通常webview渲染的界面中含有可以下载文件的链接，点击该链接后，应该开始执行下载的操作并保存文件到本地中。webview来下载页面中的文件通常有两种方式：
- 自己通过一个线程写java io的代码来下载和保存文件（可控性好）
- 调用系统download的模块（代码简单）
1.第一种下载
// 页面下载功能
mWebView.setDownloadListener(new DownloadListener() {
@Override
public void onDownloadStart(String url, String userAgent,
String contentDisposition, String mimetype,
long contentLength) {
URL = url;
// 让ProgressDialog显示
progressBar.show();
Thread loginThread = new Thread(new Runnable() {
@Override
public void run() {
InputStream in = null;
FileOutputStream fout = null;
// 獲取文件全名，包括後綴
downloadFile = new File(Environment
.getExternalStorageDirectory().getPath()
+ DirName);
if (!downloadFile.exists()) {
downloadFile.mkdirs();
}
String FolderName = getFileName(URL);
if (Environment.getExternalStorageState().equals(
Environment.MEDIA_MOUNTED)) {
sdFile = new File(downloadFile, FolderName);
if (sdFile.exists()) {
if (progressBar.isShowing()) {
progressBar.dismiss();
}
openFile(mContext, sdFile);
} else {
try {
// String[] mimetypeName =
// FolderName.split(".");
// String HouZui = "."
// + mimetypeName[mimetypeName.length - 1];
URL httpUrl = new URL(URL);
HttpURLConnection conn = (HttpURLConnection) httpUrl
.openConnection();
conn.setDoInput(true);
conn.setDoOutput(true);
in = conn.getInputStream();
FileLen = conn.getContentLength();// 根据响应获取文件大小
if (Environment.getExternalStorageState()
.equals(Environment.MEDIA_MOUNTED)) {
sdFile = new File(downloadFile,
FolderName);
fout = new FileOutputStream(sdFile);
} else {
}
byte[] buffer = new byte[1024];
int len;
int DownLoadLen = 0;
while ((len = in.read(buffer)) != -1) {
fout.write(buffer, 0, len);
// DownLoadLen += len;
// progressBar.setProgress((int)((DownLoadLen
// / FileLen) * 100));
}
if (progressBar.isShowing()) {
progressBar.dismiss();
}
openFile(mContext, sdFile);
} catch (Exception e) {
e.printStackTrace();
} finally {
if (progressBar.isShowing()) {
progressBar.dismiss();
}
if (in != null) {
try {
in.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if (fout != null) {
try {
fout.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
}
}
});
loginThread.start();
}
});
第二种下载方式
class MyDownloadListenter implements DownloadListener{
@Override
public void onDownloadStart(String url, String userAgent,
String contentDisposition, String mimetype, long contentLength) {
System.out.println("url ==== >" + url);
//new HttpThread(url).start();
Uri uri = Uri.parse(url);
Intent intent = new Intent(Intent.ACTION_VIEW, uri);
startActivity(intent);
}
}
