安卓使用WebView下载文件，安卓实现软件升级功能

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安卓使用WebView下载文件，安卓实现软件升级功能

2024-10-03 09:04:39 215人阅读

由于调用系统默认浏览器下载更新，造成用户体验非常不好，所以决定在webview中直接下载系统更新。然后直接安装。

由于要下载，所以必须用webview，联网权限这里不说了，直接写在manifafest中。

我们经常使用的下载都是调用Android默认浏览器这样写

1、设置WebView的DownloadListener：

webView.setDownloadListener(new MyWebViewDownLoadListener());

2、实现MyWebViewDownLoadListener这个类，详细能够例如以下这样：

[java] view plaincopy

private class MyWebViewDownLoadListener implements DownloadListener {
@Override
public void onDownloadStart(String url, String userAgent, String contentDisposition, String mimetype,
long contentLength) {
Uri uri = Uri.parse(url);
Intent intent = new Intent(Intent.ACTION_VIEW, uri);
startActivity(intent);
}
}

为了直接下载，

Sample：

java代码：

public class zwebxiazai extends Activity {

WebView webView;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        this.webView=(WebView) this.findViewById(R.id.webview);
        this.webView.getSettings().setSupportZoom(false);
        this.webView.getSettings().setJavaScriptCanOpenWindowsAutomatically(true);
        this.webView.loadUrl("http://a.zntx.cc/");
        this.webView.setWebViewClient(new WebViewClientDemo());
        webView.setDownloadListener(new DownloadListener() {
            public void onDownloadStart(String url, String userAgent,
                            String contentDisposition, String mimetype,
                            long contentLength) {
                    //实现下载的代码
                                          Uri uri = Uri.parse(url);
           Intent intent = new Intent(Intent.ACTION_VIEW,uri);
                    startActivity(intent);
            }
    });

    }
  private class WebViewClientDemo extends WebViewClient {
    @Override
    // 在WebView中而不是默认浏览器中显示页面
    public boolean shouldOverrideUrlLoading(WebView view, String url) {
     view.loadUrl(url);
      return true;
     }

}
}

main.xml代码：

xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >
<TextView
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:text="@string/hello"
    />
<WebView android:id="@+id/webview" android:layout_width="fill_parent"
    android:layout_height="0dip" android:layout_weight="1" />

</LinearLayout>

在AndroidManifest.xml中增加訪问internet的权限：

<uses-permission android:name="android.permission.INTERNET"></uses-permission>

Sample2 这个比較具体

WebView控制调用对应的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。

原来是由于WebView默认没有开启文件下载的功能。假设要实现文件下载的功能。须要设置WebView的DownloadListener，通过实现自己的DownloadListener来实现文件的下载。详细操作例如以下：

1、设置WebView的DownloadListener：
webView.setDownloadListener(new MyWebViewDownLoadListener());

2、实现MyWebViewDownLoadListener这个类，详细能够例如以下这样：

Java代码

private class MyWebViewDownLoadListener implements DownloadListener{
@Override
public void onDownloadStart(String url, String userAgent, String contentDisposition, String mimetype,
long contentLength) {
Log.i("tag", "url="+url);
Log.i("tag", "userAgent="+userAgent);
Log.i("tag", "contentDisposition="+contentDisposition);
Log.i("tag", "mimetype="+mimetype);
Log.i("tag", "contentLength="+contentLength);
Uri uri = Uri.parse(url);
Intent intent = new Intent(Intent.ACTION_VIEW, uri);
startActivity(intent);
}
}

[java] view plaincopy

private class MyWebViewDownLoadListener implements DownloadListener{
@Override
public void onDownloadStart(String url, String userAgent, String contentDisposition, String mimetype,
long contentLength) {
Log.i("tag", "url="+url);
Log.i("tag", "userAgent="+userAgent);
Log.i("tag", "contentDisposition="+contentDisposition);
Log.i("tag", "mimetype="+mimetype);
Log.i("tag", "contentLength="+contentLength);
Uri uri = Uri.parse(url);
Intent intent = new Intent(Intent.ACTION_VIEW, uri);
startActivity(intent);
}
}

