Android WebView 总结 —— 使用HTML5播放视频及全屏方案

参考网址：

https://www.jianshu.com/p/b9de6714482c

https://www.cnblogs.com/renhui/p/5893593.html

一，打开硬件加速

不开硬件加速，视频会黑屏，有声音没图像；

在AndroidManifest.xml中声明HardwareAccelerate的标志，一般是添加在Activity的级别上。代码如下：

下面引申一下HardwareAccelerate声明的方式：

(a).如果需要声明整个应用都要加速，则在Application级别下面进行声明：

< application ... android:hardwareAccelerated ="true">

(b).如果需要某个Activity加速，则可以进行下面的声明：

或者在代码里面进行动态的声明：

getWindow.setFlags(WindowManager.LayoutParams.FLAG_HARDWARE_ACCELERATED,
WindowManager.LayoutParams.FLAG_HARDWARE_ACCELERATED);

(c).如果Application和Activity都声明了HardwareAccelerate，但是由于某些特殊原因，一些View不需要硬件加速，那么在View里面设置：

view.setLayerType(View.LAYER_TYPE_SOFTWARE, null);

完成声明操作后，基本上WebView就能够很好的支持在页面上播放视频了，下面展示的是在Html上的Viedeo的声明方法：

二、视频播放的时候可以全屏

1.代码：

在onShowCustomView方法中，将获取到的view放到当前Activity的最上方，在onHideCustomView中，将之前的view隐藏或者删除，将原来被覆盖的webview放回来。
public class WebVideoActivity extends Activity {
  
    private WebView webView;

    /** 视频全屏参数 */
    protected static final FrameLayout.LayoutParams COVER_SCREEN_PARAMS = new FrameLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT);
    private View customView;
    private FrameLayout fullscreenContainer;
    private WebChromeClient.CustomViewCallback customViewCallback;

    @Override
    protected void onCreate(Bundle bundle) {
        super.onCreate(bundle);
        setContentView(R.layout.activity_xx);
        webView = (WebView) findViewById(R.id.xx);
        initWebView();
    }

    @Override
    protected void onStop() {
        super.onStop();
        webView.reload();
    }

    /** 展示网页界面 **/
　　public void initWebView() {
        WebChromeClient wvcc = new WebChromeClient();
        WebSettings webSettings = webView.getSettings();
        webSettings.setJavaScriptEnabled(true);
        webSettings.setUseWideViewPort(true); // 关键点
        webSettings.setAllowFileAccess(true); // 允许访问文件
        webSettings.setSupportZoom(true); // 支持缩放
        webSettings.setLoadWithOverviewMode(true);
        webSettings.setCacheMode(WebSettings.LOAD_NO_CACHE); // 不加载缓存内容

        webView.setWebChromeClient(wvcc);
        WebViewClient wvc = new WebViewClient() {
            @Override
            public boolean shouldOverrideUrlLoading(WebView view, String url) {
                webView.loadUrl(url);
                return true;
            }
        };
        webView.setWebViewClient(wvc);

        webView.setWebChromeClient(new WebChromeClient() {

            /*** 视频播放相关的方法 **/

            @Override
            public View getVideoLoadingProgressView() {
                FrameLayout frameLayout = new FrameLayout(WebVideoActivity.this);
                frameLayout.setLayoutParams(new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT));
                return frameLayout;
            }

            @Override
            public void onShowCustomView(View view, CustomViewCallback callback) {
                showCustomView(view, callback);
            }

            @Override
            public void onHideCustomView() {
                hideCustomView();
            }
        });

        // 加载Web地址
        webView.loadUrl(webUrl);
    }

    /** 视频播放全屏 **/
    private void showCustomView(View view, CustomViewCallback callback) {
        // if a view already exists then immediately terminate the new one
        if (customView != null) {
            callback.onCustomViewHidden();
            return;
        }

        WebVideoActivity.this.getWindow().getDecorView();

        FrameLayout decor = (FrameLayout) getWindow().getDecorView();
        fullscreenContainer = new FullscreenHolder(WebVideoActivity.this);
        fullscreenContainer.addView(view, COVER_SCREEN_PARAMS);
        decor.addView(fullscreenContainer, COVER_SCREEN_PARAMS);
        customView = view;
        setStatusBarVisibility(false);
        customViewCallback = callback;
    }

    /** 隐藏视频全屏 */
    private void hideCustomView() {
        if (customView == null) {
            return;
        }

        setStatusBarVisibility(true);
        FrameLayout decor = (FrameLayout) getWindow().getDecorView();
        decor.removeView(fullscreenContainer);
        fullscreenContainer = null;
        customView = null;
        customViewCallback.onCustomViewHidden();
        webView.setVisibility(View.VISIBLE);
    }

    /** 全屏容器界面 */
    static class FullscreenHolder extends FrameLayout {

        public FullscreenHolder(Context ctx) {
            super(ctx);
            setBackgroundColor(ctx.getResources().getColor(android.R.color.black));
        }

        @Override
        public boolean onTouchEvent(MotionEvent evt) {
            return true;
        }
    }

    private void setStatusBarVisibility(boolean visible) {
        int flag = visible ? 0 : WindowManager.LayoutParams.FLAG_FULLSCREEN;
        getWindow().setFlags(flag, WindowManager.LayoutParams.FLAG_FULLSCREEN);
    }

    @Override
    public boolean onKeyUp(int keyCode, KeyEvent event) {
        switch (keyCode) {
        case KeyEvent.KEYCODE_BACK:
            /** 回退键 事件处理 优先级:视频播放全屏-网页回退-关闭页面 */
            if (customView != null) {
                hideCustomView();
            } else if (webView.canGoBack()) {
                webView.goBack();
            } else {
                finish();
            }
            return true;
        default:
            return super.onKeyUp(keyCode, event);
        }
    }
}

2.在清单文件上设置configChanges，当转屏以及转屏造成的屏幕尺寸变化的时候，activity会冲走onCreate方法，前面干的所有事儿都白干了