【我的Android进阶之旅】 解决bug: Expected file scheme in URI: content://download...
一、错误描述 今天测试MM用HTC手机测试某个模块的时候crash了，抓log后发现是使用DownloadManager下载apk安装包然后自动安装的时候，抛了异常：java.lang.IllegalArgumentException: Expected file scheme in URI: content://downloads/my_downloads/12 具体crash错误信息如下所示： 11-30 09:24:21.933 28279 28279 E AndroidRuntime: FATAL EXCEPTION: main 11-30 09:24:21.933 28279 28279 E AndroidRuntime: Process: com.xtc.watch, PID: 28279 11-30 09:24:21.933 28279 28279 E AndroidRuntime: java.lang.RuntimeException: Error receiving broadcast Intent { act=android.intent.action.DOWNLOAD_COMPLETE flg=0x10 pkg=com.xtc.watch (has extras) } in com.xtc.watch.service.compatible.VersionCompatibleUpdateService$DownloadCompleteReceiver@33fa7ec 11-30 09:24:21.933 28279 28279 E AndroidRuntime: at android.app.LoadedApk$ReceiverDispatcher$Args.run(LoadedApk.java:934) 11-30 09:24:21.933 28279 28279 E AndroidRuntime: at android.os.Handler.handleCallback(Handler.java:739) 11-30 09:24:21.933 28279 28279 E AndroidRuntime: at android.os.Handler.dispatchMessage(Handler.java:95) 11-30 09:24:21.933 28279 28279 E AndroidRuntime: at android.os.Looper.loop(Looper.java:168) 11-30 09:24:21.933 28279 28279 E AndroidRuntime: at android.app.ActivityThread.main(ActivityThread.java:5885) 11-30 09:24:21.933 28279 28279 E AndroidRuntime: at java.lang.reflect.Method.invoke(Native Method) 11-30 09:24:21.933 28279 28279 E AndroidRuntime: at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:797) 11-30 09:24:21.933 28279 28279 E AndroidRuntime: at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:687) 11-30 09:24:21.933 28279 28279 E AndroidRuntime: Caused by: java.lang.IllegalArgumentException: Expected file scheme in URI: content://downloads/my_downloads/12 11-30 09:24:21.933 28279 28279 E AndroidRuntime: at java.io.File.checkURI(File.java:223) 11-30 09:24:21.933 28279 28279 E AndroidRuntime: at java.io.File.<init>(File.java:175) 11-30 09:24:21.933 28279 28279 E AndroidRuntime: at com.xtc.watch.service.compatible.VersionCompatibleUpdateService.a(Unknown Source) 11-30 09:24:21.933 28279 28279 E AndroidRuntime: at com.xtc.watch.service.compatible.VersionCompatibleUpdateService.a(Unknown Source) 11-30 09:24:21.933 28279 28279 E AndroidRuntime: at com.xtc.watch.service.compatible.VersionCompatibleUpdateService$DownloadCompleteReceiver.onReceive(Unknown Source) 11-30 09:24:21.933 28279 28279 E AndroidRuntime: at android.app.LoadedApk$ReceiverDispatcher$Args.run(LoadedApk.java:915) 11-30 09:24:21.933 28279 28279 E AndroidRuntime: ... 7 more 11-30 09:24:21.939 1785 3503 E ActivityManager: App crashed! Process: com.xtc.watch 二、错误分析 进入File.java查看代码， /** * Constructs a new File using the path of the specified URI. {@code uri} * needs to be an absolute and hierarchical Unified Resource Identifier with * file scheme and non-empty path component, but with undefined authority, * query or fragment components. * * @param uri * the Unified Resource Identifier that is used to construct this * file. * @throws IllegalArgumentException * if {@code uri} does not comply with the conditions above. * @see #toURI * @see java.net.URI */ public File(URI uri) { // check pre-conditions checkURI(uri); this.path = fixSlashes(uri.getPath()); } checkURI(URI uri)的源代码如下： private static void checkURI(URI uri) { if (!uri.isAbsolute()) { throw new IllegalArgumentException("URI is not absolute: " + uri); } else if (!uri.getRawSchemeSpecificPart().startsWith("/")) { throw new IllegalArgumentException("URI is not hierarchical: " + uri); } if (!"file".equals(uri.getScheme())) { throw new IllegalArgumentException("Expected file scheme in URI: " + uri); } String rawPath = uri.getRawPath(); if (rawPath == null || rawPath.isEmpty()) { throw new IllegalArgumentException("Expected non-empty path in URI: " + uri); } if (uri.getRawAuthority() != null) { throw new IllegalArgumentException("Found authority in URI: " + uri); } if (uri.getRawQuery() != null) { throw