Android_scrollview

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.example.android_scollview.MainActivity" >
    <Button 
        android:id="@+id/up"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="up"
    />
    <Button 
        android:id="@+id/down"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="down"
     />

    <ScrollView 
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/scroll1"
        android:scrollbars="none">
        <!-- 
            ScrollView 的种类：
                ScrollView：垂直滚动视图
                HorizontalScrollView：水平滚动视图
            隐藏ScrollView
                (1)标签属性：scrollbars 设置不显示纵向滚动条 
                (2)代码设置：
                    setVerticalScrollBarEnabled(false);隐藏纵向ScrollView
                    setHorizontalSrollBarEnabled(false);隐藏横向ScrollView
                
                
                -->
        <TextView
            android:id="@+id/text"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@string/text" />
    </ScrollView>
</LinearLayout>

package com.example.android_scollview;

import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.View.OnTouchListener;
import android.widget.Button;
import android.widget.ScrollView;
import android.widget.TextView;
/**
 * 应用案例：判断ScrollView何时滑动到底部
 * 利用setOnTouchListener
 *
 */
public class MainActivity extends Activity implements OnClickListener{

    private TextView tv;
    private ScrollView scroll;
    private Button up;
    private Button down;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        up = (Button) findViewById(R.id.up);
        down = (Button) findViewById(R.id.down);
        
        up.setOnClickListener(this);
        down.setOnClickListener(this);
        tv = (TextView) findViewById(R.id.text);
        scroll = (ScrollView) findViewById(R.id.scroll1);
        scroll.setOnTouchListener(new OnTouchListener() {
            
            @Override
            public boolean onTouch(View v, MotionEvent event) {
                // TODO Auto-generated method stub
                switch(event.getAction()){
                case MotionEvent.ACTION_MOVE:{
                    /**
                     * (1)getScrollY()--滚动条滑动的距离
                     * (2)getMeasuredHeight--显示的高度加上隐藏的高度
                     * (3)getHeight
                     */
                    //顶部状态
                    if(scroll.getScaleY()<=0){
                        Log.i("Main", "顶部状态");
                    }
                    //底部状态
                    //TextView的总高度<=一屏幕的高度+滚动条滚动的距离
                    if(scroll.getChildAt(0).getMeasuredHeight()<=scroll.getHeight()+scroll.getY()){
                        Log.i("Main", "底部状态");
                    }
                    break;
                }
                
                }
                
                return false;
            }
        });
    }

    @Override
    public void onClick(View v) {
        // TODO Auto-generated method stub
        switch(v.getId()){
        /**
         * scroll的两种滑动方式：
         *     scrollTo：以滚动视图起始位置开始计算
         *     scrollBy：相对前一次的位置，去滚动对应的距离
         */
            case R.id.up:{
                scroll.scrollBy(0, -30);
                break;
            }
            case R.id.down:{
                scroll.scrollBy(0, 30);
                break;
            }
        }
    }
    }