listview下拉刷新 上拉(滑动分页)加载更多
最 近做的类似于微博的项目中，有个Android功能要使用到listview的向下拉刷新来刷新最新消息，向上拉刷新（滑动分页）来加载更多。
新浪微博就是使用这种方式的典型。
当用户从网络上读取微博的时候，如果一下子全部加载用户未读的微博这将耗费比较长的时间，造成不好的用户体验，同时一屏的内容也不足以显示如此多的内容。这时候，我们就需要用到另一个功能，那就是listview的分页了，其实这个分页可以做成客户端的分页，也可以做成服务器端的分页（点击加载时，从服务器对应的加载第N页就好了！！！）。通过分页分次加载数据，用户看多少就去加载多少。
通常这也分为两种方式，一种是设置一个按钮，用户点击即加载。另一种是当用户滑动到底部时自动加载。今天我就和大家分享一下滑动到底端时自动加载这个功能的实现。
效果图如下所示：
下拉刷新最主要的流程是：
(1). 下拉，显示提示头部界面(HeaderView)，这个过程提示用户”下拉刷新”
(2). 下拉到一定程度，超出了刷新最基本的下拉界限，我们认为达到了刷新的条件，提示用户可以”松手刷新”了，效果上允许用户继续下拉
(3). 用户松手，可能用户下拉远远不止提示头部界面，所以这一步，先反弹回仅显示提示头部界面，然后提示用户”正在加载”。
(4). 加载完成后，隐藏提示头部界面。
那么让我们看看怎么才能实现呢？？？
第一步：既然是要显示listview ，那么就应该有个listview 的容器pulldown.xml
<?xml version="1.0" encoding="utf-8"?> <com.solo.pulldown.PullDownView xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/pull_down_view" android:layout_width="fill_parent" android:layout_height="fill_parent" android:background="@android:color/white"> </com.solo.pulldown.PullDownView>
第二步：自定义一个listview中显示的item对象pulldown_item.xml
<?xml version="1.0" encoding="utf-8"?> <TextView xmlns:android="http://schemas.android.com/apk/res/android" android:id="@android:id/text1" android:layout_width="fill_parent" android:layout_height="wrap_content" android:textAppearance="?android:attr/textAppearanceLarge" android:gravity="center_vertical" android:paddingLeft="6dip" android:minHeight="?android:attr/listPreferredItemHeight" android:textColor="@android:color/black" />
第三步：定义一个header的xml布局文件pulldown_header.xml
<?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="wrap_content" android:paddingBottom="10dp" android:paddingTop="10dp" > <ImageView android:id="@+id/pulldown_header_arrow" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignParentLeft="true" android:layout_marginLeft="20dp" android:scaleType="centerCrop" android:src="@drawable/z_arrow_down" android:visibility="invisible" /> <LinearLayout android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignBottom="@+id/pulldown_header_arrow" android:layout_alignTop="@+id/pulldown_header_arrow" android:layout_centerHorizontal="true" android:gravity="center_vertical" android:orientation="vertical" > <TextView android:id="@+id/pulldown_header_text" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="center_horizontal" android:text="加载中..." /> <TextView android:id="@+id/pulldown_header_date" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="center_horizontal" android:text="更新于:" android:visibility="gone" /> </LinearLayout> <ProgressBar android:id="@+id/pulldown_header_loading" style="@android:style/Widget.ProgressBar.Small.Inverse" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_centerVertical="true" android:layout_marginLeft="20dp" /> </RelativeLayout>
第四步：如果需要向上拉更新更多的话，那就定义一个底部的footer的布局文件，在此为方便起见，只定义一个progressbar跟textview，更加复杂的显示，就交给你们了~~~~~pulldown_footer.xml：
<?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="wrap_content" android:paddingBottom="10dp" android:paddingTop="10dp" > <TextView android:id="@+id/pulldown_footer_text" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_centerInParent="true" android:text="更多" android:textSize="15dp" /> <ProgressBar android:id="@+id/pulldown_footer_loading" style="@android:style/Widget.ProgressBar.Small.Inverse" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_centerVertical="true" android:layout_marginLeft="20dp" android:visibility="gone" /> </RelativeLayout>
