发布于 2016-05-06 12:27:19 | 258 次阅读 | 评论: 0 | 来源: 网友投递

这里有新鲜出炉的精品教程,程序狗速度看过来!

Android移动端操作系统

Android是一种基于Linux的自由及开放源代码的操作系统,主要使用于移动设备,如智能手机和平板电脑,由Google公司和开放手机联盟领导及开发。尚未有统一中文名称,中国大陆地区较多人使用“安卓”或“安致”。


这篇文章主要介绍了Android下拉刷新上拉加载控件,对所有View通用,感兴趣的小伙伴们可以参考一下

     前面写过一篇关于下拉刷新控件的文章下拉刷新控件终结者:PullToRefreshLayout,后来看到好多人还有上拉加载更多的需求,于是就在前面下拉刷新控件的基础上进行了改进,加了上拉加载的功能。不仅如此,我已经把它改成了对所有View都通用!可以随心所欲使用这两个功能~~

    我做了一个大集合的demo,实现了ListView、GridView、ExpandableListView、ScrollView、WebView、ImageView、TextView的下拉刷新和上拉加载。后面会提供demo的下载地址,最新代码已上传到github:https://github.com/jingchenUSTC/PullToRefreshAndLoad

依照惯例,下面将会是一大波效果图:

demo首页也是可下拉的ListView,在底下可以加入table:

                                            

ListView:

                

GridView:

                

ExpandableListView:

                

ScrollView:

               

WebView:

               

ImageView:

                

TextView:

                

很不错吧?最后的ImageView和TextView是最简单的,直接在下面的接口方法里返回true。
增加上拉加载很简单,和管理下拉头一样,再多管理一个上拉头,也不费事;至于把它改成通用的就需要统一一下View的行为了,为此,我定义了这样一个接口:
package com.jingchen.pulltorefresh.pullableview; 
 
public interface Pullable 

    /**
     * 判断是否可以下拉,如果不需要下拉功能可以直接return false
     * 
     * @return true如果可以下拉否则返回false
     */ 
    boolean canPullDown(); 
 
    /**
     * 判断是否可以上拉,如果不需要上拉功能可以直接return false
     * 
     * @return true如果可以上拉否则返回false
     */ 
    boolean canPullUp(); 

从接口名就可以看出它是一个提供判断是否可拉的方法的接口。这个接口的两个方法,canPullDown()是判断何时可以下拉的方法,canPullUp()则是判断何时可以上拉,我在demo中的判断是滑到顶部的时候可以下拉,滑到底部的时候可以上拉。所有需要上拉和下拉的View都需要实现这个接口。后面会给出一些View的实现。先来看看改进后的自定义的布局PullToRefreshLayout,增加了一个上拉头,下拉头和上拉头之间的View是实现了Pullable接口的pullableView。相比前面的版本,这里有改动的需要注意的地方如下:
1、增加了上拉头,相应的也增加了控制变量。

2、拉动时消除content_view事件防止误触发不再使用反射,直接设置                       event.setAction(MotionEvent.ACTION_CANCEL)。

3、消除了拉动过程中的多点触碰导致的剧变。

4、不再设置content_view的onTouListener,让使用者可以更加自由的设置监听器。

这个PullToRefreshLayout只负责管理三个控件,如果一个View需要有上拉下拉功能则只需实现接口就行了。下面看PullToRefreshLayout的代码,注释写了好多:


package com.jingchen.pulltorefresh; 
 
import java.util.Timer; 
import java.util.TimerTask; 
 
import android.content.Context; 
import android.graphics.Canvas; 
import android.graphics.LinearGradient; 
import android.graphics.Paint; 
import android.graphics.Paint.Style; 
import android.graphics.RectF; 
import android.graphics.Shader.TileMode; 
import android.os.Handler; 
import android.os.Message; 
import android.util.AttributeSet; 
import android.util.Log; 
import android.view.MotionEvent; 
import android.view.View; 
import android.view.ViewGroup; 
import android.view.animation.AnimationUtils; 
import android.view.animation.LinearInterpolator; 
import android.view.animation.RotateAnimation; 
import android.widget.RelativeLayout; 
import android.widget.TextView; 
 
import com.jingchen.pulltorefresh.pullableview.Pullable; 
 
