I get the error “Unreachable statement” return in

Why do I get the error that line 92 is an unreachable statement? The error is in this line:

final RadioButton r1 = (RadioButton) getView().findViewById(R.id.radio1);

Code:

public class TabFragmentA extends Fragment {


    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {

        if (container == null) {
            return null;
        }

        return (RelativeLayout) inflater.inflate(R.layout.tab_layout_a, container, false);


        final RadioButton r1 = (RadioButton) getView().findViewById(R.id.radio1);  //the error is here
        final RadioButton r2 = (RadioButton) getView().findViewById(R.id.radio2);

        final ImageView iv1 = (ImageView) getView().findViewById(R.id.iv1); 
        final ImageView iv2 = (ImageView) getView().findViewById(R.id.iv2);

        iv1.setVisibility(View.INVISIBLE);
        iv2.setVisibility(View.INVISIBLE);

        r1.setOnCheckedChangeListener(new OnCheckedChangeListener() {

            public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
                // TODO Auto-generated method stub
                if(r1.isChecked())
                {
                    r2.setChecked(false);
                    iv2.setVisibility(View.INVISIBLE);
                    iv1.setVisibility(View.VISIBLE);
                }
            }
        });

        r2.setOnCheckedChangeListener(new OnCheckedChangeListener() {

            public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
                // TODO Auto-generated method stub
                if(r2.isChecked())
                {
                    r1.setChecked(false);
                    iv1.setVisibility(View.INVISIBLE);
                    iv2.setVisibility(View.VISIBLE);
                }
            }
        });
    }
}

Logcat error:

01-23 02:43:31.082    1903-1903/br.com.eddboytools.PreDim E/AndroidRuntime﹕ FATAL EXCEPTION: main
    Process: br.com.eddboytools.PreDim, PID: 1903
    java.lang.NullPointerException: Attempt to invoke virtual method 'android.view.View android.view.View.findViewById(int)' on a null object reference
            at br.com.eddboytools.PreDim.TabFragmentA.onCreateView(TabFragmentA.java:29)
            at android.support.v4.app.Fragment.performCreateView(Fragment.java:1478)
            at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:927)
            at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1104)
            at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:682)
            at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1460)
            at android.support.v4.app.FragmentManagerImpl.executePendingTransactions(FragmentManager.java:472)
            at android.support.v4.app.FragmentPagerAdapter.finishUpdate(FragmentPagerAdapter.java:141)
            at android.support.v4.view.ViewPager.populate(ViewPager.java:1068)
            at android.support.v4.view.ViewPager.populate(ViewPager.java:914)
            at android.support.v4.view.ViewPager.onMeasure(ViewPager.java:1436)
            at android.view.View.measure(View.java:17430)
            at android.widget.LinearLayout.measureVertical(LinearLayout.java:875)
            at android.widget.LinearLayout.onMeasure(LinearLayout.java:613)
            at android.view.View.measure(View.java:17430)
            at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5463)
            at android.widget.FrameLayout.onMeasure(FrameLayout.java:430)
            at android.view.View.measure(View.java:17430)
            at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5463)
            at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1436)
            at android.widget.LinearLayout.measureVertical(LinearLayout.java:722)
            at android.widget.LinearLayout.onMeasure(LinearLayout.java:613)
            at android.view.View.measure(View.java:17430)
            at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5463)
            at android.widget.FrameLayout.onMeasure(FrameLayout.java:430)
            at android.view.View.measure(View.java:17430)
            at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5463)
            at com.android.internal.widget.ActionBarOverlayLayout.onMeasure(ActionBarOverlayLayout.java:447)
            at android.view.View.measure(View.java:17430)
            at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5463)
            at android.widget.FrameLayout.onMeasure(FrameLayout.java:430)
            at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2560)
            at android.view.View.measure(View.java:17430)
            at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:2001)
            at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1166)
            at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1372)
            at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1054)
            at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5779)
            at android.view.Choreographer$CallbackRecord.run(Choreographer.java:767)
            at android.view.Choreographer.doCallbacks(Choreographer.java:580)
            at android.view.Choreographer.doFrame(Choreographer.java:550)
            at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:753)
            at android.os.Handler.handleCallback(Handler.java:739)
            at android.os.Handler.dispatchMessage(Handler.java:95)
            at android.os.Looper.loop(Looper.java:135)
            at android.app.ActivityThread.main(ActivityThread.java:5221)
            at java.lang.reflect.Method.invoke(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:372)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
01-23 02:43:31.094    1903-1915/br.com.eddboytools.PreDim I/art﹕ Background partial concurrent mark sweep GC freed 261(11KB) AllocSpace objects, 0(0B) LOS objects, 27% free, 1328KB/1840KB, paused 20.856ms total 51.174ms

回答1:

We don't put return statement above any other statement unless that return is under any conditional statement. If we do that then all the statements below that would never get executed (means it would become unreachable under all circumstances) which causes the error you are getting.

Do it like this

public class TabFragmentA extends Fragment {
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
        Bundle savedInstanceState) {

    RelativeLayout rootView = (RelativeLayout) inflater.inflate(R.layout.tab_layout_a, container, false);


    final RadioButton r1 = (RadioButton) rootView.findViewById(R.id.radio1);
    final RadioButton r2 = (RadioButton) rootView.findViewById(R.id.radio2);

    final ImageView iv1 = (ImageView) rootView.findViewById(R.id.iv1);
    final ImageView iv2 = (ImageView) rootView.findViewById(R.id.iv2);

    iv1.setVisibility(View.INVISIBLE);
    iv2.setVisibility(View.INVISIBLE);

    r1.setOnCheckedChangeListener(new OnCheckedChangeListener() {

        public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
            // TODO Auto-generated method stub
            if(r1.isChecked())
            {
                r2.setChecked(false);
                iv2.setVisibility(View.INVISIBLE);
                iv1.setVisibility(View.VISIBLE);
            }
        }
    });

    r2.setOnCheckedChangeListener(new OnCheckedChangeListener() {

        public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
            // TODO Auto-generated method stub
            if(r2.isChecked())
            {
                r1.setChecked(false);
                iv1.setVisibility(View.INVISIBLE);
                iv2.setVisibility(View.VISIBLE);
            }
        }
    });
return rootView;
}
}

回答2:

You have a return right above it. When you return from a method nothing below it will get executed. That means the line below it will never get executed.

The compiler is trying to help you see this.

回答3:

The return statement should be at the end:

final RadioButton r1 = (RadioButton) getView().findViewById(R.id.radio1);  
final RadioButton r2 = (RadioButton) getView().findViewById(R.id.radio2);

return (RelativeLayout) inflater.inflate(R.layout.tab_layout_a, container, false);