Android 回到底部和返回顶部实现

效果

准备四张图片资源

首先XML布局

我们采用FrameLayout布局 
代码：

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <ScrollView
        android:id="@+id/sc"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:fillViewport="true">

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:orientation="vertical">

            <ImageView
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:src="@drawable/ad1" />

            <ImageView
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:layout_margin="10dp"
                android:src="@drawable/ad2" />

        </LinearLayout>
    </ScrollView>

    <ImageView
        android:id="@+id/btn_toTop"
        android:layout_width="25dp"
        android:layout_height="25dp"
        android:layout_gravity="bottom|right"
        android:background="@drawable/top" />

    <ImageView
        android:id="@+id/btn_toBottom"
        android:layout_width="25dp"
        android:layout_height="25dp"
        android:background="@drawable/bottom" />

</FrameLayout>

其次Activity里面实现

代码：

package com.jabony.fastscrolltop;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.ImageView;
import android.widget.ScrollView;

public class MainActivity extends Activity {
   private ImageView topBtn, bottomBtn;
   private ScrollView sc;

   @Override
   protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.main);
      sc = (ScrollView) findViewById(R.id.sc);
      topBtn = (ImageView) findViewById(R.id.btn_toTop);
      bottomBtn = (ImageView) findViewById(R.id.btn_toBottom);
      topBtn.setOnClickListener(new OnClickListener() {

         @Override
         public void onClick(View v) {
            sc.post(new Runnable() {

               @Override
               public void run() {
                  sc.post(new Runnable() {
                     public void run() {
                        // 滚动至顶部
                        sc.fullScroll(ScrollView.FOCUS_UP);
                     }
                  });
               }
            });

         }
      });
      bottomBtn.setOnClickListener(new OnClickListener() {

         @Override
         public void onClick(View v) {
            sc.post(new Runnable() {

               @Override
               public void run() {
                  sc.post(new Runnable() {
                     public void run() {
                        // 滚动到底部
                        sc.fullScroll(ScrollView.FOCUS_DOWN);
                     }
                  });
               }
            });
         }
      });

   }

}

最后运行就可以了。

源码下载地址： 
http://download.csdn.net/detail/care_about/9481210