这仅仅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。只是，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，须要使用WebView载入一个网页。
2。网页中有文件下载的链接，点击后须要下载文件到SDcard；
3。然后自己主动打开文件；
以下是详细解决的方法
第一步。对WebView进行一系列设置。

Java代码

WebView webview=(WebView)layout.findViewById(R.id.webview);
webview.getSettings().setJavaScriptEnabled(true);
webview.setWebChromeClient(new MyWebChromeClient());
webview.requestFocus();
// webview.loadUrl("file:///android_asset/risktest.html");
webview.loadUrl(jcrs_sub.get(position).addr);
// 设置web视图client
webview.setWebViewClient(new MyWebViewClient());
webview.setDownloadListener(new MyWebViewDownLoadListener());
//内部类
public class MyWebViewClient extends WebViewClient {
// 假设页面中链接，假设希望点击链接继续在当前browser中响应，
// 而不是新开Android的系统browser中响应该链接，必须覆盖 webview的WebViewClient对象。
public boolean shouldOverviewUrlLoading(WebView view, String url) {
L.i("shouldOverviewUrlLoading");
view.loadUrl(url);
return true;
}
public void onPageStarted(WebView view, String url, Bitmap favicon) {
L.i("onPageStarted");
showProgress();
}
public void onPageFinished(WebView view, String url) {
L.i("onPageFinished");
closeProgress();
}
public void onReceivedError(WebView view, int errorCode,
String description, String failingUrl) {
L.i("onReceivedError");
closeProgress();
}
}
// 假设不做不论什么处理，浏览网页，点击系统“Back”键，整个Browser会调用finish()而结束自身。
// 假设希望浏览的网页回退而不是推出浏览器，须要在当前Activity中处理并消费掉该Back事件。
public boolean onKeyDown(int keyCode, KeyEvent event) {
// if((keyCode==KeyEvent.KEYCODE_BACK)&&webview.canGoBack()){
// webview.goBack();
// return true;
// }
return false;
}

[java] view plaincopy

WebView webview=(WebView)layout.findViewById(R.id.webview);
webview.getSettings().setJavaScriptEnabled(true);
webview.setWebChromeClient(new MyWebChromeClient());
webview.requestFocus();
// webview.loadUrl("file:///android_asset/risktest.html");
webview.loadUrl(jcrs_sub.get(position).addr);
// 设置web视图client
webview.setWebViewClient(new MyWebViewClient());
webview.setDownloadListener(new MyWebViewDownLoadListener());
//内部类
public class MyWebViewClient extends WebViewClient {
// 假设页面中链接，假设希望点击链接继续在当前browser中响应。
// 而不是新开Android的系统browser中响应该链接。必须覆盖 webview的WebViewClient对象。
public boolean shouldOverviewUrlLoading(WebView view, String url) {
L.i("shouldOverviewUrlLoading");
view.loadUrl(url);
return true;
}
public void onPageStarted(WebView view, String url, Bitmap favicon) {
L.i("onPageStarted");
showProgress();
}
public void onPageFinished(WebView view, String url) {
L.i("onPageFinished");
closeProgress();
}
public void onReceivedError(WebView view, int errorCode,
String description, String failingUrl) {
L.i("onReceivedError");
closeProgress();
}
}
// 假设不做不论什么处理，浏览网页，点击系统“Back”键，整个Browser会调用finish()而结束自身。
// 假设希望浏览的网页回退而不是推出浏览器，须要在当前Activity中处理并消费掉该Back事件。
public boolean onKeyDown(int keyCode, KeyEvent event) {
// if((keyCode==KeyEvent.KEYCODE_BACK)&&webview.canGoBack()){
// webview.goBack();
// return true;
// }
return false;
}

