最近电商类项目有个需求挺头疼，要求用GridView去显示商品，滑动到底部下拉能加载更多商品，向下滑动过程中需要隐藏掉自定义的Action布局，向上滑动能显示出来，整体效果类似淘宝APP搜索结果页那样。
起初觉得挺简单的，但是后来才发现还是得转一点脑子。最开始我想用PullToRefreshGridView，但是后来发现GridView没有添加headview的方法，只能采用PullToRefreshScrollView内嵌套GridView的方法，Scrollview里多放一个空白布局当GridView的headview，高度和Action布局一样就行。这时还有一个问题，ScrollView和GridView会产生滑动冲突，还好网上很容易找到解决办法，我这里采用自定义GridView，最后就是监听方法了，最为关键的点,还是直接上代码吧：
自定义GridView：
package com.example.ztestscrollview;
import android.content.Context;
import android.util.AttributeSet;
import android.view.View.MeasureSpec;
import android.widget.GridView;
public class MyGridView extends GridView{
public MyGridView(Context context, AttributeSet attrs) {
super(context, attrs);
}
public MyGridView(Context context) {
super(context);
}
public MyGridView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
}
@Override
public void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
int expandSpec = MeasureSpec.makeMeasureSpec(Integer.MAX_VALUE >> 2,
MeasureSpec.AT_MOST);
super.onMeasure(widthMeasureSpec, expandSpec);
}
}
主界面：
package com.example.ztestscrollview;
import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnTouchListener;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ScrollView;
import com.handmark.pulltorefresh.library.PullToRefreshBase;
import com.handmark.pulltorefresh.library.PullToRefreshBase.Mode;
import com.handmark.pulltorefresh.library.PullToRefreshBase.OnRefreshListener;
import com.handmark.pulltorefresh.library.PullToRefreshScrollView;
public class MainActivity extends Activity
{
int num = 10;
private GridAdapter adapter;
private ScrollView scrollView;
private PullToRefreshScrollView ptr_scrollview;
private View actionLayout;
private MyGridView myGridview;
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
actionLayout = findViewById(R.id.actionlayout);
ptr_scrollview = (PullToRefreshScrollView) findViewById(R.id.ptr_scrollview);
ptr_scrollview.setMode(Mode.PULL_UP_TO_REFRESH);
ptr_scrollview.setOnRefreshListener(new OnRefreshListener<ScrollView>()
{
@Override
public void onRefresh(PullToRefreshBase<ScrollView> refreshView)
{
num += 10;
adapter.notifyDataSetChanged();
ptr_scrollview.onRefreshComplete();
}
});
myGridview = (MyGridView) findViewById(R.id.myGridView1);
adapter = new GridAdapter();
myGridview.setAdapter(adapter);
scrollView = ptr_scrollview.getRefreshableView();
scrollView.setOnTouchListener(new OnTouchListener()
{
// 判断是否第一个滑动值
boolean isFirst = true;
// Scrollview滑动的ScrollY值
private int ScrollY_Move;
// 第一个滑动的ScrollY值
private int First_ScrollY_Move;
// 手指抬起时ScrollY值
private int ScrollY_Up;
// ScrollY_Move和First_ScrollY_Move的差值
private int Cha;
@Override
public boolean onTouch(View v, MotionEvent event)
{
switch (event.getAction())
{
//ACTIN_DOWN没用，不用监听
case MotionEvent.ACTION_MOVE:
if (isFirst)
{
// 记录下第一个滑动的ScrollY值
First_ScrollY_Move = v.getScrollY();
isFirst = false;
}
// 记录下Scrollview滑动的ScrollY值
ScrollY_Move = v.getScrollY();
// 计算出ScrollY_Move和First_ScrollY_Move的差值
Cha = ScrollY_Move - First_ScrollY_Move;
// 当ScrollY_Move>First_ScrollY_Move时证明滑动方向是向下；
// 加上判断差值的目的：当Actionbar显示的时候，手指按住往下滑过一段距离还未抬起时，Actionbar也能隐藏
if (First_ScrollY_Move < ScrollY_Move || Cha > 200)
{
// 隐藏Actionbar
actionLayout.setVisibility(View.GONE);
}
// 当ScrollY_Move<First_ScrollY_Move时证明滑动方向是向上；
// 加上判断差值的目的：当Actionbar显示的时候，手指按住往上滑过一段距离还未抬起时，Actionbar也能显示
// 判断ScrollY_Move < 150目的：当Scrollview滑动接近顶端时必须显示Actionbar
else if (First_ScrollY_Move > ScrollY_Move || Cha < -200
|| ScrollY_Move < 150)
{
actionLayout.setVisibility(View.VISIBLE);
}
break;
case MotionEvent.ACTION_UP:
ScrollY_Up = v.getScrollY();// 记录下手指抬起时ScrollY值
isFirst = true;// 将isFirst还原为初始化
if (ScrollY_Up == 0)
{
actionLayout.setVisibility(View.VISIBLE);
}
// Log.e("ACTION_UP--->", "scrollY_up:" + scrollY_up + " "
// + "eventY_up:" + eventY_up);
break;
default:
break;
}
return false;
}
});
}
class GridAdapter extends BaseAdapter
{
@Override
public View getView(int position, View convertView, ViewGroup parent)
{
View inflate = getLayoutInflater().inflate(R.layout.griditem, null);
return inflate;
}
@Override
public int getCount()
{
// TODO Auto-generated method stub
return num;
}
@Override
public Object getItem(int position)
{
// TODO Auto-generated method stub
return null;
}
@Override
public long getItemId(int position)
{
// TODO Auto-generated method stub
return 0;
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu)
{
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
}
布局：
<RelativeLayout 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=".MainActivity" >
<com.handmark.pulltorefresh.library.PullToRefreshScrollView
android:id="@+id/ptr_scrollview"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true" >
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:descendantFocusability="blocksDescendants" >
<RelativeLayout
android:id="@+id/headview"
android:layout_width="match_parent"
android:layout_height="120dp"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true" >
</RelativeLayout>
<com.example.ztestscrollview.MyGridView
android:id="@+id/myGridView1"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_below="@+id/headview"
android:numColumns="2" >
</com.example.ztestscrollview.MyGridView>
</RelativeLayout>
</com.handmark.pulltorefresh.library.PullToRefreshScrollView>
<RelativeLayout
android:id="@+id/actionlayout"
android:layout_width="match_parent"
android:layout_height="120dp"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:background="#cdcdcd" >
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:layout_centerVertical="true"
android:text="ActionLayout" />
</RelativeLayout>
</RelativeLayout>
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