我有一个android工作室的问题我创建了一个包含webview和progressbar的片段进度条在web视图加载之前消失了url如何解决这个问题? 这是Java类文件在android工作室加载页面之前隐藏的进度条
public class FacebookPage extends Fragment {
View myView;
WebView myWebView;
WebSettings webSettings;
ProgressDialog progressDialog;
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, Bundle savedInstanceState) {
myView=inflater.inflate(R.layout.facebook_page,container,false);
return myView;
};
@Override
public void onViewCreated(final View view, @Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
myWebView = (WebView) view.findViewById(R.id.webview);
String url="https://www.facebook.com/TahrirLounge/";
myWebView.setWebViewClient(new WebViewClient() {
@Override
public boolean shouldOverrideUrlLoading(WebView view, String url) {
view.loadUrl(url);
return true;
}
@Override
public void onPageFinished(WebView webView, String url) {
super.onPageFinished(webView, url);
view.findViewById(R.id.progressBar_facebook_page).setVisibility(View.GONE);
}
});
myWebView.loadUrl(url);
webSettings = myWebView.getSettings();
webSettings.setJavaScriptEnabled(true);
}
}
这是XML文件:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<WebView
android:id="@+id/webview"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
</WebView>
<ProgressBar
android:id="@+id/progressBar_facebook_page"
style="?android:attr/progressBarStyle"
android:layout_width="50dp"
android:layout_height="50dp"
android:layout_centerInParent="true"
android:visibility="visible" />
</RelativeLayout>
,我现在也有在日志中这样的错误:
E/AndroidRuntime:致命异常:主要 进程:com.mostafa.tahrirlounge,PID:8952 java.lang.NullPointerException:尝试调用虚拟方法'android.content.res.Resources $ Theme android.content.Context.getTheme()'o na null object reference at android.app.AlertDialog.resolveDialogTheme(AlertDialog.java:154) at android.app.AlertDialog。(AlertDialog.java:109) at android.app.ProgressDialog。(ProgressDialog.java:77) 在android.app.ProgressDialog.show(ProgressDialog.java:110) 在android.app.ProgressDialog.show(ProgressDialog.java:99) 在com.mostafa.tahrirlounge.FacebookPage。(FacebookPage.java:24) at com.mostafa.tahrirlounge.MainActivity.onNavigationItemSelected(MainActivity.java:78) at android.support.design.widget.NavigationView $ 1.onMenuItemSelected(NavigationView.java:156) at android.support.v7.view.menu.MenuBuilder.dispatchMenuItemSelected(MenuBuilder.java:822) at android.support.v7.view.menu.MenuItemImpl.invoke(MenuItemImpl.java:156) at android.support。 v7.view.menu.MenuBuilder.performItemAction(MenuBuilder.java:969) at android.support.design.internal.NavigationMenuPresenter $ 1.onClick(NavigationMenuPresenter.java:342) at android.view.View.performClick(View.java :4757) at android.view.View $ PerformClick.run(View.java:19757) at android.os.Handler.handleCallback(Handler.java:739) at android.os.Handler.dispatchMessage(Handler.java :95) a吨android.os.Looper.loop(Looper.java:135) 在android.app.ActivityThread.main(ActivityThread.java:5233) 在java.lang.reflect.Method.invoke(本机方法) 在java的。 lang.reflect.Method.invoke(Method.java:372) at com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run(ZygoteInit.java:898) at com.android.internal.os.ZygoteInit.main( ZygoteInit.java:693)
你也可以显示你的xml文件? –