下拉刷新
最近学习了下拉刷新的方法，写在这里做个笔记，也跟大家分享一下。
MainActivity 类
LoadMyCourseAsyncTask 类
InitData 类
MyCourseAdapter类
GetTime类
Constants类
PullToRefreshListView类 （此类不是自己写的）
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:gravity="center"
android:paddingBottom="15dip"
android:paddingTop="10dip" >
android:id="@+id/pull_to_refresh_progress"
style="?android:attr/progressBarStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerVertical="true"
android:layout_marginLeft="30dip"
android:layout_marginRight="20dip"
android:layout_marginTop="10dip"
android:indeterminate="true"
android:visibility="gone" />
android:id="@+id/pull_to_refresh_image"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:layout_marginLeft="30dip"
android:layout_marginRight="20dip"
android:gravity="center"
android:src="@drawable/ic_pulltorefresh_arrow"
android:visibility="gone" />
android:id="@+id/pull_to_refresh_text"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:gravity="center"
android:paddingTop="5dip"
android:text="@string/pull_to_refresh_tap_label"
android:textAppearance="?android:attr/textAppearanceMedium"
android:textStyle="bold" />
android:id="@+id/pull_to_refresh_updated_at"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_below="@+id/pull_to_refresh_text"
android:layout_gravity="center"
android:gravity="center"
android:textAppearance="?android:attr/textAppearanceSmall"
android:visibility="gone" />
android:layout_width="match_parent"
android:layout_height="match_parent" >
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_centerVertical="true"
android:layout_marginLeft="5sp"
android:layout_marginRight="5sp"
android:orientation="horizontal" >
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_vertical"
android:layout_weight="1"
android:orientation="vertical" >
android:id="@+id/mycourse_id"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:singleLine="true"
android:text="001"
android:visibility="gone"
android:textSize="14sp" />
android:id="@+id/mycourse_class_name"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:gravity="center"
android:text="小苹果速成2班"
android:textColor="#475de0"
android:textSize="12sp" />
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:orientation="vertical" >
android:id="@+id/mycourse_name"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:gravity="center"
android:text="《小苹果是怎么炼成的10》"
android:textSize="22sp" />
android:id="@+id/mycourese_active"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="right"
android:layout_marginRight="22sp"
android:text="已购"
android:textColor="#9ec762"
android:textSize="10sp" />
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_vertical"
android:layout_weight="1"
android:orientation="vertical" >
android:id="@+id/mycourse_date"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:layout_gravity="center"
android:layout_marginTop="4sp"
android:gravity="center"
android:text="每周三下午第7节"
android:textColor="#e09647"
android:textSize="12sp" />
android:id="@+id/loadmore_layout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="center"
android:paddingBottom="15dip"
android:paddingTop="10dip" >
android:id="@+id/loadmore_progress"
style="?android:attr/progressBarStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerVertical="true"
android:layout_marginLeft="30dip"
android:layout_marginRight="20dip"
android:layout_marginTop="10dip"
android:indeterminate="true"
android:visibility="gone" />
android:id="@+id/loadmore_text"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:gravity="center"
android:paddingTop="5dip"
android:text="@string/loadmore_label"
