安卓断点下载小视频

断点续传的方法

public void Down(){
        new Thread(new Runnable() {
            @Override
            public void run() {
                try {
                    URL url = new URL(urlPath);
                    HttpURLConnection urlC =(HttpURLConnection) url.openConnection();
                    urlC.setRequestMethod("GET");
                    urlC.setDoOutput(true);
                    urlC.setDoInput(true);


                    RandomAccessFile randomAccessFile=new RandomAccessFile("/sdcard/hh.mp4","rw");
                    Log.e("##","23");
                     randomAccessFile.seek(start);

                    urlC.setRequestProperty("Range","bytes="+start+"-"+end);
                    if(urlC.getResponseCode()==206){   //断点续传是206
                        int contentLength = urlC.getContentLength();//总长度
                        InputStream is = urlC.getInputStream();
                        byte[] b=new byte[1024];
                        int len=0;
                        while ((len=is.read(b))!=-1){
                            randomAccessFile.write(b,0,len);
                            Message message = new Message();
                            sum+=len;
                            message.arg1=sum;
                            message.what=3;
                            String str="文件"+time+"Win"+start+"-"+end;
                            message.obj=str;
                            handler.sendMessage(message);
                        }
                    }
                    Message message=new Message();
                    if(flag){
                        message.what=0;
                        start=end+1;
                        end+=1024*1024;

                    }
                    handler.sendMessage(message);


                } catch (MalformedURLException e) {
                    e.printStackTrace();
                } catch (IOException e) {
                    e.printStackTrace();
                }

            }
        }).start();
    }

获取最大值的线程

 public void HH(){
        new Thread(new Runnable() {
            @Override
            public void run() {

                try {
                   URL url = new URL(urlPath);
                    HttpURLConnection urlC =(HttpURLConnection) url.openConnection();
                    urlC.setRequestMethod("GET");
                    if(urlC.getResponseCode()==200){
                        max = urlC.getContentLength();
                        Message message = new Message();
                        message.what=2;
                        message.arg1=max;
                        handler.sendMessage(message);
                    }

                } catch (MalformedURLException e) {
                    e.printStackTrace();
                } catch (ProtocolException e) {
                    e.printStackTrace();
                } catch (IOException e) {
                    e.printStackTrace();
                }

            }
        }).start();
    }

使用Handler来操作断点和进度条

  Handler handler=new Handler(){
        @Override
        public void handleMessage(Message msg) {
            super.handleMessage(msg);
            if(msg.what==0&&msg.obj!=null){
                if(time<5){
                    time++;
                    Down();
                }else{
                    handler.sendEmptyMessage(1);
                }
                Log.e("msg",msg.obj.toString());

            }else if(msg.what==1){

            }else if(msg.what==2){
                seekBar.setMax(msg.arg1);
            }else if(msg.what==3){
                seekBar.setProgress(msg.arg1);
            }
        }
    };