Maxwin-z/XListView-Android(下拉刷新上拉加载)源码解析(二)

转载请注明出处http://blog.csdn.net/crazy__chen/article/details/45980399

源文件下载地址http://download.csdn.net/detail/kangaroo835127729/8736887

本文主要是贴出xlistview的源代码和一个使用实例，没有过多讲解

使用实例，MainActivity

public class MainActivity extends Activity {		
	private LinkedList<String>   listItems = null;    
	private XListView     listView  = null;
    private ArrayAdapter<String> adapter;
 
    private String[]             mStrings  = { "Aaaaaa", "Bbbbbb", "Cccccc", "Dddddd", "Eeeeee",
            "Ffffff", "Gggggg", "Hhhhhh", "Iiiiii", "Jjjjjj", "Kkkkkk", "Llllll", "Mmmmmm",
            "Nnnnnn",                     };
 
    @Override
    public void onCreate(Bundle savedInstanceState) {
    	super.onCreate(savedInstanceState);
    	setContentView(R.layout.activity_main);              
        listView = (XListView)findViewById(R.id.mlist);
        listView.setXListViewListener(new IXListViewListener() {
			
			@Override
			public void onRefresh() {
				new GetDataTask(true).execute();				
			}
			
			@Override
			public void onLoadMore() {
				new GetDataTask(false).execute();				
			}
		});       
        listItems = new LinkedList<String>();
        listItems.addAll(Arrays.asList(mStrings));
        adapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, listItems);
        listView.setAdapter(adapter);
        listView.setPullLoadEnable(true);
    }
 
    private class GetDataTask extends AsyncTask<Void, Void, String[]> {
 
        private boolean isDropDown;
 
        public GetDataTask(boolean isDropDown){
            this.isDropDown = isDropDown;
        }
 
        @Override
        protected String[] doInBackground(Void... params) {
            try {
                Thread.sleep(1000);
            } catch (InterruptedException e) {
                ;
            }
            return mStrings;
        }
 
        @Override
        protected void onPostExecute(String[] result) {
 
            if (isDropDown) {
                listItems.addFirst("Added after drop down");
                adapter.notifyDataSetChanged();
                                    
                listView.stopRefresh();
            } else {
                listItems.add("Added after on bottom");
                adapter.notifyDataSetChanged();
                listView.stopLoadMore();              
            }
 
            super.onPostExecute(result);
        }
    }
}

XListView

public class XListView extends ListView implements OnScrollListener {

	private float mLastY = -1; // save event y
	/**
	 * 用于下拉后，滑动返回
	 */
	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;

	/**
	 * 下拉头部
	 */
	private XListViewHeader mHeaderView;	
	/**
	 * 下拉头主体，用于计算头部的高度
	 * 当不能刷新时，被隐藏
	 */
	private RelativeLayout mHeaderViewContent;
	/**
	 * 下拉箭头
	 */
	private TextView mHeaderTimeView;
	/**
	 * 下拉头部的高度
	 */
	private int mHeaderViewHeight;
	/**
	 * 能否下拉刷新
	 */
	private boolean mEnablePullRefresh = true;
	/**
	 * 是否正在刷新,false表示正在刷新
	 */
	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;
	/**
	 * 头部滑动返回
	 */
	private final static int SCROLLBACK_HEADER = 0;
	/**
	 * footer滑动返回
	 */
	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);

		//初始化下拉头
		mHeaderView = new XListViewHeader(context);
		mHeaderViewContent = (RelativeLayout) mHeaderView
				.findViewById(R.id.xlistview_header_content);
		mHeaderTimeView = (TextView) mHeaderView
				.findViewById(R.id.xlistview_header_time);
		addHeaderView(mHeaderView);

		//初始化底部
		mFooterView = new XListViewFooter(context);

		//初始化下拉头高度
		mHeaderView.getViewTreeObserver().addOnGlobalLayoutListener(
				new OnGlobalLayoutListener() {
					@Override
					public void onGlobalLayout() {
						mHeaderViewHeight = mHeaderViewContent.getHeight();//获得下拉头的高度
						getViewTreeObserver()
								.removeGlobalOnLayoutListener(this);
					}
				});
	}