android:textAppearance="?android:attr/textAppearanceMedium"
android:textStyle="bold" />
android:layout_width="match_parent"
android:layout_height="match_parent"
>
android:id="@+id/academy_mycourse_list"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:cacheColorHint="#00000000"
android:divider="#19000000"
android:dividerHeight="4dp"
android:fadingEdge="none"
android:fastScrollEnabled="false"
android:footerDividersEnabled="true"
android:headerDividersEnabled="false"
android:smoothScrollbar="true" />
MainActivity 类
package com.example.testpulltorefreshlistview;
import java.util.List;
import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.view.Menu;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.Toast;
import com.example.testpulltorefreshlistview.adapter.MyCourseAdapter;
import com.example.testpulltorefreshlistview.bean.MyCourseBean;
import com.example.testpulltorefreshlistview.constants.Constants;
import com.example.testpulltorefreshlistview.util.GetTime;
import com.example.testpulltorefreshlistview.views.PullToRefreshListView;
import com.example.testpulltorefreshlistview.views.PullToRefreshListView.OnRefreshListener;
/**
* 主界面
*@author Changel
*@version 2014.07.22.1
*
*/
public class MainActivity extends Activity {
private PullToRefreshListView myListView = null;
private List myList = null;
private MyCourseAdapter myAdapter = null;
private Handler mHandler;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mHandler = new Handler() {
public void handleMessage(Message msg) {
switch (msg.what) {
case 0x123:
myList = (List) msg.obj;
//设置适配器，刷新列表
myAdapter = new MyCourseAdapter(MainActivity.this, myList);
myListView.setAdapter(myAdapter);
break;
case 0x124:
myList = (List) msg.obj;
//设置适配器，刷新列表
myAdapter = new MyCourseAdapter(MainActivity.this, myList);
myListView.setAdapter(myAdapter);
Toast.makeText(MainActivity.this, "刷新成功", Toast.LENGTH_SHORT).show();
myListView.onRefreshComplete(GetTime.getLocalTime());
break;
case 0x125:
myList = (List) msg.obj;
//设置适配器，刷新列表
myAdapter = new MyCourseAdapter(MainActivity.this, myList);
myListView.setAdapter(myAdapter);
Toast.makeText(MainActivity.this, "加载成功", Toast.LENGTH_SHORT).show();
myListView.onRefreshComplete(GetTime.getLocalTime());
myListView.onLoadMoreComplete();
break;
}
}
};
//初始化界面
initListView();
//启动异步线程加载数据
new LoadMyCourseAsyncTask(MainActivity.this, Constants.FIRST_LOAD, mHandler).execute();
}
/**
* 初始化界面
* 绑定下拉刷新和加载更多的监听器
*
* */
public void initListView() {
myListView = (PullToRefreshListView) findViewById(R.id.academy_mycourse_list);
myListView.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView parent, View view,
int positon, long arg3) {
//点击每一项触发的方法
Toast.makeText(MainActivity.this, "单项点击！", positon-1).show();
}
});
myListView.setOnRefreshListener(new OnRefreshListener() {
@Override
//下拉时触发的方法
public void onRefresh() {
new LoadMyCourseAsyncTask(MainActivity.this, Constants.REFRESH, mHandler).execute();
}
@Override
//点击加载更多触发的方法
public void onLoadMore() {
new LoadMyCourseAsyncTask(MainActivity.this, Constants.MORE_LOAD, mHandler).execute();
}
});
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
}
LoadMyCourseAsyncTask 类
package com.example.testpulltorefreshlistview;
import java.util.List;
import android.app.ProgressDialog;
import android.content.Context;
import android.os.AsyncTask;
import android.os.Handler;
import android.os.Message;
import com.example.testpulltorefreshlistview.bean.MyCourseBean;
import com.example.testpulltorefreshlistview.constants.Constants;
import com.example.testpulltorefreshlistview.util.InitData;
