoint" },{ ".pptx","application/vnd.openxmlformats-officedocument.presentationml.presentation" },{ ".pqf", "application/x-cprplayer" },{ ".pqi", "application/cprplayer" },{ ".prc", "application/x-prc" },{ ".prf", "application/pics-rules" },{ ".prop", "text/plain" },{ ".proxy", "application/x-ns-proxy-autoconfig" },{ ".ps", "application/postscript" },{ ".ptlk", "application/listenup" },{ ".pub", "application/x-mspublisher" },{ ".pvx", "video/x-pv-pvx" },{ ".qcp", "audio/vnd.qcelp" },{ ".qt", "video/quicktime" },{ ".qti", "image/x-quicktime" },{ ".qtif", "image/x-quicktime" },{ ".r3t", "text/vnd.rn-realtext3d" },{ ".ra", "audio/x-pn-realaudio" },{ ".ram", "audio/x-pn-realaudio" },{ ".rar", "application/octet-stream" },{ ".ras", "image/x-cmu-raster" },{ ".rc", "text/plain" },{ ".rdf", "application/rdf+xml" },{ ".rf", "image/vnd.rn-realflash" },{ ".rgb", "image/x-rgb" },{ ".rlf", "application/x-richlink" },{ ".rm", "audio/x-pn-realaudio" },{ ".rmf", "audio/x-rmf" },{ ".rmi", "audio/mid" },{ ".rmm", "audio/x-pn-realaudio" },{ ".rmvb", "audio/x-pn-realaudio" },{ ".rnx", "application/vnd.rn-realplayer" },{ ".roff", "application/x-troff" },{ ".rp", "image/vnd.rn-realpix" },{ ".rpm", "audio/x-pn-realaudio-plugin" },{ ".rt", "text/vnd.rn-realtext" },{ ".rte", "x-lml/x-gps" },{ ".rtf", "application/rtf" },{ ".rtg", "application/metastream" },{ ".rtx", "text/richtext" },{ ".rv", "video/vnd.rn-realvideo" },{ ".rwc", "application/x-rogerwilco" },{ ".s3m", "audio/x-mod" },{ ".s3z", "audio/x-mod" },{ ".sca", "application/x-supercard" },{ ".scd", "application/x-msschedule" },{ ".sct", "text/scriptlet" },{ ".sdf", "application/e-score" },{ ".sea", "application/x-stuffit" },{ ".setpay", "application/set-payment-initiation" },{ ".setreg", "application/set-registration-initiation" },{ ".sgm", "text/x-sgml" },{ ".sgml", "text/x-sgml" },{ ".sh", "application/x-sh" },{ ".shar", "application/x-shar" },{ ".shtml", "magnus-internal/parsed-html" },{ ".shw", "application/presentations" },{ ".si6", "image/si6" },{ ".si7", "image/vnd.stiwap.sis" },{ ".si9", "image/vnd.lgtwap.sis" },{ ".sis", "application/vnd.symbian.install" },{ ".sit", "application/x-stuffit" },{ ".skd", "application/x-Koan" },{ ".skm", "application/x-Koan" },{ ".skp", "application/x-Koan" },{ ".skt", "application/x-Koan" },{ ".slc", "application/x-salsa" },{ ".smd", "audio/x-smd" },{ ".smi", "application/smil" },{ ".smil", "application/smil" },{ ".smp", "application/studiom" },{ ".smz", "audio/x-smd" },{ ".snd", "audio/basic" },{ ".spc", "application/x-pkcs7-certificates" },{ ".spl", "application/futuresplash" },{ ".spr", "application/x-sprite" },{ ".sprite", "application/x-sprite" },{ ".sdp", "application/sdp" },{ ".spt", "application/x-spt" },{ ".src", "application/x-wais-source" },{ ".sst", "application/vnd.ms-pkicertstore" },{ ".stk", "application/hyperstudio" },{ ".stl", "application/vnd.ms-pkistl" },{ ".stm", "text/html" },{ ".svg", "image/svg+xml" },{ ".sv4cpio", "application/x-sv4cpio" },{ ".sv4crc", "application/x-sv4crc" },{ ".svf", "image/vnd" },{ ".svg", "image/svg+xml" },{ ".svh", "image/svh" },{ ".svr", "x-world/x-svr" },{ ".swf", "application/x-shockwave-flash" },{ ".swfl", "application/x-shockwave-flash" },{ ".t", "application/x-troff" },{ ".tad", "application/octet-stream" },{ ".talk", "text/x-speech" },{ ".tar", "application/x-tar" },{ ".taz", "application/x-tar" },{ ".tbp", "application/x-timbuktu" },{ ".tbt", "application/x-timbuktu" },{ ".tcl", "application/x-tcl" },{ ".tex", "application/x-tex" },{ ".texi", "application/x-texinfo" },{ ".texinfo", "application/x-texinfo" },{ ".tgz", "application/x-compressed" },{ ".thm", "application/vnd.eri.thm" },{ ".tif", "image/tiff" },{ ".tiff", "image/tiff" },{ ".tki", "application/x-tkined" },{ ".tkined", "application/x-tkined" },{ ".toc", "application/toc" },{ ".toy", "image/toy" },{ ".tr", "application/x-troff" },{ ".trk", "x-lml/x-gps" },{ ".trm", "application/x-msterminal" },{ ".tsi", "audio/tsplayer" },{ ".tsp", "application/dsptype" },{ ".tsv", "text/tab-separated-values" },{ ".ttf", "application/octet-stream" },{ ".ttz", "application/t-time" },{ ".txt", "text/plain" },{ ".uls", "text/iuls" },{ ".ult", "audio/x-mod" },{ ".ustar", "application/x-ustar" },{ ".uu", "application/x-uuencode" },{ ".uue", "application/x-uuencode" },{ ".vcd", "application/x-cdlink" },{ ".vcf", "text/x-vcard" },{ ".vdo", "video/vdo" },{ ".vib", "audio/vib" },{ ".viv", "video/vivo" },{ ".vivo", "video/vivo" },{ ".vmd", "application/vocaltec-media-desc" },{ ".vmf", "application/vocaltec-media-file" },{ ".vmi", "application/x-dreamcast-vms-info" },{ ".vms", "application/x-dreamcast-vms" },{ ".vox", "audio/voxware" },{ ".vqe", "audio/x-twinvq-plugin" },{ ".vqf", "audio/x-twinvq" },{ ".vql", "audio/x-twinvq" },{ ".vre", "x-world/x-vream" },{ ".vrml", "x-world/x-vrml" },{ ".vrt", "x-world/x-vrt" },{ ".vrw", "x-world/x-vream" },{ ".vts", "workbook/formulaone" },{ ".wav", "audio/x-wav" },{ ".wax", "audio/x-ms-wax" },{ ".wbmp", "image/vnd.wap.wbmp" },{ ".wcm", "application/vnd.ms-works" },{ ".wdb", "application/vnd.ms-works" },{ ".web", "application/vnd.xara" },{ ".wi", "image/wavelet" },{ ".wis", "application/x-InstallShield" },{ ".wks", "application/vnd.ms-works" },{ ".wm", "video/x-ms-wm" },{ ".wma", "audio/x-ms-wma" },{ ".wmd", "application/x-ms-wmd" },{ ".wmf", "application/x-msmetafile" },{ ".wml", "text/vnd.wap.wml" },{ ".wmlc", "application/vnd.wap.wmlc" },{ ".wmls", "text/vnd.wap.wmlscript" },{ ".wmlsc", "application/vnd.wap.wmlscriptc" },{ ".wmlscript", "text/vnd.wap.wmlscript" },{ ".wmv", "audio/x-ms-wmv" },{ ".wmx", "video/x-ms-wmx" },{ ".wmz", "application/x-ms-wmz" },{ ".wpng", "image/x-up-wpng" },{ ".wps", "application/vnd.ms-works" },{ ".wpt", "x-lml/x-gps" },{ ".wri", "application/x-mswrite" },{ ".wrl", "x-world/x-vrml" },{ ".wrz", "x-world/x-vrml" },{ ".ws", "text/vnd.wap.wmlscript" },{ ".wsc", "application/vnd.wap.wmlscriptc" },{ ".wv", "video/wavelet" },{ ".wvx", "video/x-ms-wvx" },{ ".wxl", "application/x-wxl" },{ ".x-gzip", "application/x-gzip" },{ ".xaf", "x-world/x-vrml" },{ ".xar", "application/vnd.xara" },{ ".xbm", "image/x-xbitmap" },{ ".xdm", "application/x-xdma" },{ ".xdma", "application/x-xdma" },{ ".xdw", "application/vnd.fujixerox.docuworks" },{ ".xht", "application/xhtml+xml" },{ ".xhtm", "application/xhtml+xml" },{ ".xhtml", "application/xhtml+xml" },{ ".xla", "application/vnd.ms-excel" },{ ".xlc", "application/vnd.ms-excel" },{ ".xll", "application/x-excel" },{ ".xlm", "application/vnd.ms-excel" },{ ".xls", "application/vnd.ms-excel" },{ ".xlsx","application/vnd.openxmlformats-officedocument.spreadsheetml.sheet" },{ ".xlt", "application/vnd.ms-excel" },{ ".xlw", "application/vnd.ms-excel" }, { ".xm", "audio/x-mod" },{ ".xml", "text/plain" }, { ".xml", "application/xml" },{ ".xmz", "audio/x-mod" }, { ".xof", "x-world/x-vrml" },{ ".xpi", "application/x-xpinstall" },{ ".xpm", "image/x-xpixmap" }, { ".xsit", "text/xml" },{ ".xsl", "text/xml" }, { ".xul", "text/xul" },{ ".xwd", "image/x-xwindowdump" }, { ".xyz", "chemical/x-pdb" },{ ".yz1", "application/x-yz1" },{ ".z", "application/x-compress" },{ ".zac", "application/x-zaurus-zac" },{ ".zip", "application/zip" }, { ".json", "application/json" } };/*** 根据文件后缀名获得对应的MIME类型。* @param file*/public static String getMIMEType(File file) {String type = "*/*";String fName = file.getName();// 获取后缀名前的分隔符"."在fName中的位置。int dotIndex = fName.lastIndexOf(".");if (dotIndex < 0) {return type;}/* 获取文件的后缀名 */String end = fName.substring(dotIndex, fName.length()).toLowerCase();if (end == "")return type;// 在MIME和文件类型的匹配表中找到对应的MIME类型。for (int i = 0; i < MIME_MapTable.length; i++) { if (end.equals(MIME_MapTable[i][0]))type = MIME_MapTable[i][1];}return type;}public static void main(String[] args) {//下面输出为：application/vnd.android.package-archiveSystem.out.println(MimeTest.getMIMEType(new File("C:\\oyp.apk")));}
}

