WebView

https://jiandanxinli.github.io/2016-08-31.html

public class MainActivity extends AppCompatActivity {

private WebView mWebView;

private ProgressBar mProgressbar;
private Toolbar mToolbar;

@Override
protected void onCreate(Bundle savedInstanceState) {
supportRequestWindowFeature(Window.FEATURE_NO_TITLE);
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

  initAppBar();//初始化Toolbar

  initWebView();//初始化WebView
  initWebSettings();//初始化WebSettings
  initWebViewClient();//初始化WebViewClient
  initWebChromeClient();//初始化WebChromeClient

}

private void initAppBar() {
mToolbar = (Toolbar) findViewById(R.id.toolbar);
mToolbar.setTitle("载入中..");
mToolbar.setTitleTextColor(getResources().getColor(R.color.colorWhite));
setSupportActionBar(mToolbar);
getSupportActionBar().setDisplayHomeAsUpEnabled(false);
}

private void initWebView() {
mWebView = (WebView) findViewById(R.id.web_view);
mProgressbar = (ProgressBar) findViewById(R.id.progress_bar);
String url = "https://www.google.com";
mWebView.loadUrl(url);
}

private void initWebSettings() {
WebSettings settings = mWebView.getSettings();
//支持获取手势焦点
mWebView.requestFocusFromTouch();
//支持JS
settings.setJavaScriptEnabled(true);
//支持插件
settings.setPluginState(WebSettings.PluginState.ON);
//设置适应屏幕
settings.setUseWideViewPort(true);
settings.setLoadWithOverviewMode(true);
//支持缩放
settings.setSupportZoom(false);
//隐藏原生的缩放控件
settings.setDisplayZoomControls(false);
//支持内容重新布局
settings.setLayoutAlgorithm(WebSettings.LayoutAlgorithm.SINGLE_COLUMN);
settings.supportMultipleWindows();
settings.setSupportMultipleWindows(true);
//设置缓存模式
settings.setDomStorageEnabled(true);
settings.setDatabaseEnabled(true);
settings.setCacheMode(WebSettings.LOAD_DEFAULT);
settings.setAppCacheEnabled(true);
settings.setAppCachePath(mWebView.getContext().getCacheDir().getAbsolutePath());

  //设置可访问文件
  settings.setAllowFileAccess(true);
  //当webview调用requestFocus时为webview设置节点
  settings.setNeedInitialFocus(true);
  //支持自动加载图片
  if (Build.VERSION.SDK_INT >= 19) {
      settings.setLoadsImagesAutomatically(true);
  } else {
      settings.setLoadsImagesAutomatically(false);
  }
  settings.setNeedInitialFocus(true);
  //设置编码格式
  settings.setDefaultTextEncodingName("UTF-8");

}

private void initWebViewClient() {
mWebView.setWebViewClient(new WebViewClient() {

      //页面开始加载时
      @Override
      public void onPageStarted(WebView view, String url, Bitmap favicon) {
          super.onPageStarted(view, url, favicon);
          mProgressbar.setVisibility(View.VISIBLE);
      }


      //页面完成加载时
      @Override
      public void onPageFinished(WebView view, String url) {
          super.onPageFinished(view, url);
          mProgressbar.setVisibility(View.GONE);
      }

      //是否在WebView内加载新页面
      @Override
      public boolean shouldOverrideUrlLoading(WebView view, WebResourceRequest request) {
          view.loadUrl(request.toString());
          return true;
      }

      //网络错误时回调的方法
      @Override
      public void onReceivedError(WebView view, WebResourceRequest request, WebResourceError error) {
          super.onReceivedError(view, request, error);
          /**
           * 在这里写网络错误时的逻辑,比如显示一个错误页面
           *
           * 这里我偷个懒不写了
           * */
      }

      @TargetApi(Build.VERSION_CODES.M)
      @Override
      public void onReceivedHttpError(WebView view, WebResourceRequest request, WebResourceResponse errorResponse) {
          super.onReceivedHttpError(view, request, errorResponse);
      }
  });

}

private void initWebChromeClient() {

  mWebView.setWebChromeClient(new WebChromeClient() {

      private Bitmap mDefaultVideoPoster;//默认的视频展示图

      @Override
      public void onReceivedTitle(WebView view, String title) {
          super.onReceivedTitle(view, title);
          setToolbarTitle(title);
      }

      @Override
      public Bitmap getDefaultVideoPoster() {
          if (mDefaultVideoPoster == null) {
              mDefaultVideoPoster = BitmapFactory.decodeResource(
                      getResources(), R.drawable.video_default
              );
              return mDefaultVideoPoster;
          }
          return super.getDefaultVideoPoster();
      }
  });

}

/**

• 设置Toolbar标题
• @param title
  */
  private void setToolbarTitle(final String title) {
  Log.d("setToolbarTitle", " WebDetailActivity " + title);
  if (mToolbar != null) {
  mToolbar.post(new Runnable() {
  @Override
  public void run() {
  mToolbar.setTitle(TextUtils.isEmpty(title) ? getString(R.string.loading) : title);
  }
  });
  }
  }

@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.menu_main, menu);
return super.onCreateOptionsMenu(menu);
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case R.id.page_up:
Toast.makeText(getApplicationContext(), "页面向上", Toast.LENGTH_SHORT).show();
mWebView.pageUp(true);
break;
case R.id.page_down:
Toast.makeText(getApplicationContext(), "页面向下", Toast.LENGTH_SHORT).show();
mWebView.pageDown(true);
break;
case R.id.refresh:
Toast.makeText(getApplicationContext(), "刷新~", Toast.LENGTH_SHORT).show();
mWebView.reload();
default:
return super.onOptionsItemSelected(item);
}
return super.onOptionsItemSelected(item);
}

@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {

  //如果按下的是回退键且历史记录里确实还有页面
  if ((keyCode == KeyEvent.KEYCODE_BACK) && mWebView.canGoBack()) {
      mWebView.goBack();
      return true;
  } else {
      Toast.makeText(getApplicationContext(), "考试结束,恭喜您考试合格!", Toast.LENGTH_LONG).show();
  }
  return super.onKeyDown(keyCode, event);

}
}