Android学习之listview的下拉刷新、上拉载入

本例是在上例的基础上完成的。本例实现的listview上拉载入、下拉刷新功能，是在开源网站上别人写好的listview，主要是对listview的控件进行重写，添加了footer和header。

1.listview_footer

listview_footer是listview的底部。

 <?xml version="1.0" encoding="utf-8"?>
 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
     android:layout_width="fill_parent"
     android:layout_height="wrap_content" >

     <RelativeLayout
         android:id="@+id/xlistview_footer_content"
         android:layout_width="fill_parent"
         android:layout_height="wrap_content"
         android:padding="10dp" >

         <ProgressBar
             android:id="@+id/xlistview_footer_progressbar"
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
             android:layout_centerInParent="true"
             android:visibility="invisible" />

         <TextView
             android:id="@+id/xlistview_footer_hint_textview"
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
             android:layout_centerInParent="true"
             android:text="@string/xlistview_footer_hint_normal" />
     </RelativeLayout>

 </LinearLayout>

lsitview_footer

listview_footer由ProgressBar和textview组成。用户点击textview或者上拉的时候，会触发监听事件，实现更多数据的载入。

 public final static int STATE_NORMAL = 0;
     public final static int STATE_READY = 1;
     public final static int STATE_LOADING = 2;

     private Context mContext;

     private View mContentView;
     private View mProgressBar;
     private TextView mHintView;

     public XListViewFooter(Context context) {
         super(context);
         initView(context);
     }

     public XListViewFooter(Context context, AttributeSet attrs) {
         super(context, attrs);
         initView(context);
     }

     public void setState(int state) {
         mHintView.setVisibility(View.INVISIBLE);
         mProgressBar.setVisibility(View.INVISIBLE);
         mHintView.setVisibility(View.INVISIBLE);
         if (state == STATE_READY) {
             mHintView.setVisibility(View.VISIBLE);
             mHintView.setText(R.string.xlistview_footer_hint_ready);
         } else if (state == STATE_LOADING) {
             mProgressBar.setVisibility(View.VISIBLE);
         } else {
             mHintView.setVisibility(View.VISIBLE);
             mHintView.setText(R.string.xlistview_footer_hint_normal);
         }
     }

     public void setBottomMargin(int height) {
         if (height < 0) return ;
         LinearLayout.LayoutParams lp = (LinearLayout.LayoutParams)mContentView.getLayoutParams();
         lp.bottomMargin = height;
         mContentView.setLayoutParams(lp);
     }

     public int getBottomMargin() {
         LinearLayout.LayoutParams lp = (LinearLayout.LayoutParams)mContentView.getLayoutParams();
         return lp.bottomMargin;
     }

     /**
      * normal status
      */
     public void normal() {
         mHintView.setVisibility(View.VISIBLE);
         mProgressBar.setVisibility(View.GONE);
     }

     /**
      * loading status
      */
     public void loading() {
         mHintView.setVisibility(View.GONE);
         mProgressBar.setVisibility(View.VISIBLE);
     }

     /**
      * hide footer when disable pull load more
      */
     public void hide() {
         LinearLayout.LayoutParams lp = (LinearLayout.LayoutParams)mContentView.getLayoutParams();
         lp.height = 0;
         mContentView.setLayoutParams(lp);
     }

     /**
      * show footer
      */
     public void show() {
         LinearLayout.LayoutParams lp = (LinearLayout.LayoutParams)mContentView.getLayoutParams();
         lp.height = LayoutParams.WRAP_CONTENT;
         mContentView.setLayoutParams(lp);
     }

     private void initView(Context context) {
         mContext = context;
         LinearLayout moreView = (LinearLayout)LayoutInflater.from(mContext).inflate(R.layout.xlistview_footer, null);
         addView(moreView);
         moreView.setLayoutParams(new LinearLayout.LayoutParams(LayoutParams.FILL_PARENT, LayoutParams.WRAP_CONTENT));

         mContentView = moreView.findViewById(R.id.xlistview_footer_content);
         mProgressBar = moreView.findViewById(R.id.xlistview_footer_progressbar);
         mHintView = (TextView)moreView.findViewById(R.id.xlistview_footer_hint_textview);
     }

listview_footer

后台代码定义了listview_footer的状态变化，包括加载、停止加载等，实现了对事件的监听。

2.listview_header

listview_header是listview显示的时候头部文件。用户下拉的时候，实现数据的重新载入。

 <?xml version="1.0" encoding="utf-8"?>
 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
     android:layout_width="fill_parent"
     android:layout_height="wrap_content"
     android:gravity="bottom" >