/**
*
* 继承AsyncTask类，用异步线程来加载数据，在向主界面发送加载的信息
*
* @author Changel<[email protected]>
* @version 2014.07.22.1
*
*/
public class LoadMyCourseAsyncTask extends
AsyncTask> {
private Context context;
private int flag;
private Handler mHandler;
private ProgressDialog progressDialog;
public LoadMyCourseAsyncTask(Context context, int flag, Handler mHandler) {
this.context = context;
this.flag = flag;
this.mHandler = mHandler;
}
@Override
protected void onPostExecute(List result) {
Message msg = Message.obtain();
msg.obj = result;
msg.what = flag;
mHandler.sendMessage(msg);
if (flag == Constants.FIRST_LOAD) {
progressDialog.dismiss();
}
}
@Override
protected void onPreExecute() {
if (flag == Constants.FIRST_LOAD) {
progressDialog = new ProgressDialog(context);
progressDialog.setProgressStyle(ProgressDialog.STYLE_SPINNER);// 设置进度条的模型，有矩形，圆圈等
progressDialog.setMessage("正在获取数据");
progressDialog.onStart();
progressDialog.show();
}
}
@Override
protected List doInBackground(String... params) {
List myCourseList = new InitData().getCourseData();
return myCourseList;
}
}
InitData 类
package com.example.testpulltorefreshlistview.util;
import java.util.ArrayList;
import java.util.List;
import com.example.testpulltorefreshlistview.bean.MyCourseBean;
/**
*
* 模拟数据
*
* @author Changel<[email protected]>
* @version 2014.07.22.1
*
*/
public class InitData {
private static int i,isum;
public List getCourseData(){
List list ;
list = new ArrayList();
isum = isum + 15;
for (i=1; i < isum; i++) {
MyCourseBean myCourseBean = new MyCourseBean();
myCourseBean.setmClassName("速成班"+i+"班");
myCourseBean.setmCourseActive("已购买");
myCourseBean.setmCourseDate("每周三"+"第"+i+"节");
myCourseBean.setmCourseName("《"+"小苹果是怎么炼成的"+i+"》");
myCourseBean.setmCourseId(" "+i);
list.add(myCourseBean);
}
//模拟网络加载过程
for (int i = 0; i < 2; i++) {
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
return list;
}
}
MyCourseAdapter类
package com.example.testpulltorefreshlistview.adapter;
import java.util.List;
import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.TextView;
import com.example.testpulltorefreshlistview.R;
import com.example.testpulltorefreshlistview.bean.MyCourseBean;
/**
*
* 继承BaseAdapter基类，构造一个Adapter来显示list的内容
*
* @author Changel<[email protected]>
* @version 2014.07.22.1
*
*/
public class MyCourseAdapter extends BaseAdapter{
private List list ;
private LayoutInflater inflater;
private Context context;
public MyCourseAdapter(Context context ,List list){
this.context = context;
this.list = list;
inflater=LayoutInflater.from(context);
}
@Override
public int getCount() {
// TODO Auto-generated method stub
return list.size();
}
@Override
public Object getItem(int position) {
// TODO Auto-generated method stub
return list.get(position);
}
@Override
public long getItemId(int position) {
// TODO Auto-generated method stub
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
// TODO Auto-generated method stub
ViewHolder viewHolder;
if(convertView==null){
convertView=inflater.inflate(R.layout.my_course_item, null);
viewHolder = new ViewHolder(convertView);
convertView.setTag(viewHolder);
}else{
viewHolder=(ViewHolder) convertView.getTag();
}
//将myCourseBean的信息显示在list上
MyCourseBean myCourseBean = list.get(position);
viewHolder.getCourseIdTextView().setText(myCourseBean.getmCourseId());
viewHolder.getDateTextView().setText(myCourseBean.getmCourseDate());
viewHolder.getClassNameTextView().setText(myCourseBean.getmClassName());
viewHolder.getCourseNameTextView().setText(myCourseBean.getmCourseName());
viewHolder.getActiveTextView().setText(myCourseBean.getmCourseActive());
