项目中用到WebView加上进度条放在顶部，让用户知道加载进度情况，可以提高用户体验：
效果：

下面我们来实现这个效果：

自定义ProgressWebView 继承WebView

1. 创建WebChromeClient 继承WebChromeClie

public class WebChromeClient extends android.webkit.WebChromeClient {
        @Override
        public void onProgressChanged(WebView view, int newProgress) {
            if (newProgress == 100) {
                mProgressBar.setVisibility(GONE);
            } else {
                if (mProgressBar.getVisibility() == GONE)
                    mProgressBar.setVisibility(VISIBLE);
                mProgressBar.setProgress(newProgress);
            }
            super.onProgressChanged(view, newProgress);
        }
    }

2. 重新onScrollChanged

@Override
    protected void onScrollChanged(int l, int t, int oldl, int oldt) {
        LayoutParams lp = (LayoutParams) mProgressBar.getLayoutParams();
        lp.x = l;
        lp.y = t;
        mProgressBar.setLayoutParams(lp);
        super.onScrollChanged(l, t, oldl, oldt);
    }

3. 构造方法

public ProgressWebView(Context context, AttributeSet attrs) {
        super(context, attrs);
        mProgressBar = new ProgressBar(context, null,
                android.R.attr.progressBarStyleHorizontal);
        LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(
                LinearLayout.LayoutParams.MATCH_PARENT, 8);
        mProgressBar.setLayoutParams(layoutParams);

        Drawable drawable = context.getResources().getDrawable(
                R.drawable.web_progress_bar_states);
        mProgressBar.setProgressDrawable(drawable);
        addView(mProgressBar);
        setWebChromeClient(new WebChromeClient());
    }

完整ProgressWebView类代码 ：

public class ProgressWebView extends WebView {
    private ProgressBar mProgressBar;

    public ProgressWebView(Context context, AttributeSet attrs) {
        super(context, attrs);
        mProgressBar = new ProgressBar(context, null,
                android.R.attr.progressBarStyleHorizontal);
        LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(
                LinearLayout.LayoutParams.MATCH_PARENT, 8);
        mProgressBar.setLayoutParams(layoutParams);

        Drawable drawable = context.getResources().getDrawable(
                R.drawable.web_progress_bar_states);
        mProgressBar.setProgressDrawable(drawable);
        addView(mProgressBar);
        setWebChromeClient(new WebChromeClient());
    }

    public class WebChromeClient extends android.webkit.WebChromeClient {
        @Override
        public void onProgressChanged(WebView view, int newProgress) {
            if (newProgress == 100) {
                mProgressBar.setVisibility(GONE);
            } else {
                if (mProgressBar.getVisibility() == GONE)
                    mProgressBar.setVisibility(VISIBLE);
                mProgressBar.setProgress(newProgress);
            }
            super.onProgressChanged(view, newProgress);
        }
    }

    @Override
    protected void onScrollChanged(int l, int t, int oldl, int oldt) {
        LayoutParams lp = (LayoutParams) mProgressBar.getLayoutParams();
        lp.x = l;
        lp.y = t;
        mProgressBar.setLayoutParams(lp);
        super.onScrollChanged(l, t, oldl, oldt);
    }
}

如何使用

1. xml布局引用

<com.aikaifa.webview.ProgressWebView
        android:id="@+id/baseweb_webview"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

其中com.aikaifa.webview 为包名，你可以改成你自己的包名

2. 找到ProgressWebView控件

  mWebView = (ProgressWebView) findViewById(R.id.baseweb_webview);
        mWebView.getSettings().setJavaScriptEnabled(true);
                mWebView.setWebViewClient(new WebViewClient(){
            @Override
            public boolean shouldOverrideUrlLoading(WebView view, String url) {
                return false;
            }
        });
        String url ="http://mp.weixin.qq.com/s?__biz=MzAwODQ5MTA2NQ==&mid=402389923&idx=1&sn=3c89c329e7bf83ce8ff2364726ebd6a7#rd";
        mWebView.loadUrl(url);

注意一点，不要漏了在AndroidManifest.xml 加上网络权限

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

最终效果：

这样WebView顶部进度条就实现完毕了。