89、Android EditText 悬浮停靠

 package com.willen.topFloatDemo;

 import android.content.Context;
 import android.os.Handler;
 import android.util.AttributeSet;
 import android.view.MotionEvent;
 import android.widget.ScrollView;

 /*
  * ScrollView并没有实现滚动监听，所以我们必须自行实现对ScrollView的监听，
  * 我们很自然的想到在onTouchEvent()方法中实现对滚动Y轴进行监听
  * ScrollView的滚动Y值进行监听
  */
 public class MyScrollView extends ScrollView {

     private OnScrollListener onScrollListener;
     /**
      * 主要是用在用户手指离开MyScrollView，MyScrollView
      * 还在继续滑动，我们用来保存Y的距离，然后做比较
      */
     private int lastScrollY;

     public MyScrollView(Context context) {
         super(context, null);
     }
     public MyScrollView(Context context, AttributeSet attrs) {
         super(context, attrs, 0);
     }
     public MyScrollView(Context context, AttributeSet attrs, int defStyle) {
         super(context, attrs, defStyle);
     }

     /**
      * 设置滚动接口
      * @param onScrollListener
      */
     public void setOnScrollListener(OnScrollListener onScrollListener){
         this.onScrollListener = onScrollListener;
     }
     /**
      * 用于用户手指离开MyScrollView的时候获取MyScrollView滚动的Y距离，然后回调给onScroll方法中
      */
     private Handler handler = new Handler() {
         public void handleMessage(android.os.Message msg) {
             int scrollY = MyScrollView.this.getScrollY();
             //此时的距离和记录下的距离不相等，在隔5毫秒给handler发送消息
             if(lastScrollY != scrollY){
                 lastScrollY = scrollY;
                 handler.sendMessageDelayed(handler.obtainMessage(), 5);
             }
             if(onScrollListener != null){
                 onScrollListener.onScroll(scrollY);
             }
         };
     }; 

     /**
      * 重写onTouchEvent， 当用户的手在MyScrollView上面的时候，
      * 直接将MyScrollView滑动的Y方向距离回调给onScroll方法中，当用户抬起手的时候，
      * MyScrollView可能还在滑动，所以当用户抬起手我们隔5毫秒给handler发送消息，在handler处理
      * MyScrollView滑动的距离
      */
     @Override
     public boolean onTouchEvent(MotionEvent ev) {
         if(onScrollListener != null){
             onScrollListener.onScroll(lastScrollY = this.getScrollY());
         }
         switch(ev.getAction()){
         case MotionEvent.ACTION_UP:
              handler.sendMessageDelayed(handler.obtainMessage(), 20);
             break;
         }
         return super.onTouchEvent(ev);
     }

     /**
      * 滚动的回调接口
      */
     public interface OnScrollListener{
         // 回调方法， 返回MyScrollView滑动的Y方向距离
         public void onScroll(int scrollY);
     }
 }

package com.willen.topFloatDemo;

import android.app.Activity;
import android.os.Bundle;
import android.widget.EditText;
import android.widget.LinearLayout;
import android.widget.RelativeLayout;
import com.willen.topFloatDemo.MyScrollView.OnScrollListener;

public class MainActivity extends Activity implements OnScrollListener{
    private EditText search_edit;
    private MyScrollView myScrollView;
    private int searchLayoutTop;

    LinearLayout search01,search02;
    RelativeLayout rlayout;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        init();
    }

    private void init() {
        search_edit = (EditText)findViewById(R.id.search_edit);
        myScrollView = (MyScrollView)findViewById(R.id.myScrollView);
        search01 = (LinearLayout)findViewById(R.id.search01);
        search02 = (LinearLayout)findViewById(R.id.search02);
        rlayout = (RelativeLayout)findViewById(R.id.rlayout);
        myScrollView.setOnScrollListener(this);
    }

    @Override
    public void onWindowFocusChanged(boolean hasFocus) {
        super.onWindowFocusChanged(hasFocus);
        if(hasFocus){
            searchLayoutTop = rlayout.getBottom();//鑾峰彇searchLayout鐨勯《閮ㄤ綅缃�
        }
    }

    //鐩戝惉婊氬姩Y鍊煎彉鍖栵紝閫氳繃addView鍜宺emoveView鏉ュ疄鐜版偓鍋滄晥鏋�
    @Override
    public void onScroll(int scrollY) {
        if(scrollY >= searchLayoutTop){
            if (search_edit.getParent()!=search01) {
                search02.removeView(search_edit);
                search01.addView(search_edit);
            }
        }else{
            if (search_edit.getParent()!=search02) {
                search01.removeView(search_edit);
                search02.addView(search_edit);
            }
        }
    }
}