return convertView;
}
/**
*
* 初始化MyCourseAdapter
*
*/
class ViewHolder{
TextView idTextView;
TextView dateTextView;
TextView courseNameTextView;
TextView classNameTextView;
TextView activeTextView;
ImageView image;
View view;
public ViewHolder(View view){
this.view = view;
}
public TextView getCourseIdTextView(){
if(idTextView == null){
idTextView = (TextView)view.findViewById(R.id.mycourse_id);
}
return idTextView;
}
public TextView getDateTextView(){
if(dateTextView == null){
dateTextView = (TextView)view.findViewById(R.id.mycourse_date);
}
return dateTextView;
}
public TextView getCourseNameTextView(){
if(courseNameTextView == null){
courseNameTextView = (TextView)view.findViewById(R.id.mycourse_name);
}
return courseNameTextView;
}
public TextView getClassNameTextView(){
if(classNameTextView == null){
classNameTextView = (TextView)view.findViewById(R.id.mycourse_class_name);
}
return classNameTextView;
}
public TextView getActiveTextView(){
if(activeTextView == null){
activeTextView = (TextView)view.findViewById(R.id.mycourese_active);
}
return activeTextView;
}
}
}
GetTime类
package com.example.testpulltorefreshlistview.util;
import java.net.URL;
import java.net.URLConnection;
import java.text.SimpleDateFormat;
import java.util.Date;
/**
*
* 创建一个获取时间的Util,用于获取更新的时间
*
* @author Changel<[email protected]>
* @version 2014.07.22.1
*
*/
public class GetTime {
private static String timeString = null;
//获取网络时间
public static String getNetTime() throws Exception{
//取得资源对象
URL url = new URL("http://www.bjtime.cn");
//生成连接对象
URLConnection uc = url.openConnection();
//发出连接
uc.connect();
long time = uc.getDate();
Date date = new Date(time);
timeString = new SimpleDateFormat("yyyy-MM-dd").format(date).toString();
return timeString;
}
//获取本地时间
public static String getLocalTime(){
SimpleDateFormat sm=new SimpleDateFormat("yyyy-MM-dd");
timeString = sm.format(new Date()).toString();
System.out.println(timeString);
return timeString;
}
}
Constants类
package com.example.testpulltorefreshlistview.constants;
public class Constants {
public final static int FIRST_LOAD = 0x123;
public final static int REFRESH = 0x124;
public final static int MORE_LOAD = 0x125;
}
PullToRefreshListView类 （此类不是自己写的）
package com.example.testpulltorefreshlistview.views;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import android.content.Context;
import android.util.AttributeSet;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewGroup;
import android.view.animation.LinearInterpolator;
import android.view.animation.RotateAnimation;
import android.widget.AbsListView;
import android.widget.AbsListView.OnScrollListener;
import android.widget.ImageView;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.ProgressBar;
import android.widget.RelativeLayout;
import android.widget.TextView;
import com.example.testpulltorefreshlistview.R;
/**
* 自定义ListView，实现OnScrollListener接口
* 此ListView是为实现"下拉刷新"和"上拉加载更多"而定制的，具体效果可参考新浪微博、腾讯微博
*
*/
public class PullToRefreshListView extends ListView implements OnScrollListener {
private static final int TAP_TO_REFRESH = 1; // （未刷新）
private static final int PULL_TO_REFRESH = 2; // 下拉刷新
private static final int RELEASE_TO_REFRESH = 3; // 释放刷新
private static final int REFRESHING = 4; // 正在刷新
private static final int TAP_TO_LOADMORE = 5; // 未加载更多
private static final int LOADING = 6; // 正在加载
private static final String TAG = "PullToRefreshListView";
private OnRefreshListener mOnRefreshListener; // 刷新监听器
/**
* Listener that will receive notifications every time the list scrolls.
