Update the simple help class of the UI when downloading files based on Android

Update the simple help class of the UI when downloading files based on Android

Due to this simple requirement during project development, Google also has many Utils tool classes on the Internet, but they are relatively redundant. I wrote a simple help class.

/*** Download the file and update the simple UI help class ** @ author jarlen **/public class DownLoadHelper {private static final int DOWN_BEGIN = 0; private static final int DOWN_UPDATA = 1; private static final int DOWN_FINISH = 2; private static final int DOWN_ERROR = 3; private Context mContext; private TextView mTextView; private ProgressBar mBar; private Handler handler = new Handler () {public void handleMessage (Message msg ){ If (! Thread. currentThread (). isInterrupted () {switch (msg. what) {case DOWN_BEGIN: if (mTextView! = Null) {mTextView. setText (start download);} if (mBar! = Null) {mBar. setProgress (0);} break; case DOWN_UPDATA: int factor = msg. arg1; if (mTextView! = Null) {mTextView. setText (factor + %);} if (mBar! = Null) {mBar. setProgress (factor);} break; case DOWN_FINISH: if (mTextView! = Null) {mTextView. setText (Download complete);} if (mBar! = Null) {mBar. setProgress (100);} break; case DOWN_ERROR: if (mTextView! = Null) {mTextView. setText (download error);} if (mBar! = Null) {mBar. setProgress (0) ;}break; default: break ;}};}; public DownLoadHelper (Context context) {this. mContext = context;}/*** sets the UI TextView to be updated * @ param view */public void setUpdataView (TextView view) {this. mTextView = view;}/*** sets the UI to be updated during download. The ProgressBar * @ param bar */public void setUpdataBar (ProgressBar bar) {this. mBar = bar;}/*** start to download * @ param url * file * @ param path * File storage address */public void startDownLoad (final String url, final String path) {new Thread () {public void run () {sendMsg (DOWN_BEGIN, 0 ); try {long downloadSize = downloadUpdateFile (url, path); if (downloadSize> 0) {sendMsg (DOWN_FINISH, 0) ;}} catch (Exception e) {e. printStackTrace (); sendMsg (DOWN_ERROR, 0 );}};}. start ();} private long downloadUpdateFile (String down_url, String path) throws Exception {int down_step = 1; // The prompt is "step int totalSize"; // The total file size int downloadCount = 0; // The downloaded size int updateCount = 0; // The size of the uploaded file: InputStream inputStream; OutputStream outputStream; URL url = new URL (down_url); HttpURLConnection httpURLConnection = (HttpURLConnection) url. openConnection (); httpURLConnection. setConnectTimeout (30*1000); httpURLConnection. setReadTimeout (30*1000); // get the size of the downloaded object TotalSize = httpURLConnection. getContentLength (); if (httpURLConnection. getResponseCode () = 404) {sendMsg (DOWN_ERROR, 0); throw new Exception (fail !);} InputStream = httpURLConnection. getInputStream (); File dir = new File (path); if (! Dir. exists () {dir. mkdir ();} String name = down_url.substring (down_url.lastIndexOf (/) + 1, down_url.length (); File updateFile = new File (dir, name); outputStream = new FileOutputStream (updateFile, false); // if a file exists, it overwrites byte buffer [] = new byte [1024]; int readsize = 0; while (readsize = inputStream. read (buffer ))! =-1) {outputStream. write (buffer, 0, readsize); downloadCount + = readsize; // obtain the downloaded size from time to time // increase by 1% if (updateCount = 0 | (downloadCount * 100/totalSize-down_step)> = updateCount) {updateCount + = down_step; sendMsg (DOWN_UPDATA, updateCount) ;}} if (httpURLConnection! = Null) {httpURLConnection. disconnect ();} inputStream. close (); outputStream. close (); return downloadCount;} private void sendMsg (int flag, int factor) {Message msg = new Message (); switch (flag) {case DOWN_BEGIN: // start case DOWN_FINISH: // complete case DOWN_ERROR: // failed break; case DOWN_UPDATA: // update progress bar msg. arg1 = factor; break; default: break;} msg. what = flag; handler. sendMessage (msg );}}

Simple instructions for use;

DownLoadHelper helper1 = new DownLoadHelper(this);helper1.setUpdataView(tv1);helper1.startDownLoad(http://img1.2345.com/appsimg/wallpaper/4/139460306960.jpg, path);