     <RelativeLayout
         android:id="@+id/xlistview_header_content"
         android:layout_width="fill_parent"
         android:layout_height="60dp" >

         <LinearLayout
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
             android:layout_centerInParent="true"
             android:gravity="center"
             android:orientation="vertical" android:id="@+id/xlistview_header_text">

             <TextView
                 android:id="@+id/xlistview_header_hint_textview"
                 android:layout_width="wrap_content"
                 android:layout_height="wrap_content"
                 android:text="@string/xlistview_header_hint_normal" />

             <LinearLayout
                 android:layout_width="wrap_content"
                 android:layout_height="wrap_content"
                 android:layout_marginTop="3dp" >

                 <TextView
                     android:layout_width="wrap_content"
                     android:layout_height="wrap_content"
                     android:text="@string/xlistview_header_last_time"
                     android:textSize="12sp" />

                 <TextView
                     android:id="@+id/xlistview_header_time"
                     android:layout_width="wrap_content"
                     android:layout_height="wrap_content"
                     android:textSize="12sp" />
             </LinearLayout>
         </LinearLayout>

         <ImageView
             android:id="@+id/xlistview_header_arrow"
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
             android:layout_alignLeft="@id/xlistview_header_text"
             android:layout_centerVertical="true"
             android:layout_marginLeft="-35dp"
             android:src="@drawable/xlistview_arrow" />

         <ProgressBar
             android:id="@+id/xlistview_header_progressbar"
             android:layout_width="30dp"
             android:layout_height="30dp"
             android:layout_alignLeft="@id/xlistview_header_text"
             android:layout_centerVertical="true"
             android:layout_marginLeft="-40dp"
             android:visibility="invisible" />
     </RelativeLayout>

 </LinearLayout>

listview_header

xml部分由textview和imageview组成。

 private LinearLayout mContainer;
     private ImageView mArrowImageView;
     private ProgressBar mProgressBar;
     private TextView mHintTextView;
     private int mState = STATE_NORMAL;

     private Animation mRotateUpAnim;
     private Animation mRotateDownAnim;

     private final int ROTATE_ANIM_DURATION = 180;

     public final static int STATE_NORMAL = 0;
     public final static int STATE_READY = 1;
     public final static int STATE_REFRESHING = 2;

     public XListViewHeader(Context context) {
         super(context);
         initView(context);
     }

     /**
      * @param context
      * @param attrs
      */
     public XListViewHeader(Context context, AttributeSet attrs) {
         super(context, attrs);
         initView(context);
     }

     private void initView(Context context) {
         // 鍒濆鎯呭喌锛岃缃笅鎷夊埛鏂皏iew楂樺害涓?
         LinearLayout.LayoutParams lp = new LinearLayout.LayoutParams(
                 LayoutParams.FILL_PARENT, 0);
         mContainer = (LinearLayout) LayoutInflater.from(context).inflate(
                 R.layout.xlistview_header, null);
         addView(mContainer, lp);
         setGravity(Gravity.BOTTOM);

         mArrowImageView = (ImageView)findViewById(R.id.xlistview_header_arrow);
         mHintTextView = (TextView)findViewById(R.id.xlistview_header_hint_textview);
         mProgressBar = (ProgressBar)findViewById(R.id.xlistview_header_progressbar);

         mRotateUpAnim = new RotateAnimation(0.0f, -180.0f,
                 Animation.RELATIVE_TO_SELF, 0.5f, Animation.RELATIVE_TO_SELF,
                 0.5f);
         mRotateUpAnim.setDuration(ROTATE_ANIM_DURATION);
         mRotateUpAnim.setFillAfter(true);
         mRotateDownAnim = new RotateAnimation(-180.0f, 0.0f,
                 Animation.RELATIVE_TO_SELF, 0.5f, Animation.RELATIVE_TO_SELF,
                 0.5f);
         mRotateDownAnim.setDuration(ROTATE_ANIM_DURATION);
         mRotateDownAnim.setFillAfter(true);
     }