4.ContentProvider类

4.1概述

ContentProvider主要以 表格的形式 组织数据，同时也支持文件数据，只是表格形式用得比较多

每个表格中包含多张表，每张表包含行 & 列，分别对应记录 & 字段

4.2主要方法

进程间共享数据的本质是：添加、删除、获取 & 修改（更新）数据，所以ContentProvider的核心方法也主要是上述4个作用

<-- 4个核心方法 -->public Uri insert(Uri uri, ContentValues values) // 外部进程向 ContentProvider 中添加数据public int delete(Uri uri, String selection, String[] selectionArgs) // 外部进程 删除 ContentProvider 中的数据public int update(Uri uri, ContentValues values, String selection, String[] selectionArgs)// 外部进程更新 ContentProvider 中的数据public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs,  String sortOrder)　 // 外部应用 获取 ContentProvider 中的数据// 注：// 1. 上述4个方法由外部进程回调，并运行在ContentProvider进程的Binder线程池中（不是主线程）// 2. 存在多线程并发访问，需要实现线程同步// a. 若ContentProvider的数据存储方式是使用SQLite & 一个，则不需要，因为SQLite内部实现好了线程同步，若是多个SQLite则需要，因为SQL对象之间无法进行线程同步// b. 若ContentProvider的数据存储方式是内存，则需要自己实现线程同步<-- 2个其他方法 -->
public boolean onCreate()
// ContentProvider创建后 或 打开系统后其它进程第一次访问该ContentProvider时 由系统进行调用
// 注：运行在ContentProvider进程的主线程，故不能做耗时操作public String getType(Uri uri)
// 得到数据类型，即返回当前 Url 所代表数据的MIME类型
  • Android为常见的数据（如通讯录、日程表等）提供了内置了默认的ContentProvider，本文主要讲解自定义ContentProvider
  • 但也可根据需求自定义ContentProvider，但上述6个方法必须重写
  • ContentProvider类并不会直接与外部进程交互，而是通过ContentResolver 类

5.ContentResolver类

5.1概述

统一管理不同 ContentProvider间的操作，即通过 URI 即可操作 不同的ContentProvider 中的数据

外部进程通过 ContentResolver类 从而与ContentProvider类进行交互

为什么要使用通过ContentResolver类从而与ContentProvider类进行交互，而不直接访问ContentProvider类？

答：一般来说，一款应用要使用多个ContentProvider，若需要了解每个ContentProvider的不同实现从而再完成数据交互，操作成本高 & 难度大，所以再ContentProvider类上加多了一个 ContentResolver类对所有的ContentProvider进行统一管理。

5.2方法

// 外部进程向 ContentProvider 中添加数据
public Uri insert(Uri uri, ContentValues values)　 // 外部进程 删除 ContentProvider 中的数据
public int delete(Uri uri, String selection, String[] selectionArgs)// 外部进程更新 ContentProvider 中的数据
public int update(Uri uri, ContentValues values, String selection, String[] selectionArgs)　 // 外部应用 获取 ContentProvider 中的数据
public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder)

实例

// 使用ContentResolver前，需要先获取ContentResolver
// 可通过在所有继承Context的类中 通过调用getContentResolver()来获得ContentResolver
ContentResolver resolver =  getContentResolver(); // 设置ContentProvider的URI
Uri uri = Uri.parse("content://cn.scu.myprovider/user"); // 根据URI 操作 ContentProvider中的数据
// 此处是获取ContentProvider中 user表的所有记录
Cursor cursor = resolver.query(uri, null, null, null, "userid desc");

Android 提供了3个用于辅助ContentProvide的工具类：

  • ContentUris 操作 URI

// withAppendedId（）作用：向URI追加一个id
Uri uri = Uri.parse("content://cn.scu.myprovider/user")
Uri resultUri = ContentUris.withAppendedId(uri, 7);
// 最终生成后的Uri为：content://cn.scu.myprovider/user/7// parseId（）作用：从URL中获取ID
Uri uri = Uri.parse("content://cn.scu.myprovider/user/7")
long personid = ContentUris.parseId(uri);
//获取的结果为:7

  • UriMatcher

  1. 在ContentProvider 中注册URI
  2. 根据 URI 匹配 ContentProvider 中对应的数据表
// 步骤1：初始化UriMatcher对象UriMatcher matcher = new UriMatcher(UriMatcher.NO_MATCH); //常量UriMatcher.NO_MATCH  = 不匹配任何路径的返回码// 即初始化时不匹配任何东西// 步骤2：在ContentProvider 中注册URI（addURI（））int URI_CODE_a = 1；int URI_CODE_b = 2；matcher.addURI("cn.scu.myprovider", "user1", URI_CODE_a); matcher.addURI("cn.scu.myprovider", "user2", URI_CODE_b); // 若URI资源路径 = content://cn.scu.myprovider/user1 ，则返回注册码URI_CODE_a// 若URI资源路径 = content://cn.scu.myprovider/user2 ，则返回注册码URI_CODE_b// 步骤3：根据URI 匹配 URI_CODE，从而匹配ContentProvider中相应的资源（match（））@Override   public String getType(Uri uri) {   Uri uri = Uri.parse(" content://cn.scu.myprovider/user1");   switch(matcher.match(uri)){   // 根据URI匹配的返回码是URI_CODE_a// 即matcher.match(uri) == URI_CODE_acase URI_CODE_a:   return tableNameUser1;   // 如果根据URI匹配的返回码是URI_CODE_a，则返回ContentProvider中的名为tableNameUser1的表case URI_CODE_b:   return tableNameUser2;// 如果根据URI匹配的返回码是URI_CODE_b，则返回ContentProvider中的名为tableNameUser2的表}
}