*/
private OnScrollListener mOnScrollListener; // 列表滚动监听器
private LayoutInflater mInflater; // 用于加载布局文件
private RelativeLayout mRefreshHeaderView; // 刷新视图(也就是头部那部分)
private TextView mRefreshViewText; // 刷新提示文本
private ImageView mRefreshViewImage; // 刷新向上向下的那个图片
private ProgressBar mRefreshViewProgress; // 这里是圆形进度条
private TextView mRefreshViewLastUpdated; // 最近更新的文本
private RelativeLayout mLoadMoreFooterView; // 加载更多
private TextView mLoadMoreText; // 提示文本
private ProgressBar mLoadMoreProgress; // 加载更多进度条
private int mCurrentScrollState; // 当前滚动位置
private int mRefreshState; // 刷新状态
private int mLoadState; // 加载状态
private RotateAnimation mFlipAnimation; // 下拉动画
private RotateAnimation mReverseFlipAnimation; // 恢复动画
private int mRefreshViewHeight; // 刷新视图高度
private int mRefreshOriginalTopPadding; // 原始上部间隙
private int mLastMotionY; // 记录点击位置
public PullToRefreshListView(Context context) {
super(context);
init(context);
}
public PullToRefreshListView(Context context, AttributeSet attrs) {
super(context, attrs);
init(context);
}
public PullToRefreshListView(Context context, AttributeSet attrs,
int defStyle) {
super(context, attrs, defStyle);
init(context);
}
private void init(Context context) {
// Load all of the animations we need in code rather than through XML
/** 定义旋转动画 **/
// 参数：1.旋转开始的角度 2.旋转结束的角度 3. X轴伸缩模式 4.X坐标的伸缩值 5.Y轴的伸缩模式 6.Y坐标的伸缩值
mFlipAnimation = new RotateAnimation(0, -180,
RotateAnimation.RELATIVE_TO_SELF, 0.5f,
RotateAnimation.RELATIVE_TO_SELF, 0.5f);
mFlipAnimation.setInterpolator(new LinearInterpolator());
mFlipAnimation.setDuration(250); // 设置持续时间
mFlipAnimation.setFillAfter(true); // 动画执行完是否停留在执行完的状态
mReverseFlipAnimation = new RotateAnimation(-180, 0,
RotateAnimation.RELATIVE_TO_SELF, 0.5f,
RotateAnimation.RELATIVE_TO_SELF, 0.5f);
mReverseFlipAnimation.setInterpolator(new LinearInterpolator());
mReverseFlipAnimation.setDuration(250);
mReverseFlipAnimation.setFillAfter(true);
// 获取LayoutInflater实例对象
mInflater = (LayoutInflater) context
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
// 加载下拉刷新的头部视图
mRefreshHeaderView = (RelativeLayout) mInflater.inflate(
R.layout.pull_to_refresh_header, this, false);
mRefreshViewText = (TextView) mRefreshHeaderView
.findViewById(R.id.pull_to_refresh_text);
mRefreshViewImage = (ImageView) mRefreshHeaderView
.findViewById(R.id.pull_to_refresh_image);
mRefreshViewProgress = (ProgressBar) mRefreshHeaderView
.findViewById(R.id.pull_to_refresh_progress);
mRefreshViewLastUpdated = (TextView) mRefreshHeaderView
.findViewById(R.id.pull_to_refresh_updated_at);
mLoadMoreFooterView = (RelativeLayout) mInflater.inflate(
R.layout.loadmore_footer, this, false);
mLoadMoreText = (TextView) mLoadMoreFooterView
.findViewById(R.id.loadmore_text);
mLoadMoreProgress = (ProgressBar) mLoadMoreFooterView
.findViewById(R.id.loadmore_progress);
mRefreshViewImage.setMinimumHeight(50); // 设置图片最小高度
mRefreshHeaderView.setOnClickListener(new OnClickRefreshListener());
mRefreshOriginalTopPadding = mRefreshHeaderView.getPaddingTop();
mLoadMoreFooterView.setOnClickListener(new OnClickLoadMoreListener());
mRefreshState = TAP_TO_REFRESH; // 初始刷新状态
mLoadState = TAP_TO_LOADMORE;
addHeaderView(mRefreshHeaderView); // 增加头部视图
addFooterView(mLoadMoreFooterView); // 增加尾部视图
super.setOnScrollListener(this);
measureView(mRefreshHeaderView); // 测量视图
mRefreshViewHeight = mRefreshHeaderView.getMeasuredHeight(); // 得到视图的高度
}
@Override
protected void onAttachedToWindow() {
setSelection(1); // 设置当前选中的项
}
@Override
public void setAdapter(ListAdapter adapter) {
super.setAdapter(adapter);
setSelection(1);
}
/**
* Set the listener that will receive notifications every time the list
* scrolls.
