android 项目学习随笔十一（ListView下拉刷新提示）

1、 设置mHeaderView.setPadding TOPPADING为负值，隐藏刷新提示头布局

在onTouchEvent事件中进行头布局显示隐藏切换

import java.text.SimpleDateFormat;
import java.util.Date;

import android.content.Context;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import android.view.animation.Animation;
import android.view.animation.RotateAnimation;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.ProgressBar;
import android.widget.TextView;

import com.itheima.zhsh66.R;

/**
 * 下拉刷新的listview
 * 
 */
public class RefreshListView extends ListView {

    private static final int STATE_PULL_TO_REFRESH = 1;// 下拉刷新
    private static final int STATE_RELEASE_TO_REFRESH = 2;// 松开刷新
    private static final int STATE_REFRESHING = 3;// 正在刷新

    // 下拉刷新头布局
    private View mHeaderView;
    // 头布局高度
    private int mHeaderViewHeight;

    private int startY = -1;
    // 当前下拉刷新的状态
    private int mCurrentState = STATE_PULL_TO_REFRESH;// 默认是下拉刷新

    private TextView tvTitle;
    private ImageView ivArrow;
    private ProgressBar pbLoading;
    private TextView tvTime;

    private RotateAnimation animUp;// 箭头向上动画
    private RotateAnimation animDown;// 箭头向下动画

    public RefreshListView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        initView();
    }

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

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

    private void initView() {
        mHeaderView = View.inflate(getContext(), R.layout.list_refresh_header,
                null);
        this.addHeaderView(mHeaderView);// 添加头布局

        // 隐藏头布局(1, 获取头布局高度, 2.设置负paddingTop,布局就会往上走)
        // int height = mHeaderView.getHeight();//此处无法获取高度,因为布局还没有绘制完成
        // 绘制之前就要获取布局高度
        mHeaderView.measure(0, 0);// 手动测量布局
        mHeaderViewHeight = mHeaderView.getMeasuredHeight();// 测量之后的高度
        // 隐藏头布局
        mHeaderView.setPadding(0, -mHeaderViewHeight, 0, 0);

        tvTitle = (TextView) mHeaderView.findViewById(R.id.tv_title);
        ivArrow = (ImageView) mHeaderView.findViewById(R.id.iv_arrow);
        pbLoading = (ProgressBar) mHeaderView.findViewById(R.id.pb_loading);
        tvTime = (TextView) mHeaderView.findViewById(R.id.tv_time);

        initAnim();
        setCurrentTime();// 设置初始时间
    }

    @Override
    public boolean onTouchEvent(MotionEvent ev) {
        switch (ev.getAction()) {
        case MotionEvent.ACTION_DOWN:
            startY = (int) ev.getY();
            break;
        case MotionEvent.ACTION_MOVE:
            if (startY == -1) {// 如果用户按住头条新闻向下滑动, 会导致listview无法拿到ACTION_DOWN,
                                //因为此时事件会被交给父控件处理
                                // 此时要重新获取startY
                startY = (int) ev.getY();
            }

            // 如果当前正在刷新, 什么都不做了
            if (mCurrentState == STATE_REFRESHING) {
                break;
            }

            int endY = (int) ev.getY();
            int dy = endY - startY;

            if (dy > 0 && getFirstVisiblePosition() == 0) {// 向下滑动&当前显示的是第一个item,才允许下拉刷新
                int paddingTop = dy - mHeaderViewHeight;// 计算当前的paddingtop值

                // 根据padding切换状态
                if (paddingTop >= 0
                        && mCurrentState != STATE_RELEASE_TO_REFRESH) {
                    // 切换到松开刷新
                    mCurrentState = STATE_RELEASE_TO_REFRESH;
                    refreshState();
                } else if (paddingTop < 0
                        && mCurrentState != STATE_PULL_TO_REFRESH) {
                    // 切换到下拉刷新
                    mCurrentState = STATE_PULL_TO_REFRESH;
                    refreshState();
                }

                mHeaderView.setPadding(0, paddingTop, 0, 0);// 重新设置头布局padding
                return true;
            }

            break;
        case MotionEvent.ACTION_UP:
            startY = -1;// 起始坐标归零

            if (mCurrentState == STATE_RELEASE_TO_REFRESH) {
                // 如果当前是松开刷新, 就要切换为正在刷新
                mCurrentState = STATE_REFRESHING;
                // 显示头布局
                mHeaderView.setPadding(0, 0, 0, 0);

                refreshState();

