Java tutorial
/* * Copyright (C) 2010 The Android Open Source Project * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package com.android.browser; import android.app.Activity; import android.app.AlertDialog; import android.app.DownloadManager; import android.content.ActivityNotFoundException; import android.content.ComponentName; import android.content.Context; import android.content.Intent; import android.content.pm.PackageManager; import android.content.pm.ResolveInfo; import android.net.Uri; import android.net.WebAddress; import android.os.Environment; import android.support.v4.app.ActivityCompat; import android.support.v4.content.ContextCompat; import android.text.TextUtils; import android.util.Log; import android.webkit.CookieManager; import android.webkit.URLUtil; import android.widget.Toast; /** * Handle download requests */ public class DownloadHandler { private static final boolean LOGD_ENABLED = com.android.browser.Browser.LOGD_ENABLED; private static final String LOGTAG = "DLHandler"; //Singleton to hold the information about any pending downloads private static PendingDownloadBundle pendingDownloadBundle; private static class PendingDownloadBundle { String url; String userAgent; String contentDisposition; String mimetype; String referer; boolean privateBrowsing; public static PendingDownloadBundle create(String url, String userAgent, String contentDisposition, String mimetype, String referer, boolean privateBrowsing) { PendingDownloadBundle pdb = new PendingDownloadBundle(); pdb.url = url; pdb.userAgent = userAgent; pdb.contentDisposition = contentDisposition; pdb.mimetype = mimetype; pdb.referer = referer; pdb.privateBrowsing = privateBrowsing; return pdb; } } /** * Check if there is any pending download and start the download automatically in case * there is one. * @param activity Activity requesting the download. */ public static void checkPendingDownloads(Activity activity) { if (pendingDownloadBundle != null) { onDownloadStartNoStream(activity, pendingDownloadBundle.url, pendingDownloadBundle.userAgent, pendingDownloadBundle.contentDisposition, pendingDownloadBundle.mimetype, pendingDownloadBundle.referer, pendingDownloadBundle.privateBrowsing); pendingDownloadBundle = null; } } /** * Notify the host application a download should be done, or that * the data should be streamed if a streaming viewer is available. * @param activity Activity requesting the download. * @param url The full url to the content that should be downloaded * @param userAgent User agent of the downloading application. * @param contentDisposition Content-disposition http header, if present. * @param mimetype The mimetype of the content reported by the server * @param referer The referer associated with the downloaded url * @param privateBrowsing If the request is coming from a private browsing tab. */ public static void onDownloadStart(Activity activity, String url, String userAgent, String contentDisposition, String mimetype, String referer, boolean privateBrowsing) { // if we're dealing wih A/V content that's not explicitly marked // for download, check if it's streamable. if (contentDisposition == null || !contentDisposition.regionMatches(true, 0, "attachment", 0, 10)) { // query the package manager to see if there's a registered handler // that matches. Intent intent = new Intent(Intent.ACTION_VIEW); intent.setDataAndType(Uri.parse(url), mimetype); ResolveInfo info = activity.getPackageManager().resolveActivity(intent, PackageManager.MATCH_DEFAULT_ONLY); if (info != null) { ComponentName myName = activity.getComponentName(); // If we resolved to ourselves, we don't want to attempt to // load the url only to try and download it again. if (!myName.getPackageName().equals(info.activityInfo.packageName) || !myName.getClassName().equals(info.activityInfo.name)) { // someone (other than us) knows how to handle this mime // type with this scheme, don't download. try { activity.startActivity(intent); return; } catch (ActivityNotFoundException ex) { if (LOGD_ENABLED) { Log.d(LOGTAG, "activity not found for " + mimetype + " over " + Uri.parse(url).getScheme(), ex); } // Best behavior is to fall back to a download in this // case } } } } onDownloadStartNoStream(activity, url, userAgent, contentDisposition, mimetype, referer, privateBrowsing); } // This is to work around the fact that java.net.URI throws Exceptions // instead of just encoding URL's properly // Helper method for onDownloadStartNoStream private static String encodePath(String path) { char[] chars = path.toCharArray(); boolean needed = false; for (char c : chars) { if (c == '[' || c == ']' || c == '|') { needed = true; break; } } if (needed == false) { return path; } StringBuilder sb = new StringBuilder(""); for (char c : chars) { if (c == '[' || c == ']' || c == '|') { sb.append('%'); sb.append(Integer.toHexString(c)); } else { sb.append(c); } } return sb.toString(); } /** * Notify the host application a