*
* @param l
* The scroll listener.
*/
@Override
public void setOnScrollListener(AbsListView.OnScrollListener l) {
mOnScrollListener = l;
}
/**
* Register a callback to be invoked when this list should be refreshed.
* 注册监听器
*
* @param onRefreshListener
* The callback to run.
*/
public void setOnRefreshListener(OnRefreshListener onRefreshListener) {
mOnRefreshListener = onRefreshListener;
}
/**
* Set a text to represent when the list was last updated.
* 设置一个文本来表示最近更新的列表，显示的是最近更新列表的时间
*
* @param lastUpdated
* Last updated at.
*/
public void setLastUpdated(CharSequence lastUpdated) {
if (lastUpdated != null) {
mRefreshViewLastUpdated.setVisibility(View.VISIBLE);
mRefreshViewLastUpdated.setText("更新于: " + lastUpdated);
} else {
mRefreshViewLastUpdated.setVisibility(View.GONE);
}
}
@Override
public boolean onTouchEvent(MotionEvent event) {
final int y = (int) event.getY(); // 获取点击位置的Y坐标
switch (event.getAction()) {
case MotionEvent.ACTION_UP: // 手指抬起
if (!isVerticalScrollBarEnabled()) {
setVerticalScrollBarEnabled(true);
}
if (getFirstVisiblePosition() == 0 && mRefreshState != REFRESHING) {
if ((mRefreshHeaderView.getBottom() > mRefreshViewHeight || mRefreshHeaderView
.getTop() >= 0) && mRefreshState == RELEASE_TO_REFRESH) {
// Initiate the refresh
mRefreshState = REFRESHING; // 刷新状态
prepareForRefresh();
onRefresh();
} else if (mRefreshHeaderView.getBottom() < mRefreshViewHeight
|| mRefreshHeaderView.getTop() < 0) {
// Abort refresh and scroll down below the refresh view
resetHeader();
setSelection(1);
}
}
break;
case MotionEvent.ACTION_DOWN:
mLastMotionY = y;
break;
case MotionEvent.ACTION_MOVE:
applyHeaderPadding(event);
break;
}
return super.onTouchEvent(event);
}
private void applyHeaderPadding(MotionEvent ev) {
final int historySize = ev.getHistorySize();
// Workaround for getPointerCount() which is unavailable in 1.5
// (it's always 1 in 1.5)
int pointerCount = 1;
try {
Method method = MotionEvent.class.getMethod("getPointerCount");
pointerCount = (Integer) method.invoke(ev);
} catch (NoSuchMethodException e) {
pointerCount = 1;
} catch (IllegalArgumentException e) {
throw e;
} catch (IllegalAccessException e) {
System.err.println("unexpected " + e);
} catch (InvocationTargetException e) {
System.err.println("unexpected " + e);
}
for (int h = 0; h < historySize; h++) {
for (int p = 0; p < pointerCount; p++) {
if (mRefreshState == RELEASE_TO_REFRESH) {
if (isVerticalFadingEdgeEnabled()) {
setVerticalScrollBarEnabled(false);
}
int historicalY = 0;
try {
// For Android > 2.0
Method method = MotionEvent.class.getMethod(
"getHistoricalY", Integer.TYPE, Integer.TYPE);
historicalY = ((Float) method.invoke(ev, p, h))
.intValue();
} catch (NoSuchMethodException e) {
// For Android < 2.0
historicalY = (int) (ev.getHistoricalY(h));
} catch (IllegalArgumentException e) {
throw e;
} catch (IllegalAccessException e) {
System.err.println("unexpected " + e);
} catch (InvocationTargetException e) {
System.err.println("unexpected " + e);
}
// Calculate the padding to apply, we divide by 1.7 to
// simulate a more resistant effect during pull.
