WebView控制调用相应的WEB页面进行展示。当碰到页面有下载链接的时候,点击上去是一点反应都没有的。原来是因为WebView默认没有开启文件下载的功能,如果要实现文件下载的功能,需要设置WebView的DownloadListener,通过实现自己的DownloadListener来实现文
WebView控制调用相应的WEB页面进行展示。当碰到页面有下载链接的时候,点击上去是一点反应都没有的。原来是因为WebView默认没有开启文件下载的功能,如果要实现文件下载的功能,需要设置WebView的DownloadListener,通过实现自己的DownloadListener来实现文件的下载。具体操作如下:
1、设置WebView的DownloadListener:
webView.setDownloadListener(new MyWebViewDownLoadListener());
2、实现MyWebViewDownLoadListener这个类,具体可以如下这样:
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private class MyWebViewDownLoadListener implements DownloadListener{
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@Override
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public void onDownloadStart(String url, String userAgent, String contentDisposition, String mimetype,
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long contentLength) {
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Log.i("tag", "url="+url);
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Log.i("tag", "userAgent="+userAgent);
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Log.i("tag", "contentDisposition="+contentDisposition);
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Log.i("tag", "mimetype="+mimetype);
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Log.i("tag", "contentLength="+contentLength);
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Uri uri = Uri.parse(url);
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Intent intent = new Intent(Intent.ACTION_VIEW, uri);
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startActivity(intent);
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}
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}
这只是调用系统中已经内置的浏览器进行下载,还没有WebView本身进行的文件下载,不过,这也基本上满足我们的应用场景了。
我在项目中的运用
项目要求这样:
1,需要使用WebView加载一个网页;
2,网页中有文件下载的链接,点击后需要下载文件到SDcard;
3,然后自动打开文件;
下面是具体解决办法
第一步,对WebView进行一系列设置。
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WebView webview=(WebView)layout.findViewById(R.id.webview);
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webview.getSettings().setJavaScriptEnabled(true);
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webview.setWebChromeClient(new MyWebChromeClient());
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webview.requestFocus();
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webview.loadUrl(jcrs_sub.get(position).addr);
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webview.setWebViewClient(new MyWebViewClient());
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webview.setDownloadListener(new MyWebViewDownLoadListener());
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public class MyWebViewClient extends WebViewClient {
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public boolean shouldOverviewUrlLoading(WebView view, String url) {
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L.i("shouldOverviewUrlLoading");
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view.loadUrl(url);
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return true;
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}
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public void onPageStarted(WebView view, String url, Bitmap favicon) {
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L.i("onPageStarted");
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showProgress();
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}
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public void onPageFinished(WebView view, String url) {
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L.i("onPageFinished");
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closeProgress();
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}
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public void onReceivedError(WebView view, int errorCode,
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String description, String failingUrl) {
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L.i("onReceivedError");
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closeProgress();
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}
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}
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public boolean onKeyDown(int keyCode, KeyEvent event) {
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return false;
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}
第二步,起线程开始下载文件。
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private class MyWebViewDownLoadListener implements DownloadListener {
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@Override
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public void onDownloadStart(String url, String userAgent, String contentDisposition, String mimetype,
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long contentLength) {
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if(!Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)){
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Toast t=Toast.makeText(mContext, "需要SD卡。", Toast.LENGTH_LONG);
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t.setGravity(Gravity.CENTER, 0, 0);
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t.show();
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return;
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}
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DownloaderTask task=new DownloaderTask();
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task.execute(url);
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}
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}
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private class DownloaderTask extends AsyncTask<String, Void, String> {
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public DownloaderTask() {
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}
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@Override
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protected String doInBackground(String... params) {
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String url=params[0];
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String fileName=url.substring(url.lastIndexOf("/")+1);
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fileName=URLDecoder.decode(fileName);
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Log.i("tag", "fileName="+fileName);
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File directory=Environment.getExternalStorageDirectory();
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File file=new File(directory,fileName);
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if(file.exists()){
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Log.i("tag", "The file has already exists.");
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return fileName;
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}
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try {
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HttpClient client = new DefaultHttpClient();
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HttpGet get = new HttpGet(url);
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HttpResponse response = client.execute(get);
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if(HttpStatus.SC_OK==response.getStatusLine().getStatusCode()){
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HttpEntity entity = response.getEntity();
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InputStream input = entity.getContent();
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writeToSDCard(fileName,input);
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input.close();
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return fileName;
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}else{
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return null;
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}
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} catch (Exception e) {
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e.printStackTrace();
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return null;
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}
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}
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@Override
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protected void onCancelled() {
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super.onCancelled();
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}
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@Override
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protected void onPostExecute(String result) {
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super.onPostExecute(result);
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closeProgressDialog();
