整个是一个scrollView,嵌套一个线性布局,下拉刷新、或者上拉加载后,通过addView()方法,加载消息体,每一个消息体是一个复杂的子view。
做一个类似qq客户端“好友动态“刷新的东西,在网上找了很多,大体有3种布局类型的下拉刷新,listView、scrollView、gridView。
下拉刷新的原理网上很详细,简单点说,,拿 "好友动态" 举例,有
1、ElasticScrollViewActivity.java(对应的xml文件是main.xml,里面嵌套com.ElasticScrollView.view.ElasticScrollView)、
2、ElasticScrollView.java(继承自scrollView,定义一个ScrollView类,然后再friendCircleActivity里定义一个scrollView,scrollView的addChild方法,或者通过activityactivity_friendCircle布局里面的LinearLayout friendList的addView方法,添加singleMessage。scrollView绑定onFreshListener。这个类里面定义刷新的各个状态,下拉刷新头的更新等,下拉刷新header各个控件:下拉箭头、相关文字提示、刷新日期提示等,里面通过inflate引入headerView、coverImageView,本身是个View,没有专门对应xml文件)、
3、SingleMessageView.java(下拉刷新后,动态添加的一条条消息体,是消息体的布局,通过inflate引入sing_msg.xml),
4、activity_friendCircle.xml 就是在你的滚动布局scrollFreshview里面,根据需要再添加一个类似 ”好友动态“里自定义封面的view视图
5、single_msg.xml,定义每个消息体的布局
框架结构如图:
动态添加view,用的是linearLayout的addView方法,这样,需要在scrollFreshview的代码中定义一个LayoutInflate innerLayout,然后在这个layout里面inflate进headerView、coverImageView:
- LayoutInflater inflater = LayoutInflater.from(context);
- innerLayout = new LinearLayout(context);
- innerLayout.setLayoutParams(new LinearLayout.LayoutParams(
- LinearLayout.LayoutParams.FILL_PARENT,
- LinearLayout.LayoutParams.WRAP_CONTENT));
- innerLayout.setOrientation(LinearLayout.VERTICAL);
- headView = (LinearLayout) inflater.inflate(R.layout.mylistview_head,
- null);
- coverScrollView = (ScrollView) inflater.inflate(R.layout.activity_friends_circle,
- null);
- innerLayout.addView(headView);
- innerLayout.addView(coverScrollView);
- addView(innerLayout);
整个工程:ElasticScrollView,下载链接:
来源参考:(怎么加自定义封面,怎么定义动态添加消息的顺序,博主写的很详细,原博主用的是thread线程添加的,我的用的是异步任务)
添加上拉加载功能的时候,需要修改一下touchEvent事件,并且添加一个footView:
@Override public boolean onTouchEvent(MotionEvent ev) { // TODO Auto-generated method stub switch (ev.getAction()) { case MotionEvent.ACTION_DOWN: if (this.getScrollY() == 0 && !isRecored) { startY = (int) ev.getY(); isRecored = true; } break; case MotionEvent.ACTION_MOVE: int tempY = (int) ev.getY(); if (!isScroll) isScroll = true; if (!isRecored && this.getScrollY() == 0) { isRecored = true; startY = tempY; } if (tempY - startY < 0) { startY = tempY; } if (state != REFRESHING && state != LOADING && isRecored) { if (state == RELEASE_To_REFRESH) { if ((tempY - startY) > 0 && (tempY - startY) / RATIO < headContentHeight + 10) { state = PULL_To_REFRESH; changeHeaderViewByState(); } else if (tempY - startY <= 0) { state = DONE; changeHeaderViewByState(); } } if (state == PULL_To_REFRESH) { if ((tempY - startY) / RATIO >= headContentHeight + 10) { state = RELEASE_To_REFRESH; isBack = true; changeHeaderViewByState(); } else if (tempY - startY <= 0) { state = DONE; changeHeaderViewByState(); } } if (state == DONE) { if (tempY - startY > 0) { state = PULL_To_REFRESH; changeHeaderViewByState(); isSeeHead = true; } } if (state == RELEASE_To_REFRESH) { headView.setPadding(0, (tempY - startY) / RATIO - headContentHeight, 0, 0); headView.invalidate(); } else if (state == PULL_To_REFRESH) { headView.setPadding(0, -1 * headContentHeight + (tempY - startY) / RATIO, 0, 0); headView.invalidate(); } } break; case MotionEvent.ACTION_UP: Message message = new Message(); message.obj = myScrollView; handler.sendMessageDelayed(message, 5); if (state == PULL_To_REFRESH) { state = DONE; changeHeaderViewByState(); innerlayout_checkVisibility(); } if (state == RELEASE_To_REFRESH) { state = REFRESHING; changeHeaderViewByState(); onRefresh(); } isRecored = false; isSeeHead = false; isBack = false; viewHeight = innerLayout.getHeight(); y = this.getScrollY(); if ((viewHeight - y - this.getHeight()) == 0 && isScroll && state != REFRESHING && state != LOADING) { onLoad(); } isScroll = false; break; } if (isSeeHead) { return true; } else { return super.onTouchEvent(ev); } }
像定义刷新接口一样,这时也需要定义一个上拉加载的load接口,整个scrollView绑定上拉加载监听器,定义Onload()方法,
public void setOnLoadListener(OnLoadListener loadListener) { this.loadListener = loadListener; } public interface OnLoadListener { public void onLoad(); } private void onLoad() { if (loadListener != null) { state = LOADING; footView.setVisibility(View.VISIBLE); moreProgressBar.setVisibility(View.VISIBLE); loadMoreView.setText("正在加载更多..."); loadListener.onLoad(); //onRefresh(); } } public void onLoadComplete() { state = DONE; moreProgressBar.setVisibility(View.GONE); loadMoreView.setText("上拉加载更多"); //footView.setVisibility(View.INVISIBLE); }
然后在朋友圈界面,绑定load监听器,定义上拉加载的异步任务就可以了。下拉刷新、上拉加载的区别,就是上拉加载需要实时判定用户的动作,更改刷新header的状态,而下拉加载就是一个固定在整个view的尾部的布局,当用户手指离开屏幕,并且滑动偏移量滑到底端的时候执行onload()方法就ok了。