Android ListView下拉刷新上拉自动加载更多DEMO示例
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
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