/** 
 * 自定义的布局,用来管理三个子控件,其中一个是下拉头,一个是包含内容的pullableView(可以是实现Pullable接口的的任何View), 
 * 还有一个上拉头 
 * 
 * @author 陈靖 
 */ 
public class PullToRefreshLayout extends RelativeLayout 
{ 
 public static final String TAG = "PullToRefreshLayout"; 
 // 初始状态 
 public static final int INIT = 0; 
 // 释放刷新 
 public static final int RELEASE_TO_REFRESH = 1; 
 // 正在刷新 
 public static final int REFRESHING = 2; 
 // 释放加载 
 public static final int RELEASE_TO_LOAD = 3; 
 // 正在加载 
 public static final int LOADING = 4; 
 // 操作完毕 
 public static final int DONE = 5; 
 // 当前状态 
 private int state = INIT; 
 // 刷新回调接口 
 private OnRefreshListener mListener; 
 // 刷新成功 
 public static final int SUCCEED = 0; 
 // 刷新失败 
 public static final int FAIL = 1; 
 // 按下Y坐标,上一个事件点Y坐标 
 private float downY, lastY; 
 
 // 下拉的距离。注意:pullDownY和pullUpY不可能同时不为0 
 public float pullDownY = 0; 
 // 上拉的距离 
 private float pullUpY = 0; 
 
 // 释放刷新的距离 
 private float refreshDist = 200; 
 // 释放加载的距离 
 private float loadmoreDist = 200; 
 
 private MyTimer timer; 
 // 回滚速度 
 public float MOVE_SPEED = 8; 
 // 第一次执行布局 
 private boolean isLayout = false; 
 // 在刷新过程中滑动操作 
 private boolean isTouch = false; 
 // 手指滑动距离与下拉头的滑动距离比,中间会随正切函数变化 
 private float radio = 2; 
 
 // 下拉箭头的转180°动画 
 private RotateAnimation rotateAnimation; 
 // 均匀旋转动画 
 private RotateAnimation refreshingAnimation; 
 
 // 下拉头 
 private View refreshView; 
 // 下拉的箭头 
 private View pullView; 
 // 正在刷新的图标 
 private View refreshingView; 
 // 刷新结果图标 
 private View refreshStateImageView; 
 // 刷新结果:成功或失败 
 private TextView refreshStateTextView; 
 
 // 上拉头 
 private View loadmoreView; 
 // 上拉的箭头 
 private View pullUpView; 
 // 正在加载的图标 
 private View loadingView; 
 // 加载结果图标 
 private View loadStateImageView; 
 // 加载结果:成功或失败 
 private TextView loadStateTextView; 
 
 // 实现了Pullable接口的View 
 private View pullableView; 
 // 过滤多点触碰 
 private int mEvents; 
 // 这两个变量用来控制pull的方向,如果不加控制,当情况满足可上拉又可下拉时没法下拉 
 private boolean canPullDown = true; 
 private boolean canPullUp = true; 
 
 /** 
  * 执行自动回滚的handler 
  */ 
 Handler updateHandler = new Handler() 
 { 
 
  @Override 
  public void handleMessage(Message msg) 
  { 
   // 回弹速度随下拉距离moveDeltaY增大而增大 
   MOVE_SPEED = (float) (8 + 5 * Math.tan(Math.PI / 2 
     / getMeasuredHeight() * (pullDownY + Math.abs(pullUpY)))); 
   if (!isTouch) 
   { 
    // 正在刷新,且没有往上推的话则悬停,显示"正在刷新..." 
    if (state == REFRESHING && pullDownY <= refreshDist) 
    { 
     pullDownY = refreshDist; 
     timer.cancel(); 
    } else if (state == LOADING && -pullUpY <= loadmoreDist) 
    { 
     pullUpY = -loadmoreDist; 
     timer.cancel(); 
    } 
 
