Android——实现网络下载资源

青旅半醒 2022-06-03 06:22 193阅读 0赞

**网络权限：**

<uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>

**MainActivity**

downloadAPK(bean.getData().getApkUrl(),"APK");

private void downloadAPK(String versionUrl, String versionName) {
        //创建下载任务 DownloadManager.Request request = new DownloadManager.Request(Uri.parse(versionUrl));
        request.setAllowedOverRoaming(false);//漫游网络是否可以下载 //设置文件类型，可以在下载结束后自动打开该文件 MimeTypeMap mimeTypeMap = MimeTypeMap.getSingleton();
        String mimeString = mimeTypeMap.getMimeTypeFromExtension(MimeTypeMap.getFileExtensionFromUrl(versionUrl));
        request.setMimeType(mimeString);
    
        //在通知栏中显示，默认就是显示的 request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE);
        request.setVisibleInDownloadsUi(true);
    
        //sdcard的目录下的download文件夹，必须设置 request.setDestinationInExternalPublicDir("/download/", versionName);
        //request.setDestinationInExternalFilesDir(),也可以自己制定下载路径 //将下载请求加入下载队列 downloadManager = (DownloadManager) MainActivity.this.getSystemService(MainActivity.this.DOWNLOAD_SERVICE);
        //加入下载队列后会给该任务返回一个long型的id， //通过该id可以取消任务，重启任务等等，看上面源码中框起来的方法 mTaskId = downloadManager.enqueue(request);
    
        //注册广播接收者，监听下载状态 MainActivity.this.registerReceiver(receiver,new IntentFilter(DownloadManager.ACTION_DOWNLOAD_COMPLETE));
    }
    
    private BroadcastReceiver receiver = new BroadcastReceiver() {
        @Override public void onReceive(Context context, Intent intent) {
            checkDownloadStatus();//检查下载状态 }
    };
    
    private void checkDownloadStatus() {
        DownloadManager.Query query = new DownloadManager.Query();
        query.setFilterById(mTaskId);//筛选下载任务，传入任务ID，可变参数 Cursor c = downloadManager.query(query);
        if (c.moveToFirst()) {
            int status = c.getInt(c.getColumnIndex(DownloadManager.COLUMN_STATUS));
            switch (status) {
                case DownloadManager.STATUS_PAUSED:
                    Log.i("zzz",">>>下载暂停");
                case DownloadManager.STATUS_PENDING:
                    Log.i("zzz",">>>下载延迟");
                case DownloadManager.STATUS_RUNNING:
                    Log.i("zzz",">>>正在下载");
                    break;
                case DownloadManager.STATUS_SUCCESSFUL:
                    Log.i("zzz",">>>下载完成");
                    File file = Environment.getExternalStorageDirectory();
                    installAPK(new File(file+"/Download"));
                    break;
                case DownloadManager.STATUS_FAILED:
                    Log.i("zzz",">>>下载失败");
                    break;
            }
        }
    }
    
    protected void installAPK(File file) {
        if (!file.exists()) return;
        Intent intent = new Intent(Intent.ACTION_VIEW);
        Uri uri = Uri.parse("file://" + file.toString());
        intent.setDataAndType(uri, "application/vnd.android.package-archive");
        //在服务中开启activity必须设置flag,后面解释 intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
        MainActivity.this.startActivity(intent);
    }