从Kotlin Android的url下载视频?

1)下载管理器

android下载管理器在android 2.3中作为一项优化长期下载处理的服务引入。

下载管理器处理HTTP连接并监视连接更改。使用下载是一个很好的实践。

管理器在大多数情况下,特别是在用户会话之间的后台可能继续下载的情况下。

此类的实例应通过传递download_service通过getsystemservice(string)获取。

通过此API请求下载的应用程序应注册一个广播接收器,以便用户在通知中或从下载用户界面单击正在运行的下载时,单击“操作通知”以适当处理。

2)在前台运行服务

前台服务是一种被认为是用户主动意识到的服务,因此当内存不足时,它不是系统要终止的候选服务。前台服务必须为状态栏提供通知,该状态栏位于“正在进行”标题下,这意味着除非服务停止或从前台删除,否则无法取消通知。

例如,从服务下载视频应设置为在前台运行,因为用户明确知道其操作。状态栏中的通知可能指示当前下载,并允许用户启动活动以与下载过程交互。

若要请求您的服务在前台运行,请调用StartForeground()。此方法接受两个参数:一个唯一标识通知和状态栏通知的整数。

我有一个视频文件(.mp4格式),我希望允许用户将视频下载到他们的SD卡。我目前使用此代码,但它不起作用。

String PATHSdcard = "/sdcard/Video/";  

public void DownloadFromUrl(String VideoURL, String fileName)         


try { URL url = new URL("https://javmed-prod.s3.amazonaws.com/666034cbe81045f2a2da50e5205e376b.mp4");
         File file = new File(fileName);

         long sTime = System.currentTimeMillis();
         URLConnection URLcon = url.openConnection();

         InputStream is = URLcon.getInputStream();
         BufferedInputStream bis = new BufferedInputStream(is);

         ByteArrayBuffer baf = new ByteArrayBuffer(50);
         int current = 0;
         while ((current = bis.read()) != -1) {
                 baf.append((byte) current);
         }

         FileOutputStream fos = new FileOutputStream(PATHSdcard+file);
         fos.write(baf.toByteArray());
         fos.close();

 } catch (IOException e) {
         Log.d("ERROR.......",e+"");
 }

    import java.io.File;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import android.content.Intent;
import android.os.AsyncTask;
import android.os.Environment;
import android.util.Log;


public class VideoSaveSDCARD extends Activity{

public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        ProgressBack PB = new ProgressBack();
        PB.execute("");
    }

    private class ProgressBack extends AsyncTask<String,String,String> {
         ProgressDialog PD;
        @Override
        protected void onPreExecute() {
            PD= ProgressDialog.show(LoginPage.this,null, "Please Wait ...", true);
            PD.setCancelable(true);
        }

        @Override
        protected void doInBackground(String... arg0) {
        downloadFile("http://beta-vidizmo.com/hilton.mp4","Sample.mp4");            

        }
        protected void onPostExecute(Boolean result) {
            PD.dismiss();

        }

    }



    private void downloadFile(String fileURL, String fileName) {
        try {
        String rootDir = Environment.getExternalStorageDirectory()
                + File.separator + "Video";
           File rootFile = new File(rootDir);
           rootFile.mkdir();
            URL url = new URL(fileURL);
            HttpURLConnection c = (HttpURLConnection) url.openConnection();
            c.setRequestMethod("GET");
            c.setDoOutput(true);
            c.connect();
            FileOutputStream f = new FileOutputStream(new File(rootFile,
                    fileName));
            InputStream in = c.getInputStream();
            byte[] buffer = new byte[1024];
            int len1 = 0;
            while ((len1 = in.read(buffer)) > 0) {
                f.write(buffer, 0, len1);
            }
            f.close();
    } catch (IOException e) {
        Log.d("Error....", e.toString());
    }

}

使用以下库:

  implementation 'com.mindorks.android:prdownloader:0.5.0'

