android ListView TV 通过遥控器上下 smooth滑动

直接上代码

import java.util.Timer;
import java.util.TimerTask;

import android.content.Context;
import android.util.AttributeSet;
import android.view.KeyEvent;
import android.view.View;
import android.view.View.OnKeyListener;
import android.widget.ListAdapter;
import android.widget.ListView;

import com.letv.tvos.lechou.utils.LogCat;

public class SmoothScrollListView extends ListView implements OnKeyListener {

	private int itemsCount;

	private int itemHeight;

	private ListAdapter adapter;

	private int scrollDuration = 1000;

	private boolean isScrollTop;
	
    private Timer timer;

	private OnScrollBottomListener onScrollBottomListener;

	private OnScrollTopListener onScrollTopListener;
	

	public SmoothScrollListView(Context context) {
		this(context, null);
	}

	public SmoothScrollListView(Context context, AttributeSet attrs) {
		super(context, attrs);
		this.setOnKeyListener(this);
		this.setSmoothScrollbarEnabled(true);
		
	}

	@Override
	protected void onLayout(boolean changed, int l, int t, int r, int b) {
		super.onLayout(changed, l, t, r, b);
		if (adapter != null) {
			//获取每个item 的高度，因为要调用滑动的方法，每次滑动的距离就是item 的高度
			itemHeight = this.getChildAt(0).getHeight();
		}

	}

	@Override
	public void setAdapter(ListAdapter adapter) {
		super.setAdapter(adapter);
		this.adapter = adapter;
		//获取listview  item的count，一定要是由adapter获得，不能通过listView，因为listView是动态添加删除孩子的，可以打印一下比较看看
		itemsCount = adapter.getCount();
		
	}

	/**
	 * 设置滚动动画的滚动时间
	 * 
	 * @param scrollDutation
	 */
	public void setScrollDuration(int scrollDutation) {
		this.scrollDuration = scrollDutation;

	}
	

	@Override
	public boolean onKey(View v, int keyCode, KeyEvent event) {
		if (event.getAction() == KeyEvent.ACTION_UP) {
			return false;
		}
		//获取当前被选中的状态
		int currentItemPosition = this.getSelectedItemPosition();

		if (keyCode == KeyEvent.KEYCODE_DPAD_DOWN) {

			//当时倒数第二个的时候
			if (currentItemPosition == itemsCount - 2) {
				//如果listView的最后一个可见Item是倒数第二个item，或者是倒数第一个item同时timer不为空，这时要滚动一次，并让最后一个item获取焦点
				if(this.getLastVisiblePosition() == itemsCount - 2 || (this.getLastVisiblePosition() == itemsCount - 1 && timer != null)){
					LogCat.e("倒数第二个");
					this.smoothScrollBy(itemHeight, scrollDuration);
					
					if(timer == null){
						smoothScrollToBottom();
					}else{
						timer.cancel();
						timer = null;
						//延迟一下，再让最后一个item编程selected状态，不让没有动画，太突兀
						smoothScrollToBottom();
					}
					
//					this.smoothScrollToPositionFromTop(itemsCount - 1, 0, scrollDuration);
//					this.setSelection(itemsCount - 1);
				}
				return false;
			} else if (currentItemPosition == itemsCount - 1) {
				//当是最后一个item是selectionItem，则给出回调，让他不要在滚动了
				if (onScrollBottomListener != null) {
					onScrollBottomListener.onScrollBottom();
				}
				return true;
			} else {
				//是中间其他状态的时候，滚动一个item的距离
				this.smoothScrollBy(itemHeight, scrollDuration);
//				this.smoothScrollToPositionFromTop(currentItemPosition + 1, 0, scrollDuration);
				return false;
			}
		}
		
		if (keyCode == KeyEvent.KEYCODE_DPAD_UP) {
			if (currentItemPosition == 1) {
				
				if(this.getChildAt(0).isFocusable() == false){
					this.smoothScrollBy(-itemHeight, scrollDuration);
				}
				return false;
			} else if (currentItemPosition == 0) {
				
				if (onScrollTopListener != null) {
					onScrollTopListener.onScrollTop();
				}
				
				return isScrollTop;
			} else {
				this.smoothScrollBy(-itemHeight, scrollDuration);
				return false;
			}
		}

		return false;
	}
	

	private void smoothScrollToBottom(){
		LogCat.e("平滑移动到最后");
		timer = new Timer();
		timer.schedule(new TimerTask() {
			
			@Override
			public void run() {
				SmoothScrollListView.this.post(new Runnable() {
					
					@Override
					public void run() {
						SmoothScrollListView.this.setSelection(SmoothScrollListView.this.getLastVisiblePosition());
						
					}
				});
				
			}
		}, scrollDuration / 3);
	}


	/**
	 * 当滚动到底部的时候的监听
	 */
	public interface OnScrollBottomListener {
		void onScrollBottom();
	}

	public void setOnScrollBottomListener(
			OnScrollBottomListener onScrollBottomListener) {
		
		this.onScrollBottomListener = onScrollBottomListener;
	}

	/**
	 * 当滚动到顶部的时候的监听
	 */
	public interface OnScrollTopListener {
		void onScrollTop();
	}

	public void setOnScrollTopListener(OnScrollTopListener onScrollTopListener) {
		isScrollTop = true;
		this.onScrollTopListener = onScrollTopListener;
	}





}