片段的启动活动引发ClassNotFoundException

Question

I know it's a long shot but I tried a lot of solutions and none worked. I'm trying to launch an activity from a fragment when a button is tapped.

Fragment.java

public class Lev1 extends Fragment implements OnClickListener {

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

        View v = inflater.inflate(R.layout.lev1, null);     
        Button button1= (Button) v.findViewById(R.id.level1);

        button1.setOnClickListener(this);           

        return v;

    }

    @Override
    public void onClick(View v) {

        try {
            Intent intent = new Intent(getActivity(), getActivity().getClassLoader().loadClass("es.uam.eps.dadm.SESSION"));
            startActivity(intent);
        }
        catch(ClassNotFoundException e) {
            //to handle carefully
            Toast.makeText(context, "Class not found",
                     Toast.LENGTH_SHORT).show();
        }
    } 

Fragment.xml

<?xml version="1.0" encoding="UTF-8"?>
<LinearLayout        
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent">

    <Button
        android:id="@+id/level1"            
        android:layout_width="300dp"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_margin="8dp"
        android:background="@drawable/fr1"
         />        
</LinearLayout>

I suppose that is not a package problem, because if I use an activity and not a fragment the following works well:

Button button1= (Button)findViewById(R.id.level1);

button1.setOnClickListener(new OnClickListener() {

public void onClick(View v) {
        startActivity(new Intent("es.uam.eps.dadm.SESSION"));
}

So I don't know why the other way rises an ClassNotFoundException when I try to load my SESSION class. Maybe the declaration of intent is wrong? Thanks in advance to any help.

Answer 1

I don't know why the other way rises an ClassNotFoundException

es.uam.eps.dadm.SESSION is Action name which you have added during Activity declaration in AndroidManifest.xml .

From Activity on Button click using action to prepare Intent for starting Activity. but from Fragment trying to load a class using action String instead of class name with package name :

Use class name for loading class using loadClass :

Intent intent = new Intent(getActivity(), getActivity().getClassLoader().
                                      loadClass("es.uam.eps.dadm.<Class_Name>"));

Answer 2

似乎是您的es.uam.eps.dadm.SESSION软件包文件夹中没有SESSION.java文件，或者您在清单文件中错过了它