使用x5cloud云平台来做网络彩讯-------------文件上传下载进度条使用（八）
进度条是一个很头疼的问题，当然弄明白了也很好理解，用起来也很方便，大都会涉及到两个，一个是圆形，另外一个则是长方形，一点一点推进的
对于圆形比较简单，先说说长方形的原理：
?????? 首先需要获取文件大小，在循环写的时候就进行加减乘法运算，哈哈，就这么简单！
给个例子吧：
public class Android_X5_SOSO_9_9_2Activity extends Activity { /** Called when the activity is first created. */ProgressBar pb;TextView tv;int fileSize;int downLoadFileSize;String fileEx,fileNa,filename;private Handler handler = new Handler() { @Override public void handleMessage(Message msg) {//定义一个Handler，用于处理下载线程与UI间通讯 if (!Thread.currentThread().isInterrupted()) { switch (msg.what) { case 0: pb.setMax(fileSize); case 1: pb.setProgress(downLoadFileSize); int result = downLoadFileSize * 100 / fileSize; tv.setText(result + "%"); break; case 2: Toast.makeText(Android_X5_SOSO_9_9_2Activity.this, "文件下载完成", 1000).show(); break; case -1: String error = msg.getData().getString("error"); Toast.makeText(Android_X5_SOSO_9_9_2Activity.this, error, 1000).show(); break; } } super.handleMessage(msg); } }; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); pb=(ProgressBar)findViewById(R.id.down_pb); tv=(TextView)findViewById(R.id.tv); new Thread(){ public void run(){ try { String localpath=Environment .getExternalStorageDirectory() .getAbsolutePath()+"/CXSOSO/" +"20110901005.3gp"; down_file(localpath,"/sdcard/");//下载文件，参数：第一个URL，第二个存放路径} catch (ClientProtocolException e) {// TODO Auto-generated catch blocke.printStackTrace();} catch (IOException e) {// TODO Auto-generated catch blocke.printStackTrace();} } }.start(); } public void down_file(String url,String path) throws IOException{ //下载函数 filename=url.substring(url.lastIndexOf("/") + 1); //获取文件名 /*URL myURL = new URL(url); URLConnection conn = myURL.openConnection(); conn.connect();*/ /*InputStream is = conn.getInputStream(); this.fileSize = conn.getContentLength();//根据响应获取文件大小*/ File file = new File(url); DataInputStream is = new DataInputStream(new BufferedInputStream(new FileInputStream(file))); try {this.fileSize=read(file).length;} catch (Throwable e) {// TODO Auto-generated catch blocke.printStackTrace();} if (this.fileSize <= 0) throw new RuntimeException("无法获知文件大小 "); if (is == null) throw new RuntimeException("stream is null"); FileOutputStream fos = new FileOutputStream(path+filename); //把数据存入路径+文件名 byte buf[] = new byte[1024]; downLoadFileSize = 0; sendMsg(0); do { //循环读取 int numread = is.read(buf); if (numread == -1) { break; } fos.write(buf, 0, numread); downLoadFileSize += numread; sendMsg(1);//更新进度条 } while (true); sendMsg(2);//通知下载完成 try { is.close(); } catch (Exception ex) { Log.e("tag", "error: " + ex.getMessage(), ex); } }private void sendMsg(int flag){ Message msg = new Message(); msg.what = flag; handler.sendMessage(msg);} public byte[] read(File myfile) throws Throwable{ //定义输入流，将文件写入到fpath中 DataInputStream inStream = new DataInputStream(new BufferedInputStream(new FileInputStream(myfile))); byte[] data = readFile(inStream); // data.length; return data; } public static byte[] readFile(InputStream inStream) throws Throwable{ int len = 0; byte[] buffer = new byte[1024]; ByteArrayOutputStream outStream = new ByteArrayOutputStream(); while((len = inStream.read(buffer))!=-1){ outStream.write(buffer,0,len); } outStream.close(); return outStream.toByteArray(); } }?