第五步：那么主要的文件这才登场：：：：：：：重写listview这个文件主要任务是提供触摸的事件的处理方法。
/** * <p>一个可以监听ListView是否滚动到最顶部或最底部的自定义控件</p> * 只能监听由触摸产生的，如果是ListView本身Flying导致的，则不能监听</br> * 如果加以改进，可以实现监听scroll滚动的具体位置等 */ public class ScrollOverListView extends ListView { private int mLastY; private int mTopPosition; private int mBottomPosition; public ScrollOverListView(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); init(); } public ScrollOverListView(Context context, AttributeSet attrs) { super(context, attrs); init(); } public ScrollOverListView(Context context) { super(context); init(); } private void init(){ mTopPosition = 0; mBottomPosition = 0; } @Override public boolean onTouchEvent(MotionEvent ev) { final int action = ev.getAction(); final int y = (int) ev.getRawY(); switch(action){ case MotionEvent.ACTION_DOWN:{ mLastY = y; final boolean isHandled = mOnScrollOverListener.onMotionDown(ev); if (isHandled) { mLastY = y; return isHandled; } break; } case MotionEvent.ACTION_MOVE:{ final int childCount = getChildCount(); if(childCount == 0) return super.onTouchEvent(ev); final int itemCount = getAdapter().getCount() - mBottomPosition; final int deltaY = y - mLastY; //DLog.d("lastY=%d y=%d", mLastY, y); final int firstTop = getChildAt(0).getTop(); final int listPadding = getListPaddingTop(); final int lastBottom = getChildAt(childCount - 1).getBottom(); final int end = getHeight() - getPaddingBottom(); final int firstVisiblePosition = getFirstVisiblePosition(); final boolean isHandleMotionMove = mOnScrollOverListener.onMotionMove(ev, deltaY); if(isHandleMotionMove){ mLastY = y; return true; } //DLog.d("firstVisiblePosition=%d firstTop=%d listPaddingTop=%d deltaY=%d", firstVisiblePosition, firstTop, listPadding, deltaY); if (firstVisiblePosition <= mTopPosition && firstTop >= listPadding && deltaY > 0) { final boolean isHandleOnListViewTopAndPullDown; isHandleOnListViewTopAndPullDown = mOnScrollOverListener.onListViewTopAndPullDown(deltaY); if(isHandleOnListViewTopAndPullDown){ mLastY = y; return true; } } // DLog.d("lastBottom=%d end=%d deltaY=%d", lastBottom, end, deltaY); if (firstVisiblePosition + childCount >= itemCount && lastBottom <= end && deltaY < 0) { final boolean isHandleOnListViewBottomAndPullDown; isHandleOnListViewBottomAndPullDown = mOnScrollOverListener.onListViewBottomAndPullUp(deltaY); if(isHandleOnListViewBottomAndPullDown){ mLastY = y; return true; } } break; } case MotionEvent.ACTION_UP:{ final boolean isHandlerMotionUp = mOnScrollOverListener.onMotionUp(ev); if (isHandlerMotionUp) { mLastY = y; return true; } break; } } mLastY = y; return super.onTouchEvent(ev); } /**空的*/ private OnScrollOverListener mOnScrollOverListener = new OnScrollOverListener(){ @Override public boolean onListViewTopAndPullDown(int delta) { return false; } @Override public boolean onListViewBottomAndPullUp(int delta) { return false; } @Override public boolean onMotionDown(MotionEvent ev) { return false; } @Override public boolean onMotionMove(MotionEvent ev, int delta) { return false; } @Override public boolean onMotionUp(MotionEvent ev) { return false; } }; // =============================== public