Android开发下载管理器DownloadManager详解

茉莉清梦 發表於 2020-7-14 16:46:00

Android开发下载管理器DownloadManager详解

<h1>版权声明</h1>
本文来自博客园，作者：观心静 ，转载请注明原文链接：https://www.cnblogs.com/guanxinjing/p/13299949.html
<div>本文版权归作者和博客园共有，欢迎转载，但必须给出原文链接，并保留此段声明，否则保留追究法律责任的权利。</div>
<h1>前言</h1>
　　DownloadManager是Android系统自带的下载管理工具，此工具可以很好的调度好下载。在没有特殊需求的情况下，一般是推荐使用此工具下载的。另外这个工具下载还有有优势就是可以在下载app完成后直接跳转到安装页面。
　　参考：https://www.jianshu.com/p/e0496200769c
<h1>需要的权限</h1>
需要网络权限和文件读写权限
<div class="cnblogs_code">
<pre><uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
<uses-permission android:name="android.permission.INTERNET"/></pre>
</div>
请求安装包权限
 
<div class="cnblogs_code">
<pre> <uses-permission android:name="android.permission.REQUEST_INSTALL_PACKAGES" /></pre>
</div>
 
<h1>创建下载请求</h1>
<div>
<pre class="language-java highlighter-hljs" data-dark-theme="true"><code>fun downloadApp(downloadUrl: String) : Long{
val request = DownloadManager.Request(Uri.parse(downloadUrl))
val downloadsDir = AppHelper.I().app.getExternalFilesDir(Environment.DIRECTORY_DOWNLOADS)
request.setDestinationUri(Uri.fromFile(File(downloadsDir, "YTHOME.apk")))
request.setTitle("下载测试")
request.setDescription(AppHelper.I().app.getString(R.string.main_please_wait))
request.setAllowedNetworkTypes(DownloadManager.Request.NETWORK_MOBILE or DownloadManager.Request.NETWORK_WIFI) //设置下载的网络类型
request.setVisibleInDownloadsUi(true)
request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED)
return mDownloadManager.enqueue(request)
}</code></pre>
</div>
加入列队后，下载就进行了。我们可以在下拉通知栏里看到正在下载的文件。
另外注意 setDestinationInExternalPublicDir方法已经包含根目录路径了，所以直接传入DIRECTORY_DOWNLOADS就可以了，千万不要在导入一个 Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DCIM).getPath() 这样他会自动在创建多层目录
<h1>查询即将保存的下载文件路径与文件名称</h1>
<div class="cnblogs_code">
<pre>private void queryFileName(long id){
 DownloadManager downloadManager = (DownloadManager) MainActivity.this.getApplication().getSystemService(Context.DOWNLOAD_SERVICE);
 DownloadManager.Query query = new DownloadManager.Query();
 query.setFilterById(id);
 Cursor cursor = downloadManager.query(query);
 if (cursor.moveToFirst()) {
 String file = cursor.getString(cursor.getColumnIndexOrThrow(DownloadManager.COLUMN_LOCAL_URI));
 Log.e("调试_临时_log", "this_" + file);
 }
}</pre>
</div>
<h1>监听下载状态</h1>
<div class="cnblogs_code">
<pre> AppDownReceiver appDownReceiver = new AppDownReceiver();
 registerReceiver(appDownReceiver, new IntentFilter(DownloadManager.ACTION_DOWNLOAD_COMPLETE));</pre>
</div>
 广播部分代码
<div class="cnblogs_code">
<pre>public class DownloadReceiver extends BroadcastReceiver {
@Override
public void onReceive(Context context, Intent intent) {
 String action = intent.getAction();
 if (!TextUtils.equals(action, DownloadManager.ACTION_DOWNLOAD_COMPLETE)){
 return;
 }
 long downloadId = intent.getLongExtra(DownloadManager.EXTRA_DOWNLOAD_ID, -1);
 if (downloadId == -1){
 return;
 }
 DownloadManager downloadManager = (DownloadManager) context.getApplicationContext().getSystemService(Context.DOWNLOAD_SERVICE);
 int status = getDownloadStatus(downloadManager, downloadId);
 if (status != DownloadManager.STATUS_SUCCESSFUL){ //下载状态不等于成功就跳出
 return;
 }
 Uri uri = downloadManager.getUriForDownloadedFile(downloadId);//获取下载完成文件uri
 if (uri == null){
 return;
 }
}
/**
* 获取下载状态
* @param downloadManager
* @param downloadId
* @return
*/
private int getDownloadStatus(DownloadManager downloadManager, long downloadId) {
 DownloadManager.Query query = new DownloadManager.Query().setFilterById(downloadId);
 Cursor c = downloadManager.query(query);
 if (c != null) {
 try {
 if (c.moveToFirst()) {
 return c.getInt(c.getColumnIndexOrThrow(DownloadManager.COLUMN_STATUS));
 }
 } finally {
 c.close();
 }
 }
 return -1;
}