第二步。起线程開始下载文件。

Java代码

//内部类
private class MyWebViewDownLoadListener implements DownloadListener {
@Override
public void onDownloadStart(String url, String userAgent, String contentDisposition, String mimetype,
long contentLength) {
if(!Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)){
Toast t=Toast.makeText(mContext, "须要SD卡。", Toast.LENGTH_LONG);
t.setGravity(Gravity.CENTER, 0, 0);
t.show();
return;
}
DownloaderTask task=new DownloaderTask();
task.execute(url);
}
}
//内部类
private class DownloaderTask extends AsyncTask<String, Void, String> {
public DownloaderTask() {
}
@Override
protected String doInBackground(String... params) {
// TODO Auto-generated method stub
String url=params[0];
// Log.i("tag", "url="+url);
String fileName=url.substring(url.lastIndexOf("/")+1);
fileName=URLDecoder.decode(fileName);
Log.i("tag", "fileName="+fileName);
File directory=Environment.getExternalStorageDirectory();
File file=new File(directory,fileName);
if(file.exists()){
Log.i("tag", "The file has already exists.");
return fileName;
}
try {
HttpClient client = new DefaultHttpClient();
// client.getParams().setIntParameter("http.socket.timeout",3000);//设置超时
HttpGet get = new HttpGet(url);
HttpResponse response = client.execute(get);
if(HttpStatus.SC_OK==response.getStatusLine().getStatusCode()){
HttpEntity entity = response.getEntity();
InputStream input = entity.getContent();
writeToSDCard(fileName,input);
input.close();
// entity.consumeContent();
return fileName;
}else{
return null;
}
} catch (Exception e) {
e.printStackTrace();
return null;
}
}
@Override
protected void onCancelled() {
// TODO Auto-generated method stub
super.onCancelled();
}
@Override
protected void onPostExecute(String result) {
// TODO Auto-generated method stub
super.onPostExecute(result);
closeProgressDialog();
if(result==null){
Toast t=Toast.makeText(mContext, "连接错误！
请稍后再试！
", Toast.LENGTH_LONG);
t.setGravity(Gravity.CENTER, 0, 0);
t.show();
return;
}
Toast t=Toast.makeText(mContext, "已保存到SD卡。", Toast.LENGTH_LONG);
t.setGravity(Gravity.CENTER, 0, 0);
t.show();
File directory=Environment.getExternalStorageDirectory();
File file=new File(directory,result);
Log.i("tag", "Path="+file.getAbsolutePath());
Intent intent = getFileIntent(file);
startActivity(intent);
}
@Override
protected void onPreExecute() {
// TODO Auto-generated method stub
super.onPreExecute();
showProgressDialog();
}
@Override
protected void onProgressUpdate(Void... values) {
// TODO Auto-generated method stub
super.onProgressUpdate(values);
}
}

[java] view plaincopy

//内部类
private class MyWebViewDownLoadListener implements DownloadListener {
@Override
public void onDownloadStart(String url, String userAgent, String contentDisposition, String mimetype,
long contentLength) {
if(!Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)){
Toast t=Toast.makeText(mContext, "须要SD卡。", Toast.LENGTH_LONG);
t.setGravity(Gravity.CENTER, 0, 0);
t.show();
return;
}
DownloaderTask task=new DownloaderTask();
task.execute(url);
}
}
//内部类
private class DownloaderTask extends AsyncTask<String, Void, String> {
public DownloaderTask() {
}
@Override
protected String doInBackground(String... params) {
// TODO Auto-generated method stub
String url=params[0];
// Log.i("tag", "url="+url);
String fileName=url.substring(url.lastIndexOf("/")+1);
fileName=URLDecoder.decode(fileName);
Log.i("tag", "fileName="+fileName);
File directory=Environment.getExternalStorageDirectory();
File file=new File(directory,fileName);
if(file.exists()){
Log.i("tag", "The file has already exists.");
return fileName;
}
try {
HttpClient client = new DefaultHttpClient();
// client.getParams().setIntParameter("http.socket.timeout",3000);//设置超时
HttpGet get = new HttpGet(url);
HttpResponse response = client.execute(get);
if(HttpStatus.SC_OK==response.getStatusLine().getStatusCode()){
HttpEntity entity = response.getEntity();
InputStream input = entity.getContent();
writeToSDCard(fileName,input);
input.close();
// entity.consumeContent();
return fileName;
}else{
return null;
}
} catch (Exception e) {
e.printStackTrace();
return null;
}
}
@Override
protected void onCancelled() {
// TODO Auto-generated method stub
super.onCancelled();
}
@Override
protected void onPostExecute(String result) {
// TODO Auto-generated method stub
super.onPostExecute(result);
closeProgressDialog();
if(result==null){
Toast t=Toast.makeText(mContext, "连接错误。请稍后再试！", Toast.LENGTH_LONG);
t.setGravity(Gravity.CENTER, 0, 0);
t.show();
return;
}
Toast t=Toast.makeText(mContext, "已保存到SD卡。
", Toast.LENGTH_LONG);
t.setGravity(Gravity.CENTER, 0, 0);
t.show();
File directory=Environment.getExternalStorageDirectory();
File file=new File(directory,result);
Log.i("tag", "Path="+file.getAbsolutePath());
Intent intent = getFileIntent(file);
startActivity(intent);
}
@Override
protected void onPreExecute() {
// TODO Auto-generated method stub
super.onPreExecute();
showProgressDialog();
}
@Override
protected void onProgressUpdate(Void... values) {
// TODO Auto-generated method stub
super.onProgressUpdate(values);
}
}