   } 
   if (pullDownY > 0) 
    pullDownY -= MOVE_SPEED; 
   else if (pullUpY < 0) 
    pullUpY += MOVE_SPEED; 
   if (pullDownY < 0) 
   { 
    // 已完成回弹 
    pullDownY = 0; 
    pullView.clearAnimation(); 
    // 隐藏下拉头时有可能还在刷新,只有当前状态不是正在刷新时才改变状态 
    if (state != REFRESHING && state != LOADING) 
     changeState(INIT); 
    timer.cancel(); 
   } 
   if (pullUpY > 0) 
   { 
    // 已完成回弹 
    pullUpY = 0; 
    pullUpView.clearAnimation(); 
    // 隐藏下拉头时有可能还在刷新,只有当前状态不是正在刷新时才改变状态 
    if (state != REFRESHING && state != LOADING) 
     changeState(INIT); 
    timer.cancel(); 
   } 
   // 刷新布局,会自动调用onLayout 
   requestLayout(); 
  } 
 
 }; 
 
 public void setOnRefreshListener(OnRefreshListener listener) 
 { 
  mListener = listener; 
 } 
 
 public PullToRefreshLayout(Context context) 
 { 
  super(context); 
  initView(context); 
 } 
 
 public PullToRefreshLayout(Context context, AttributeSet attrs) 
 { 
  super(context, attrs); 
  initView(context); 
 } 
 
 public PullToRefreshLayout(Context context, AttributeSet attrs, int defStyle) 
 { 
  super(context, attrs, defStyle); 
  initView(context); 
 } 
 
 private void initView(Context context) 
 { 
  timer = new MyTimer(updateHandler); 
  rotateAnimation = (RotateAnimation) AnimationUtils.loadAnimation( 
    context, R.anim.reverse_anim); 
  refreshingAnimation = (RotateAnimation) AnimationUtils.loadAnimation( 
    context, R.anim.rotating); 
  // 添加匀速转动动画 
  LinearInterpolator lir = new LinearInterpolator(); 
  rotateAnimation.setInterpolator(lir); 
  refreshingAnimation.setInterpolator(lir); 
 } 
 
 private void hide() 
 { 
  timer.schedule(5); 
 } 
 
 /** 
  * 完成刷新操作,显示刷新结果。注意:刷新完成后一定要调用这个方法 
  */ 
 /** 
  * @param refreshResult 
  *   PullToRefreshLayout.SUCCEED代表成功,PullToRefreshLayout.FAIL代表失败 
  */ 
 public void refreshFinish(int refreshResult) 
 { 
  refreshingView.clearAnimation(); 
  refreshingView.setVisibility(View.GONE); 
  switch (refreshResult) 
  { 
  case SUCCEED: 
   // 刷新成功 
   refreshStateImageView.setVisibility(View.VISIBLE); 
   refreshStateTextView.setText(R.string.refresh_succeed); 
   refreshStateImageView 
     .setBackgroundResource(R.drawable.refresh_succeed); 
   break; 
  case FAIL: 
  default: 
   // 刷新失败 
   refreshStateImageView.setVisibility(View.VISIBLE); 
   refreshStateTextView.setText(R.string.refresh_fail); 
   refreshStateImageView 
     .setBackgroundResource(R.drawable.refresh_failed); 
   break; 
  } 
  // 刷新结果停留1秒 
  new Handler() 
  { 
   @Override 
   public void handleMessage(Message msg) 
   { 
    changeState(DONE); 
    hide(); 
   } 
  }.sendEmptyMessageDelayed(0, 1000); 
 } 
 
 /** 
  * 加载完毕,显示加载结果。注意:加载完成后一定要调用这个方法 
  * 
  * @param refreshResult 
  *   PullToRefreshLayout.SUCCEED代表成功,PullToRefreshLayout.FAIL代表失败 
  */ 
 public void loadmoreFinish(int refreshResult) 
 { 
  loadingView.clearAnimation(); 
  loadingView.setVisibility(View.GONE); 
  switch (refreshResult) 
  { 
  case SUCCEED: 
   // 加载成功 
   loadStateImageView.setVisibility(View.VISIBLE); 
   loadStateTextView.setText(R.string.load_succeed); 
   loadStateImageView.setBackgroundResource(R.drawable.load_succeed); 
   break; 
  case FAIL: 
  default: 
   // 加载失败 
   loadStateImageView.setVisibility(View.VISIBLE); 
   loadStateTextView.setText(R.string.load_fail); 
   loadStateImageView.setBackgroundResource(R.drawable.load_failed); 
   break; 
  } 
  // 刷新结果停留1秒 
  new Handler() 
  { 
   @Override 
   public void handleMessage(Message msg) 
   { 
    changeState(DONE); 
    hide(); 
   } 
  }.sendEmptyMessageDelayed(0, 1000); 
 } 
 
