我是初学者。我正在使用android studio中的标准示例，并使用3个滚动选项卡创建Tabbed Activity。在选项卡textview和webview中。 Textview工作得很好。在WebView内容中有时（10-15中有1个）没有加载到我的设备上（Android 4.4 KitKat） - WebView显示为空白，但如果我滚动或点击屏幕，则显示WebView中的内容。 Adnroid Emulator（Nexus One Api 23，Android 6.0）都运行良好。如何解决？
视频：https://www.youtube.com/watch?v=oQWTszMoNZc（23秒和65秒的错误）
<RelativeLayout 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:paddingBottom="0dp"
android:paddingLeft="0dp"
android:paddingRight="0dp"
android:paddingTop="0dp"
tools:context="appname.MyClass$PlaceholderFragment">
<TextView
android:text="Section"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/textView5"
android:paddingLeft="10dp"
android:layout_alignParentRight="true"
android:layout_alignParentEnd="true"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true" />
<WebView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:id="@+id/webView"
android:layout_below="@+id/textView5">
</WebView>
</RelativeLayout>
代码
import ...
public class MyClass extends AppCompatActivity {
/**
* The {@link android.support.v4.view.PagerAdapter} that will provide
* fragments for each of the sections. We use a
* {@link FragmentPagerAdapter} derivative, which will keep every
* loaded fragment in memory. If this becomes too memory intensive, it
* may be best to switch to a
* {@link android.support.v4.app.FragmentStatePagerAdapter}.
*/
private SectionsPagerAdapter mSectionsPagerAdapter;
/**
* The {@link ViewPager} that will host the section contents.
*/
private ViewPager mViewPager;
private AdView mAdView2;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_show_diet);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
// Create the adapter that will return a fragment for each of the three
// primary sections of the activity.
mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager());
this.setTitle("My title");
// Set up the ViewPager with the sections adapter.
mViewPager = (ViewPager) findViewById(R.id.container);
mViewPager.setAdapter(mSectionsPagerAdapter);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_show_diet, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
/**
* A placeholder fragment containing a simple view.
*/
public static class PlaceholderFragment extends Fragment {
/**
* The fragment argument representing the section number for this
* fragment.
*/
private static final String ARG_SECTION_NUMBER = "section_number";
public String jsonstr = "NOT";
public String consultJson = "NOT";
public Context context;
ProgressDialog dialog;
public PlaceholderFragment() {
}
/**
* Returns a new instance of this fragment for the given section
* number.
*/
public static PlaceholderFragment newInstance(int sectionNumber) {
PlaceholderFragment fragment = new PlaceholderFragment();
Bundle args = new Bundle();
args.putInt(ARG_SECTION_NUMBER, sectionNumber);
fragment.setArguments(args);
return fragment;
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_show_diet, container, false);
TextView textView = (TextView) rootView.findViewById(R.id.textView5);
String url = "file:///android_asset/herba1.html";
context = getContext();
dialog = ProgressDialog.show(getActivity(), "", "Loading...", true);
//get sec num
int section = getArguments().getInt(ARG_SECTION_NUMBER);
textView.setText("Section= "+String.valueOf(section));
url = "file:///android_asset/herba"+section+".html";
WebView webView = (WebView) rootView.findViewById(R.id.webView);
WebSettings webSettings = webView.getSettings();
webSettings.setJavaScriptEnabled(true);
webSettings.setLoadWithOverviewMode(true);
webSettings.setAllowFileAccess(true);
webView.setWebViewClient(new Client());
webView.setWebChromeClient(new ChromeClient());
if (Build.VERSION.SDK_INT >= 19) {
webView.setLayerType(View.LAYER_TYPE_HARDWARE, null);
}
else if(Build.VERSION.SDK_INT >=11 && Build.VERSION.SDK_INT < 19) {
webView.setLayerType(View.LAYER_TYPE_SOFTWARE, null);
}
webView.addJavascriptInterface(new JavaScriptInterface(), "android");
webView.loadUrl(url);
Log.d("my_tag", "Load="+url+" frag="+section);
return rootView;
}
class JavaScriptInterface {
@JavascriptInterface
public void openBrowser(String url) {
Intent browserIntent = new Intent(Intent.ACTION_VIEW, Uri.parse(url));
startActivity(browserIntent);
}
}
public class ChromeClient extends WebChromeClient {
}
public class Client extends WebViewClient {
public void onReceivedError(WebView view, WebResourceRequest request, WebResourceError error){
//view.loadUrl("file:///android_asset/eror.html");
}
public boolean shouldOverrideUrlLoading(WebView view, String url) {
// If url contains
if (url.contains("mailto:") || url.contains("tel:")) {
//Open links in new browser
view.getContext().startActivity(
new Intent(Intent.ACTION_VIEW, Uri.parse(url)));
return true;
}else {
// Stay within this webview and load url
view.loadUrl(url);
return true;
}
}
//Show loader on url load
public void onPageStarted(WebView view, String url, Bitmap favicon) {
dialog.show();
}
public void onPageFinished(WebView view, String url) {
try {
dialog.dismiss();
} catch (Exception exception) {
exception.printStackTrace();
}
}
}
}
/**
* A {@link FragmentPagerAdapter} that returns a fragment corresponding to
* one of the sections/tabs/pages.
*/
public class SectionsPagerAdapter extends FragmentPagerAdapter {
public SectionsPagerAdapter(FragmentManager fm) {
super(fm);
}
@Override
public Fragment getItem(int position) {
// getItem is called to instantiate the fragment for the given page.
// Return a PlaceholderFragment (defined as a static inner class below).
Log.d("My tag getItem", String.valueOf((position + 1)));
return PlaceholderFragment.newInstance(position + 1);
}
@Override
public int getCount() {
// Show 3 total pages.
return 3;
}
@Override
public CharSequence getPageTitle(int position) {
Log.d("My tag getPageTitle", String.valueOf((position)));
switch (position) {
case 0:
return "SECTION 1";
case 1:
return "SECTION 2";
case 2:
return "SECTION 3";
}
return null;
}
}
}