	@Override
	public void setAdapter(ListAdapter adapter) {
		/*
		 * 将上拉加载更多footer加入listview的底部
		 * 并且保证只加入一次
		 */
		if (mIsFooterReady == false) {
			mIsFooterReady = true;
			addFooterView(mFooterView);//listview原生方法
		}
		super.setAdapter(adapter);
	}

	/**	 
	 * 设置下拉刷新功能是否开启
	 * @param enable
	 */
	public void setPullRefreshEnable(boolean enable) {
		mEnablePullRefresh = enable;
		if (!mEnablePullRefresh) {//不开启，隐藏头部
			mHeaderViewContent.setVisibility(View.INVISIBLE);
		} else {
			mHeaderViewContent.setVisibility(View.VISIBLE);
		}
	}

	/**
	 * 设置上拉加载更多功能是否开启
	 * 如果要开启，必须主动调用这个函数	 
	 * @param enable
	 */
	public void setPullLoadEnable(boolean enable) {
		mEnablePullLoad = enable;
		if (!mEnablePullLoad) {//如果不开启
			mFooterView.hide();//隐藏footer
			mFooterView.setOnClickListener(null);//取消监听
			//make sure "pull up" don't show a line in bottom when listview with one page 
			//保证listview的item之间的分割线消失(最后一条)
			setFooterDividersEnabled(false);//listview原生方法
		} else {
			mPullLoading = false;
			mFooterView.show();
			mFooterView.setState(XListViewFooter.STATE_NORMAL);
			//make sure "pull up" don't show a line in bottom when listview with one page  
			setFooterDividersEnabled(true);
			// 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.
	 * 停止刷新，重置头部
	 */
	public void stopRefresh() {
		if (mPullRefreshing == true) {
			mPullRefreshing = false;
			resetHeaderHeight();
		}
	}

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

	/**
	 * set last refresh time
	 * 设置最后一次下来刷新时间
	 * @param time
	 */
	public void setRefreshTime(String time) {
		mHeaderTimeView.setText(time);
	}

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

	/**
	 * 更新头部高度
	 * 这个函数用于下拉时，记录下拉了多少
	 * @param delta
	 */
	private void updateHeaderHeight(float delta) {
		mHeaderView.setVisiableHeight((int) delta
				+ mHeaderView.getVisiableHeight());
		if (mEnablePullRefresh && !mPullRefreshing) {//未处于刷新状态，更新箭头
			if (mHeaderView.getVisiableHeight() > mHeaderViewHeight) {
				mHeaderView.setState(XListViewHeader.STATE_READY);
			} else {
				mHeaderView.setState(XListViewHeader.STATE_NORMAL);
			}
		}
		
		//滑动到头部
		setSelection(0); // scroll to top each time
	}

	/**
	 * reset header view's height.
	 * 重置头部高度
	 */
	private void resetHeaderHeight() {
		int height = mHeaderView.getVisiableHeight();
		if (height == 0) // not visible.
			return;
		// refreshing and header isn't shown fully. do nothing.
		//正在刷新，或者头部没有完全显示，返回
		if (mPullRefreshing && height <= mHeaderViewHeight) {
			return;
		}
		int finalHeight = 0; // 默认最终高度，也就是说要让头部消失
		// is refreshing, just scroll back to show all the header.
		//正在刷新，并且下拉头部完全显示
		if (mPullRefreshing && height > mHeaderViewHeight) {
			finalHeight = mHeaderViewHeight;
		}
		mScrollBack = SCROLLBACK_HEADER;
		//从当前位置，返回到头部被隐藏
		mScroller.startScroll(0, height, 0, finalHeight - height,
				SCROLL_DURATION);
		// trigger computeScroll
		invalidate();
	}

	/**
	 * 更新footer离底部的距离
	 * @param delta
	 */
	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上拉足够高才去加载
													// more.
				mFooterView.setState(XListViewFooter.STATE_READY);
			} else {
				mFooterView.setState(XListViewFooter.STATE_NORMAL);
			}
		}
		mFooterView.setBottomMargin(height);