                // 下拉刷新回调
                if (mListener != null) {
                    mListener.onRefresh();
                }

            } else if (mCurrentState == STATE_PULL_TO_REFRESH) {
                // 隐藏头布局
                mHeaderView.setPadding(0, -mHeaderViewHeight, 0, 0);
            }

            break;

        default:
            break;
        }

        return super.onTouchEvent(ev);
    }

    /**
     * 初始化箭头动画
     */
    private void initAnim() {
        animUp = new RotateAnimation(0, -180, Animation.RELATIVE_TO_SELF, 0.5f,
                Animation.RELATIVE_TO_SELF, 0.5f);
        animUp.setDuration(500);
        animUp.setFillAfter(true);// 保持状态

        animDown = new RotateAnimation(-180, 0, Animation.RELATIVE_TO_SELF,
                0.5f, Animation.RELATIVE_TO_SELF, 0.5f);
        animDown.setDuration(500);
        animDown.setFillAfter(true);// 保持状态
    }

    /**
     * 根据当前状态刷新界面
     */
    private void refreshState() {
        switch (mCurrentState) {
        case STATE_PULL_TO_REFRESH:
            tvTitle.setText("下拉刷新");
            // 箭头向下移动
            ivArrow.startAnimation(animDown);
            // 隐藏进度条
            pbLoading.setVisibility(View.INVISIBLE);
            ivArrow.setVisibility(View.VISIBLE);
            break;
        case STATE_RELEASE_TO_REFRESH:
            tvTitle.setText("松开刷新");
            // 箭头向上移动
            ivArrow.startAnimation(animUp);
            // 隐藏进度条
            pbLoading.setVisibility(View.INVISIBLE);
            ivArrow.setVisibility(View.VISIBLE);
            break;
        case STATE_REFRESHING:
            tvTitle.setText("正在刷新...");
            pbLoading.setVisibility(View.VISIBLE);
            ivArrow.clearAnimation();// 必须清除动画,才能隐藏控件
            ivArrow.setVisibility(View.INVISIBLE);
            break;

        default:
            break;
        }
    }

    private OnRefreshListener mListener;

    public void setOnRefreshListener(OnRefreshListener listener) {
        mListener = listener;
    }

    /**
     * 设置上次刷新时间
     */
    private void setCurrentTime() {
        // 08:10 8:10 1
        SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");// HH表示24小时制
        String time = format.format(new Date());
        tvTime.setText(time);
    }

    // 刷新完成
    public void onRefreshComplete(boolean success) {
        // 隐藏头布局
        mHeaderView.setPadding(0, -mHeaderViewHeight, 0, 0);
        mCurrentState = STATE_PULL_TO_REFRESH;
        // 隐藏进度条
        pbLoading.setVisibility(View.INVISIBLE);
        ivArrow.setVisibility(View.VISIBLE);
        tvTitle.setText("下拉刷新");

        // 刷新失败,不需要更新时间
        if (success) {
            setCurrentTime();
        }
    }

    public interface OnRefreshListener {
        // 下拉刷新的回调
        public void onRefresh();
    }
}

 2、给箭头图片设置动画

public class RefreshListView extends ListView {

private static final int STATE_PULL_TO_REFRESH = 1;// 下拉刷新
private static final int STATE_RELEASE_TO_REFRESH = 2;// 松开刷新
private static final int STATE_REFRESHING = 3;// 正在刷新

// 下拉刷新头布局
private View mHeaderView;
// 头布局高度
private int mHeaderViewHeight;

private int startY = -1;
// 当前下拉刷新的状态
private int mCurrentState = STATE_PULL_TO_REFRESH;// 默认是下拉刷新

private TextView tvTitle;
private ImageView ivArrow;
private ProgressBar pbLoading;
private TextView tvTime;

private RotateAnimation animUp;// 箭头向上动画
private RotateAnimation animDown;// 箭头向下动画

public RefreshListView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
initView();
}

