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listview 下拉刷新 上拉加载 Android ListView下拉刷新上拉自动加载更多DEMO示例

SunnyCoffee 人气:0
想了解Android ListView下拉刷新上拉自动加载更多DEMO示例的相关内容吗,SunnyCoffee在本文为您仔细讲解listview 下拉刷新 上拉加载的相关知识和一些Code实例,欢迎阅读和指正,我们先划重点:listview下拉刷新上拉加载,下面大家一起来学习吧。

代码下载地址已经更新。因为代码很久没更新,已经很落伍了,建议大家使用RecyclerView实现。

参考项目:

https://github.com/bingoogolapple/BGARefreshLayout-Android

https://github.com/baoyongzhang/android-PullRefreshLayout

下拉刷新,Android中非常普遍的功能。为了方便便重写的ListView来实现下拉刷新,同时添加了上拉自动加载更多的功能。设计最初是参考开源中国的Android客户端源码。先看示例图。

图1 图2


图3 图4


图5 图6

下拉刷新的时动画效果: 图1 ==》 图2 ==》 图3 ==》 图4 ==》 图1。

上拉自动加载更多的效果:图5

图6是示例demo的截图

重写后的listview动画效果来源于添加的头部(header)和尾部(footer),listview提供了addHeaderView和addFooterView方法来添加header和footer。大家也可以通过修改头部、尾部的xml文件来定义自己的动画效果。

实现原理

1.下拉刷新

通过onTouchEvent判断手势,来改变listview的header。header的状态共4种,自己定义为:

NONE(对应图1):初始状态

PULL(对应图2):下拉状态,此时松开会还原到状态NONE,并不进行刷新

RELEASE(对应图3):同样是下拉状态,但此刻松开会执行刷新,进入状态REFRESHING

REFRESHING(对应图4):正在执行刷新,刷新结束后进入状态NONE。

header在四种状态切换时不仅改变内部组件,同时改变自身的大小。改变内部组件的体现比如,箭头的朝上或者朝下,文字提示的变化,等待圆圈的显示与否。大小的改变其实就是高度的改变,NONE时header高度为0,RELEASE时header的高度由你下拉的程度决定。

2.加载更多

在listview滑动停止后,判断listview的最后一个item是否已经显示,如果显示说明listview已经滑动到了最底部,这时便触发加载更多的方法,方法结束根据结果改变footer。