 private void changeState(int to) 
 { 
  state = to; 
  switch (state) 
  { 
  case INIT: 
   // 下拉布局初始状态 
   refreshStateImageView.setVisibility(View.GONE); 
   refreshStateTextView.setText(R.string.pull_to_refresh); 
   pullView.clearAnimation(); 
   pullView.setVisibility(View.VISIBLE); 
   // 上拉布局初始状态 
   loadStateImageView.setVisibility(View.GONE); 
   loadStateTextView.setText(R.string.pullup_to_load); 
   pullUpView.clearAnimation(); 
   pullUpView.setVisibility(View.VISIBLE); 
   break; 
  case RELEASE_TO_REFRESH: 
   // 释放刷新状态 
   refreshStateTextView.setText(R.string.release_to_refresh); 
   pullView.startAnimation(rotateAnimation); 
   break; 
  case REFRESHING: 
   // 正在刷新状态 
   pullView.clearAnimation(); 
   refreshingView.setVisibility(View.VISIBLE); 
   pullView.setVisibility(View.INVISIBLE); 
   refreshingView.startAnimation(refreshingAnimation); 
   refreshStateTextView.setText(R.string.refreshing); 
   break; 
  case RELEASE_TO_LOAD: 
   // 释放加载状态 
   loadStateTextView.setText(R.string.release_to_load); 
   pullUpView.startAnimation(rotateAnimation); 
   break; 
  case LOADING: 
   // 正在加载状态 
   pullUpView.clearAnimation(); 
   loadingView.setVisibility(View.VISIBLE); 
   pullUpView.setVisibility(View.INVISIBLE); 
   loadingView.startAnimation(refreshingAnimation); 
   loadStateTextView.setText(R.string.loading); 
   break; 
  case DONE: 
   // 刷新或加载完毕,啥都不做 
   break; 
  } 
 } 
 
 /** 
  * 不限制上拉或下拉 
  */ 
 private void releasePull() 
 { 
  canPullDown = true; 
  canPullUp = true; 
 } 
 
