前言：可以说，这是一篇关于WebView整体使用的一个示例。在WebView中，有几个地方是我们可以使用来定制我们的WebView各种行为的，分别是：WebSettings、JavaScriptInterface、WebViewClient以及WebChromeClient。以下代码给出了xml和java的相关核心代码，涵盖了很多核心却基础的知识点，
XML：
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<android.support.design.widget.AppBarLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">
<android.support.v7.widget.Toolbar
android:id="@+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="?attr/colorPrimary"
app:theme="@style/ThemeOverlay.AppCompat.Light" />
</android.support.design.widget.AppBarLayout>
<FrameLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<WebView
android:id="@+id/web_view"
android:layout_width="match_parent"
android:layout_height="match_parent" />
<ProgressBar
android:id="@+id/progress_bar"
android:layout_width="50dp"
android:layout_height="50dp"
android:layout_gravity="center"
android:visibility="gone" />
</FrameLayout>
</LinearLayout>
Java部分：
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);
}
}
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