}</pre>
</div>
<h1>下载状态查询</h1>
<div class="cnblogs_code">
<pre> /**
* 获取下载状态
*
* @param downloadId an ID for the download, unique across the system.
* This ID is used to make future calls related to this download.
* @return int
* @see DownloadManager#STATUS_PENDING　　下载等待开始时
* @see DownloadManager#STATUS_PAUSED 　　下载暂停
* @see DownloadManager#STATUS_RUNNING　正在下载中　
* @see DownloadManager#STATUS_SUCCESSFUL 下载成功
* @see DownloadManager#STATUS_FAILED 下载失败
*/
public int getDownloadStatus(long downloadId) {
 DownloadManager.Query query = new DownloadManager.Query().setFilterById(downloadId);
 Cursor c = downloadManager.query(query);
 if (c != null) {
 try {
 if (c.moveToFirst()) {
 return c.getInt(c.getColumnIndexOrThrow(DownloadManager.COLUMN_STATUS));
 }
 } finally {
 c.close();
 }
 }
 return -1;
}</pre>
</div>
<h1>下载进度查询</h1>
<div class="cnblogs_code">
<pre>/**
* 获取当前下载进度
*
* @return
*/
private int getDownloadProgress() {
 DownloadManager.Query query = new DownloadManager.Query().setFilterById(mDownloadId);
 Cursor c = mDownloadManager.query(query);
 if (c != null) {
 try {
 if (c.moveToFirst()) {
 return c.getInt(c.getColumnIndex(DownloadManager.COLUMN_BYTES_DOWNLOADED_SO_FAR));
 }
 } finally {
 c.close();
 }
 }
 return -1;

}

/**
* 获取下载总大小
*
* @return
*/
private int getDownloadTotal() {
 DownloadManager.Query query = new DownloadManager.Query().setFilterById(mDownloadId);
 Cursor c = mDownloadManager.query(query);
 if (c != null) {
 try {
 if (c.moveToFirst()) {
 return c.getInt(c.getColumnIndex(DownloadManager.COLUMN_TOTAL_SIZE_BYTES));
 }
 } finally {
 c.close();
 }
 }
 return -1;
}</pre>
</div>
<h1>安装下载完成的App</h1>
<div class="cnblogs_code">
<pre> /**
* 安装apk
*/
private void installApk(long id) {
 Uri uri = mDownloadManager.getUriForDownloadedFile(id);
 Intent install = new Intent(Intent.ACTION_VIEW);
 install.setDataAndType(uri, "application/vnd.android.package-archive");
 install.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_GRANT_READ_URI_PERMISSION);
 getApplication().startActivity(install);

}</pre>
</div>
 
 
 
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</div>
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<div style="text-align: center">
本文来自博客园，作者：观心静，转载请注明原文链接：https://www.cnblogs.com/guanxinjing/p/13299949.html 
<div style="color:orange;font-size:16px;">本文版权归作者和博客园共有，欢迎转载，但必须给出原文链接，并保留此段声明，否则保留追究法律责任的权利。 </div>
</div> 
来源：https://www.cnblogs.com/guanxinjing/p/13299949.html

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Android开发 下载管理器DownloadManager详解

Android开发下载管理器DownloadManager详解