  • ContentObserver

内容观察者，观察 Uri引起 ContentProvider 中的数据变化 & 通知外界（即访问该数据访问者），当ContentProvider 中的数据发生变化（增、删 & 改）时，就会触发该 ContentObserver类

// 步骤1：注册内容观察者ContentObservergetContentResolver().registerContentObserver（uri）；// 通过ContentResolver类进行注册，并指定需要观察的URI// 步骤2：当该URI的ContentProvider数据发生变化时，通知外界（即访问该ContentProvider数据的访问者）public class UserContentProvider extends ContentProvider { public Uri insert(Uri uri, ContentValues values) { db.insert("user", "userid", values); getContext().getContentResolver().notifyChange(uri, null); // 通知访问者}
}// 步骤3：解除观察者getContentResolver().unregisterContentObserver（uri）；// 同样需要通过ContentResolver类进行解除

6.实例

6.1实例说明

  • 由于ContentProvider不仅常用于进程间通信，同时也适用于进程内通信
  • 所以本实例会采用ContentProvider讲解：
    1. 进程内通信
    2. 进程间通信
  • 采用的数据源是Android中的SQLite数据库

6.2进程内通信

步骤1：创建数据库类

public class DBHelper extends SQLiteOpenHelper {// 数据库名private static final String DATABASE_NAME = "finch.db";// 表名public static final String USER_TABLE_NAME = "user";public static final String JOB_TABLE_NAME = "job";private static final int DATABASE_VERSION = 1;//数据库版本号public DBHelper(Context context) {super(context, DATABASE_NAME, null, DATABASE_VERSION);}@Overridepublic void onCreate(SQLiteDatabase db) {// 创建两个表格:用户表 和职业表db.execSQL("CREATE TABLE IF NOT EXISTS " + USER_TABLE_NAME + "(_id INTEGER PRIMARY KEY AUTOINCREMENT," + " name TEXT)");db.execSQL("CREATE TABLE IF NOT EXISTS " + JOB_TABLE_NAME + "(_id INTEGER PRIMARY KEY AUTOINCREMENT," + " job TEXT)");}@Overridepublic void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion)   {}
}