     public void setState(int state) {
         if (state == mState) return ;

         if (state == STATE_REFRESHING) {    // 鏄剧ず杩涘害
             mArrowImageView.clearAnimation();
             mArrowImageView.setVisibility(View.INVISIBLE);
             mProgressBar.setVisibility(View.VISIBLE);
         } else {    // 鏄剧ず绠ご鍥剧墖
             mArrowImageView.setVisibility(View.VISIBLE);
             mProgressBar.setVisibility(View.INVISIBLE);
         }

         switch(state){
         case STATE_NORMAL:
             if (mState == STATE_READY) {
                 mArrowImageView.startAnimation(mRotateDownAnim);
             }
             if (mState == STATE_REFRESHING) {
                 mArrowImageView.clearAnimation();
             }
             mHintTextView.setText(R.string.xlistview_header_hint_normal);
             break;
         case STATE_READY:
             if (mState != STATE_READY) {
                 mArrowImageView.clearAnimation();
                 mArrowImageView.startAnimation(mRotateUpAnim);
                 mHintTextView.setText(R.string.xlistview_header_hint_ready);
             }
             break;
         case STATE_REFRESHING:
             mHintTextView.setText(R.string.xlistview_header_hint_loading);
             break;
             default:
         }

         mState = state;
     }

     public void setVisiableHeight(int height) {
         if (height < 0)
             height = 0;
         LinearLayout.LayoutParams lp = (LinearLayout.LayoutParams) mContainer
                 .getLayoutParams();
         lp.height = height;
         mContainer.setLayoutParams(lp);
     }

     public int getVisiableHeight() {
         return mContainer.getHeight();
     }

listview_header

后台通过状态的改变，控制header的高度。

3.xlistview

xlistview是对listview控件的重写

 public class XListView extends ListView implements OnScrollListener {

     private float mLastY = -1; // save event y
     private Scroller mScroller; // used for scroll back
     private OnScrollListener mScrollListener; // user's scroll listener

     // the interface to trigger refresh and load more.
     private IXListViewListener mListViewListener;

     // -- header view
     private XListViewHeader mHeaderView;
     // header view content, use it to calculate the Header's height. And hide it
     // when disable pull refresh.
     private RelativeLayout mHeaderViewContent;
     private TextView mHeaderTimeView;
     private int mHeaderViewHeight; // header view's height
     private boolean mEnablePullRefresh = true;
     private boolean mPullRefreshing = false; // is refreashing.

     // -- footer view
     private XListViewFooter mFooterView;
     private boolean mEnablePullLoad;
     private boolean mPullLoading;
     private boolean mIsFooterReady = false;

     // total list items, used to detect is at the bottom of listview.
     private int mTotalItemCount;

     // for mScroller, scroll back from header or footer.
     private int mScrollBack;
     private final static int SCROLLBACK_HEADER = 0;
     private final static int SCROLLBACK_FOOTER = 1;

     private final static int SCROLL_DURATION = 400; // scroll back duration
     private final static int PULL_LOAD_MORE_DELTA = 50; // when pull up >= 50px
                                                         // at bottom, trigger
                                                         // load more.
     private final static float OFFSET_RADIO = 1.8f; // support iOS like pull
                                                     // feature.

     /**
      * @param context
      */
     public XListView(Context context) {
         super(context);
         initWithContext(context);
     }

     public XListView(Context context, AttributeSet attrs) {
         super(context, attrs);
         initWithContext(context);
     }

     public XListView(Context context, AttributeSet attrs, int defStyle) {
         super(context, attrs, defStyle);
         initWithContext(context);
     }

     private void initWithContext(Context context) {
         mScroller = new Scroller(context, new DecelerateInterpolator());
         // XListView need the scroll event, and it will dispatch the event to
         // user's listener (as a proxy).
         super.setOnScrollListener(this);

