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>

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);
    }

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>

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();
    }

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();
    }
}

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);
    }

    @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);
    }

刷新和加载都是新建了一个handler。在handler中执行。

5.demo