method =============================== /** * 可以自定义其中一个条目为头部，头部触发的事件将以这个为准，默认为第一个 * * @param index 正数第几个，必须在条目数范围之内 */ public void setTopPosition(int index){ if(getAdapter() == null) throw new NullPointerException("You must set adapter before setTopPosition!"); if(index < 0) throw new IllegalArgumentException("Top position must > 0"); mTopPosition = index; } /** * 可以自定义其中一个条目为尾部，尾部触发的事件将以这个为准，默认为最后一个 * * @param index 倒数第几个，必须在条目数范围之内 */ public void setBottomPosition(int index){ if(getAdapter() == null) throw new NullPointerException("You must set adapter before setBottonPosition!"); if(index < 0) throw new IllegalArgumentException("Bottom position must > 0"); mBottomPosition = index; } /** * 设置这个Listener可以监听是否到达顶端，或者是否到达低端等事件</br> * * @see OnScrollOverListener */ public void setOnScrollOverListener(OnScrollOverListener onScrollOverListener){ mOnScrollOverListener = onScrollOverListener; } /** * 滚动监听接口</br> * @see ScrollOverListView#setOnScrollOverListener(OnScrollOverListener) * */ public interface OnScrollOverListener { /** * 到达最顶部触发 * * @param delta 手指点击移动产生的偏移量 * @return */ boolean onListViewTopAndPullDown(int delta); /** * 到达最底部触发 * * @param delta 手指点击移动产生的偏移量 * @return */ boolean onListViewBottomAndPullUp(int delta); /** * 手指触摸按下触发，相当于{@link MotionEvent#ACTION_DOWN} * * @return 返回true表示自己处理 * @see View#onTouchEvent(MotionEvent) */ boolean onMotionDown(MotionEvent ev); /** * 手指触摸移动触发，相当于{@link MotionEvent#ACTION_MOVE} * * @return 返回true表示自己处理 * @see View#onTouchEvent(MotionEvent) */ boolean onMotionMove(MotionEvent ev, int delta); /** * 手指触摸后提起触发，相当于{@link MotionEvent#ACTION_UP} * * @return 返回true表示自己处理 * @see View#onTouchEvent(MotionEvent) */ boolean onMotionUp(MotionEvent ev); } }
第六步：下拉刷新控件，真正实现下拉刷新的是这个控件，而上面的那个ScrollOverListView只是提供触摸的事件等
/** * 下拉刷新控件</br> * 真正实现下拉刷新的是这个控件， * ScrollOverListView只是提供触摸的事件等 */ public class PullDownView extends LinearLayout implements OnScrollOverListener{ private static final String TAG = "PullDownView"; private static final int START_PULL_DEVIATION = 50; // 移动误差 private static final int AUTO_INCREMENTAL = 10; // 自增量，用于回弹 private static final int WHAT_DID_LOAD_DATA = 1; // Handler what 数据加载完毕 private static final int WHAT_ON_REFRESH = 2; // Handler what 刷新中 private static final int WHAT_DID_REFRESH = 3; // Handler what 已经刷新完 private static final int WHAT_SET_HEADER_HEIGHT = 4;// Handler what 设置高度 private static final int WHAT_DID_MORE = 5; // Handler what 已经获取完更多 private static final int DEFAULT_HEADER_VIEW_HEIGHT = 105; // 头部文件原本的高度 private static SimpleDateFormat dateFormat = new SimpleDateFormat("MM-dd HH:mm"); private View mHeaderView; private LayoutParams mHeaderViewParams; private TextView mHeaderViewDateView; private TextView mHeaderTextView; private ImageView mHeaderArrowView; private View mHeaderLoadingView; private View mFooterView; private TextView mFooterTextView; private View mFooterLoadingView; private ScrollOverListView mListView; private OnPullDownListener mOnPullDownListener; private RotateAnimation mRotateOTo180Animation; private RotateAnimation mRotate180To0Animation; private int mHeaderIncremental; // 增量 private float mMotionDownLastY; // 按下时候的Y轴坐标 private boolean mIsDown; // 是否按下 private boolean mIsRefreshing; // 