I'm having a trouble with findViewByid
but I can't find where the problem is.
Here's my FirstFragment
class code:
import android.app.Fragment;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.webkit.WebSettings;
import android.webkit.WebView;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.ProgressBar;
import java.util.ArrayList;
import java.util.List;
public class FirstFragment extends Fragment {
public static final String TAG = "first";
private WebView mWebView;
ProgressBar progressBar;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mWebView = (WebView) findViewById(R.id.activity_main_webview);
progressBar = (ProgressBar) findViewById(R.id.progressBar1);
WebSettings webSettings = mWebView.getSettings();
webSettings.setJavaScriptEnabled(true);
mWebView.loadUrl("http://www.google.com");
}
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
return inflater.inflate(R.layout.secondefragment, container, false);
}
@Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
}
}
You need to do this in onCreateView:
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.secondefragment, container, false);
mWebView = (WebView) view.findViewById(R.id.activity_main_webview);
progressBar = (ProgressBar) view.findViewById(R.id.progressBar1);
WebSettings webSettings = mWebView.getSettings();
webSettings.setJavaScriptEnabled(true);
mWebView.loadUrl("http://www.google.com");
return view;
}
Fragment
doesn't provide thefindViewById()
method. This is provided in Activity
or View
. When implementing a Fragment
you don't inflate your views in onCreate()
(like you normally do in an Activity
.) Instead, you do it in onCreateView()
and you need to use the inflated root View
to find the ID within the layout you inflated.
getActivity().findViewById()
works. However, this isn't a good practice because the fragment may be reused in another activity.
The recommended way for this is to define an interface.
The interface should contain methods by which the fragment needs to communicate with its parent activity.
public interface MyInterfcae { void showTextView(); }
Then your activity implements that Interface.
public class MyActivity extends Activity implements MyInterfcae { @Override public void showTextView(){ findViewById(R.id.textview).setVisibility(View.VISIBLE); } }
In that fragment grab a reference to the interface.
MyInterface mif = (MyInterface) getActivity();
Call a method.
mif.showTextView();
This way, the fragment and the activity are fully decoupled and every activity which implements that fragment, is able to attach that fragment to itself.
I had this problem when I downloaded sample project from github. This project had
compileSdkVersion 23
buildToolsVersion "23.0.0"
targetSdkVersion 23
in Activity context
and findViewById()
were in red color inside onCreate() method. So I updated the above versions to
compileSdkVersion 25
buildToolsVersion "25.0.3"
targetSdkVersion 25
and error got resolved.
I meet the same question in Android studio learning,just because I create the project by Fragment
. Choose Blank Activity
with no Fragment
would solve it.
I found solution by changing targetSdkVersion from 23 to 21
Add getView()
before findViewById()
method.
Like this:
getView().findViewById(R.id.potatoes);
getActivity().findViewById() This works it removes the red colour of findviewby id and it doesnt say cannot resolve symbol but when i put a colin in the end the whole statement is underlined and it says unreachable statement. barChart =(BarChart)getActivity().findViewById(R.id.barchart); I am also doing this in fragment.
This is how you can solve the problem:
toggleButton1=(ToggleButton)findViewById(R.id.toggleButton1);
toggleButton2=(ToggleButton)findViewById(R.id.toggleButton2);
来源:https://stackoverflow.com/questions/30598871/can-not-resolve-method-findviewbyidint