int topPadding = (int) (((historicalY - mLastMotionY) - mRefreshViewHeight) / 1.7);
// 设置上、下、左、右四个位置的间隙间隙
mRefreshHeaderView.setPadding(
mRefreshHeaderView.getPaddingLeft(), topPadding,
mRefreshHeaderView.getPaddingRight(),
mRefreshHeaderView.getPaddingBottom());
}
}
}
}
/**
* Sets the header padding back to original size. 设置头部填充会原始大小
*/
private void resetHeaderPadding() {
mRefreshHeaderView.setPadding(mRefreshHeaderView.getPaddingLeft(),
mRefreshOriginalTopPadding,
mRefreshHeaderView.getPaddingRight(),
mRefreshHeaderView.getPaddingBottom());
}
/**
* Resets the header to the original state. 重新设置头部为原始状态
*/
private void resetHeader() {
if (mRefreshState != TAP_TO_REFRESH) {
mRefreshState = TAP_TO_REFRESH;
resetHeaderPadding();
// Set refresh view text to the pull label
mRefreshViewText.setText(R.string.pull_to_refresh_tap_label);
// Replace refresh drawable with arrow drawable
mRefreshViewImage
.setImageResource(R.drawable.ic_pulltorefresh_arrow);
// Clear the full rotation animation
mRefreshViewImage.clearAnimation();
// Hide progress bar and arrow.
mRefreshViewImage.setVisibility(View.GONE);
mRefreshViewProgress.setVisibility(View.GONE);
}
}
/**
* 重设ListView尾部视图为初始状态
*/
private void resetFooter() {
if (mLoadState != TAP_TO_LOADMORE) {
mLoadState = TAP_TO_LOADMORE;
// 进度条设置为不可见
mLoadMoreProgress.setVisibility(View.GONE);
// 按钮的文本替换为“加载更多”
mLoadMoreText.setText(R.string.loadmore_label);
}
}
/**
* 测量视图的大小
*
* @param child
*/
private void measureView(View child) {
ViewGroup.LayoutParams p = child.getLayoutParams();
if (p == null) {
p = new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT,
ViewGroup.LayoutParams.WRAP_CONTENT);
}
int childWidthSpec = ViewGroup.getChildMeasureSpec(0, 0 + 0, p.width);
int lpHeight = p.height;
int childHeightSpec;
if (lpHeight > 0) {
childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight,
MeasureSpec.EXACTLY);
} else {
childHeightSpec = MeasureSpec.makeMeasureSpec(0,
MeasureSpec.UNSPECIFIED);
}
child.measure(childWidthSpec, childHeightSpec);
}
@Override
public void onScroll(AbsListView view, int firstVisibleItem,
int visibleItemCount, int totalItemCount) {
// When the refresh view is completely visible, change the text to say
// "Release to refresh..." and flip the arrow drawable.
if (mCurrentScrollState == SCROLL_STATE_TOUCH_SCROLL
&& mRefreshState != REFRESHING) {
if (firstVisibleItem == 0) { // 如果第一个可见条目为0
mRefreshViewImage.setVisibility(View.VISIBLE); // 让指示箭头变得可见
/** 如果头部视图相对与父容器的位置大于其自身高度+20或者头部视图的顶部位置>0,并且要在刷新状态不等于"释放以刷新" **/
if ((mRefreshHeaderView.getBottom() > mRefreshViewHeight + 20 || mRefreshHeaderView
.getTop() >= 0) && mRefreshState != RELEASE_TO_REFRESH) {
mRefreshViewText
.setText(R.string.pull_to_refresh_release_label);// 设置刷新文本为"Release to refresh..."
mRefreshViewImage.clearAnimation(); // 清除动画
mRefreshViewImage.startAnimation(mFlipAnimation); // 启动动画
mRefreshState = RELEASE_TO_REFRESH; // 更改刷新状态为“释放以刷新"
} else if (mRefreshHeaderView.getBottom() < mRefreshViewHeight + 20
&& mRefreshState != PULL_TO_REFRESH) {
mRefreshViewText
.setText(R.string.pull_to_refresh_pull_label);// 设置刷新文本为"Pull to refresh..."