3.回调方法

在类中定义了两个接口OnRefreshListener和OnLoadListener,用来定义和提供加载数据的方法,具体实现则交给它们的实现类去做。

package com.example.autolistview.widget; 
import com.example.autolistview.R; 
import com.example.autolistview.utils.Utils; 
import android.content.Context; 
import android.util.AttributeSet; 
import android.view.LayoutInflater; 
import android.view.MotionEvent; 
import android.view.View; 
import android.view.ViewGroup; 
import android.view.animation.LinearInterpolator; 
import android.view.animation.RotateAnimation; 
import android.widget.AbsListView; 
import android.widget.ImageView; 
import android.widget.ProgressBar; 
import android.widget.TextView; 
import android.widget.AbsListView.OnScrollListener; 
import android.widget.ListView; 
/** 
* @author SunnyCoffee 
* @create 2013-10-24 
* @version 1.0 
* @desc 自定义Listview 下拉刷新,上拉加载更多 
*/ 
public class AutoListView extends ListView implements OnScrollListener { 
// 区分当前操作是刷新还是加载 
public static final int REFRESH = 0; 
public static final int LOAD = 1; 
// 区分PULL和RELEASE的距离的大小 
private static final int SPACE = 20; 
// 定义header的四种状态和当前状态 
private static final int NONE = 0; 
private static final int PULL = 1; 
private static final int RELEASE = 2; 
private static final int REFRESHING = 3; 
private int state; 
private LayoutInflater inflater; 
private View header; 
private View footer; 
private TextView tip; 
private TextView lastUpdate; 
private ImageView arrow; 
private ProgressBar refreshing; 
private TextView noData; 
private TextView loadFull; 
private TextView more; 
private ProgressBar loading; 
private RotateAnimation animation; 
private RotateAnimation reverseAnimation; 
private int startY; 
private int firstVisibleItem; 
private int scrollState; 
private int headerContentInitialHeight; 
private int headerContentHeight; 
// 只有在listview第一个item显示的时候(listview滑到了顶部)才进行下拉刷新, 否则此时的下拉只是滑动listview 
private boolean isRecorded; 
private boolean isLoading;// 判断是否正在加载 
private boolean loadEnable = true;// 开启或者关闭加载更多功能 
private boolean isLoadFull; 
private int pageSize = 10; 
private OnRefreshListener onRefreshListener; 
private OnLoadListener onLoadListener; 
public AutoListView(Context context) { 
super(context); 
initView(context); 
} 
public AutoListView(Context context, AttributeSet attrs) { 
super(context, attrs); 
initView(context); 
} 
public AutoListView(Context context, AttributeSet attrs, int defStyle) { 
super(context, attrs, defStyle); 
initView(context); 
} 
// 下拉刷新监听 
public void setOnRefreshListener(OnRefreshListener onRefreshListener) { 
this.onRefreshListener = onRefreshListener; 
} 
// 加载更多监听 
public void setOnLoadListener(OnLoadListener onLoadListener) { 
this.loadEnable = true; 
this.onLoadListener = onLoadListener; 
} 
public boolean isLoadEnable() { 
return loadEnable; 
} 
// 这里的开启或者关闭加载更多,并不支持动态调整 
public void setLoadEnable(boolean loadEnable) { 
this.loadEnable = loadEnable; 
this.removeFooterView(footer); 
} 
public int getPageSize() { 
return pageSize; 
} 
public void setPageSize(int pageSize) { 
this.pageSize = pageSize; 
} 
// 初始化组件 
private void initView(Context context) { 
// 设置箭头特效 
animation = new RotateAnimation(0, -180, 
RotateAnimation.RELATIVE_TO_SELF, 0.5f, 
RotateAnimation.RELATIVE_TO_SELF, 0.5f); 
animation.setInterpolator(new LinearInterpolator()); 
animation.setDuration(100); 
animation.setFillAfter(true); 
reverseAnimation = new RotateAnimation(-180, 0, 
RotateAnimation.RELATIVE_TO_SELF, 0.5f, 
RotateAnimation.RELATIVE_TO_SELF, 0.5f); 
