WebView文件下載
本節(jié)引言
本節(jié)給大家介紹的是WebView下載文件的知識(shí)點(diǎn),當(dāng)我們?cè)谑褂闷胀g覽器的時(shí)候,比如UC, 當(dāng)我們點(diǎn)擊到一個(gè)可供下載鏈接的時(shí)候,就會(huì)進(jìn)行下載,WebView作為一個(gè)瀏覽器般的組件, 當(dāng)然也是支持下載,我們可以自己來寫下載的流程,設(shè)置下載后的文件放哪,以什么文件名 保存,當(dāng)然也可以調(diào)用其它內(nèi)置的瀏覽器來進(jìn)行下載,比如Chrome,UC等等! 下面給大家演示下用法!
1.調(diào)用其它瀏覽器下載文件:
這個(gè)很簡(jiǎn)單,我們只需為WebView設(shè)置setDownloadListener,然后重寫DownloadListener的 onDownloadStart,然后在里面寫個(gè)Intent,然后startActivity對(duì)應(yīng)的Activity即可!
關(guān)鍵代碼如下:
wView.setDownloadListener(new DownloadListener(){ @Override public void onDownloadStart(String url, String userAgent, String contentDisposition, String mimetype, long contentLength) { Log.e("HEHE","開始下載"); Uri uri = Uri.parse(url); Intent intent = new Intent(Intent.ACTION_VIEW,uri); startActivity(intent); } });
如果你手機(jī)內(nèi)存在多個(gè)瀏覽器的話,會(huì)打開一個(gè)對(duì)話框供你選擇其中一個(gè)瀏覽器進(jìn)行下載~
2.自己寫線程下載文件
當(dāng)然,你可能不想把下載文件放到默認(rèn)路徑下,或者想自己定義文件名等等,你都可以自己來寫 一個(gè)線程來下載文件,實(shí)現(xiàn)示例代碼如下:
核心代碼:
我們自己另外寫一個(gè)下載的線程類:
DownLoadThread.java
/** * Created by Jay on 2015/9/14 0014. */ public class DownLoadThread implements Runnable { private String dlUrl; public DownLoadThread(String dlUrl) { this.dlUrl = dlUrl; } @Override public void run() { Log.e("HEHE", "開始下載~~~~~"); InputStream in = null; FileOutputStream fout = null; try { URL httpUrl = new URL(dlUrl); HttpURLConnection conn = (HttpURLConnection) httpUrl.openConnection(); conn.setDoInput(true); conn.setDoOutput(true); in = conn.getInputStream(); File downloadFile, sdFile; if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) { Log.e("HEHE","SD卡可寫"); downloadFile = Environment.getExternalStorageDirectory(); sdFile = new File(downloadFile, "csdn_client.apk"); fout = new FileOutputStream(sdFile); }else{ Log.e("HEHE","SD卡不存在或者不可讀寫"); } byte[] buffer = new byte[1024]; int len; while ((len = in.read(buffer)) != -1) { fout.write(buffer, 0, len); } } catch (Exception e) { e.printStackTrace(); } finally { if (in != null) { try { in.close(); } catch (IOException e) { e.printStackTrace(); } } if (fout != null) { try { fout.close(); } catch (IOException e) { e.printStackTrace(); } } } Log.e("HEHE", "下載完畢~~~~"); } }
然后MainActivity.java中創(chuàng)建并啟動(dòng)該線程:
wView.setDownloadListener(new DownloadListener(){ @Override public void onDownloadStart(String url, String userAgent, String contentDisposition, String mimetype, long contentLength) { Log.e("HEHE","onDownloadStart被調(diào)用:下載鏈接:" + url); new Thread(new DownLoadThread(url)).start(); } });
運(yùn)行結(jié)果:
我們打開SD卡可以看到,下載好的文件已經(jīng)安安靜靜地躺在SD卡里了:
注意事項(xiàng):
好的,另外,別忘了寫SD卡的讀寫權(quán)限以及Internet訪問網(wǎng)絡(luò)的權(quán)限:
還有,in = conn.getInputStream();要寫在conn設(shè)置完所有東西的后面??!切記,不然什么都讀不了!
本節(jié)小結(jié):
本節(jié)非常簡(jiǎn)單,代碼就不貼出了,其實(shí)就是setDownloadListener這個(gè)玩意,自己重寫下 onDownloadStart方法來處理下載過程而已~,本節(jié)就到這里,謝謝~