listview header animation

MyActivity.java

package com.example.tedliang.myapplication;

import android.animation.Animator;
import android.animation.AnimatorSet;
import android.animation.ObjectAnimator;
import android.animation.ValueAnimator;
import android.app.ActionBar;
import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.text.method.CharacterPickerDialog;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.view.animation.AnimationSet;
import android.widget.AdapterView;
import android.widget.BaseAdapter;
import android.widget.ListView;
import android.widget.RelativeLayout;
import android.widget.TextView;


public class MyActivity extends Activity {
    private ListView listview;
    private TextView textview;
    int height;
    private class MyAdapter extends BaseAdapter{
        LayoutInflater inflater;
        public MyAdapter(Context context){
            inflater = LayoutInflater.from(context);

        }
        @Override
        public int getCount() {
            return 100;
        }

        @Override
        public Object getItem(int i) {
            return i;
        }

        @Override
        public long getItemId(int i) {
            return i;
        }

        @Override
        public View getView(int i, View view, ViewGroup viewGroup) {
            view = inflater.inflate(R.layout.adapter_layout,null);
            TextView textivew = (TextView)view.findViewById(R.id.textview);
            textivew.setText(String.valueOf(i));
            return view;
        }
    }

    boolean isUp = true;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_my);
        textview = (TextView) findViewById(R.id.textview);
        listview = (ListView)findViewById(R.id.listview);
        listview.setAdapter(new MyAdapter(this));

        listview.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
                if(isUp) {
                    height = listview.getHeight();
                    ObjectAnimator animX = ObjectAnimator.ofFloat(listview, "translationY", 0f, -textview.getHeight());
                    ObjectAnimator animY = ObjectAnimator.ofFloat(textview, "translationY", 0f, -textview.getHeight());

                    AnimatorSet set = new AnimatorSet();
                    set.playTogether(animX, animY);

                    set.start();
                    ValueAnimator.AnimatorUpdateListener listUpdater = new ValueAnimator.AnimatorUpdateListener() {
                        @Override
                        public void onAnimationUpdate(ValueAnimator animation) {

                            Log.d("Ted", "listview height" + listview.getHeight());
                            RelativeLayout.LayoutParams p = (RelativeLayout.LayoutParams) listview.getLayoutParams();
                            p.bottomMargin = -textview.getHeight();
                            listview.setLayoutParams(p);
                            listview.requestLayout();
                            isUp = false;
                        }
                    };

                    animX.addUpdateListener(listUpdater);
                }else{
                    ObjectAnimator animX = ObjectAnimator.ofFloat(listview, "translationY", -textview.getHeight(),0f);
                    ObjectAnimator animY = ObjectAnimator.ofFloat(textview, "translationY", -textview.getHeight(),0f);

                    AnimatorSet set = new AnimatorSet();
                    set.playTogether(animX, animY);

                    set.start();
                    ValueAnimator.AnimatorUpdateListener listUpdater = new ValueAnimator.AnimatorUpdateListener() {
                        @Override
                        public void onAnimationUpdate(ValueAnimator animation) {
                            RelativeLayout.LayoutParams p = (RelativeLayout.LayoutParams) listview.getLayoutParams();
                            p.bottomMargin =0;
                            listview.setLayoutParams(p);
                            listview.requestLayout();
                            isUp = true;
                        }
                    };

                    animX.addUpdateListener(listUpdater);
                }
            }
        });
    }

}