android通過代碼控制ListView上下滾動

本文將介紹一種通過代碼控制ListView上下滾動的方法。

先上圖：

按下按鈕會觸發ListView滾動或停止。

實現該功能並不難，下面給出主要代碼MainActivity.java

package cn.guet.levide;

import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.ListView;

public class MainActivity extends Activity implements OnClickListener {
	private Button btn_up, btn_down, btn_stop; // 三個按鈕
	private ListView listview;
	private Adapter adapter;

	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);
		findBy();
		init();
	}

	private void init() {
		btn_up.setOnClickListener(this);
		btn_down.setOnClickListener(this);
		btn_stop.setOnClickListener(this);

		adapter = new Adapter(this);
		listview.setAdapter(adapter);
	}

	private void findBy() {
		btn_up = (Button) findViewById(R.id.btn_scroll_up);
		btn_down = (Button) findViewById(R.id.btn_scroll_down);
		btn_stop = (Button) findViewById(R.id.btn_scroll_stop);

		listview = (ListView) findViewById(R.id.listview);
	}

	@Override
	public void onClick(View v) {
		switch (v.getId()) {
		case R.id.btn_scroll_down:
			listScrollDown();
			break;
		case R.id.btn_scroll_up:
			listScrollUp();
			break;
		case R.id.btn_scroll_stop:
			listScrollOff();
			break;
		}
	}

	Handler handler = new Handler() {
		@Override
		public void handleMessage(Message msg) {
			handler.removeCallbacks(run_scroll_down);
			handler.removeCallbacks(run_scroll_up);
		}
	};

	/**
	 * 向上滾動
	 */
	public void listScrollUp() {
		listScrollOff();
		handler.postDelayed(run_scroll_up, 0);
	}

	/**
	 * 向下滾動
	 */
	public void listScrollDown() {
		listScrollOff();
		handler.postDelayed(run_scroll_down, 0);
	}

	/**
	 * 停止滾動
	 */
	public void listScrollOff() {
		handler.removeCallbacks(run_scroll_down);
		handler.removeCallbacks(run_scroll_up);
	}

	Runnable run_scroll_up = new Runnable() {
		@Override
		public void run() {
			/**
			 * public void smoothScrollBy (int distance, int duration) 
			 * 
			 * Added in API level 8 Smoothly scroll by distance pixels over duration milliseconds.
			 * 
			 * Parameters 
			 *     distance Distance to scroll in pixels.
			 *     duration Duration of the scroll animation in milliseconds.
			 */
			listview.smoothScrollBy(1, 10);
			handler.postDelayed(run_scroll_up, 10);
		}
	};
	Runnable run_scroll_down = new Runnable() {
		@Override
		public void run() {
			listview.smoothScrollBy(-1, 10);
			handler.postDelayed(run_scroll_down, 10);
		}
	};
}

public void smoothScrollBy (int distance, int duration) 
    Smoothly scroll by distance pixels over duration milliseconds.

Parameters
    distance  Distance to scroll in pixels. 
    duration  Duration of the scroll animation in milliseconds.  

Android listview 代碼控制上下移動