Android中使用ScrollView实现滑动到底部显示加载更多

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"  android:layout_width="fill_parent"  android:layout_height="fill_parent">  <ScrollView  android:id="@+id/scrollview"  android:layout_width="fill_parent"  android:layout_height="wrap_content"  android:scrollbars="none" >  <TextView  android:id="@+id/text"  android:layout_width="fill_parent"  android:layout_height="wrap_content" />  </ScrollView>  <Button  android:id="@+id/next" android:layout_gravity="bottom|center_horizontal"  android:layout_width="wrap_content"  android:layout_height="wrap_content"  android:visibility="invisible"  android:text="点击加载更多" /> </FrameLayout> 

package com.example.scrollview; import android.opengl.Visibility; import android.os.Bundle; import android.app.Activity; import android.support.v4.app.NotificationCompat.Action; import android.util.Log; import android.view.Menu; import android.view.MotionEvent; import android.view.View; import android.view.View.OnClickListener; import android.view.View.OnTouchListener; import android.view.Window; import android.widget.Button; import android.widget.ScrollView; import android.widget.TextView; import android.widget.Toast; public class MainActivity extends Activity {  private ScrollView scroll;  private TextView text;  private Button button;  @Override  protected void onCreate(Bundle savedInstanceState) {  super.onCreate(savedInstanceState);  requestWindowFeature(Window.FEATURE_NO_TITLE);  setContentView(R.layout.activity_main);  scroll=(ScrollView) findViewById(R.id.scrollview);  text=(TextView) findViewById(R.id.text);  button=(Button) findViewById(R.id.next);  text.setText(getResources().getString(R.string.lyric));  button.setOnClickListener(new OnClickListener() {  @Override  public void onClick(View v) {  // TODO Auto-generated method stub  text.append(getResources().getString(R.string.lyric));  button.setVisibility(View.INVISIBLE);  }  });  scroll.setOnTouchListener(new OnTouchListener() {  @Override  public boolean onTouch(View v, MotionEvent event) {  // TODO Auto-generated method stub  switch(event.getAction()){   case MotionEvent.ACTION_MOVE:{   break;   }   case MotionEvent.ACTION_DOWN:{   break;   }   case MotionEvent.ACTION_UP:{   //当文本的measureheight 等于scroll滚动的长度+scroll的height   if(scroll.getChildAt(0).getMeasuredHeight()<=scroll.getScrollY()+scroll.getHeight()){   button.setVisibility(View.VISIBLE);   }else{   }   break;   }  }  return false;  }  });  } }