从给定URL下载视频的代码如下:

 fun downfile(urll:String,fileName:String){



    if(!isFilePresent(fileName)) {
        var mFile2: File? = File(Environment.getExternalStorageDirectory(), "WallpapersBillionaire")
        System.out.println("File Foond " + mFile2!!.absolutePath)
        var mFile3: File? = File(Environment.getExternalStorageDirectory(), "WallpapersBillionaire")

        var downloadId = PRDownloader.download(urll, mFile2!!.absolutePath, fileName)
                .build()
                .setOnStartOrResumeListener(object : OnStartOrResumeListener {
                    override fun onStartOrResume() {
                        System.out.println("??????????????????? start")
                    }
                })
                .setOnPauseListener(object : OnPauseListener {
                    override fun onPause() {
                    }
                })
                .setOnCancelListener(object : OnCancelListener {
                    override fun onCancel() {
                    }
                })
                .setOnProgressListener(object : OnProgressListener {
                    override fun onProgress(progress: Progress) {
                        circlePeView.visibility = View.VISIBLE

                        var per = (progress.currentBytes.toFloat() / progress.totalBytes.toFloat()) * 100.00
                        //var perint = per*100
                        System.out.println("::??????????????????? Per : " + per + " ?? : " + progress.currentBytes + " ?? : " + progress.totalBytes)

                        circlePeView.setProgress(per.toInt())
                    }
                })
                .start(object : OnDownloadListener {
                    override fun onDownloadComplete() {

                        circlePeView.visibility = View.GONE
                        circlePeView.setProgress(0)
                        prefs = getSharedPreferences(PREFS_FILENAME, 0)

                        val editor = prefs!!.edit()
                        editor.putString(wall, "WallpapersBillionaire/" + fileName)
                        editor.apply()

                        try {
                            val myWallpaperManager = WallpaperManager.getInstance(applicationContext)
                            try {
                                myWallpaperManager.setResource(R.raw.wallp)
                            } catch (e: IOException) {
                                // TODO Auto-generated catch block
                                e.printStackTrace()
                            }

                            val intent = Intent(WallpaperManager.ACTION_CHANGE_LIVE_WALLPAPER)
                            intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK)
                            intent.putExtra(WallpaperManager.EXTRA_LIVE_WALLPAPER_COMPONENT,
                                    ComponentName(this@AnimattedViewpagerActivity, VideoLiveWallpaperService::class.java))
                            startActivity(intent)
                        } catch (e: Exception) {
                            val intent = Intent()
                            intent.setAction(WallpaperManager.ACTION_LIVE_WALLPAPER_CHOOSER)
                            try {
                                startActivity(intent)
                            }catch (e2: java.lang.Exception){
                                Toast.makeText(applicationContext,"Please long click on your home screen. Select Video Live Wallpapers form thier. Thanks",Toast.LENGTH_LONG).show()
                            }

                        }
                        System.out.println("??????????????????? complete")
                    }

                    override fun onError(error: Error) {
                        System.out.println("??????????????????? error " + error)
                    }
                })
        System.out.println("??????????????????? called")
    }else{
        System.out.println("File Foond ")
        circlePeView.visibility = View.GONE
        circlePeView.setProgress(0)
        prefs = getSharedPreferences(PREFS_FILENAME, 0)

        val editor = prefs!!.edit()
        editor.putString(wall, "WallpapersBillionaire/" + fileName)
        editor.apply()

        try {
            val myWallpaperManager = WallpaperManager.getInstance(applicationContext)
            try {
                myWallpaperManager.setResource(R.raw.wallp)
            } catch (e: IOException) {
                // TODO Auto-generated catch block
                e.printStackTrace()
            }

            val intent = Intent(WallpaperManager.ACTION_CHANGE_LIVE_WALLPAPER)
            intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK)
            intent.putExtra(WallpaperManager.EXTRA_LIVE_WALLPAPER_COMPONENT,
                    ComponentName(this@AnimattedViewpagerActivity, VideoLiveWallpaperService::class.java))
            startActivity(intent)
        } catch (e: Exception) {
            val intent = Intent()
            intent.setAction(WallpaperManager.ACTION_LIVE_WALLPAPER_CHOOSER)

            try {
                startActivity(intent)
            }catch (e2: java.lang.Exception){
                Toast.makeText(applicationContext,"Please long click on your home screen. Select Video Live Wallpapers form thier. Thanks",Toast.LENGTH_LONG).show()
            }

        }
        System.out.println("??????????????????? complete")
    }
}