 /* 
  * (非 Javadoc)由父控件决定是否分发事件,防止事件冲突 
  * 
  * @see android.view.ViewGroup#dispatchTouchEvent(android.view.MotionEvent) 
  */ 
 @Override 
 public boolean dispatchTouchEvent(MotionEvent ev) 
 { 
  switch (ev.getActionMasked()) 
  { 
  case MotionEvent.ACTION_DOWN: 
   downY = ev.getY(); 
   lastY = downY; 
   timer.cancel(); 
   mEvents = 0; 
   releasePull(); 
   break; 
  case MotionEvent.ACTION_POINTER_DOWN: 
  case MotionEvent.ACTION_POINTER_UP: 
   // 过滤多点触碰 
   mEvents = -1; 
   break; 
  case MotionEvent.ACTION_MOVE: 
   if (mEvents == 0) 
   { 
    if (((Pullable) pullableView).canPullDown() && canPullDown 
      && state != LOADING) 
    { 
     // 可以下拉,正在加载时不能下拉 
     // 对实际滑动距离做缩小,造成用力拉的感觉 
     pullDownY = pullDownY + (ev.getY() - lastY) / radio; 
     if (pullDownY < 0) 
     { 
      pullDownY = 0; 
      canPullDown = false; 
      canPullUp = true; 
     } 
     if (pullDownY > getMeasuredHeight()) 
      pullDownY = getMeasuredHeight(); 
     if (state == REFRESHING) 
     { 
      // 正在刷新的时候触摸移动 
      isTouch = true; 
     } 
    } else if (((Pullable) pullableView).canPullUp() && canPullUp 
      && state != REFRESHING) 
    { 
     // 可以上拉,正在刷新时不能上拉 
     pullUpY = pullUpY + (ev.getY() - lastY) / radio; 
     if (pullUpY > 0) 
     { 
      pullUpY = 0; 
      canPullDown = true; 
      canPullUp = false; 
     } 
     if (pullUpY < -getMeasuredHeight()) 
      pullUpY = -getMeasuredHeight(); 
     if (state == LOADING) 
     { 
      // 正在加载的时候触摸移动 
      isTouch = true; 
     } 
    } else 
     releasePull(); 
   } else 
    mEvents = 0; 
   lastY = ev.getY(); 
   // 根据下拉距离改变比例 
   radio = (float) (2 + 2 * Math.tan(Math.PI / 2 / getMeasuredHeight() 
     * (pullDownY + Math.abs(pullUpY)))); 
   requestLayout(); 
   if (pullDownY <= refreshDist 
<span style="white-space:pre">     </span>&& (state == RELEASE_TO_REFRESH || state == DONE)) { 
<span style="white-space:pre">    </span>// 如果下拉距离没达到刷新的距离且当前状态是释放刷新,改变状态为下拉刷新 
<span style="white-space:pre">    </span>changeState(INIT); 
<span style="white-space:pre">   </span>} 
<span style="white-space:pre">   </span>if (pullDownY >= refreshDist && (state == INIT || state == DONE)) { 
<span style="white-space:pre">    </span>// 如果下拉距离达到刷新的距离且当前状态是初始状态刷新,改变状态为释放刷新 
<span style="white-space:pre">    </span>changeState(RELEASE_TO_REFRESH); 
<span style="white-space:pre">   </span>} 
<span style="white-space:pre">   </span>// 下面是判断上拉加载的,同上,注意pullUpY是负值 
<span style="white-space:pre">   </span>if (-pullUpY <= loadmoreDist 
<span style="white-space:pre">     </span>&& (state == RELEASE_TO_LOAD || state == DONE)) { 
<span style="white-space:pre">    </span>changeState(INIT); 
<span style="white-space:pre">   </span>} 
<span style="white-space:pre">   </span>if (-pullUpY >= loadmoreDist && (state == INIT || state == DONE)) { 
<span style="white-space:pre">    </span>changeState(RELEASE_TO_LOAD); 
<span style="white-space:pre">   </span>} 
   // 因为刷新和加载操作不能同时进行,所以pullDownY和pullUpY不会同时不为0,因此这里用(pullDownY + 
   // Math.abs(pullUpY))就可以不对当前状态作区分了 
   if ((pullDownY + Math.abs(pullUpY)) > 8) 
   { 
    // 防止下拉过程中误触发长按事件和点击事件 
    ev.setAction(MotionEvent.ACTION_CANCEL); 
   } 
   break; 
  case MotionEvent.ACTION_UP: 
   if (pullDownY > refreshDist || -pullUpY > loadmoreDist) 
    // 正在刷新时往下拉(正在加载时往上拉),释放后下拉头(上拉头)不隐藏 
    isTouch = false; 
   if (state == RELEASE_TO_REFRESH) 
   { 
    changeState(REFRESHING); 
    // 刷新操作 
    if (mListener != null) 
     mListener.onRefresh(this); 
   } else if (state == RELEASE_TO_LOAD) 
   { 
    changeState(LOADING); 
    // 加载操作 
    if (mListener != null) 
     mListener.onLoadMore(this); 
   } 
   hide(); 
  default: 
   break; 
  } 
  // 事件分发交给父类 
  super.dispatchTouchEvent(ev); 
  return true; 
 } 
 
 private void initView() 
 { 
  // 初始化下拉布局 
  pullView = refreshView.findViewById(R.id.pull_icon); 
  refreshStateTextView = (TextView) refreshView 
    .findViewById(R.id.state_tv); 
  refreshingView = refreshView.findViewById(R.id.refreshing_icon); 
  refreshStateImageView = refreshView.findViewById(R.id.state_iv); 
  // 初始化上拉布局 
  pullUpView = loadmoreView.findViewById(R.id.pullup_icon); 
  loadStateTextView = (TextView) loadmoreView 
    .findViewById(R.id.loadstate_tv); 
  loadingView = loadmoreView.findViewById(R.id.loading_icon); 
  loadStateImageView = loadmoreView.findViewById(R.id.loadstate_iv); 
 } 
 