步骤2：自定义 ContentProvider 类

public class MyProvider extends ContentProvider {private Context mContext;DBHelper mDbHelper = null;SQLiteDatabase db = null;public static final String AUTOHORITY = "cn.scu.myprovider";// 设置ContentProvider的唯一标识public static final int User_Code = 1;public static final int Job_Code = 2;// UriMatcher类使用:在ContentProvider 中注册URIprivate static final UriMatcher mMatcher;static{mMatcher = new UriMatcher(UriMatcher.NO_MATCH);// 初始化mMatcher.addURI(AUTOHORITY,"user", User_Code);mMatcher.addURI(AUTOHORITY, "job", Job_Code);// 若URI资源路径 = content://cn.scu.myprovider/user ，则返回注册码User_Code// 若URI资源路径 = content://cn.scu.myprovider/job ，则返回注册码Job_Code}// 以下是ContentProvider的6个方法/*** 初始化ContentProvider*/@Overridepublic boolean onCreate() {mContext = getContext();// 在ContentProvider创建时对数据库进行初始化// 运行在主线程，故不能做耗时操作,此处仅作展示mDbHelper = new DBHelper(getContext());db = mDbHelper.getWritableDatabase();// 初始化两个表的数据(先清空两个表,再各加入一个记录)db.execSQL("delete from user");db.execSQL("insert into user values(1,'Carson');");db.execSQL("insert into user values(2,'Kobe');");db.execSQL("delete from job");db.execSQL("insert into job values(1,'Android');");db.execSQL("insert into job values(2,'iOS');");return true;}/*** 添加数据*/@Overridepublic Uri insert(Uri uri, ContentValues values) {// 根据URI匹配 URI_CODE，从而匹配ContentProvider中相应的表名// 该方法在最下面String table = getTableName(uri);// 向该表添加数据db.insert(table, null, values);// 当该URI的ContentProvider数据发生变化时，通知外界（即访问该ContentProvider数据的访问者）mContext.getContentResolver().notifyChange(uri, null);//        // 通过ContentUris类从URL中获取ID
//        long personid = ContentUris.parseId(uri);
//        System.out.println(personid);return uri;}/*** 查询数据*/@Overridepublic Cursor query(Uri uri, String[] projection, String selection,String[] selectionArgs, String sortOrder) {// 根据URI匹配 URI_CODE，从而匹配ContentProvider中相应的表名// 该方法在最下面String table = getTableName(uri);//        // 通过ContentUris类从URL中获取ID
//        long personid = ContentUris.parseId(uri);
//        System.out.println(personid);// 查询数据return db.query(table,projection,selection,selectionArgs,null,null,sortOrder,null);}/*** 更新数据*/@Overridepublic int update(Uri uri, ContentValues values, String selection,String[] selectionArgs) {// 由于不展示,此处不作展开return 0;}/*** 删除数据*/@Overridepublic int delete(Uri uri, String selection, String[] selectionArgs) {// 由于不展示,此处不作展开return 0;}@Overridepublic String getType(Uri uri) {// 由于不展示,此处不作展开return null;}/*** 根据URI匹配 URI_CODE，从而匹配ContentProvider中相应的表名*/private String getTableName(Uri uri){String tableName = null;switch (mMatcher.match(uri)) {case User_Code:tableName = DBHelper.USER_TABLE_NAME;break;case Job_Code:tableName = DBHelper.JOB_TABLE_NAME;break;}return tableName;}}

步骤3：注册 创建的 ContentProvider类

AndroidManifest.xml

<provider android:name="MyProvider"android:authorities="cn.scu.myprovider"/>

步骤4：进程内访问 ContentProvider的数据

public class MainActivity extends AppCompatActivity {@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);/*** 对user表进行操作*/// 设置URIUri uri_user = Uri.parse("content://cn.scu.myprovider/user");// 插入表中数据ContentValues values = new ContentValues();values.put("_id", 3);values.put("name", "Iverson");// 获取ContentResolverContentResolver resolver =  getContentResolver();// 通过ContentResolver 根据URI 向ContentProvider中插入数据resolver.insert(uri_user,values);// 通过ContentResolver 向ContentProvider中查询数据Cursor cursor = resolver.query(uri_user, new String[]{"_id","name"}, null, null, null);while (cursor.moveToNext()){System.out.println("query book:" + cursor.getInt(0) +" "+ cursor.getString(1));// 将表中数据全部输出}cursor.close();// 关闭游标/*** 对job表进行操作*/// 和上述类似,只是URI需要更改,从而匹配不同的URI CODE,从而找到不同的数据资源Uri uri_job = Uri.parse("content://cn.scu.myprovider/job");// 插入表中数据ContentValues values2 = new ContentValues();values2.put("_id", 3);values2.put("job", "NBA Player");// 获取ContentResolverContentResolver resolver2 =  getContentResolver();// 通过ContentResolver 根据URI 向ContentProvider中插入数据resolver2.insert(uri_job,values2);// 通过ContentResolver 向ContentProvider中查询数据Cursor cursor2 = resolver2.query(uri_job, new String[]{"_id","job"}, null, null, null);while (cursor2.moveToNext()){System.out.println("query job:" + cursor2.getInt(0) +" "+ cursor2.getString(1));// 将表中数据全部输出}cursor2.close();// 关闭游标
}
}