是否下拉刷新中 private boolean mIsFetchMoreing; // 是否获取更多中 private boolean mIsPullUpDone; // 是否回推完成 private boolean mEnableAutoFetchMore; // 是否允许自动获取更多 // 头部文件的状态 private static final int HEADER_VIEW_STATE_IDLE = 0; // 空闲 private static final int HEADER_VIEW_STATE_NOT_OVER_HEIGHT = 1; // 没有超过默认高度 private static final int HEADER_VIEW_STATE_OVER_HEIGHT = 2; // 超过默认高度 private int mHeaderViewState = HEADER_VIEW_STATE_IDLE; public PullDownView(Context context, AttributeSet attrs) { super(context, attrs); initHeaderViewAndFooterViewAndListView(context); } public PullDownView(Context context) { super(context); initHeaderViewAndFooterViewAndListView(context); } /* * ================================== * Public method * 外部使用，具体就是用这几个就可以了 * * ================================== */ /** * 刷新事件接口 */ public interface OnPullDownListener { void onRefresh(); void onMore(); } /** * 通知加载完了数据，要放在Adapter.notifyDataSetChanged后面 * 当你加载完数据的时候，调用这个notifyDidLoad() * 才会隐藏头部，并初始化数据等 */ public void notifyDidLoad() { mUIHandler.sendEmptyMessage(WHAT_DID_LOAD_DATA); } /** * 通知已经刷新完了，要放在Adapter.notifyDataSetChanged后面 * 当你执行完刷新任务之后，调用这个notifyDidRefresh() * 才会隐藏掉头部文件等操作 */ public void notifyDidRefresh() { mUIHandler.sendEmptyMessage(WHAT_DID_REFRESH); } /** * 通知已经获取完更多了，要放在Adapter.notifyDataSetChanged后面 * 当你执行完更多任务之后，调用这个notyfyDidMore() * 才会隐藏加载圈等操作 */ public void notifyDidMore() { mUIHandler.sendEmptyMessage(WHAT_DID_MORE); } /** * 设置监听器 * @param listener */ public void setOnPullDownListener(OnPullDownListener listener){ mOnPullDownListener = listener; } /** * 获取内嵌的listview * @return ScrollOverListView */ public ListView getListView(){ return mListView; } /** * 是否开启自动获取更多 * 自动获取更多，将会隐藏footer，并在到达底部的时候自动刷新 * @param index 倒数第几个触发 */ public void enableAutoFetchMore(boolean enable, int index){ if(enable){ mListView.setBottomPosition(index); mFooterLoadingView.setVisibility(View.VISIBLE); }else{ mFooterTextView.setText("更多"); mFooterLoadingView.setVisibility(View.GONE); } mEnableAutoFetchMore = enable; } /* * ================================== * Private method * 具体实现下拉刷新等操作 * * ================================== */ /** * 初始化界面 */ private void initHeaderViewAndFooterViewAndListView(Context context){ setOrientation(LinearLayout.VERTICAL); //setDrawingCacheEnabled(false); /* * 自定义头部文件 * 放在这里是因为考虑到很多界面都需要使用 * 如果要修改，和它相关的设置都要更改 */ mHeaderView = LayoutInflater.from(context).inflate(R.layout.pulldown_header, null); mHeaderViewParams = new LayoutParams(LayoutParams.FILL_PARENT, LayoutParams.WRAP_CONTENT); addView(mHeaderView, 0, mHeaderViewParams); mHeaderTextView = (TextView) mHeaderView.findViewById(R.id.pulldown_header_text); mHeaderArrowView = (ImageView) mHeaderView.findViewById(R.id.pulldown_header_arrow); mHeaderLoadingView = mHeaderView.findViewById(R.id.pulldown_header_loading); // 注意，图片旋转之后，再执行旋转，坐标会重新开始计算 mRotateOTo180Animation = new RotateAnimation(0, 180, Animation.RELATIVE_TO_SELF, 0.5f, Animation.RELATIVE_TO_SELF, 0.5f); mRotateOTo180Animation.setDuration(250); mRotateOTo180Animation.setFillAfter(true); mRotate180To0Animation = new RotateAnimation(180, 0, Animation.RELATIVE_TO_SELF, 0.5f, Animation.RELATIVE_TO_SELF, 0.5f); mRotate180To0Animation.setDuration(250); mRotate180To0Animation.setFillAfter(true); /** * 自定义脚部文件 */ mFooterView = LayoutInflater.from(context).inflate(R.layout.pulldown_footer, null); mFooterTextView = (TextView) mFooterView.findViewById(R.id.pulldown_footer_text); mFooterLoadingView = mFooterView.findViewById(R.id.pulldown_footer_loading); mFooterView.