WebView进度栏仅在页面加载时显示第一次。如何每次设置？

Question

我已经尝试过此代码，但是其进度栏仅在第一次使用时有效：

import android.annotation.SuppressLint;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.content.res.ColorStateList;
import android.graphics.Bitmap;
import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.design.widget.NavigationView;
import android.support.v4.widget.DrawerLayout;
import android.support.v4.widget.SwipeRefreshLayout;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.app.AppCompatActivity;
import android.view.MenuItem;
import android.view.View;
import android.webkit.WebChromeClient;
import android.webkit.WebSettings;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import android.view.KeyEvent;
import android.widget.ProgressBar;


public class MainActivity extends AppCompatActivity {
    public WebView webView;
    private DrawerLayout dl;
    private ActionBarDrawerToggle t;
    private NavigationView nv;
    SwipeRefreshLayout mySwipeRefreshLayout;
    ProgressBar progressBar;
    @SuppressLint("ResourceAsColor")
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        if (savedInstanceState != null) {
            webView.restoreState(savedInstanceState);
        }

        setContentView(R.layout.activity_main);

        mySwipeRefreshLayout = this.findViewById(R.id.swipeContainer);
        progressBar = (ProgressBar) findViewById(R.id.awv_progressBar);
        progressBar.setMax(100);
        progressBar.setProgress(1);
        webView = findViewById(R.id.wv);

        dl = (DrawerLayout)findViewById(R.id.activity_main);
        t = new ActionBarDrawerToggle(this, dl,R.string.Open, R.string.Close);

        dl.addDrawerListener(t);
        t.syncState();

        getSupportActionBar().setDisplayHomeAsUpEnabled(true);

        nv = findViewById(R.id.nv);
        nv.setItemTextColor(ColorStateList.valueOf(R.color.colorPrimary));
        nv.setNavigationItemSelectedListener(new NavigationView.OnNavigationItemSelectedListener() {
            @Override
            public boolean onNavigationItemSelected(@NonNull MenuItem item) {
                int id = item.getItemId();
                switch(id)
                {
                    case R.id.home:
                        webView.loadUrl("https://uniqueby.com");
                        dl.closeDrawers();
                        break;
                    case R.id.products:
                        webView.loadUrl("https://uniqueby.com/collection/hot-deals-today");
                        dl.closeDrawers();
                        break;
                    case R.id.myaccount:
                        webView.loadUrl("https://uniqueby.com/my-account");
                        dl.closeDrawers();
                        break;
                    default:
                        return true;
                }


                return true;

            }
        });



        init();
        mySwipeRefreshLayout.setOnRefreshListener(
                new SwipeRefreshLayout.OnRefreshListener() {
                    @Override
                    public void onRefresh() {
                        webView.reload();

                        if (null != mySwipeRefreshLayout) {
                            mySwipeRefreshLayout.setRefreshing(false);
                        }
                    }
                }
        );

    }

    @SuppressLint("SetJavaScriptEnabled")
    public void init() {
        webView.getSettings().setJavaScriptEnabled(true);
        webView.getSettings().setCacheMode(WebSettings.LOAD_CACHE_ELSE_NETWORK);
        webView.getSettings().setAppCacheEnabled(true);
        webView.getSettings().setCacheMode(WebSettings.LOAD_DEFAULT);
        webView.getSettings().setDomStorageEnabled(true);
        webView.getSettings().setDatabaseEnabled(true);
        webView.getSettings().setGeolocationEnabled(true);
        webView.getSettings().setSupportZoom(true);
        webView.getSettings().setBuiltInZoomControls(false);
        //webview.setScrollBarStyle(0);
        webView.setWebViewClient(new WebViewClient() {
            @Override
            public boolean shouldOverrideUrlLoading(WebView view, String url) {
                view.loadUrl(url);
                return true;
            }
        });
        webView.setWebChromeClient(new WebChromeClient() {
            public void onProgressChanged(WebView view, int progress) {

                progressBar.setProgress(progress);
            }
        });
        webView.setWebViewClient(new WebViewClient() {
            @Override
            public void onPageStarted(WebView view, String url, Bitmap favicon) {
                super.onPageStarted(view, url, favicon);
                if (progressBar == null) {
                    progressBar.setVisibility(View.VISIBLE);}
            }

            public void onLoadResource(WebView view, String url) { //Doesn't work
                //swipe.setRefreshing(true);
            }

            public void onPageFinished(WebView view, String url) {

                //Hide the SwipeReefreshLayout
                progressBar.setVisibility(View.GONE);
            }