 @Override 
 protected void onLayout(boolean changed, int l, int t, int r, int b) 
 { 
  if (!isLayout) 
  { 
   // 这里是第一次进来的时候做一些初始化 
   refreshView = getChildAt(0); 
   pullableView = getChildAt(1); 
   loadmoreView = getChildAt(2); 
   isLayout = true; 
   initView(); 
   refreshDist = ((ViewGroup) refreshView).getChildAt(0) 
     .getMeasuredHeight(); 
   loadmoreDist = ((ViewGroup) loadmoreView).getChildAt(0) 
     .getMeasuredHeight(); 
  } 
  // 改变子控件的布局,这里直接用(pullDownY + pullUpY)作为偏移量,这样就可以不对当前状态作区分 
  refreshView.layout(0, 
    (int) (pullDownY + pullUpY) - refreshView.getMeasuredHeight(), 
    refreshView.getMeasuredWidth(), (int) (pullDownY + pullUpY)); 
  pullableView.layout(0, (int) (pullDownY + pullUpY), 
    pullableView.getMeasuredWidth(), (int) (pullDownY + pullUpY) 
      + pullableView.getMeasuredHeight()); 
  loadmoreView.layout(0, 
    (int) (pullDownY + pullUpY) + pullableView.getMeasuredHeight(), 
    loadmoreView.getMeasuredWidth(), 
    (int) (pullDownY + pullUpY) + pullableView.getMeasuredHeight() 
      + loadmoreView.getMeasuredHeight()); 
 } 
 
 class MyTimer 
 { 
  private Handler handler; 
  private Timer timer; 
  private MyTask mTask; 
 
  public MyTimer(Handler handler) 
  { 
   this.handler = handler; 
   timer = new Timer(); 
  } 
 
  public void schedule(long period) 
  { 
   if (mTask != null) 
   { 
    mTask.cancel(); 
    mTask = null; 
   } 
   mTask = new MyTask(handler); 
   timer.schedule(mTask, 0, period); 
  } 
 
  public void cancel() 
  { 
   if (mTask != null) 
   { 
    mTask.cancel(); 
    mTask = null; 
   } 
  } 
 
  class MyTask extends TimerTask 
  { 
   private Handler handler; 
 
   public MyTask(Handler handler) 
   { 
    this.handler = handler; 
   } 
 
   @Override 
   public void run() 
   { 
    handler.obtainMessage().sendToTarget(); 
   } 
 
  } 
 } 
 
 /** 
  * 刷新加载回调接口 
  * 
  * @author chenjing 
  * 
  */ 
 public interface OnRefreshListener 
 { 
  /** 
   * 刷新操作 
   */ 
  void onRefresh(PullToRefreshLayout pullToRefreshLayout); 
 
  /** 
   * 加载操作 
   */ 
  void onLoadMore(PullToRefreshLayout pullToRefreshLayout); 
 } 
 
} 

上面就是整个布局的代码,并不是很难。
下面看各个View对Pullable接口的实现,ListView和GridView还有ExpandableListView的判断方法是一样的:
PullableListView:


package com.jingchen.pulltorefresh.pullableview; 
 
import android.content.Context; 
import android.util.AttributeSet; 
import android.util.Log; 
import android.widget.ListView; 
 
public class PullableListView extends ListView implements Pullable 
{ 
 
 public PullableListView(Context context) 
 { 
  super(context); 
 } 
 
 public PullableListView(Context context, AttributeSet attrs) 
 { 
  super(context, attrs); 
 } 
 
 public PullableListView(Context context, AttributeSet attrs, int defStyle) 
 { 
  super(context, attrs, defStyle); 
 } 
 
 @Override 
 public boolean canPullDown() 
 { 
  if (getCount() == 0) 
  { 
   // 没有item的时候也可以下拉刷新 
   return true; 
  } else if (getFirstVisiblePosition() == 0 
    && getChildAt(0).getTop() >= 0) 
  { 
   // 滑到ListView的顶部了 
   return true; 
  } else 
   return false; 
 } 
 