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { if(!mIsFetchMoreing){ mIsFetchMoreing = true; mFooterLoadingView.setVisibility(View.VISIBLE); mOnPullDownListener.onMore(); } } }); /* * ScrollOverListView 同样是考虑到都是使用，所以放在这里 * 同时因为，需要它的监听事件 */ mListView = new ScrollOverListView(context); mListView.setOnScrollOverListener(this); mListView.setCacheColorHint(0); addView(mListView, LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT); // 空的listener mOnPullDownListener = new OnPullDownListener() { @Override public void onRefresh() {} @Override public void onMore() {} }; } /** * 在下拉和回推的时候检查头部文件的状态</br> * 如果超过了默认高度，就显示松开可以刷新， * 否则显示下拉可以刷新 */ private void checkHeaderViewState(){ if(mHeaderViewParams.height >= DEFAULT_HEADER_VIEW_HEIGHT){ if(mHeaderViewState == HEADER_VIEW_STATE_OVER_HEIGHT) return; mHeaderViewState = HEADER_VIEW_STATE_OVER_HEIGHT; mHeaderTextView.setText("松开可以刷新"); mHeaderArrowView.startAnimation(mRotateOTo180Animation); }else{ if(mHeaderViewState == HEADER_VIEW_STATE_NOT_OVER_HEIGHT || mHeaderViewState == HEADER_VIEW_STATE_IDLE) return; mHeaderViewState = HEADER_VIEW_STATE_NOT_OVER_HEIGHT; mHeaderTextView.setText("下拉可以刷新"); mHeaderArrowView.startAnimation(mRotate180To0Animation); } } private void setHeaderHeight(final int height){ mHeaderIncremental = height; mHeaderViewParams.height = height; mHeaderView.setLayoutParams(mHeaderViewParams); } /** * 自动隐藏动画 */ class HideHeaderViewTask extends TimerTask{ @Override public void run() { if(mIsDown) { cancel(); return; } mHeaderIncremental -= AUTO_INCREMENTAL; if(mHeaderIncremental > 0){ mUIHandler.sendEmptyMessage(WHAT_SET_HEADER_HEIGHT); }else{ mHeaderIncremental = 0; mUIHandler.sendEmptyMessage(WHAT_SET_HEADER_HEIGHT); cancel(); } } } /** * 自动显示动画 */ class ShowHeaderViewTask extends TimerTask{ @Override public void run() { if(mIsDown) { cancel(); return; } mHeaderIncremental -= AUTO_INCREMENTAL; if(mHeaderIncremental > DEFAULT_HEADER_VIEW_HEIGHT){ mUIHandler.sendEmptyMessage(WHAT_SET_HEADER_HEIGHT); }else{ mHeaderIncremental = DEFAULT_HEADER_VIEW_HEIGHT; mUIHandler.sendEmptyMessage(WHAT_SET_HEADER_HEIGHT); if(!mIsRefreshing){ mIsRefreshing = true; mUIHandler.sendEmptyMessage(WHAT_ON_REFRESH); } cancel(); } } } private Handler mUIHandler = new Handler(){ @Override public void handleMessage(Message msg) { switch (msg.what) { case WHAT_DID_LOAD_DATA:{ mHeaderViewParams.height = 0; mHeaderLoadingView.setVisibility(View.GONE); mHeaderTextView.setText("下拉可以刷新"); mHeaderViewDateView = (TextView) mHeaderView.findViewById(R.id.pulldown_header_date); mHeaderViewDateView.setVisibility(View.VISIBLE); mHeaderViewDateView.setText("更新于：" + dateFormat.format(new Date(System.currentTimeMillis()))); mHeaderArrowView.setVisibility(View.VISIBLE); showFooterView(); return; } case WHAT_ON_REFRESH:{ // 要清除掉动画，否则无法隐藏 mHeaderArrowView.clearAnimation(); mHeaderArrowView.setVisibility(View.INVISIBLE); mHeaderLoadingView.setVisibility(View.VISIBLE); mOnPullDownListener.onRefresh(); return; } case