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

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

private void initView() {
mHeaderView = View.inflate(getContext(), R.layout.list_refresh_header,
null);
this.addHeaderView(mHeaderView);// 添加头布局

// 隐藏头布局(1, 获取头布局高度, 2.设置负paddingTop,布局就会往上走)
// int height = mHeaderView.getHeight();//此处无法获取高度,因为布局还没有绘制完成
// 绘制之前就要获取布局高度
mHeaderView.measure(0, 0);// 手动测量布局
mHeaderViewHeight = mHeaderView.getMeasuredHeight();// 测量之后的高度
// 隐藏头布局
mHeaderView.setPadding(0, -mHeaderViewHeight, 0, 0);

tvTitle = (TextView) mHeaderView.findViewById(R.id.tv_title);
ivArrow = (ImageView) mHeaderView.findViewById(R.id.iv_arrow);
pbLoading = (ProgressBar) mHeaderView.findViewById(R.id.pb_loading);
tvTime = (TextView) mHeaderView.findViewById(R.id.tv_time);

initAnim();
setCurrentTime();// 设置初始时间
}

@Override
public boolean onTouchEvent(MotionEvent ev) {
switch (ev.getAction()) {
case MotionEvent.ACTION_DOWN:
startY = (int) ev.getY();
break;
case MotionEvent.ACTION_MOVE:
if (startY == -1) {// 如果用户按住头条新闻向下滑动, 会导致listview无法拿到ACTION_DOWN,
//因为此时事件会被交给父控件处理
// 此时要重新获取startY
startY = (int) ev.getY();
}

// 如果当前正在刷新, 什么都不做了
if (mCurrentState == STATE_REFRESHING) {
break;
}

int endY = (int) ev.getY();
int dy = endY - startY;

if (dy > 0 && getFirstVisiblePosition() == 0) {// 向下滑动&当前显示的是第一个item,才允许下拉刷新
int paddingTop = dy - mHeaderViewHeight;// 计算当前的paddingtop值

// 根据padding切换状态
if (paddingTop >= 0
&& mCurrentState != STATE_RELEASE_TO_REFRESH) {
// 切换到松开刷新
mCurrentState = STATE_RELEASE_TO_REFRESH;
refreshState();
} else if (paddingTop < 0
&& mCurrentState != STATE_PULL_TO_REFRESH) {
// 切换到下拉刷新
mCurrentState = STATE_PULL_TO_REFRESH;
refreshState();
}

mHeaderView.setPadding(0, paddingTop, 0, 0);// 重新设置头布局padding
return true;
}

break;
case MotionEvent.ACTION_UP:
startY = -1;// 起始坐标归零

if (mCurrentState == STATE_RELEASE_TO_REFRESH) {
// 如果当前是松开刷新, 就要切换为正在刷新
mCurrentState = STATE_REFRESHING;
// 显示头布局
mHeaderView.setPadding(0, 0, 0, 0);

refreshState();

// 下拉刷新回调
if (mListener != null) {
mListener.onRefresh();
}

} else if (mCurrentState == STATE_PULL_TO_REFRESH) {
// 隐藏头布局
mHeaderView.setPadding(0, -mHeaderViewHeight, 0, 0);
}

break;

default:
break;
}

return super.onTouchEvent(ev);
}

/**
* 初始化箭头动画
*/
private void initAnim() {
animUp = new RotateAnimation(0, -180, Animation.RELATIVE_TO_SELF, 0.5f,
Animation.RELATIVE_TO_SELF, 0.5f);
animUp.setDuration(500);
animUp.setFillAfter(true);// 保持状态

animDown = new RotateAnimation(-180, 0, Animation.RELATIVE_TO_SELF,
0.5f, Animation.RELATIVE_TO_SELF, 0.5f);
animDown.setDuration(500);
animDown.setFillAfter(true);// 保持状态
}