//		setSelection(mTotalItemCount - 1); // scroll to bottom
	}
	
	/**
	 * 重置footer位置
	 */
	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) {//获得触摸时的y坐标
			mLastY = ev.getRawY();
		}

		switch (ev.getAction()) {
		case MotionEvent.ACTION_DOWN:
			mLastY = ev.getRawY();
			break;
		case MotionEvent.ACTION_MOVE:
			final float deltaY = ev.getRawY() - mLastY;//下拉或者上拉了多少offset
			mLastY = ev.getRawY();
			if (getFirstVisiblePosition() == 0
					&& (mHeaderView.getVisiableHeight() > 0 || deltaY > 0)) {//第一个item可见并且头部部分显示或者下拉操作,则表示处于下拉刷新状态
				// 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)) {//最后一个item可见并且footer被上拉显示或者上拉操作,则表示处于上拉刷新状态
				// last item, already pulled up or want to pull up.
				updateFooterHeight(-deltaY / OFFSET_RADIO);
			}
			break;
		default://action_up			
			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();
			} else if (getLastVisiblePosition() == mTotalItemCount - 1) {
				// invoke load more.
				if (mEnablePullLoad
				    && mFooterView.getBottomMargin() > PULL_LOAD_MORE_DELTA
				    && !mPullLoading) {
					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.
	 * 下拉和上拉监听器
	 */
	public interface IXListViewListener {
		public void onRefresh();

		public void onLoadMore();
	}
}

XListViewHeader

public class XListViewHeader extends LinearLayout {
	/**
	 * 下拉布局主体
	 */
	private LinearLayout mContainer;
	/**
	 * 下拉箭头
	 */
	private ImageView mArrowImageView;
	/**
	 * 环形进度条
	 */
	private ProgressBar mProgressBar;
	/**
	 * 提示文本
	 */
	private TextView mHintTextView;
	private int mState = STATE_NORMAL;
	
	private Animation mRotateUpAnim;
	private Animation mRotateDownAnim;
	/**
	 * 动画时间
	 */
	private final int ROTATE_ANIM_DURATION = 180;
	
	public final static int STATE_NORMAL = 0;//普通状态
	public final static int STATE_READY = 1;//下拉准备刷新
	public final static int STATE_REFRESHING = 2;//正在加载

	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) {
		// 初始情况，设置下拉刷新view高度为0
		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);
		//旋转动画
		mRotateUpAnim = new RotateAnimation(0.0f, -180.0f,
				Animation.RELATIVE_TO_SELF, 0.5f, Animation.RELATIVE_TO_SELF,
				0.5f);
		//设置动画时间
		mRotateUpAnim.setDuration(ROTATE_ANIM_DURATION);
		//动画终止时停留在最后一帧,也就是保留动画以后的状态
		mRotateUpAnim.setFillAfter(true);
		//旋转动画
		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) {// 显示进度
			mArrowImageView.clearAnimation();
			mArrowImageView.setVisibility(View.INVISIBLE);
			mProgressBar.setVisibility(View.VISIBLE);
		} else {// 显示箭头图片
			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;
	}
	
	/**
	 * 设置下拉头有效高度
	 * @param height
	 */
	public void setVisiableHeight(int height) {
		if (height < 0)
			height = 0;
		LinearLayout.LayoutParams lp = (LinearLayout.LayoutParams) mContainer
				.getLayoutParams();
		lp.height = height;
		mContainer.setLayoutParams(lp);
	}

	/**
	 * 获得下拉头有效高度
	 * @return
	 */
	public int getVisiableHeight() {
		return mContainer.getLayoutParams().height;
	}

}

XListViewFooter

public class XListViewFooter extends LinearLayout {
	public final static int STATE_NORMAL = 0;//普通状态
	public final static int STATE_READY = 1;//上拉准备刷新
	public final static int STATE_LOADING = 2;//正在加载

	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);
	}

	/**
	 * 设置状态
	 * @param state
	 */
	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);
		}
	}
	
	/**
	 * 设置footer里底部的高度
	 * @param height
	 */
	public void setBottomMargin(int height) {
		if (height < 0) return ;
		LinearLayout.LayoutParams lp = (LinearLayout.LayoutParams)mContentView.getLayoutParams();
		lp.bottomMargin = height;
		mContentView.setLayoutParams(lp);
	}
	
	/**
	 * 获得footer里底部的高度
	 * @return
	 */
	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);
	}
	
	/**
	 * 初始化布局
	 * @param context
	 */
	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);
	}
	
	
}