         // init header view
         mHeaderView = new XListViewHeader(context);
         mHeaderViewContent = (RelativeLayout) mHeaderView
                 .findViewById(R.id.xlistview_header_content);
         mHeaderTimeView = (TextView) mHeaderView
                 .findViewById(R.id.xlistview_header_time);
         addHeaderView(mHeaderView);

         // init footer view
         mFooterView = new XListViewFooter(context);

         // init header height
         mHeaderView.getViewTreeObserver().addOnGlobalLayoutListener(
                 new OnGlobalLayoutListener() {
                     @SuppressWarnings("deprecation")
                     @Override
                     public void onGlobalLayout() {
                         mHeaderViewHeight = mHeaderViewContent.getHeight();
                         getViewTreeObserver()
                                 .removeGlobalOnLayoutListener(this);
                     }
                 });
     }

     @Override
     public void setAdapter(ListAdapter adapter) {
         // make sure XListViewFooter is the last footer view, and only add once.
         if (mIsFooterReady == false) {
             mIsFooterReady = true;
             addFooterView(mFooterView);
         }
         super.setAdapter(adapter);
     }

     /**
      * enable or disable pull down refresh feature.
      *
      * @param enable
      */
     public void setPullRefreshEnable(boolean enable) {
         mEnablePullRefresh = enable;
         if (!mEnablePullRefresh) { // disable, hide the content
             mHeaderViewContent.setVisibility(View.INVISIBLE);
         } else {
             mHeaderViewContent.setVisibility(View.VISIBLE);
         }
     }

     /**
      * enable or disable pull up load more feature.
      *
      * @param enable
      */
     public void setPullLoadEnable(boolean enable) {
         mEnablePullLoad = enable;
         if (!mEnablePullLoad) {
             mFooterView.hide();
             mFooterView.setOnClickListener(null);
         } else {
             mPullLoading = false;
             mFooterView.show();
             mFooterView.setState(XListViewFooter.STATE_NORMAL);
             // both "pull up" and "click" will invoke load more.
             mFooterView.setOnClickListener(new OnClickListener() {
                 @Override
                 public void onClick(View v) {
                     startLoadMore();
                 }
             });
         }
     }

     /**
      * stop refresh, reset header view.
      */
     public void stopRefresh() {
         if (mPullRefreshing == true) {
             mPullRefreshing = false;
             resetHeaderHeight();
         }
     }

     /**
      * stop load more, reset footer view.
      */
     public void stopLoadMore() {
         if (mPullLoading == true) {
             mPullLoading = false;
             mFooterView.setState(XListViewFooter.STATE_NORMAL);
         }
     }

     /**
      * set last refresh time
      *
      * @param time
      */
     public void setRefreshTime(String time) {
         mHeaderTimeView.setText(time);
     }

     private void invokeOnScrolling() {
         if (mScrollListener instanceof OnXScrollListener) {
             OnXScrollListener l = (OnXScrollListener) mScrollListener;
             l.onXScrolling(this);
         }
     }

     private void updateHeaderHeight(float delta) {
         mHeaderView.setVisiableHeight((int) delta
                 + mHeaderView.getVisiableHeight());
         if (mEnablePullRefresh && !mPullRefreshing) { // 鏈浜庡埛鏂扮姸鎬侊紝鏇存柊绠ご
             if (mHeaderView.getVisiableHeight() > mHeaderViewHeight) {
                 mHeaderView.setState(XListViewHeader.STATE_READY);
             } else {
                 mHeaderView.setState(XListViewHeader.STATE_NORMAL);
             }
         }
         setSelection(0); // scroll to top each time
     }

     /**
      * reset header view's height.
      */
     private void resetHeaderHeight() {
         int height = mHeaderView.getVisiableHeight();
         if (height == 0) // not visible.
             return;
         // refreshing and header isn't shown fully. do nothing.
         if (mPullRefreshing && height <= mHeaderViewHeight) {
             return;
         }
         int finalHeight = 0; // default: scroll back to dismiss header.
         // is refreshing, just scroll back to show all the header.
         if (mPullRefreshing && height > mHeaderViewHeight) {
             finalHeight = mHeaderViewHeight;
         }
         mScrollBack = SCROLLBACK_HEADER;
         mScroller.startScroll(0, height, 0, finalHeight - height,
                 SCROLL_DURATION);
         // trigger computeScroll
         invalidate();
     }

     private void updateFooterHeight(float delta) {
         int height = mFooterView.getBottomMargin() + (int) delta;
         if (mEnablePullLoad && !mPullLoading) {
             if (height > PULL_LOAD_MORE_DELTA) { // height enough to invoke load
                                                     // more.
                 mFooterView.setState(XListViewFooter.STATE_READY);
             } else {
                 mFooterView.setState(XListViewFooter.STATE_NORMAL);
             }
         }
         mFooterView.setBottomMargin(height);