        });
        webView.loadUrl("https://google.com");

    }

    public boolean onKeyDown(int keyCode, KeyEvent event) {
        if ((keyCode == KeyEvent.KEYCODE_BACK) && webView.canGoBack()) {
            webView.goBack();
            return true;
        } else if (keyCode == KeyEvent.KEYCODE_BACK) {
            ConfirmExit();
            return true;
        }
        return super.onKeyDown(keyCode, event);
    }

    public void ConfirmExit() {
        AlertDialog.Builder ad = new AlertDialog.Builder(MainActivity.this);
        ad.setTitle("Stop");
        ad.setMessage("Do you really want to quit?");
        ad.setPositiveButton("Yes", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int i) {
                MainActivity.this.finish();

            }
        });
        ad.setNegativeButton("No", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int i) {

            }
        });
        ad.show();
    }
    @Override
    public void onBackPressed() {

        if (webView.canGoBack()) {
            webView.goBack();
        } else {
            finish();
        }

    }
    @Override
    public boolean onOptionsItemSelected(MenuItem item) {

        if(t.onOptionsItemSelected(item))
            return true;

        return super.onOptionsItemSelected(item);
    }
}


<?xml version="1.0" encoding="UTF-8"?>
<android.support.v4.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:id="@+id/activity_main"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:orientation="vertical">

    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_marginTop="17dp"
        android:layout_height="wrap_content">
        <ProgressBar
            android:id="@+id/awv_progressBar"
            style="?android:attr/progressBarStyleHorizontal"
            android:layout_width="match_parent"
            android:layout_height="15dp"
            android:indeterminate="true" />
    </LinearLayout>
    <android.support.v4.widget.SwipeRefreshLayout
        android:id="@+id/swipeContainer"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:layout_behavior="@string/appbar_scrolling_view_behavior">

        <android.support.v4.widget.NestedScrollView
            android:layout_width="match_parent"
            android:layout_height="match_parent">
    <WebView
        android:id="@+id/wv"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

    </android.support.v4.widget.NestedScrollView>
</android.support.v4.widget.SwipeRefreshLayout>
    <android.support.design.widget.NavigationView
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        app:menu="@menu/navigation_menu"
        android:layout_gravity="start"
        app:headerLayout="@layout/nav_header"
        android:id="@+id/nv">

    </android.support.design.widget.NavigationView>
</android.support.v4.widget.DrawerLayout>

Answer 1

XML :

<?xml version="1.0" encoding="UTF-8"?>
<android.support.v4.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:id="@+id/activity_main"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:orientation="vertical">

    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_marginTop="17dp"
        android:layout_height="wrap_content"
        android:orientation="vertical">
        <ProgressBar
            android:id="@+id/awv_progressBar"
            style="?android:attr/progressBarStyleHorizontal"
            android:layout_width="match_parent"
            android:layout_height="15dp"
            android:indeterminate="true" />
        <android.support.v4.widget.SwipeRefreshLayout
            android:id="@+id/swipeContainer"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            >

            <android.support.v4.widget.NestedScrollView
                android:layout_width="match_parent"
                android:layout_height="match_parent">
                <WebView
                    android:id="@+id/wv"
                    android:layout_width="match_parent"
                    android:layout_height="match_parent" />

            </android.support.v4.widget.NestedScrollView>
        </android.support.v4.widget.SwipeRefreshLayout>
    </LinearLayout>

    <android.support.design.widget.NavigationView
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        app:menu="@menu/navigation_menu"
        android:layout_gravity="start"
        app:headerLayout="@layout/nav_header"
        android:id="@+id/nv">

    </android.support.design.widget.NavigationView>
</android.support.v4.widget.DrawerLayout>

ACTIVITY CODE UPDATE:

webView.setWebViewClient(new WebViewClient() {
            @Override
            public void onPageStarted(WebView view, String url, Bitmap favicon) {
                super.onPageStarted(view, url, favicon);
               // if (progressBar == null) {
                    progressBar.setVisibility(View.VISIBLE);
            }

            public void onLoadResource(WebView view, String url) { //Doesn't work
                //swipe.setRefreshing(true);
            }

            public void onPageFinished(WebView view, String url) {

                //Hide the SwipeReefreshLayout
                progressBar.setVisibility(View.GONE);
            }

        });