new IllegalArgumentException("Found query in URI: " + uri); } if (uri.getRawFragment() != null) { throw new IllegalArgumentException("Found fragment in URI: " + uri); } } 原来就是下面这一段代码抛出的异常，如果uri不是以file开头的就抛异常IllegalArgumentException(“Expected file scheme in URI: ” + uri)， if (!"file".equals(uri.getScheme())) { throw new IllegalArgumentException("Expected file scheme in URI: " + uri); } 而我们的uri 是通过下面代码获取而来的 Uri downloadFileUri = manager.getUriForDownloadedFile(downId); File file = new File(new URI(downloadFileUri.toString())); 得到的uri信息为 content://downloads/my_downloads/12 因此就抛了该异常出来。 getUriForDownloadedFile(long id)源代码如下： /** * Returns the {@link Uri} of the given downloaded file id, if the file is * downloaded successfully. Otherwise, null is returned. *<p> * If the specified downloaded file is in external storage (for example, /sdcard dir), * then it is assumed to be safe for anyone to read and the returned {@link Uri} corresponds * to the filepath on sdcard. * * @param id the id of the downloaded file. * @return the {@link Uri} of the given downloaded file id, if download was successful. null * otherwise. */ public Uri getUriForDownloadedFile(long id) { // to check if the file is in cache, get its destination from the database Query query = new Query().setFilterById(id); Cursor cursor = null; try { cursor = query(query); if (cursor == null) { return null; } if (cursor.moveToFirst()) { int status = cursor.getInt(cursor.getColumnIndexOrThrow(COLUMN_STATUS)); if (DownloadManager.STATUS_SUCCESSFUL == status) { int indx = cursor.getColumnIndexOrThrow( Downloads.Impl.COLUMN_DESTINATION); int destination = cursor.getInt(indx); // TODO: if we ever add API to DownloadManager to let the caller specify // non-external storage for a downloaded file, then the following code // should also check for that destination. if (destination == Downloads.Impl.DESTINATION_CACHE_PARTITION || destination == Downloads.Impl.DESTINATION_SYSTEMCACHE_PARTITION || destination == Downloads.Impl.DESTINATION_CACHE_PARTITION_NOROAMING || destination == Downloads.Impl.DESTINATION_CACHE_PARTITION_PURGEABLE) { // return private uri return ContentUris.withAppendedId(Downloads.Impl.CONTENT_URI, id); } else { // return public uri String path = cursor.getString( cursor.getColumnIndexOrThrow(COLUMN_LOCAL_FILENAME)); return Uri.fromFile(new File(path)); } } } } finally { if (cursor != null) { cursor.close(); } } // downloaded file not found or its status is not 'successfully completed' return null; } 三、错误解决 将之前查找下载好的apk文件的代码 Uri downloadFileUri = manager.getUriForDownloadedFile(downId); File file = new File(new URI(downloadFileUri.toString())); 改为通过downId来查询DownloadManager下载的数据库的记录，然后查找本地文件的路径，如下所示： Cursor c = manager.query(new DownloadManager.Query().setFilterById(downId)); if(c != null){ c.moveToFirst(); int fileNameIdx = c.getColumnIndex(DownloadManager.COLUMN_LOCAL_FILENAME); String fileName = c.getString(fileNameIdx); File file = new File(fileName); LogUtil.d(TAG, "安装文件：" + file.getAbsolutePath()); c.close(); } 安装apk的代码由 //自动安装apk Intent install = new Intent(Intent.ACTION_VIEW); install.setDataAndType(downloadFileUri, "application/vnd.android.package-archive"); install.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK); context.startActivity(install); 改为 //自动安装apk Intent install = new Intent(Intent.ACTION_VIEW); //install.setDataAndType(downloadFileUri, "application/vnd.android.package-archive"); install.setDataAndType(Uri.parse("file://" + fileName.toString()), "application/vnd.android.package-archive"); install.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK); context.startActivity(install); 这样通过查询本地真实的下载好apk的真实本地路径，然后再进行安装的话就不会报异常了。 参考文章： http://blog.csdn.net/q445697127/article/details/40537945 http://www.xuebuyuan.com/2163407.html http://www.2cto.com/kf/201502/376975.html 作者：欧阳鹏 欢迎转载，与人分享是进步的源泉！ 转载请保留原文地址：http://blog.csdn.net/ouyang_peng/article/details/53404379