         // setSelection(mTotalItemCount - 1); // scroll to bottom
     }

     private void resetFooterHeight() {
         int bottomMargin = mFooterView.getBottomMargin();
         if (bottomMargin > 0) {
             mScrollBack = SCROLLBACK_FOOTER;
             mScroller.startScroll(0, bottomMargin, 0, -bottomMargin,
                     SCROLL_DURATION);
             invalidate();
         }
     }

     private void startLoadMore() {
         mPullLoading = true;
         mFooterView.setState(XListViewFooter.STATE_LOADING);
         if (mListViewListener != null) {
             mListViewListener.onLoadMore();
         }
     }

     @Override
     public boolean onTouchEvent(MotionEvent ev) {
         if (mLastY == -1) {
             mLastY = ev.getRawY();
         }

         switch (ev.getAction()) {
         case MotionEvent.ACTION_DOWN:
             mLastY = ev.getRawY();
             break;
         case MotionEvent.ACTION_MOVE:
             final float deltaY = ev.getRawY() - mLastY;
             mLastY = ev.getRawY();
             System.out.println(getFirstVisiblePosition() + "---->"
                     + getLastVisiblePosition());
             if (getFirstVisiblePosition() == 0
                     && (mHeaderView.getVisiableHeight() > 0 || deltaY > 0)) {
                 // the first item is showing, header has shown or pull down.
                 updateHeaderHeight(deltaY / OFFSET_RADIO);
                 invokeOnScrolling();
             } else if (getLastVisiblePosition() == mTotalItemCount - 1
                     && (mFooterView.getBottomMargin() > 0 || deltaY < 0)) {
                 // last item, already pulled up or want to pull up.
                 updateFooterHeight(-deltaY / OFFSET_RADIO);
             }
             break;
         default:
             mLastY = -1; // reset
             if (getFirstVisiblePosition() == 0) {
                 // invoke refresh
                 if (mEnablePullRefresh
                         && mHeaderView.getVisiableHeight() > mHeaderViewHeight) {
                     mPullRefreshing = true;
                     mHeaderView.setState(XListViewHeader.STATE_REFRESHING);
                     if (mListViewListener != null) {
                         mListViewListener.onRefresh();
                     }
                 }
                 resetHeaderHeight();
             }
             if (getLastVisiblePosition() == mTotalItemCount - 1) {
                 // invoke load more.
                 if (mEnablePullLoad
                         && mFooterView.getBottomMargin() > PULL_LOAD_MORE_DELTA) {
                     startLoadMore();
                 }
                 resetFooterHeight();
             }
             break;
         }
         return super.onTouchEvent(ev);
     }

     @Override
     public void computeScroll() {
         if (mScroller.computeScrollOffset()) {
             if (mScrollBack == SCROLLBACK_HEADER) {
                 mHeaderView.setVisiableHeight(mScroller.getCurrY());
             } else {
                 mFooterView.setBottomMargin(mScroller.getCurrY());
             }
             postInvalidate();
             invokeOnScrolling();
         }
         super.computeScroll();
     }

     @Override
     public void setOnScrollListener(OnScrollListener l) {
         mScrollListener = l;
     }

     @Override
     public void onScrollStateChanged(AbsListView view, int scrollState) {
         if (mScrollListener != null) {
             mScrollListener.onScrollStateChanged(view, scrollState);
         }
     }

     @Override
     public void onScroll(AbsListView view, int firstVisibleItem,
             int visibleItemCount, int totalItemCount) {
         // send to user's listener
         mTotalItemCount = totalItemCount;
         if (mScrollListener != null) {
             mScrollListener.onScroll(view, firstVisibleItem, visibleItemCount,
                     totalItemCount);
         }
     }

     public void setXListViewListener(IXListViewListener l) {
         mListViewListener = l;
     }

