默认情况下，Android的WebView不支持文件上传，需要手动适配，原理就是获取到选择文件的uri,然后传给页面去上传。

做的时候遇到不少坑，这里记录一下。

效果截图：

在小米上：

在原生上：

public class SelectFileWebClient extends WebChromeClient {
    private static final int REQUEST_FILE_PICKER = 1;
    private final Activity mActivity;
    private ValueCallback<Uri> mFilePathCallback4;
    private ValueCallback<Uri[]> mFilePathCallback5;


    public SelectFileWebClient(Activity activity) {

        this.mActivity = activity;
    }



    public void openFileChooser(ValueCallback<Uri> filePathCallback)
    {
        mFilePathCallback4 = filePathCallback;
        Intent intent = new Intent(Intent.ACTION_GET_CONTENT);
        intent.addCategory(Intent.CATEGORY_OPENABLE);
        intent.setType("*/*");
        mActivity.startActivityForResult(Intent.createChooser(intent, "File Chooser"), REQUEST_FILE_PICKER);
    }

    public void openFileChooser(ValueCallback filePathCallback, String acceptType)
    {
        mFilePathCallback4 = filePathCallback;
        Intent intent = new Intent(Intent.ACTION_GET_CONTENT);
        intent.addCategory(Intent.CATEGORY_OPENABLE);
        intent.setType("*/*");
        mActivity.startActivityForResult(Intent.createChooser(intent, "File Chooser"), REQUEST_FILE_PICKER);
    }

    public void openFileChooser(ValueCallback<Uri> filePathCallback, String acceptType, String capture)
    {
        mFilePathCallback4 = filePathCallback;
        Intent intent = new Intent(Intent.ACTION_GET_CONTENT);
        intent.addCategory(Intent.CATEGORY_OPENABLE);
        intent.setType("*/*");
        mActivity.startActivityForResult(Intent.createChooser(intent, "File Chooser"), REQUEST_FILE_PICKER);
    }

    //5.0+
    @Override
    public boolean onShowFileChooser(WebView webView, ValueCallback<Uri[]> filePathCallback, WebChromeClient.FileChooserParams fileChooserParams)
    {
        mFilePathCallback5 = filePathCallback;
        Intent intent = new Intent(Intent.ACTION_GET_CONTENT);
        intent.addCategory(Intent.CATEGORY_OPENABLE);
        intent.setType("*/*");
        mActivity.startActivityForResult(Intent.createChooser(intent, "File Chooser"), REQUEST_FILE_PICKER);
        return true;
    }

//外部在Activity的onActivityResult 调用
    public  void onActivityResult(int requestCode, int resultCode, Intent intent){
        if(requestCode==REQUEST_FILE_PICKER){
            if(mFilePathCallback4!=null)
            {
                Uri result = intent==null || resultCode!= Activity.RESULT_OK ? null : intent.getData();
                if(result!=null)
                {
                    mFilePathCallback4.onReceiveValue(result);
                }
                else
                {
                    mFilePathCallback4.onReceiveValue(null);
                }
            }
            if(mFilePathCallback5!=null)
            {
                Uri result = intent==null || resultCode!=Activity.RESULT_OK ? null : intent.getData();
                if(result!=null)
                {
                    mFilePathCallback5.onReceiveValue(new Uri[]{ result });
                }
                else
                {
                    mFilePathCallback5.onReceiveValue(null);
                }
            }
            mFilePathCallback4 = null;
            mFilePathCallback5 = null;
        }
        }

}

Activity中

 mWebView.setWebChromeClient(new SelectFileWebClient())

@Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if(mSelectFileWebClient!=null){
            mSelectFileWebClient.onActivityResult(requestCode,resultCode,data);
        }
    }

当然这只能打开file文件，如果想调用相机、录音的功能就需要另外来做

public class SelectFileWebClient extends WebChromeClient {
    private static final int REQUEST_FILE_PICKER = 1;
    private final Activity mActivity;
    private ValueCallback<Uri> mFilePathCallback4;
    private ValueCallback<Uri[]> mFilePathCallback5;


    public SelectFileWebClient(Activity activity) {

        this.mActivity = activity;
    }


     // For Android 3.0+
     public void openFileChooser(ValueCallback<Uri> uploadMsg, String acceptType) {  
                if (mUploadMessage != null) return;
                mUploadMessage = uploadMsg;
                startActivityForResult(createDefaultOpenableIntent(),
                        BrowserActivity.FILECHOOSER_RESULTCODE);
            }
        }
             // For Android < 3.0
    public void openFileChooser(ValueCallback<Uri> uploadMsg) {
                openFileChooser( uploadMsg, "" );
         }


    private Intent createDefaultOpenableIntent() {
           // Create and return a chooser with the default OPENABLE
           // actions including the camera, camcorder and sound
           // recorder where available.
             Intent i = new Intent(Intent.ACTION_GET_CONTENT);
             i.addCategory(Intent.CATEGORY_OPENABLE);
             i.setType("*/*");

             Intent chooser = createChooserIntent(createCameraIntent(), createCamcorderIntent(),
                    createSoundRecorderIntent());
            chooser.putExtra(Intent.EXTRA_INTENT, i);
            return chooser;
        }

        private Intent createChooserIntent(Intent... intents) {
            Intent chooser = new Intent(Intent.ACTION_CHOOSER);
            chooser.putExtra(Intent.EXTRA_INITIAL_INTENTS, intents);
            chooser.putExtra(Intent.EXTRA_TITLE, "File Chooser");
           return chooser;
          }

    private Intent createCameraIntent() {
          Intent cameraIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
          File externalDataDir = Environment.getExternalStoragePublicDirectory(
                    Environment.DIRECTORY_DCIM);
          File cameraDataDir = new File(externalDataDir.getAbsolutePath() +
                    File.separator + "browser-photos");
          cameraDataDir.mkdirs();
          String mCameraFilePath = cameraDataDir.getAbsolutePath() + File.separator +
                    System.currentTimeMillis() + ".jpg";
          cameraIntent.putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(new File(mCameraFilePath)));
          return cameraIntent;
        }

    private Intent createCamcorderIntent() {
         return new Intent(MediaStore.ACTION_VIDEO_CAPTURE);
        }

    private Intent createSoundRecorderIntent() {
         return new Intent(MediaStore.Audio.Media.RECORD_SOUND_ACTION);
        }

//外部在Activity的onActivityResult 调用
    public  void onActivityResult(int requestCode, int resultCode, Intent intent){
        if(requestCode==REQUEST_FILE_PICKER){

            if (null == mUploadMessage) return;  
                        Uri result = data == null || resultCode != RESULT_OK ? null  
                                : data.getData();
                            if (result == null && data == null && resultCode == Activity.RESULT_OK) {
                            File cameraFile = new File(mCameraFilePath);
                            if (cameraFile.exists()) {
                                result = Uri.fromFile(cameraFile);
                                // Broadcast to the media scanner that we have a new photo
                                // so it will be added into the gallery for the user.
                                sendBroadcast(
                                        new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE, result));
                                    }
                             }
                        mUploadMessage.onReceiveValue(result);  
                        mUploadMessage = null;
              }

        }
        }
}

Activity中

    mWebView.setWebChromeClient(new SelectFileWebClient())

@Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if(mSelectFileWebClient!=null){
            mSelectFileWebClient.onActivityResult(requestCode,resultCode,data);
        }
    }