针对Webview 支持上传本地图片情况，查询大量资料后发现对版本4.4兼容没有现成的解决方案，目前根据现有开源源码做个修改，可以支持兼容支持4.4版本上传图片：

具体是在onActivityResult 里多加了层判断：

 /*
                        * 若当前版本API为19, 则把Uri路径转换成new File性质的Uri路径
                        * 若非 则按照之前方法调用即可
                        * */
                        if (Build.VERSION.SDK_INT == 19) {
                           
                            String realPathFromURI = getRealPathFromURI(intent.getData());
                            File file = new File(realPathFromURI);
                           if(file.exists()){
                               Uri uri = Uri.fromFile(file);
                               mFileUploadCallbackFirst.onReceiveValue(uri);
                           }

                        } else {
                            mFileUploadCallbackFirst.onReceiveValue(intent.getData());
                        }

  /*
    * 
    * 获取Uri图片真实路径的方法
    * */
    public String getRealPathFromURI(Uri contentUri) {
        String res = null;
        String[] proj = {MediaStore.Images.Media.DATA};
        Cursor cursor = mContext.getContentResolver().query(contentUri, proj, null, null, null);
        if (cursor.moveToFirst()) {
            int column_index = cursor.getColumnIndexOrThrow(MediaStore.Images.Media.DATA);
            res = cursor.getString(column_index);
        }
        cursor.close();
        return res;
    }

修改源码后的所有代码 如下：

import android.annotation.SuppressLint;
import android.app.Activity;
import android.app.DownloadManager;
import android.app.Fragment;
import android.content.Context;
import android.content.Intent;
import android.content.pm.ApplicationInfo;
import android.content.pm.PackageManager;
import android.database.Cursor;
import android.graphics.Bitmap;
import android.net.Uri;
import android.net.http.SslError;
import android.os.Build;
import android.os.Environment;
import android.os.Message;
import android.provider.MediaStore;
import android.util.AttributeSet;
import android.util.Base64;
import android.view.InputEvent;
import android.view.KeyEvent;
import android.view.View;
import android.view.ViewGroup;
import android.webkit.ClientCertRequest;
import android.webkit.ConsoleMessage;
import android.webkit.CookieManager;
import android.webkit.DownloadListener;
import android.webkit.GeolocationPermissions;
import android.webkit.HttpAuthHandler;
import android.webkit.JsPromptResult;
import android.webkit.JsResult;
import android.webkit.PermissionRequest;
import android.webkit.SslErrorHandler;
import android.webkit.URLUtil;
import android.webkit.ValueCallback;
import android.webkit.WebChromeClient;
import android.webkit.WebResourceRequest;
import android.webkit.WebResourceResponse;
import android.webkit.WebSettings;
import android.webkit.WebStorage;
import android.webkit.WebView;
import android.webkit.WebViewClient;


import java.io.File;
import java.io.UnsupportedEncodingException;
import java.lang.ref.WeakReference;
import java.util.Arrays;
import java.util.Collection;
import java.util.HashMap;
import java.util.LinkedList;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.MissingResourceException;

/*
 * Android-AdvancedWebView (https://github.com/delight-im/Android-AdvancedWebView)
 * Copyright (c) delight.im (https://www.delight.im/)
 * Licensed under the MIT License (https://opensource.org/licenses/MIT)
 */

/**
 * Advanced WebView component for Android that works as intended out of the box
 */
@SuppressWarnings("deprecation")
public class MyWebView extends WebView {

    private Context mContext;

    public interface Listener {
        void onPageStarted(String url, Bitmap favicon);

        void onPageFinished(String url);

        void onPageError(int errorCode, String description, String failingUrl);

        void onDownloadRequested(String url, String suggestedFilename, String mimeType, long contentLength, String contentDisposition, String userAgent);

        void onExternalPageRequest(String url);
    }

    public static final String PACKAGE_NAME_DOWNLOAD_MANAGER = "com.android.providers.downloads";
    protected static final int REQUEST_CODE_FILE_PICKER = 51426;
    protected static final String DATABASES_SUB_FOLDER = "/databases";
    protected static final String LANGUAGE_DEFAULT_ISO3 = "eng";
    protected static final String CHARSET_DEFAULT = "UTF-8";
    /**
     * Alternative browsers that have their own rendering engine and *may* be installed on this device
     */
    protected static final String[] ALTERNATIVE_BROWSERS = new String[]{"org.mozilla.firefox", "com.android.chrome", "com.opera.browser", "org.mozilla.firefox_beta", "com.chrome.beta", "com.opera.browser.beta"};
    protected WeakReference<Activity> mActivity;
    protected WeakReference<Fragment> mFragment;
    protected Listener mListener;
    protected final List<String> mPermittedHostnames = new LinkedList<String>();
    /**
     * File upload callback for platform versions prior to Android 5.0
     */
    protected ValueCallback<Uri> mFileUploadCallbackFirst;
    /**
     * File upload callback for Android 5.0+
     */
    protected ValueCallback<Uri[]> mFileUploadCallbackSecond;
    protected long mLastError;
    protected String mLanguageIso3;
    protected int mRequestCodeFilePicker = REQUEST_CODE_FILE_PICKER;
    protected WebViewClient mCustomWebViewClient;
    protected WebChromeClient mCustomWebChromeClient;
    protected boolean mGeolocationEnabled;
    protected String mUploadableFileTypes = "*/*";
    protected final Map<String, String> mHttpHeaders = new HashMap<String, String>();