     /**
      * you can listen ListView.OnScrollListener or this one. it will invoke
      * onXScrolling when header/footer scroll back.
      */
     public interface OnXScrollListener extends OnScrollListener {
         public void onXScrolling(View view);
     }

     /**
      * implements this interface to get refresh/load more event.
      */
     public interface IXListViewListener {
         public void onRefresh();

         public void onLoadMore();
     }
 }

xlistview

在xlistview中定义了一个事件接口，来监听加载和刷新。

4.mainactivity

 protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);
         handler=new Handler();
         sqlhelper=new SQLiteHelper(MainActivity.this, "test", null, 1);
         list=new ArrayList<PersonInfo>();
         getData();
         listview=(XListView)findViewById(R.id.listView1);
         registerForContextMenu(listview);
         listview.setPullLoadEnable(true);
         // View moreview=getLayoutInflater().inflate(R.layout.moredata, null);
         //listview.addFooterView(moreview);
          adapter=new MyAdapter(this);
         listview.setAdapter(adapter);
         listview.setXListViewListener(this);
         listview.setOnItemLongClickListener(new OnItemLongClickListener() {
             @Override
             public boolean onItemLongClick(AdapterView<?> arg0, View arg1,
                     int arg2, long arg3) {
                 // TODO Auto-generated method stub
                 PersonInfo person=list.get(arg2);
                  delname=person.getName();
                 return false;
             }
         });

         /* btnpro=(Button)moreview.findViewById(R.id.bt_load);
          pg=(ProgressBar)moreview.findViewById(R.id.pg);
         btnpro.setOnClickListener(new View.OnClickListener() {

             @Override
             public void onClick(View v) {
                 // TODO Auto-generated method stub
                 pg.setVisibility(View.VISIBLE);// 将进度条可见
                    btnpro.setVisibility(View.GONE);// 按钮不可见
                     Handler hanldre=new Handler();
                     hanldre.postDelayed(new Runnable(){

                         @Override
                         public void run() {
                             // TODO Auto-generated method stub

                             adapter.count+=5;

                              btnpro.setVisibility(View.VISIBLE);
                                pg.setVisibility(View.GONE);
                                if(adapter.count>list.size())

                                {
                                    adapter. count=list.size();
                                    btnpro.setVisibility(View.INVISIBLE);
                                }
                                 adapter.notifyDataSetChanged();
                         }}, 2000);
             }
         });*/

     }
     private void getData()
     {
         Cursor cur=sqlhelper.getReadableDatabase().query("person", null, null, null, null, null, null);
         if(cur.moveToFirst())
         {
             while(cur.moveToNext())
             {
             PersonInfo person=new PersonInfo();
             person.name=cur.getString(cur.getColumnIndex("name"));
             person.age=cur.getInt(cur.getColumnIndex("age"));
             list.add(person);
             }
         }
     }
     private void onLoad() {
         listview.stopRefresh();
         listview.stopLoadMore();
         SimpleDateFormat timeFormat = new SimpleDateFormat("HH:mm:ss");
     String    strTime = timeFormat.format(new java.util.Date());
         listview.setRefreshTime(strTime);
     }

oncreate

     @Override
     public void onRefresh() {
         // TODO Auto-generated method stub
         handler.postDelayed(new Runnable(){

             @Override
             public void run() {
                 // TODO Auto-generated method stub
                 if(list!=null &&list.size()>0)
                 {
                     list.clear();
                     getData();
                     adapter.notifyDataSetChanged();
                     onLoad();
                 }
             }}, 2000);
     }
     @Override
     public void onLoadMore() {
         // TODO Auto-generated method stub

         handler.postDelayed(new Runnable(){

             @Override
             public void run() {
                 // TODO Auto-generated method stub
                 adapter.count+=5;

                    if(adapter.count>list.size())

                    {
                        adapter. count=list.size();
                    }
                     adapter.notifyDataSetChanged();
                     onLoad();
             }}, 2000);
     }

onloadmore

刷新和加载都是新建了一个handler。在handler中执行。

5.demo