/**
* 根据当前状态刷新界面
*/
private void refreshState() {
switch (mCurrentState) {
case STATE_PULL_TO_REFRESH:
tvTitle.setText("下拉刷新");
// 箭头向下移动
ivArrow.startAnimation(animDown);
// 隐藏进度条
pbLoading.setVisibility(View.INVISIBLE);
ivArrow.setVisibility(View.VISIBLE);
break;
case STATE_RELEASE_TO_REFRESH:
tvTitle.setText("松开刷新");
// 箭头向上移动
ivArrow.startAnimation(animUp);
// 隐藏进度条
pbLoading.setVisibility(View.INVISIBLE);
ivArrow.setVisibility(View.VISIBLE);
break;
case STATE_REFRESHING:
tvTitle.setText("正在刷新...");
pbLoading.setVisibility(View.VISIBLE);
ivArrow.clearAnimation();// 必须清除动画,才能隐藏控件
ivArrow.setVisibility(View.INVISIBLE);
break;

default:
break;
}
}

//ListView调用此方法，回调接口中的方法进行刷新数据

private OnRefreshListener mListener;

public void setOnRefreshListener(OnRefreshListener listener) {
mListener = listener;
}

/**
* 设置上次刷新时间
*/
private void setCurrentTime() {
// 08:10 8:10 1
SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");// HH表示24小时制
String time = format.format(new Date());
tvTime.setText(time);
}

// 刷新完成时调用此方法
public void onRefreshComplete(boolean success) {
// 隐藏头布局
mHeaderView.setPadding(0, -mHeaderViewHeight, 0, 0);
mCurrentState = STATE_PULL_TO_REFRESH;
// 隐藏进度条
pbLoading.setVisibility(View.INVISIBLE);
ivArrow.setVisibility(View.VISIBLE);
tvTitle.setText("下拉刷新");

// 刷新失败,不需要更新时间
if (success) {
setCurrentTime();
}
}

public interface OnRefreshListener {
// 下拉刷新的回调
public void onRefresh();
}
}

---------------------------------------------------------------------------------------------------------------------------------------

public class TabDetailPager extends BaseMenuDetailPager {

// 页签分类的网络信息
private NewsTabData mTabData;
// 网络返回的新闻列表数据
private NewsData mNewsTabData;
// 加载新闻列表的url
private String mUrl;

// 头条新闻的网络数据
private ArrayList<TopNews> mTopNewsList;
// 头条新闻的数据适配器
private TopNewsAdapter mTopNewsAdapter;
// 新闻列表的集合
private ArrayList<News> mNewsList;
private NewsAdapter mNewsAdapter;

@ViewInject(R.id.vp_tab_detail)
private HorizontalScrollViewPager mViewPager;

@ViewInject(R.id.lv_tab_detail)
private RefreshListView lvList;

@ViewInject(R.id.indicator)
private CirclePageIndicator mIndicator;

@ViewInject(R.id.tv_title)
private TextView tvTopNewsTitle;

public TabDetailPager(Activity activity, NewsTabData tabData) {
super(activity);
mTabData = tabData;
mUrl = Constants.SERVER_URL + mTabData.url;
}

@Override
public View initView() {
View view = View.inflate(mActivity, R.layout.pager_tab_detail, null);
ViewUtils.inject(this, view);

View header = View.inflate(mActivity, R.layout.list_header_topnews,
null);
ViewUtils.inject(this, header);// 必须也将头布局注入到ViewUtils

// 给listview添加头布局
lvList.addHeaderView(header);

// 设置下拉刷新监听
lvList.setOnRefreshListener(new OnRefreshListener() {

@Override
public void onRefresh() {
// 从网络加载数据
getDataFromServer();
}
});

return view;
}

@Override
public void initData() {
String cache = CacheUtils.getCache(mUrl, mActivity);
if (!TextUtils.isEmpty(cache)) {
processResult(cache);
}

getDataFromServer();
}

private void getDataFromServer() {
HttpUtils utils = new HttpUtils();
utils.send(HttpMethod.GET, mUrl, new RequestCallBack<String>() {

@Override
public void onSuccess(ResponseInfo<String> responseInfo) {
String result = responseInfo.result;
processResult(result);

System.out.println("访问网络成功!!!");
CacheUtils.setCache(mUrl, result, mActivity);