reverseAnimation.setInterpolator(new LinearInterpolator()); 
reverseAnimation.setDuration(100); 
reverseAnimation.setFillAfter(true); 
inflater = LayoutInflater.from(context); 
footer = inflater.inflate(R.layout.listview_footer, null); 
loadFull = (TextView) footer.findViewById(R.id.loadFull); 
noData = (TextView) footer.findViewById(R.id.noData); 
more = (TextView) footer.findViewById(R.id.more); 
loading = (ProgressBar) footer.findViewById(R.id.loading); 
header = inflater.inflate(R.layout.pull_to_refresh_header, null); 
arrow = (ImageView) header.findViewById(R.id.arrow); 
tip = (TextView) header.findViewById(R.id.tip); 
lastUpdate = (TextView) header.findViewById(R.id.lastUpdate); 
refreshing = (ProgressBar) header.findViewById(R.id.refreshing); 
// 为listview添加头部和尾部,并进行初始化 
headerContentInitialHeight = header.getPaddingTop(); 
measureView(header); 
headerContentHeight = header.getMeasuredHeight(); 
topPadding(-headerContentHeight); 
this.addHeaderView(header); 
this.addFooterView(footer); 
this.setOnScrollListener(this); 
} 
public void onRefresh() { 
if (onRefreshListener != null) { 
onRefreshListener.onRefresh(); 
} 
} 
public void onLoad() { 
if (onLoadListener != null) { 
onLoadListener.onLoad(); 
} 
} 
public void onRefreshComplete(String updateTime) { 
lastUpdate.setText(this.getContext().getString(R.string.lastUpdateTime, 
lastUpdate)); 
state = NONE; 
refreshHeaderViewByState(); 
} 
// 用于下拉刷新结束后的回调 
public void onRefreshComplete() { 
String currentTime = Utils.getCurrentTime(); 
onRefreshComplete(currentTime); 
} 
// 用于加载更多结束后的回调 
public void onLoadComplete() { 
isLoading = false; 
} 
@Override 
public void onScroll(AbsListView view, int firstVisibleItem, 
int visibleItemCount, int totalItemCount) { 
this.firstVisibleItem = firstVisibleItem; 
} 
@Override 
public void onScrollStateChanged(AbsListView view, int scrollState) { 
this.scrollState = scrollState; 
ifNeedLoad(view, scrollState); 
} 
// 根据listview滑动的状态判断是否需要加载更多 
private void ifNeedLoad(AbsListView view, int scrollState) { 
if (!loadEnable) { 
return; 
} 
try { 
if (scrollState == OnScrollListener.SCROLL_STATE_IDLE 
&& !isLoading 
&& view.getLastVisiblePosition() == view 
.getPositionForView(footer) && !isLoadFull) { 
onLoad(); 
isLoading = true; 
} 
} catch (Exception e) { 
} 
} 
/** 
* 监听触摸事件,解读手势 
*/ 
@Override 
public boolean onTouchEvent(MotionEvent ev) { 
switch (ev.getAction()) { 
case MotionEvent.ACTION_DOWN: 
if (firstVisibleItem == 0) { 
isRecorded = true; 
startY = (int) ev.getY(); 
} 
break; 
case MotionEvent.ACTION_CANCEL: 
case MotionEvent.ACTION_UP: 
if (state == PULL) { 
state = NONE; 
refreshHeaderViewByState(); 
} else if (state == RELEASE) { 
state = REFRESHING; 
refreshHeaderViewByState(); 
onRefresh(); 
} 
isRecorded = false; 
break; 
case MotionEvent.ACTION_MOVE: 
whenMove(ev); 
break; 
} 
return super.onTouchEvent(ev); 
} 
// 解读手势,刷新header状态 
private void whenMove(MotionEvent ev) { 
if (!isRecorded) { 
return; 
} 
int tmpY = (int) ev.getY(); 
int space = tmpY - startY; 
int topPadding = space - headerContentHeight; 
switch (state) { 
case NONE: 
if (space > 0) { 
state = PULL; 
refreshHeaderViewByState(); 
} 
break; 
case PULL: 
topPadding(topPadding); 
if (scrollState == SCROLL_STATE_TOUCH_SCROLL 
&& space > headerContentHeight + SPACE) { 
state = RELEASE; 
refreshHeaderViewByState(); 
} 
break; 
case RELEASE: 
topPadding(topPadding); 
if (space > 0 && space < headerContentHeight + SPACE) { 
