PullToRefreshScrollView+GridView，實(shí)現(xiàn)向下滑動中隱藏自定義Action布局

最近電商類項目有個需求挺頭疼，要求用GridView去顯示商品，滑動到底部下拉能加載更多商品，向下滑動過程中需要隱藏掉自定義的Action布局，向上滑動能顯示出來，整體效果類似淘寶APP搜索結(jié)果頁那樣。

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起初覺得挺簡單的，但是后來才發(fā)現(xiàn)還是得轉(zhuǎn)一點(diǎn)腦子。最開始我想用PullToRefreshGridView，但是后來發(fā)現(xiàn)GridView沒有添加headview的方法，只能采用PullToRefreshScrollView內(nèi)嵌套GridView的方法，Scrollview里多放一個空白布局當(dāng)GridView的headview，高度和Action布局一樣就行。這時還有一個問題，ScrollView和GridView會產(chǎn)生滑動沖突，還好網(wǎng)上很容易找到解決辦法，我這里采用自定義GridView，最后就是監(jiān)聽方法了，最為關(guān)鍵的點(diǎn),還是直接上代碼吧：

自定義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()

{

@Override

public void onRefresh(PullToRefreshBase 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()

{

// 判斷是否第一個滑動值

boolean isFirst = true;

// Scrollview滑動的ScrollY值

private int ScrollY_Move;

// 第一個滑動的ScrollY值

private int First_ScrollY_Move;

// 手指抬起時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沒用，不用監(jiān)聽

case MotionEvent.ACTION_MOVE:

if (isFirst)

{

// 記錄下第一個滑動的ScrollY值

First_ScrollY_Move = v.getScrollY();

isFirst = false;

}

// 記錄下Scrollview滑動的ScrollY值

ScrollY_Move = v.getScrollY();

// 計算出ScrollY_Move和First_ScrollY_Move的差值

Cha = ScrollY_Move - First_ScrollY_Move;

// 當(dāng)ScrollY_Move>First_ScrollY_Move時證明滑動方向是向下；

// 加上判斷差值的目的：當(dāng)Actionbar顯示的時候，手指按住往下滑過一段距離還未抬起時，Actionbar也能隱藏

if (First_ScrollY_Move < ScrollY_Move || Cha > 200)

{

// 隱藏Actionbar

actionLayout.setVisibility(View.GONE);

}

// 當(dāng)ScrollY_Move

// 加上判斷差值的目的：當(dāng)Actionbar顯示的時候，手指按住往上滑過一段距離還未抬起時，Actionbar也能顯示

// 判斷ScrollY_Move < 150目的：當(dāng)Scrollview滑動接近頂端時必須顯示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();// 記錄下手指抬起時ScrollY值

isFirst = true;// 將isFirst還原為初始化

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：

xmlns:tools="http://schemas.android.com/tools"