Month: February 2012

很久以前写过一篇《How to Use Android Downloads Provider》，到了Android 2.2(froyo)，Android 提供了更优雅的接口：

public static long startDownloadByUri(Context context,
                                      String url,
                                      String cookieData,
                                      boolean showDownload,
                                      int downloadDestination,
                                      boolean allowRoaming,
                                      boolean skipIntegrityCheck,
                                      String title,
                                      String notification_package,
                                      String notification_class,
                                      String notification_extras)

当然这些接口都是hide的，做ROM系统开发的才可以直接使用，用mmm方式编译。签于这个原因，一些国内第三方电子市场直接拿Downloads组件的代码修改成自己的提供使用。代码实现在：

[deli@violet frameworks]$ find . -type f -name Downloads.java
./base/core/java/android/provider/Downloads.java
./base/core/java/android/net/Downloads.java
还有 packages/providers/DownloadProvider

startDownloadByUri 即这个函数很容易理解，有网友给我发email说不知道如何使用，我贴出系统升级使用的代码片段，希望对大家有帮助。

[deli@violet update]$ cat Download.java

/*
 * Copyright (C) 2010 lytsing.org
 *
 * 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.google.android.gsf.update;

import com.google.android.gsf.R;

import android.content.Context;
import android.util.Log;
import android.net.Downloads;

public class Download {

    private final Context mContext;

    private String mNotificationClass;

    private String mNotificationPackage;

    public Download(Context context) {
        mContext = context;
        mNotificationPackage = context.getPackageName();
        mNotificationClass = SystemUpdateService.Receiver.class.getName();
    }

    public boolean downloadUpdate(String url, boolean showDownload, boolean allowRoaming) {
        removeAllDownloads();
        try {
            if (Downloads.ByUri.startDownloadByUri(
                        mContext,
                        url,
                        null,
                        showDownload,
                        2,
                        allowRoaming,
                        true,
                        mContext.getString(R.string.system_update_downloading_notification_title),
                        mNotificationPackage,
                        mNotificationClass,
                        null)== -1) {
                Log.w("update.Download", "Could not insert download entry into provider");
                return false;
            } 

            Log.i("update.Download",new StringBuilder()
                    .append("Started a new update download: ").append(url).toString());
        } catch (Exception e) {
            Log.e("update.Download", "Could not start update download", e);
            return false;
        }

        return true;
    }

    public Downloads.StatusInfo getStatus(String url) {
        return Downloads.ByUri.getStatus(mContext, url, 24 * 3600 * 1000);
    }

    public void removeAllDownloads() {
        Log.v("update.Download", "deleting all update downloads");
        try {
            Downloads.ByUri.removeAllDownloadsByPackage(mContext, mNotificationPackage,
                    mNotificationClass);
        } catch (Exception ex) {
            Log.e("update.Download", "Couldn\'t delete downloads", ex);
        }
    }
}