// 收起下拉刷新控件
lvList.onRefreshComplete(true);
}

@Override
public void onFailure(HttpException error, String msg) {
// 收起下拉刷新控件
lvList.onRefreshComplete(false);

error.printStackTrace();
Toast.makeText(mActivity, msg, Toast.LENGTH_SHORT).show();
}
});
}

protected void processResult(String result) {
Gson gson = new Gson();
mNewsTabData = gson.fromJson(result, NewsData.class);

// 初始化头条新闻
mTopNewsList = mNewsTabData.data.topnews;
if (mTopNewsList != null) {
mTopNewsAdapter = new TopNewsAdapter();
mViewPager.setAdapter(mTopNewsAdapter);
mIndicator.setViewPager(mViewPager);// 将指示器和viewpager绑定
mIndicator.setSnap(true);// 快照模式
mIndicator.setOnPageChangeListener(new OnPageChangeListener() {

@Override
public void onPageSelected(int position) {
System.out.println("position:" + position);
TopNews topNews = mTopNewsList.get(position);
tvTopNewsTitle.setText(topNews.title);
}

@Override
public void onPageScrolled(int position, float positionOffset,
int positionOffsetPixels) {
}

@Override
public void onPageScrollStateChanged(int state) {
}
});

mIndicator.onPageSelected(0);// 将小圆点位置归零, 解决它会在页面销毁时仍记录上次位置的bug
tvTopNewsTitle.setText(mTopNewsList.get(0).title);// 初始化第一页标题
}

// 初始化新闻列表
mNewsList = mNewsTabData.data.news;
if (mNewsList != null) {
mNewsAdapter = new NewsAdapter();
lvList.setAdapter(mNewsAdapter);
}
}

class TopNewsAdapter extends PagerAdapter {

BitmapUtils mBitmapUtils;

public TopNewsAdapter() {
// 初始化xutils中的加载图片的工具
mBitmapUtils = new BitmapUtils(mActivity);
// 设置默认加载图片
mBitmapUtils
.configDefaultLoadingImage(R.drawable.topnews_item_default);
}

@Override
public int getCount() {
return mTopNewsList.size();
}

@Override
public boolean isViewFromObject(View arg0, Object arg1) {
return arg0 == arg1;
}

@Override
public Object instantiateItem(ViewGroup container, int position) {
ImageView view = new ImageView(mActivity);
view.setScaleType(ScaleType.FIT_XY);// 设置图片填充效果, 表示填充父窗体
// 获取图片链接, 使用链接下载图片, 将图片设置给ImageView, 考虑内存溢出问题, 图片本地缓存
mBitmapUtils.display(view, mTopNewsList.get(position).topimage);
container.addView(view);
return view;
}

@Override
public void destroyItem(ViewGroup container, int position, Object object) {
container.removeView((View) object);
}

}

class NewsAdapter extends BaseAdapter {

public BitmapUtils mBitmapUtils;

public NewsAdapter() {
mBitmapUtils = new BitmapUtils(mActivity);
mBitmapUtils
.configDefaultLoadingImage(R.drawable.pic_item_list_default);
}

@Override
public int getCount() {
return mNewsList.size();
}

@Override
public News getItem(int position) {
return mNewsList.get(position);
}

@Override
public long getItemId(int position) {
return position;
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder holder;
if (convertView == null) {
convertView = View.inflate(mActivity, R.layout.list_item_news,
null);
holder = new ViewHolder();
holder.tvTitle = (TextView) convertView
.findViewById(R.id.tv_title);
holder.tvDate = (TextView) convertView
.findViewById(R.id.tv_date);
holder.ivIcon = (ImageView) convertView
.findViewById(R.id.iv_icon);
convertView.setTag(holder);
} else {
holder = (ViewHolder) convertView.getTag();
}

News news = getItem(position);
holder.tvTitle.setText(news.title);
holder.tvDate.setText(news.pubdate);

mBitmapUtils.display(holder.ivIcon, news.listimage);

return convertView;
}

}

static class ViewHolder {
public TextView tvTitle;
public TextView tvDate;
public ImageView ivIcon;
}

}