state = PULL; 
refreshHeaderViewByState(); 
} else if (space <= 0) { 
state = NONE; 
refreshHeaderViewByState(); 
} 
break; 
} 
} 
// 调整header的大小。其实调整的只是距离顶部的高度。 
private void topPadding(int topPadding) { 
header.setPadding(header.getPaddingLeft(), topPadding, 
header.getPaddingRight(), header.getPaddingBottom()); 
header.invalidate(); 
} 
/** 
* 这个方法是根据结果的大小来决定footer显示的。 
* <p> 
* 这里假定每次请求的条数为10。如果请求到了10条。则认为还有数据。如过结果不足10条,则认为数据已经全部加载,这时footer显示已经全部加载 
* </p> 
* 
* @param resultSize 
*/ 
public void setResultSize(int resultSize) { 
if (resultSize == 0) { 
isLoadFull = true; 
loadFull.setVisibility(View.GONE); 
loading.setVisibility(View.GONE); 
more.setVisibility(View.GONE); 
noData.setVisibility(View.VISIBLE); 
} else if (resultSize > 0 && resultSize < pageSize) { 
isLoadFull = true; 
loadFull.setVisibility(View.VISIBLE); 
loading.setVisibility(View.GONE); 
more.setVisibility(View.GONE); 
noData.setVisibility(View.GONE); 
} else if (resultSize == pageSize) { 
isLoadFull = false; 
loadFull.setVisibility(View.GONE); 
loading.setVisibility(View.VISIBLE); 
more.setVisibility(View.VISIBLE); 
noData.setVisibility(View.GONE); 
} 
} 
// 根据当前状态,调整header 
private void refreshHeaderViewByState() { 
switch (state) { 
case NONE: 
topPadding(-headerContentHeight); 
tip.setText(R.string.pull_to_refresh); 
refreshing.setVisibility(View.GONE); 
arrow.clearAnimation(); 
arrow.setImageResource(R.drawable.pull_to_refresh_arrow); 
break; 
case PULL: 
arrow.setVisibility(View.VISIBLE); 
tip.setVisibility(View.VISIBLE); 
lastUpdate.setVisibility(View.VISIBLE); 
refreshing.setVisibility(View.GONE); 
tip.setText(R.string.pull_to_refresh); 
arrow.clearAnimation(); 
arrow.setAnimation(reverseAnimation); 
break; 
case RELEASE: 
arrow.setVisibility(View.VISIBLE); 
tip.setVisibility(View.VISIBLE); 
lastUpdate.setVisibility(View.VISIBLE); 
refreshing.setVisibility(View.GONE); 
tip.setText(R.string.pull_to_refresh); 
tip.setText(R.string.release_to_refresh); 
arrow.clearAnimation(); 
arrow.setAnimation(animation); 
break; 
case REFRESHING: 
topPadding(headerContentInitialHeight); 
refreshing.setVisibility(View.VISIBLE); 
arrow.clearAnimation(); 
arrow.setVisibility(View.GONE); 
tip.setVisibility(View.GONE); 
lastUpdate.setVisibility(View.GONE); 
break; 
} 
} 
// 用来计算header大小的。比较隐晦。 
private void measureView(View child) { 
ViewGroup.LayoutParams p = child.getLayoutParams(); 
if (p == null) { 
p = new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, 
ViewGroup.LayoutParams.WRAP_CONTENT); 
} 
int childWidthSpec = ViewGroup.getChildMeasureSpec(0, 0 + 0, p.width); 
int lpHeight = p.height; 
int childHeightSpec; 
if (lpHeight > 0) { 
childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, 
MeasureSpec.EXACTLY); 
} else { 
childHeightSpec = MeasureSpec.makeMeasureSpec(0, 
MeasureSpec.UNSPECIFIED); 
} 
child.measure(childWidthSpec, childHeightSpec); 
} 
/* 
* 定义下拉刷新接口 
*/ 
public interface OnRefreshListener { 
public void onRefresh(); 
} 
/* 
* 定义加载更多接口 
*/ 
public interface OnLoadListener { 
public void onLoad(); 
} 
}

这个类的逻辑复杂的地方就是header四种状态的判断和切换。

以下是几种状态的切换情况

NONE ==》 PULL
NONE 《== PULL ==》 RELEASE
PULL 《== RELEASE ==》 REFRESHING
REFRESHING ==》 NONE

代码中对于 RELEASE ==》PULL 状态的切换处理的不太理想,好像是纵坐标的记录方式有问题,如果有谁解决,希望能够留言告知。

为了减少篇幅,其他代码就不在贴了。

注意:定义header的xml最外层必须使用线性布局,不然的话会出错。

以上所述是小编给大家介绍的Android ListView下拉刷新上拉自动加载更多DEMO示例,希望对大家有所帮助,如果大家有任何疑问请给我留言,小编会及时回复大家的。在此也非常感谢大家对网站的支持!

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