android通過代碼控制ListView上下滾動

標籤：android   listview   滾動   

本文將介紹一種通過代碼控制ListView上下滾動的方法。

先：

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;@Overridepublic 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);}@Overridepublic 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() {@Overridepublic 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() {@Overridepublic 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() {@Overridepublic void run() {listview.smoothScrollBy(-1, 10);handler.postDelayed(run_scroll_down, 10);}};}

實現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.  

工程源碼：

Android listview 代碼控制上下移動

android通過代碼控制ListView上下滾動