滑动到点击位置的ListView

一个ListView的小Demo,根据点击的位置自动滑动到当前的位置。
主界面
`public class MainActivity extends Activity {
protected static final String TAG = “MainActivity”;
private List list = new ArrayList();
private ListView lv;
private int current_Position = 0;
private LayoutInflater inflater;
private adapter a;
private int firstVisiblePosition;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.activity_main);
inflater = LayoutInflater.from(this);
initData();

      lv = (ListView) findViewById(R.id.listView1);
      firstVisiblePosition =  lv.getFirstVisiblePosition();
      a = new adapter(list);
      lv.setAdapter(a);

      lv.setOnItemClickListener(new OnItemClickListener() {

        @Override
        public void onItemClick(AdapterView<?> parent, View view,
                int position, long id) {
            current_Position = position;
            // int lastVisiblePosition = lv.getLastVisiblePosition();
            int top = getScrollY();
            lv.smoothScrollBy((view.getHeight())* (position - firstVisiblePosition) + top, 500);
            a.notifyDataSetChanged();

        }
    });
}

private void initData() {
    for (int i = 0; i < 20; i++) {
        list.add("Jack"+i);
    }
}

public int getScrollY() {
    View c = lv.getChildAt(0);
    if (c == null) {
        return 0;
    }
    firstVisiblePosition = lv.getFirstVisiblePosition();
    int top = c.getTop();
    return top;
}

class adapter extends BaseAdapter{

private List<String> list;

public adapter(List<String> list) {
    this.list=list;
}

@Override
public int getCount() {
    return list.size();
}

@Override
public Object getItem(int position) {
    return list.get(position);
}

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

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    convertView = inflater.inflate(R.layout.item, parent, false);
    View view = convertView.findViewById(R.id.view1);
    TextView tv = (TextView) convertView.findViewById(R.id.textView1);
    if(current_Position ==position){
        view.setVisibility(View.VISIBLE);
    }else{
        view.setVisibility(View.GONE);
    }
    tv.setText(list.get(position));
    return convertView;
}   

}
}

主界面的XML就一个ListView
ListView的item

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="horizontal" >

    <View 
        android:id="@+id/view1"
        android:layout_width="5dp"
        android:background="#ff0000"
        android:layout_height="40dp"
        />
    <TextView
        android:gravity="center_vertical"
        android:id="@+id/textView1"
        android:layout_width="match_parent"
        android:layout_height="40dp"
        android:text="TextView" />
</LinearLayout>

        <p>版权声明：本文为博主原创文章，未经博主允许不得转载。</p>