if (mRefreshState != TAP_TO_REFRESH) {
mRefreshViewImage.clearAnimation();
mRefreshViewImage.startAnimation(mReverseFlipAnimation);
}
mRefreshState = PULL_TO_REFRESH;
}
} else {
mRefreshViewImage.setVisibility(View.GONE); // 让刷新箭头不可见
resetHeader(); // 重新设置头部为原始状态
}
} else if (mCurrentScrollState == SCROLL_STATE_FLING
&& firstVisibleItem == 0 && mRefreshState != REFRESHING) {
setSelection(1);
}
if (mOnScrollListener != null) {
mOnScrollListener.onScroll(view, firstVisibleItem,
visibleItemCount, totalItemCount);
}
}
@Override
public void onScrollStateChanged(AbsListView view, int scrollState) {
mCurrentScrollState = scrollState;
if (mOnScrollListener != null) {
mOnScrollListener.onScrollStateChanged(view, scrollState);
}
}
/** 为刷新做准备 **/
public void prepareForRefresh() {
resetHeaderPadding();
mRefreshViewImage.setVisibility(View.GONE); // 去掉刷新的箭头
// We need this hack, otherwise it will keep the previous drawable.
mRefreshViewImage.setImageDrawable(null);
mRefreshViewProgress.setVisibility(View.VISIBLE); // 圆形进度条变为可见
// Set refresh view text to the refreshing label
mRefreshViewText.setText(R.string.pull_to_refresh_refreshing_label);
mRefreshState = REFRESHING;
}
/** 为加载更多做准备 **/
public void prepareForLoadMore() {
mLoadMoreProgress.setVisibility(View.VISIBLE);
mLoadMoreText.setText(R.string.loading_label);
mLoadState = LOADING;
}
public void onRefresh() {
Log.d(TAG, "onRefresh");
if (mOnRefreshListener != null) {
mOnRefreshListener.onRefresh();
}
}
public void OnLoadMore() {
Log.d(TAG, "onLoadMore");
if (mOnRefreshListener != null) {
mOnRefreshListener.onLoadMore();
}
}
/**
* Resets the list to a normal state after a refresh.
*
* @param lastUpdated
* Last updated at.
*/
public void onRefreshComplete(CharSequence lastUpdated) {
setLastUpdated(lastUpdated); // 显示更新时间
onRefreshComplete();
}
/**
* Resets the list to a normal state after a refresh.
*/
public void onRefreshComplete() {
Log.d(TAG, "onRefreshComplete");
resetHeader();
// If refresh view is visible when loading completes, scroll down to
// the next item.
if (mRefreshHeaderView.getBottom() > 0) {
invalidateViews();
setSelection(1);
}
}
public void onLoadMoreComplete() {
Log.d(TAG, "onLoadMoreComplete");
resetFooter();
}
/**
* Invoked when the refresh view is clicked on. This is mainly used when
* there's only a few items in the list and it's not possible to drag the
* list. 点击刷新
*/
private class OnClickRefreshListener implements OnClickListener {
@Override
public void onClick(View v) {
if (mRefreshState != REFRESHING) {
prepareForRefresh();
onRefresh();
}
}
}
/**
*
* 加载更多
*/
private class OnClickLoadMoreListener implements OnClickListener {
@Override
public void onClick(View v) {
if (mLoadState != LOADING) {
prepareForLoadMore();
OnLoadMore();
}
}
}
/**
* Interface definition for a callback to be invoked when list should be
* refreshed. 接口定义一个回调方法当列表应当被刷新
*/
public interface OnRefreshListener {
/**
* Called when the list should be refreshed. 当列表应当被刷新是调用这个方法
*
* A call to {@link PullToRefreshListView #onRefreshComplete()} is
* expected to indicate that the refresh has completed.
*/
public void onRefresh();
public void onLoadMore();
}
}