Android通過代碼控制ListView上下滾動的方法

更新時間：2018年12月13日 14:13:09 作者：chadeltu

今天小編就為大家分享一篇關于Android通過代碼控制ListView上下滾動的方法，小編覺得內容挺不錯的，現(xiàn)在分享給大家，具有很好的參考價值，需要的朋友一起跟隨小編來看看吧

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(fā)ListView滾動或停止。

實現(xiàn)該功能并不難，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?jié)L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);
 }
 };
}

實現(xiàn)ListView位置變動的是smoothScrollBy方法。

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.

總結

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