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if(result==null){
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Toast t=Toast.makeText(mContext, "连接错误!请稍后再试!", Toast.LENGTH_LONG);
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t.setGravity(Gravity.CENTER, 0, 0);
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t.show();
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return;
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}
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Toast t=Toast.makeText(mContext, "已保存到SD卡。", Toast.LENGTH_LONG);
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t.setGravity(Gravity.CENTER, 0, 0);
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t.show();
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File directory=Environment.getExternalStorageDirectory();
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File file=new File(directory,result);
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Log.i("tag", "Path="+file.getAbsolutePath());
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Intent intent = getFileIntent(file);
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startActivity(intent);
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}
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@Override
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protected void onPreExecute() {
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super.onPreExecute();
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showProgressDialog();
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}
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@Override
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protected void onProgressUpdate(Void... values) {
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super.onProgressUpdate(values);
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}
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}
第三步,实现一些工具方法。
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<span style="font-family:Helvetica, Tahoma, Arial, sans-serif;">private ProgressDialog mDialog;
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private void showProgressDialog(){
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if(mDialog==null){
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mDialog = new ProgressDialog(mContext);
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mDialog.setProgressStyle(ProgressDialog.STYLE_SPINNER);
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mDialog.setMessage("正在加载 ,请等待...");
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mDialog.setIndeterminate(false);
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mDialog.setCancelable(true);
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mDialog.setCanceledOnTouchOutside(false);
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mDialog.setOnDismissListener(new OnDismissListener() {
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@Override
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public void onDismiss(DialogInterface dialog) {
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mDialog=null;
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}
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});
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mDialog.show();
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}
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}
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private void closeProgressDialog(){
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if(mDialog!=null){
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mDialog.dismiss();
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mDialog=null;
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}
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}
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public Intent getFileIntent(File file){
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Uri uri = Uri.fromFile(file);
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String type = getMIMEType(file);
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Log.i("tag", "type="+type);
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Intent intent = new Intent("android.intent.action.VIEW");
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intent.addCategory("android.intent.category.DEFAULT");
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intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
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intent.setDataAndType(uri, type);
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return intent;
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}
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public void writeToSDCard(String fileName,InputStream input){
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if(Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)){
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File directory=Environment.getExternalStorageDirectory();
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File file=new File(directory,fileName);
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try {
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FileOutputStream fos = new FileOutputStream(file);
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byte[] b = new byte[2048];
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int j = 0;
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while ((j = input.read(b)) != -1) {
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fos.write(b, 0, j);
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}
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fos.flush();
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fos.close();
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} catch (FileNotFoundException e) {
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e.printStackTrace();
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} catch (IOException e) {
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e.printStackTrace();
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}
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}else{
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Log.i("tag", "NO SDCard.");
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}
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}
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private String getMIMEType(File f){
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String type="";
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String fName=f.getName();
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String end=fName.substring(fName.lastIndexOf(".")+1,fName.length()).toLowerCase();
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if(end.equals("pdf")){
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type = "application/pdf";
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}
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else if(end.equals("m4a")||end.equals("mp3")||end.equals("mid")||
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end.equals("xmf")||end.equals("ogg")||end.equals("wav")){
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type = "audio/*";
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}
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else if(end.equals("3gp")||end.equals("mp4")){
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type = "video/*";
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}
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else if(end.equals("jpg")||end.equals("gif")||end.equals("png")||
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end.equals("jpeg")||end.equals("bmp")){
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type = "image/*";
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}
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else if(end.equals("apk")){
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/* android.permission.INSTALL_PACKAGES */
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type = "application/vnd.android.package-archive";
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}
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else{
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type="*/*";
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}
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return type;
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} </span>
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<span style="font-family:Helvetica, Tahoma, Arial, sans-serif;">转自:<a href="http://gundumw100.iteye.com/blog/1338645">http://gundumw100.iteye.com/blog/1338645</a>
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</span>