第三步，实现一些工具方法。

Java代码

private ProgressDialog mDialog;
private void showProgressDialog(){
if(mDialog==null){
mDialog = new ProgressDialog(mContext);
mDialog.setProgressStyle(ProgressDialog.STYLE_SPINNER);//设置风格为圆形进度条
mDialog.setMessage("正在载入，请等待...");
mDialog.setIndeterminate(false);//设置进度条是否为不明白
mDialog.setCancelable(true);//设置进度条能否够按退回键取消
mDialog.setCanceledOnTouchOutside(false);
mDialog.setOnDismissListener(new OnDismissListener() {
@Override
public void onDismiss(DialogInterface dialog) {
// TODO Auto-generated method stub
mDialog=null;
}
});
mDialog.show();
}
}
private void closeProgressDialog(){
if(mDialog!=null){
mDialog.dismiss();
mDialog=null;
}
}
public Intent getFileIntent(File file){
// Uri uri = Uri.parse("http://m.ql18.com.cn/hpf10/1.pdf");
Uri uri = Uri.fromFile(file);
String type = getMIMEType(file);
Log.i("tag", "type="+type);
Intent intent = new Intent("android.intent.action.VIEW");
intent.addCategory("android.intent.category.DEFAULT");
intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
intent.setDataAndType(uri, type);
return intent;
}
public void writeToSDCard(String fileName,InputStream input){
if(Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)){
File directory=Environment.getExternalStorageDirectory();
File file=new File(directory,fileName);
// if(file.exists()){
// Log.i("tag", "The file has already exists.");
// return;
// }
try {
FileOutputStream fos = new FileOutputStream(file);
byte[] b = new byte[2048];
int j = 0;
while ((j = input.read(b)) != -1) {
fos.write(b, 0, j);
}
fos.flush();
fos.close();
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}else{
Log.i("tag", "NO SDCard.");
}
}
private String getMIMEType(File f){
String type="";
String fName=f.getName();
/* 取得扩展名 */
String end=fName.substring(fName.lastIndexOf(".")+1,fName.length()).toLowerCase();
/* 依扩展名的类型决定MimeType */
if(end.equals("pdf")){
type = "application/pdf";//
}
else if(end.equals("m4a")||end.equals("mp3")||end.equals("mid")||
end.equals("xmf")||end.equals("ogg")||end.equals("wav")){
type = "audio/*";
}
else if(end.equals("3gp")||end.equals("mp4")){
type = "video/*";
}
else if(end.equals("jpg")||end.equals("gif")||end.equals("png")||
end.equals("jpeg")||end.equals("bmp")){
type = "image/*";
}
else if(end.equals("apk")){
/* android.permission.INSTALL_PACKAGES */
type = "application/vnd.android.package-archive";
}
// else if(end.equals("pptx")||end.equals("ppt")){
// type = "application/vnd.ms-powerpoint";
// }else if(end.equals("docx")||end.equals("doc")){
// type = "application/vnd.ms-word";
// }else if(end.equals("xlsx")||end.equals("xls")){
// type = "application/vnd.ms-excel";
// }
else{
// /*假设无法直接打开，就跳出软件列表给用户选择 */
type="*/*";
}
return type;
}

安卓使用WebView下载文件，安卓实现软件升级功能

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安卓使用WebView下载文件，安卓实现软件升级功能

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