Android使用DocumentFile读写外置存储的问题
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2022-06-09 19:38:32
最近在维护项目,app遇到安装在高版本的android时,以往直接授权和new file(path)的形式不再支持,日志也是说permission denied。。。。。好吧,换为documentfi...
最近在维护项目,app遇到安装在高版本的android时,以往直接授权和new file(path)的形式不再支持,日志也是说permission denied。。。。。好吧,换为documentfile。
经过一番操作,也终于实再对存储目录的读和写了,下面记录一下:
首先建一个documentfile的utils类:
import android.annotation.targetapi; import android.content.context; import android.content.sharedpreferences; import android.net.uri; import android.os.build; import android.os.parcelfiledescriptor; import android.preference.preferencemanager; import android.provider.documentscontract; import android.util.log; import androidx.documentfile.provider.documentfile; import java.io.file; import java.io.filedescriptor; import java.io.fileinputstream; import java.io.filenotfoundexception; import java.io.fileoutputstream; import java.io.ioexception; import java.io.inputstream; import java.io.outputstream; import java.io.randomaccessfile; import java.util.arraylist; import java.util.list; public class documentsutils { private static final string tag = documentsutils.class.getsimplename(); public static final int open_document_tree_code = 8000; private static list<string> sextsdcardpaths = new arraylist<>(); private documentsutils() { } public static void cleancache() { sextsdcardpaths.clear(); } /** * get a list of external sd card paths. (kitkat or higher.) * * @return a list of external sd card paths. */ @targetapi(build.version_codes.kitkat) private static string[] getextsdcardpaths(context context) { if (sextsdcardpaths.size() > 0) { return sextsdcardpaths.toarray(new string[0]); } for (file file : context.getexternalfilesdirs("external")) { if (file != null && !file.equals(context.getexternalfilesdir("external"))) { int index = file.getabsolutepath().lastindexof("/android/data"); if (index < 0) { log.w(tag, "unexpected external file dir: " + file.getabsolutepath()); } else { string path = file.getabsolutepath().substring(0, index); try { path = new file(path).getcanonicalpath(); } catch (ioexception e) { // keep non-canonical path. } sextsdcardpaths.add(path); } } } if (sextsdcardpaths.isempty()) sextsdcardpaths.add("/storage/sdcard1"); return sextsdcardpaths.toarray(new string[0]); } /** * determine the main folder of the external sd card containing the given file. * * @param file the file. * @return the main folder of the external sd card containing this file, if the file is on an sd * card. otherwise, * null is returned. */ @targetapi(build.version_codes.kitkat) private static string getextsdcardfolder(final file file, context context) { string[] extsdpaths = getextsdcardpaths(context); try { for (int i = 0; i < extsdpaths.length; i++) { if (file.getcanonicalpath().startswith(extsdpaths[i])) { return extsdpaths[i]; } } } catch (ioexception e) { return null; } return null; } /** * determine if a file is on external sd card. (kitkat or higher.) * * @param file the file. * @return true if on external sd card. */ @targetapi(build.version_codes.kitkat) public static boolean isonextsdcard(final file file, context c) { return getextsdcardfolder(file, c) != null; } /** * get a documentfile corresponding to the given file (for writing on extsdcard on android 5). * if the file is not * existing, it is created. * * @param file the file. * @param isdirectory flag indicating if the file should be a directory. * @return the documentfile */ public static documentfile getdocumentfile(final file file, final boolean isdirectory, context context) { if (build.version.sdk_int <= build.version_codes.kitkat) { return documentfile.fromfile(file); } string basefolder = getextsdcardfolder(file, context); // log.i(tag,"lum_ basefolder " + basefolder); boolean originaldirectory = false; if (basefolder == null) { return null; } string relativepath = null; try { string fullpath = file.getcanonicalpath(); if (!basefolder.equals(fullpath)) { relativepath = fullpath.substring(basefolder.length() + 1); } else { originaldirectory = true; } } catch (ioexception e) { return null; } catch (exception f) { originaldirectory = true; //continue } string as = preferencemanager.getdefaultsharedpreferences(context).getstring(basefolder, null); uri treeuri = null; if (as != null) treeuri = uri.parse(as); if (treeuri == null) { return null; } // start with root of sd card and then parse through document tree. documentfile document = documentfile.fromtreeuri(context, treeuri); if (originaldirectory) return document; string[] parts = relativepath.split("/"); for (int i = 0; i < parts.length; i++) { documentfile nextdocument = document.findfile(parts[i]); if (nextdocument == null) { if ((i < parts.length - 1) || isdirectory) { nextdocument = document.createdirectory(parts[i]); } else { nextdocument = document.createfile("image", parts[i]); } } document = nextdocument; } return document; } public static boolean mkdirs(context context, file dir) { boolean res = dir.mkdirs(); if (!res) { if (documentsutils.isonextsdcard(dir, context)) { documentfile documentfile = documentsutils.getdocumentfile(dir, true, context); res = documentfile != null && documentfile.canwrite(); } } return res; } public static boolean delete(context context, file file) { boolean ret = file.delete(); if (!ret && documentsutils.isonextsdcard(file, context)) { documentfile f = documentsutils.getdocumentfile(file, false, context); if (f != null) { ret = f.delete(); } } return ret; } public static boolean canwrite(file file) { boolean res = file.exists() && file.canwrite(); if (!res && !file.exists()) { try { if (!file.isdirectory()) { res = file.createnewfile() && file.delete(); } else { res = file.mkdirs() && file.delete(); } } catch (ioexception e) { e.printstacktrace(); } } return res; } public static boolean canwrite(context context, file file) { boolean res = canwrite(file); if (!res && documentsutils.isonextsdcard(file, context)) { documentfile documentfile = documentsutils.getdocumentfile(file, true, context); res = documentfile != null && documentfile.canwrite(); } return res; } /** * 重命名 * @param context * @param src * @param dest * @return */ public static boolean renameto(context context, file src, file dest) { boolean res = src.renameto(dest); if (!res && isonextsdcard(dest, context)) { documentfile srcdoc; if (isonextsdcard(src, context)) { srcdoc = getdocumentfile(src, false, context); } else { srcdoc = documentfile.fromfile(src); } documentfile destdoc = getdocumentfile(dest.getparentfile(), true, context); if (srcdoc != null && destdoc != null) { try { log.i("renameto", "src.getparent():" + src.getparent() + ",dest.getparent():" + dest.getparent()); if (src.getparent().equals(dest.getparent())) {//同一目录 res = srcdoc.renameto(dest.getname()); } else if (build.version.sdk_int >= build.version_codes.n) {//不同一目录 uri renamesrcuri = documentscontract.renamedocument(context.getcontentresolver(),//先重命名 srcdoc.geturi(), dest.getname()); res = documentscontract.movedocument(context.getcontentresolver(),//再移动 renamesrcuri, srcdoc.getparentfile().geturi(), destdoc.geturi()) != null; } } catch (exception e) { e.printstacktrace(); } } } return res; } public static inputstream getinputstream(context context, file destfile) { inputstream in = null; try { if (!canwrite(destfile) && isonextsdcard(destfile, context)) { documentfile file = documentsutils.getdocumentfile(destfile, false, context); if (file != null && file.canwrite()) { in = context.getcontentresolver().openinputstream(file.geturi()); } } else { in = new fileinputstream(destfile); } } catch (filenotfoundexception e) { e.printstacktrace(); } return in; } public static outputstream getoutputstream(context context, file destfile) { outputstream out = null; try { if (!canwrite(destfile) && isonextsdcard(destfile, context)) { documentfile file = documentsutils.getdocumentfile(destfile, false, context); if (file != null && file.canwrite()) { out = context.getcontentresolver().openoutputstream(file.geturi()); } } else { out = new fileoutputstream(destfile); } } catch (filenotfoundexception e) { e.printstacktrace(); } return out; } /** * 获取文件流 * @param context * @param destfile 目标文件 * @param mode may be "w", "wa", "rw", or "rwt". * @return */ public static outputstream getoutputstream(context context, file destfile, string mode) { outputstream out = null; try { if (!canwrite(destfile) && isonextsdcard(destfile, context)) { documentfile file = documentsutils.getdocumentfile(destfile, false, context); if (file != null && file.canwrite()) { out = context.getcontentresolver().openoutputstream(file.geturi(), mode); } } else { out = new fileoutputstream(destfile, mode.equals("rw") || mode.equals("wa")); } } catch (filenotfoundexception e) { e.printstacktrace(); } return out; } public static filedescriptor getfiledescriptor(context context, file destfile) { filedescriptor fd = null; try { if (/*!canwrite(destfile) && */isonextsdcard(destfile, context)) { documentfile file = documentsutils.getdocumentfile(destfile, false, context); if (file != null && file.canwrite()) { parcelfiledescriptor out = context.getcontentresolver().openfiledescriptor(file.geturi(), "rw"); fd = out.getfiledescriptor(); } } else { randomaccessfile file = null; try { file = new randomaccessfile(destfile, "rws"); file.setlength(0); fd = file.getfd(); } catch (exception e){ e.printstacktrace(); } finally { if (file != null) { try { file.close(); } catch (ioexception e) { e.printstacktrace(); } } } } } catch (filenotfoundexception e) { e.printstacktrace(); } return fd; } public static boolean savetreeuri(context context, string rootpath, uri uri) { documentfile file = documentfile.fromtreeuri(context, uri); if (file != null && file.canwrite()) { sharedpreferences perf = preferencemanager.getdefaultsharedpreferences(context); perf.edit().putstring(rootpath, uri.tostring()).apply(); log.e(tag, "save uri" + rootpath); return true; } else { log.e(tag, "no write permission: " + rootpath); } return false; } /** * 返回true表示没有权限 * @param context * @param rootpath * @return */ public static boolean checkwritablerootpath(context context, string rootpath) { file root = new file(rootpath); if (!root.canwrite()) { log.e(tag,"sd card can not write:" + rootpath + ",is on extsdcard:" + documentsutils.isonextsdcard(root, context)); if (documentsutils.isonextsdcard(root, context)) { documentfile documentfile = documentsutils.getdocumentfile(root, true, context); if (documentfile != null) { log.i(tag, "get document file:" + documentfile.canwrite()); } return documentfile == null || !documentfile.canwrite(); } else { sharedpreferences perf = preferencemanager.getdefaultsharedpreferences(context); string documenturi = perf.getstring(rootpath, ""); log.i(tag,"lum_2 get perf documenturi:" + documenturi); if (documenturi == null || documenturi.isempty()) { return true; } else { documentfile file = documentfile.fromtreeuri(context, uri.parse(documenturi)); if (file != null) log.i(tag,"lum get perf documenturi:" + file.canwrite()); return !(file != null && file.canwrite()); } } }else{ log.e(tag,"sd card can write..."); } return false; } }
然后在app启动的地方检查下是否需要授权才能操作:
if (documentsutils.checkwritablerootpath(this, stringutils.storage_path)) { //检查sd卡路径是否有 权限 没有显示dialog showopendocumenttree(); } private void showopendocumenttree() { log.e("showopendocumenttree", "start check sd card..."); intent intent = null; if (android.os.build.version.sdk_int >= android.os.build.version_codes.n) { storagemanager sm = getsystemservice(storagemanager.class); storagevolume volume = sm.getstoragevolume(new file(stringutils.storage_path)); if (volume != null) { intent = volume.createaccessintent(null); } } log.e("showopendocumenttree", "intent=" + intent); if (intent == null) { intent = new intent(intent.action_open_document_tree); } startactivityforresult(intent, documentsutils.open_document_tree_code); } //................................ @override protected void onactivityresult(int requestcode, int resultcode, intent data) { switch (requestcode) { case documentsutils.open_document_tree_code: if (data != null && data.getdata() != null) { uri uri = data.getdata(); documentsutils.savetreeuri(this, stringutils.storage_path, uri); log.i(tag,"documentsutils.open_document_tree_code : " + uri); } break; } super.onactivityresult(requestcode, resultcode, data); }
按以上代码,是可以实现对外置存储卡进行读和写操作了,只要机器没关机,多关打开关闭app,都不会弹下面这个授权框:
但是-----如果关机再重新开机,就要重新授权,这样很麻烦,用户体验也极其不好,所以又查询了很多资料,最后在*上找到办法,关键是下面这句:
granturipermission(getpackagename(), uri, intent.flag_grant_read_uri_permission | intent.flag_grant_write_uri_permission); getcontentresolver().takepersistableuripermission(uri, intent.flag_grant_read_uri_permission | intent.flag_grant_write_uri_permission);
是在activityresult回调里,添加上面这两行代码,就不用每次都弹授权,影响体验了
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