本文将介绍一种通过代码控制ListView上下滚动的方法。
先上图：
按下按钮会触发ListView滚动或停止。
实现该功能并不难，下面给出主要代码MainActivity.java
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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; // 三个按钮 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); } }; /** * 向上滚动 */ public void listScrollUp() { listScrollOff(); handler.postDelayed(run_scroll_up, 0); } /** * 向下滚动 */ public void listScrollDown() { listScrollOff(); handler.postDelayed(run_scroll_down, 0); } /** * 停止滚动 */ 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); } };} |
实现ListView位置变动的是smoothScrollBy方法。
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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. |
总结
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原文链接：https://blog.csdn.net/chadeltu/article/details/44078213