WHAT_DID_REFRESH :{ mIsRefreshing = false; mHeaderViewState = HEADER_VIEW_STATE_IDLE; mHeaderArrowView.setVisibility(View.VISIBLE); mHeaderLoadingView.setVisibility(View.GONE); mHeaderViewDateView.setText("更新于：" + dateFormat.format(new Date(System.currentTimeMillis()))); setHeaderHeight(0); showFooterView(); return; } case WHAT_SET_HEADER_HEIGHT :{ setHeaderHeight(mHeaderIncremental); return; } case WHAT_DID_MORE :{ mIsFetchMoreing = false; mFooterTextView.setText("更多"); mFooterLoadingView.setVisibility(View.GONE); } } } }; /** * 显示脚步脚部文件 */ private void showFooterView(){ if(mListView.getFooterViewsCount() == 0 && isFillScreenItem()){ mListView.addFooterView(mFooterView); mListView.setAdapter(mListView.getAdapter()); } } /** * 条目是否填满整个屏幕 */ private boolean isFillScreenItem(){ final int firstVisiblePosition = mListView.getFirstVisiblePosition(); final int lastVisiblePostion = mListView.getLastVisiblePosition() - mListView.getFooterViewsCount(); final int visibleItemCount = lastVisiblePostion - firstVisiblePosition + 1; final int totalItemCount = mListView.getCount() - mListView.getFooterViewsCount(); if(visibleItemCount < totalItemCount) return true; return false; } /* * ================================== * 实现 OnScrollOverListener接口 * * * ================================== */ @Override public boolean onListViewTopAndPullDown(int delta) { if(mIsRefreshing || mListView.getCount() - mListView.getFooterViewsCount() == 0) return false; int absDelta = Math.abs(delta); final int i = (int) Math.ceil((double)absDelta / 2); mHeaderIncremental += i; if(mHeaderIncremental >= 0){ // && mIncremental <= mMaxHeight setHeaderHeight(mHeaderIncremental); checkHeaderViewState(); } return true; } @Override public boolean onListViewBottomAndPullUp(int delta) { if(!mEnableAutoFetchMore || mIsFetchMoreing) return false; // 数量充满屏幕才触发 if(isFillScreenItem()){ mIsFetchMoreing = true; mFooterTextView.setText("加载更多中..."); mFooterLoadingView.setVisibility(View.VISIBLE); mOnPullDownListener.onMore(); return true; } return false; } @Override public boolean onMotionDown(MotionEvent ev) { mIsDown = true; mIsPullUpDone = false; mMotionDownLastY = ev.getRawY(); return false; } @Override public boolean onMotionMove(MotionEvent ev, int delta) { //当头部文件回推消失的时候，不允许滚动 if(mIsPullUpDone) return true; // 如果开始按下到滑动距离不超过误差值，则不滑动 final int absMotionY = (int) Math.abs(ev.getRawY() - mMotionDownLastY); if(absMotionY < START_PULL_DEVIATION) return true; final int absDelta = Math.abs(delta); final int i = (int) Math.ceil((double)absDelta / 2); // onTopDown在顶部，并上回推和onTopUp相对 if(mHeaderViewParams.height > 0 && delta < 0){ mHeaderIncremental -= i; if(mHeaderIncremental > 0){ setHeaderHeight(mHeaderIncremental); checkHeaderViewState(); }else{ mHeaderViewState = HEADER_VIEW_STATE_IDLE; mHeaderIncremental = 0; setHeaderHeight(mHeaderIncremental); mIsPullUpDone = true; } return true; } return false; } @Override public boolean onMotionUp(MotionEvent ev) { mIsDown = false; // 避免和点击事件冲突 if(mHeaderViewParams.height > 0){ // 判断头文件拉动的距离与设定的高度，小了就隐藏，多了就固定高度 int x = mHeaderIncremental - DEFAULT_HEADER_VIEW_HEIGHT; Timer timer = new Timer(true); if(x < 0){ timer.scheduleAtFixedRate(new HideHeaderViewTask(), 0, 10); }else{ timer.scheduleAtFixedRate(new ShowHeaderViewTask(), 0, 10); } return true; } return false; } }
