Pass ArrayList from Activity to CustomDialog

Question

I need to pass an ArrayList from an Activity to a CustomDialog, but i'm getting Nullpointer exception, I know I am definitely doing something wrong and I need some guidance. This is my code below. Please help!

Or maybe there is better way I need to implement passing ArrayList to CustomDialog, you can please guide me through. Thanks

MainActivity

public class MainActivity extends AppCompatActivity {

    /** List **/
    private ArrayList<String> groupList;


    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main_activity);

        groupList = new ArrayList<String>();
        groupList.add("One");
        groupList.add("Two");
        groupList.add("Three");
        groupList.add("Four");

        CustomDialog customdialog = new CustomDialog();
        customdialog.show(getFragmentManager(), "My Alert");
        // Supply input as an argument.
        if(groupList.size()!=0) {
            Bundle args = new Bundle();
            args.putSerializable("groupList", groupList);
            customdialog.setArguments(args);
        }
    }

} 

CustomDialog

public class CustomDialog extends DialogFragment{

    ArrayList<String> groupList;

    @Override
    public Dialog onCreateDialog(Bundle savedInstanceState) {

        int radiochoice=0;
        Bundle extras = getActivity().getIntent().getExtras();
        if (extras != null) {
            groupList = (ArrayList<String>) getActivity().getIntent().getSerializableExtra("groupList");
            if(groupList.size()!=0) {
                Log.d("groupList size:", Integer.toString(groupList.size()));
            }
        }

        /** The rest of the Custom dialog code under here **/
    }
}

This is my stack trace below

Process: com.example.practice, PID: 9203
    java.lang.NullPointerException
            at com.example.practice.dialog.CustomDialog.onCreateDialog(CustomDialog.java:34)
            at android.app.DialogFragment.getLayoutInflater(DialogFragment.java:398)
            at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:890)
            at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:1062)
            at android.app.BackStackRecord.run(BackStackRecord.java:698)
            at android.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1447)
            at android.app.FragmentManagerImpl$1.run(FragmentManager.java:443)
            at android.os.Handler.handleCallback(Handler.java:808)
            at android.os.Handler.dispatchMessage(Handler.java:103)
            at android.os.Looper.loop(Looper.java:193)
            at android.app.ActivityThread.main(ActivityThread.java:5323)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:515)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:824)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:640)
            at dalvik.system.NativeStart.main(Native Method)

Answer 1

有一个对应的getArguments（）方法来检索通过setArguments()保存的包。