6.3进程间通信

本文需要创建2个进程，即创建两个工程，作用如下

进程1：创建ContentProvider+储存数据sqlite

进程2：访问ContentProvider中的储存数据

进程1

步骤1：创建数据库类

步骤2：自定义 ContentProvider 类

前2个步骤同上例相同

步骤3：注册 创建的 ContentProvider类
AndroidManifest.xml

<provider android:name="MyProvider"android:authorities="scut.carson_ho.myprovider"// 声明外界进程可访问该Provider的权限（读 & 写）android:permission="scut.carson_ho.PROVIDER"             // 权限可细分为读 & 写的权限// 外界需要声明同样的读 & 写的权限才可进行相应操作，否则会报错// android:readPermisson = "scut.carson_ho.Read"// android:writePermisson = "scut.carson_ho.Write"// 设置此provider是否可以被其他进程使用android:exported="true"/>// 声明本应用 可允许通信的权限<permission android:name="scut.carson_ho.Read" android:protectionLevel="normal"/>// 细分读 & 写权限如下，但本Demo直接采用全权限// <permission android:name="scut.carson_ho.Write" android:protectionLevel="normal"/>// <permission android:name="scut.carson_ho.PROVIDER" android:protectionLevel="normal"/>

进程2

步骤1：声明可访问的权限

AndroidManifest.xml

    // 声明本应用可允许通信的权限（全权限）<uses-permission android:name="scut.carson_ho.PROVIDER"/>// 细分读 & 写权限如下，但本Demo直接采用全权限// <uses-permission android:name="scut.carson_ho.Read"/>//  <uses-permission android:name="scut.carson_ho.Write"/>// 注：声明的权限必须与进程1中设置的权限对应

步骤2：访问 ContentProvider的类

public class MainActivity extends AppCompatActivity {@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);/*** 对user表进行操作*/// 设置URIUri uri_user = Uri.parse("content://scut.carson_ho.myprovider/user");// 插入表中数据ContentValues values = new ContentValues();values.put("_id", 4);values.put("name", "Jordan");// 获取ContentResolverContentResolver resolver =  getContentResolver();// 通过ContentResolver 根据URI 向ContentProvider中插入数据resolver.insert(uri_user,values);// 通过ContentResolver 向ContentProvider中查询数据Cursor cursor = resolver.query(uri_user, new String[]{"_id","name"}, null, null, null);while (cursor.moveToNext()){System.out.println("query book:" + cursor.getInt(0) +" "+ cursor.getString(1));// 将表中数据全部输出}cursor.close();// 关闭游标/*** 对job表进行操作*/// 和上述类似,只是URI需要更改,从而匹配不同的URI CODE,从而找到不同的数据资源Uri uri_job = Uri.parse("content://scut.carson_ho.myprovider/job");// 插入表中数据ContentValues values2 = new ContentValues();values2.put("_id", 4);values2.put("job", "NBA Player");// 获取ContentResolverContentResolver resolver2 =  getContentResolver();// 通过ContentResolver 根据URI 向ContentProvider中插入数据resolver2.insert(uri_job,values2);// 通过ContentResolver 向ContentProvider中查询数据Cursor cursor2 = resolver2.query(uri_job, new String[]{"_id","job"}, null, null, null);while (cursor2.moveToNext()){System.out.println("query job:" + cursor2.getInt(0) +" "+ cursor2.getString(1));// 将表中数据全部输出}cursor2.close();// 关闭游标}
}

在进程展示时，需要先运行准备数据的进程1，再运行需要访问数据的进程2

  1. 在进程1中，我们准备好了一系列数据

  2. 在进程2中，我们先向ContentProvider中插入数据，再查询数据

注意：

SQLite数据库使用详见

https://www.jianshu.com/p/8e3f294e2828

参考链接

https://www.jianshu.com/p/ea8bc4aaf057

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