第七步：这个java文件就是封装数据，然后调用上两个文件就好了。废话不多说，上代码：：：：：
public class PullDownActivity extends Activity implements OnPullDownListener, OnItemClickListener{ private static final int WHAT_DID_LOAD_DATA = 0; private static final int WHAT_DID_REFRESH = 1; private static final int WHAT_DID_MORE = 2; private ListView mListView; private ArrayAdapter<String> mAdapter; private PullDownView mPullDownView; private List<String> mStrings = new ArrayList<String>(); @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.pulldown); /* * 1.使用PullDownView * 2.设置OnPullDownListener * 3.从mPullDownView里面获取ListView */ mPullDownView = (PullDownView) findViewById(R.id.pull_down_view); mPullDownView.setOnPullDownListener(this); mListView = mPullDownView.getListView(); mListView.setOnItemClickListener(this); mAdapter = new ArrayAdapter<String>(this, R.layout.pulldown_item, mStrings); mListView.setAdapter(mAdapter); mPullDownView.enableAutoFetchMore(true, 1); loadData(); } private void loadData(){ new Thread(new Runnable() { @Override public void run() { try { Thread.sleep(2000); } catch (InterruptedException e) { e.printStackTrace(); } List<String> strings = new ArrayList<String>(); for (String body : mStringArray) { strings.add(body); } Message msg = mUIHandler.obtainMessage(WHAT_DID_LOAD_DATA); msg.obj = strings; msg.sendToTarget(); } }).start(); } @Override public void onRefresh() { new Thread(new Runnable() { @Override public void run() { try { Thread.sleep(2000); } catch (InterruptedException e) { e.printStackTrace(); } Message msg = mUIHandler.obtainMessage(WHAT_DID_REFRESH); msg.obj = "After refresh " + System.currentTimeMillis(); msg.sendToTarget(); } }).start(); } @Override public void onMore() { new Thread(new Runnable() { @Override public void run() { try { Thread.sleep(2000); } catch (InterruptedException e) { e.printStackTrace(); } Message msg = mUIHandler.obtainMessage(WHAT_DID_MORE); msg.obj = "After more " + System.currentTimeMillis(); msg.sendToTarget(); } }).start(); } private Handler mUIHandler = new Handler(){ @Override public void handleMessage(Message msg) { switch (msg.what) { case WHAT_DID_LOAD_DATA:{ if(msg.obj != null){ List<String> strings = (List<String>) msg.obj; if(!strings.isEmpty()){ mStrings.addAll(strings); mAdapter.notifyDataSetChanged(); } } // 诉它数据加载完毕; mPullDownView.notifyDidLoad(); break; } case WHAT_DID_REFRESH :{ String body = (String) msg.obj; mStrings.add(0, body); mAdapter.notifyDataSetChanged(); // 告诉它更新完毕 mPullDownView.notifyDidRefresh(); break; } case WHAT_DID_MORE:{ String body = (String) msg.obj; mStrings.add(body); mAdapter.notifyDataSetChanged(); // 告诉它获取更多完毕 mPullDownView.notifyDidMore(); break; } } } }; @Override public void onItemClick(AdapterView<?> parent, View view, int position, long id) { Toast.makeText(this, "啊，你点中我了 " + position, Toast.LENGTH_SHORT).show(); } // 模拟数据 private String[] mStringArray = { "Abbaye de Belloc", "Abbaye du Mont des Cats", "Abertam", "Abondance", "Ackawi", "Acorn", "Adelost", "Affidelice au Chablis", "Afuega'l Pitu", "Airag", "Airedale", "Aisy Cendre", "Allgauer Emmentaler", "Alverca", "Ambert", "American Cheese" }; }
整个程序就这么完成了，总之，可以使用前两个封装好的文件，然后，调用就好了~~~~没什么太难的地方。
