Network WebView

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" tools:context=".MainActivity">

<TextView
android:id="@+id/textview"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
<Button
android:id="@+id/button_connection"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="获取网络连接"/>
<FrameLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<ProgressBar
android:id="@+id/progressbar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
style="@style/Base.Widget.AppCompat.ProgressBar.Horizontal"/>
<WebView
android:id="@+id/webview"
android:layout_width="match_parent"
android:layout_height="match_parent"></WebView>
<TextView
android:id="@+id/textview_error"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:text="加载失败"
android:gravity="center"
android:visibility="invisible"/>
</FrameLayout>

</LinearLayout>

public class MainActivity extends Activity implements View.OnClickListener{
private Button mButtonConnection;
private TextView mTextView;
private ConnectivityManager mConnectivityManager;
private WebView mWebView;
private TextView mTextViewError;
private ProgressBar mProgressBar;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mProgressBar= (ProgressBar) findViewById(R.id.progressbar);
mTextViewError= (TextView) findViewById(R.id.textview_error);
mConnectivityManager= (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
mButtonConnection= (Button) findViewById(R.id.button_connection);
mButtonConnection.setOnClickListener(this);
mTextView= (TextView) findViewById(R.id.textview);
mWebView= (WebView) findViewById(R.id.webview);
mWebView.getSettings().setJavaScriptEnabled(true);
//mWebView.getSettings().setBuiltInZoomControls(true);
mWebView.setWebViewClient(new WebViewClient(){
@Override
public void onPageStarted(WebView view, String url, Bitmap favicon) {
super.onPageStarted(view, url, favicon);
mProgressBar.setProgress(View.VISIBLE);
}

@Override
public void onPageFinished(WebView view, String url) {
super.onPageFinished(view, url);
mProgressBar.setProgress(View.INVISIBLE);
}

@Override
public void onReceivedError(WebView view, int errorCode, String description, String failingUrl) {
super.onReceivedError(view, errorCode, description, failingUrl);
mWebView.setVisibility(View.GONE);
mTextViewError.setVisibility(View.VISIBLE);
// Toast.makeText(MainActivity.this, "加载失败", Toast.LENGTH_SHORT).show();
mTextViewError.setText("加载失败");
}
});
mWebView.setWebChromeClient(new WebChromeClient(){
@Override
public void onProgressChanged(WebView view, int newProgress) {
super.onProgressChanged(view, newProgress);
mProgressBar.setProgress(newProgress);
}
});

}

@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
if (keyCode==event.KEYCODE_BACK){
if (mWebView.canGoBack()){
mWebView.goBack();
return true;
}else {
finish();
}
}
return super.onKeyDown(keyCode, event);
}

@Override
public void onClick(View v) {
switch (v.getId()){
case R.id.button_connection:
mWebView.loadUrl("http://www.baidu.com");
//               NetworkInfo info= mConnectivityManager.getActiveNetworkInfo();
//                if (info!=null&&info.isConnected()){
//                    Toast.makeText(getApplicationContext(),"有网络连接",Toast.LENGTH_SHORT).show();
//                    mTextView.setText( info.getTypeName());
//                }else {
//                    Toast.makeText(getApplicationContext(),"无网络连接",Toast.LENGTH_SHORT).show();
//                    mTextView.setText("无网络连接");
//                }
break;
default:
break;
}

}
}