    public MyWebView(Context context) {
        super(context);
        init(context);
    }

    public MyWebView(Context context, AttributeSet attrs) {
        super(context, attrs);
        init(context);
    }

    public MyWebView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        init(context);
    }

    public void setListener(final Activity activity, final Listener listener) {
        setListener(activity, listener, REQUEST_CODE_FILE_PICKER);
    }

    public void setListener(final Activity activity, final Listener listener, final int requestCodeFilePicker) {
        if (activity != null) {
            mActivity = new WeakReference<Activity>(activity);
        } else {
            mActivity = null;
        }

        setListener(listener, requestCodeFilePicker);
    }

    public void setListener(final Fragment fragment, final Listener listener) {
        setListener(fragment, listener, REQUEST_CODE_FILE_PICKER);
    }

    public void setListener(final Fragment fragment, final Listener listener, final int requestCodeFilePicker) {
        if (fragment != null) {
            mFragment = new WeakReference<Fragment>(fragment);
        } else {
            mFragment = null;
        }

        setListener(listener, requestCodeFilePicker);
    }

    protected void setListener(final Listener listener, final int requestCodeFilePicker) {
        mListener = listener;
        mRequestCodeFilePicker = requestCodeFilePicker;
    }

    @Override
    public void setWebViewClient(final WebViewClient client) {
        mCustomWebViewClient = client;
    }

    @Override
    public void setWebChromeClient(final WebChromeClient client) {
        mCustomWebChromeClient = client;
    }

    @SuppressLint("SetJavaScriptEnabled")
    public void setGeolocationEnabled(final boolean enabled) {
        if (enabled) {
            getSettings().setJavaScriptEnabled(true);
            getSettings().setGeolocationEnabled(true);
            setGeolocationDatabasePath();
        }

        mGeolocationEnabled = enabled;
    }

    @SuppressLint("NewApi")
    protected void setGeolocationDatabasePath() {
        final Activity activity;

        if (mFragment != null && mFragment.get() != null && Build.VERSION.SDK_INT >= 11 && mFragment.get().getActivity() != null) {
            activity = mFragment.get().getActivity();
        } else if (mActivity != null && mActivity.get() != null) {
            activity = mActivity.get();
        } else {
            return;
        }

        getSettings().setGeolocationDatabasePath(activity.getFilesDir().getPath());
    }

    public void setUploadableFileTypes(final String mimeType) {
        mUploadableFileTypes = mimeType;
    }

    /**
     * Loads and displays the provided HTML source text
     *
     * @param html the HTML source text to load
     */
    public void loadHtml(final String html) {
        loadHtml(html, null);
    }

    /**
     * Loads and displays the provided HTML source text
     *
     * @param html    the HTML source text to load
     * @param baseUrl the URL to use as the page's base URL
     */
    public void loadHtml(final String html, final String baseUrl) {
        loadHtml(html, baseUrl, null);
    }

    /**
     * Loads and displays the provided HTML source text
     *
     * @param html       the HTML source text to load
     * @param baseUrl    the URL to use as the page's base URL
     * @param historyUrl the URL to use for the page's history entry
     */
    public void loadHtml(final String html, final String baseUrl, final String historyUrl) {
        loadHtml(html, baseUrl, historyUrl, "utf-8");
    }

    /**
     * Loads and displays the provided HTML source text
     *
     * @param html       the HTML source text to load
     * @param baseUrl    the URL to use as the page's base URL
     * @param historyUrl the URL to use for the page's history entry
     * @param encoding   the encoding or charset of the HTML source text
     */
    public void loadHtml(final String html, final String baseUrl, final String historyUrl, final String encoding) {
        loadDataWithBaseURL(baseUrl, html, "text/html", encoding, historyUrl);
    }

    @SuppressLint("NewApi")
    @SuppressWarnings("all")
    public void onResume() {
        if (Build.VERSION.SDK_INT >= 11) {
            super.onResume();
        }
        resumeTimers();
    }

    @SuppressLint("NewApi")
    @SuppressWarnings("all")
    public void onPause() {
        pauseTimers();
        if (Build.VERSION.SDK_INT >= 11) {
            super.onPause();
        }
    }

    public void onDestroy() {
        // try to remove this view from its parent first
        try {
            ((ViewGroup) getParent()).removeView(this);
        } catch (Exception ignored) {
        }

        // then try to remove all child views from this view
        try {
            removeAllViews();
        } catch (Exception ignored) {
        }

        // and finally destroy this view
        destroy();
    }

    public void onActivityResult(final int requestCode, final int resultCode, final Intent intent) {
        if (requestCode == mRequestCodeFilePicker) {
            if (resultCode == Act