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问题:

I'm trying to build web project using android, from webview. I have a input field of type file <input type="file" > to let user upload files to server, but it seem not to work on android webview, when I tap on the browse button, nothing happens.

Comp.java

package com.gururaju.bbmp;

import android.app.Activity;
import android.os.Bundle;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import android.webkit.WebChromeClient;

public class Comp extends Activity {
    WebView comp;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_comp);

        WebView myWebView = (WebView) findViewById(R.id.comp);
        myWebView.setWebChromeClient(new WebChromeClient());
        myWebView.loadUrl("file:///android_asset/comp.html");

    }
}

activity_comp.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="match_parent"
    android:layout_height="match_parent">

    <WebView
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:id="@+id/comp"
        >

        </WebView>
</LinearLayout>

comp.html (in assets folder)

<!DOCTYPE html>
<html lang="en">
<head>
    <link rel="stylesheet" type="text/css" href="comp.css">
    <meta charset="UTF-8">
    <title></title>
</head>
<body>
    <h2 align="center">Post your Complaints here</h2>
    <form enctype="multipart/form-data" action="" name="complaints" method="POST">
        <input class="title" type="text" name="title" placeholder="Enter the Complaint Title" /><br />

        <div class="spacer-welcome"></div>
        <textarea name="desc" class="desc" placeholder="Your complaint description here..."></textarea><br />
        <div class="spacer-welcome1"></div>

            <input id="center" type="file" name="image" ><br />
        <input class="upload" type="submit" name="submit" value="Submit" >
    </form>
</body>
</html>

Any help would be appreciated.

回答1:

The answer by Riad points into the right direction, but that single callback is not enough to implement.

There are, in total, four hidden API methods that you have to implement. Their usage depends on the Android version. These methods are:

public void openFileChooser(ValueCallback<Uri> uploadMsg)
public void openFileChooser(ValueCallback<Uri> uploadMsg, String acceptType)
public void openFileChooser(ValueCallback<Uri> uploadMsg, String acceptType, String capture)
public boolean onShowFileChooser(WebView webView, ValueCallback<Uri[]> filePathCallback, WebChromeClient.FileChooserParams fileChooserParams)

You can use the following library which does all these things for you:

https://github.com/delight-im/Android-AdvancedWebView

Alternatively, you may take a look at the source code to see how it's done:

https://github.com/delight-im/Android-AdvancedWebView/blob/master/Source/src/im/delight/android/webview/AdvancedWebView.java

回答2:

Webview class alone does not support file upload on facebook. You need to use both web chrome client and webview client to handle file upload on your android application as shown below. View more details and a working demo

package com.whatsonline.androidphotouploadonfacebook;

import android.app.Activity;
import android.content.ActivityNotFoundException;
import android.content.Intent;
import android.content.res.Configuration;
import android.graphics.Bitmap;
import android.net.Uri;
import android.os.Bundle;
import android.view.ViewGroup;
import android.webkit.ValueCallback;
import android.webkit.WebChromeClient;
import android.webkit.WebSettings;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import android.widget.LinearLayout;

/**
 * Created by sada on 6/17/2016.
 */
public class upload extends Activity {

    WebView web;
    private ValueCallback<Uri> mUploadMessage;
    private final static int FILECHOOSER_RESULTCODE=1;
    LinearLayout ln1;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.upload);

        web = new WebView(this);
        web.setLayoutParams(new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.FILL_PARENT));

        ln1=(LinearLayout) findViewById(R.id.ln1);

        WebSettings settings=web.getSettings();
        settings.setJavaScriptEnabled(true);


        web.loadUrl("http://www.facebook.com");
        web.setWebViewClient(new myWebClient());

        web.setWebChromeClient(new WebChromeClient() {
            //The undocumented magic method override
            //Eclipse will swear at you if you try to put @Override here
            // For Android 3.0+
            public void openFileChooser(ValueCallback<Uri> uploadMsg) {

                mUploadMessage = uploadMsg;
                Intent i = new Intent(Intent.ACTION_GET_CONTENT);
                i.addCategory(Intent.CATEGORY_OPENABLE);
                i.setType("image/*");
                upload.this.startActivityForResult(Intent.createChooser(i, "File Chooser"), FILECHOOSER_RESULTCODE);

            }

            // For Android 3.0+
            public void openFileChooser(ValueCallback uploadMsg, String acceptType) {
                mUploadMessage = uploadMsg;
                Intent i = new Intent(Intent.ACTION_GET_CONTENT);
                i.addCategory(Intent.CATEGORY_OPENABLE);
                i.setType("*/*");
                upload.this.startActivityForResult(
                        Intent.createChooser(i, "File Browser"),
                        FILECHOOSER_RESULTCODE);
            }

            //For Android 4.1
            public void openFileChooser(ValueCallback<Uri> uploadMsg, String acceptType, String capture) {
                mUploadMessage = uploadMsg;
                Intent i = new Intent(Intent.ACTION_GET_CONTENT);
                i.addCategory(Intent.CATEGORY_OPENABLE);
                i.setType("image/*");
                upload.this.startActivityForResult(Intent.createChooser(i, "File Chooser"), upload.FILECHOOSER_RESULTCODE);

            }

          });
        ln1.addView(web);
    }
    public class myWebClient extends WebViewClient
    {
        @Override

        public void onPageStarted(WebView view, String url, Bitmap favicon) {
            super.onPageStarted(view, url, favicon);

        }

        @Override

        public boolean shouldOverrideUrlLoading(WebView view, String url) {
            view.loadUrl(url);
            return true;
        }

        @Override
        public void onPageFinished(WebView view, String url) {
            super.onPageFinished(view, url);
        }
    }

    //flipscreen not loading again
    @Override
    public void onConfigurationChanged(Configuration newConfig){
        super.onConfigurationChanged(newConfig);
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent intent) {

        if(requestCode==FILECHOOSER_RESULTCODE){
            if (null == mUploadMessage) return;
            Uri result = intent == null || resultCode != RESULT_OK ? null : intent.getData();
            mUploadMessage.onReceiveValue(result);
            mUploadMessage = null;

        }
   }
    }

回答3:

Try implementing the file Chooser method like this, as mentioned in the article link provided at the end:

webView.setWebChromeClient(new WebChromeClient() {

   // openFileChooser for Android 3.0+

    public void openFileChooser(ValueCallback<Uri> uploadMsg, String acceptType){ 

     // Update message
     mUploadMessage = uploadMsg;

     try{  
         // do work....

     }catch(Exception e){

          Toast.makeText(getBaseContext(), "Exception:"+e,
          Toast.LENGTH_LONG).show();
     }
}

View Details Here