download should be done, even if there * is a streaming viewer available for this type. * @param activity Activity requesting the download. * @param url The full url to the content that should be downloaded * @param userAgent User agent of the downloading application. * @param contentDisposition Content-disposition http header, if present. * @param mimetype The mimetype of the content reported by the server * @param referer The referer associated with the downloaded url * @param privateBrowsing If the request is coming from a private browsing tab. */ /*package */ static void onDownloadStartNoStream(Activity activity, String url, String userAgent, String contentDisposition, String mimetype, String referer, boolean privateBrowsing) { // Check permissions first when download will be start. int permissionCheck = ContextCompat.checkSelfPermission(activity, android.Manifest.permission.WRITE_EXTERNAL_STORAGE); if (permissionCheck == PackageManager.PERMISSION_GRANTED) { onDownloadNoStreamImpl(activity, url, userAgent, contentDisposition, mimetype, referer, privateBrowsing); } else { pendingDownloadBundle = PendingDownloadBundle.create(url, userAgent, contentDisposition, mimetype, referer, privateBrowsing); // Permission not granted, request it from the user ActivityCompat.requestPermissions(activity, new String[] { android.Manifest.permission.WRITE_EXTERNAL_STORAGE }, BrowserActivity.PERMISSIONS_REQUEST_WRITE_EXTERNAL_STORAGE); } } private static void onDownloadNoStreamImpl(Activity activity, String url, String userAgent, String contentDisposition, String mimetype, String referer, boolean privateBrowsing) { String filename = URLUtil.guessFileName(url, contentDisposition, mimetype); // Check to see if we have an SDCard String status = Environment.getExternalStorageState(); if (!status.equals(Environment.MEDIA_MOUNTED)) { int title; String msg; // Check to see if the SDCard is busy, same as the music app if (status.equals(Environment.MEDIA_SHARED)) { msg = activity.getString(R.string.download_sdcard_busy_dlg_msg); title = R.string.download_sdcard_busy_dlg_title; } else { msg = activity.getString(R.string.download_no_sdcard_dlg_msg, filename); title = R.string.download_no_sdcard_dlg_title; } new AlertDialog.Builder(activity).setTitle(title).setIconAttribute(android.R.attr.alertDialogIcon) .setMessage(msg).setPositiveButton(R.string.ok, null).show(); return; } // java.net.URI is a lot stricter than KURL so we have to encode some // extra characters. Fix for b 2538060 and b 1634719 WebAddress webAddress; try { webAddress = new WebAddress(url); webAddress.setPath(encodePath(webAddress.getPath())); } catch (Exception e) { // This only happens for very bad urls, we want to chatch the // exception here Log.e(LOGTAG, "Exception trying to parse url:" + url); return; } String addressString = webAddress.toString(); Uri uri = Uri.parse(addressString); final DownloadManager.Request request; try { request = new DownloadManager.Request(uri); } catch (IllegalArgumentException e) { Toast.makeText(activity, R.string.cannot_download, Toast.LENGTH_SHORT).show(); return; } request.setMimeType(mimetype); // set downloaded file destination to /sdcard/Download. // or, should it be set to one of several Environment.DIRECTORY* dirs depending on mimetype? try { request.setDestinationInExternalPublicDir(Environment.DIRECTORY_DOWNLOADS, filename); } catch (IllegalStateException ex) { // This only happens when directory Downloads can't be created or it isn't a directory // this is most commonly due to temporary problems with sdcard so show appropriate string Log.w(LOGTAG, "Exception trying to create Download dir:", ex); Toast.makeText(activity, R.string.download_sdcard_busy_dlg_title, Toast.LENGTH_SHORT).show(); return; } // let this downloaded file be scanned by MediaScanner - so that it can // show up in Gallery app, for example. request.allowScanningByMediaScanner(); request.setDescription(webAddress.getHost()); // XXX: Have to use the old url since the cookies were stored using the // old percent-encoded url. String cookies = CookieManager.getInstance().getCookie(url, privateBrowsing); request.addRequestHeader("cookie", cookies); request.addRequestHeader("User-Agent", userAgent); if (!TextUtils.isEmpty(referer)) { request.addRequestHeader("Referer", referer); } request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED); if (mimetype == null) { if (TextUtils.isEmpty(addressString)) { return; } // We must have long pressed on a link or image to download it. We // are not sure of the mimetype in this case, so do a head request new FetchUrlMimeType(activity, request, addressString, cookies, userAgent).start(); } else { final DownloadManager manager = (DownloadManager) activity.getSystemService(Context.DOWNLOAD_SERVICE); new Thread("Browser download") { public void run() { manager.enqueue(request); } }.start(); } Toast.makeText(activity, R.string.download_pending, Toast.LENGTH_SHORT).show(); } }