Android listview 代码控制上下移动

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; 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); } }; public void listScrollUp() { listScrollOff(); handler.postDelayed(run_scroll_up, 0); } public void listScrollDown() { listScrollOff(); handler.postDelayed(run_scroll_down, 0); } public void listScrollOff() { handler.removeCallbacks(run_scroll_down); handler.removeCallbacks(run_scroll_up); } Runnable run_scroll_up = new Runnable() { @Override public void run() { 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); } }; }