 @Override 
 public boolean canPullUp() 
 { 
  if (getCount() == 0) 
  { 
   // 没有item的时候也可以上拉加载 
   return true; 
  } else if (getLastVisiblePosition() == (getCount() - 1)) 
  { 
   // 滑到底部了 
   if (getChildAt(getLastVisiblePosition() - getFirstVisiblePosition()) != null 
     && getChildAt( 
       getLastVisiblePosition() 
         - getFirstVisiblePosition()).getBottom() <= getMeasuredHeight()) 
    return true; 
  } 
  return false; 
 } 
}

PullableExpandableListView:


package com.jingchen.pulltorefresh.pullableview; 
 
import android.content.Context; 
import android.util.AttributeSet; 
import android.widget.ExpandableListView; 
 
public class PullableExpandableListView extends ExpandableListView implements 
  Pullable 
{ 
 
 public PullableExpandableListView(Context context) 
 { 
  super(context); 
 } 
 
 public PullableExpandableListView(Context context, AttributeSet attrs) 
 { 
  super(context, attrs); 
 } 
 
 public PullableExpandableListView(Context context, AttributeSet attrs, 
   int defStyle) 
 { 
  super(context, attrs, defStyle); 
 } 
 
 @Override 
 public boolean canPullDown() 
 { 
  if (getCount() == 0) 
  { 
   // 没有item的时候也可以下拉刷新 
   return true; 
  } else if (getFirstVisiblePosition() == 0 
    && getChildAt(0).getTop() >= 0) 
  { 
   // 滑到顶部了 
   return true; 
  } else 
   return false; 
 } 
 
 @Override 
 public boolean canPullUp() 
 { 
  if (getCount() == 0) 
  { 
   // 没有item的时候也可以上拉加载 
   return true; 
  } else if (getLastVisiblePosition() == (getCount() - 1)) 
  { 
   // 滑到底部了 
   if (getChildAt(getLastVisiblePosition() - getFirstVisiblePosition()) != null 
     && getChildAt( 
       getLastVisiblePosition() 
         - getFirstVisiblePosition()).getBottom() <= getMeasuredHeight()) 
    return true; 
  } 
  return false; 
 } 
 
} 

PullableGridView:


package com.jingchen.pulltorefresh.pullableview; 
 
import android.content.Context; 
import android.util.AttributeSet; 
import android.widget.GridView; 
 
public class PullableGridView extends GridView implements Pullable 
{ 
 
 public PullableGridView(Context context) 
 { 
  super(context); 
 } 
 
 public PullableGridView(Context context, AttributeSet attrs) 
 { 
  super(context, attrs); 
 } 
 
 public PullableGridView(Context context, AttributeSet attrs, int defStyle) 
 { 
  super(context, attrs, defStyle); 
 } 
 
 @Override 
 public boolean canPullDown() 
 { 
  if (getCount() == 0) 
  { 
   // 没有item的时候也可以下拉刷新 
   return true; 
  } else if (getFirstVisiblePosition() == 0 
    && getChildAt(0).getTop() >= 0) 
  { 
   // 滑到顶部了 
   return true; 
  } else 
   return false; 
 } 
 
 @Override 
 public boolean canPullUp() 
 { 
  if (getCount() == 0) 
  { 
   // 没有item的时候也可以上拉加载 
   return true; 
  } else if (getLastVisiblePosition() == (getCount() - 1)) 
  { 
   // 滑到底部了 
   if (getChildAt(getLastVisiblePosition() - getFirstVisiblePosition()) != null 
     && getChildAt( 
       getLastVisiblePosition() 
         - getFirstVisiblePosition()).getBottom() <= getMeasuredHeight()) 
    return true; 
  } 
  return false; 
 } 
 
} 

PullableScrollView:


package com.jingchen.pulltorefresh.pullableview; 
 
import android.content.Context; 
import android.util.AttributeSet; 
import android.widget.ScrollView; 
 
public class PullableScrollView extends ScrollView implements Pullable 
{ 
 
 public PullableScrollView(Context context) 
 { 
  super(context); 
 } 
 
 public PullableScrollView(Context context, AttributeSet attrs) 
 { 
  super(context, attrs); 
 } 
 
 public PullableScrollView(Context context, AttributeSet attrs, int defStyle) 
 { 
  super(context, attrs, defStyle); 
 } 
 
 @Override 
 public boolean canPullDown() 
 { 
  if (getScrollY() == 0) 
   return true; 
  else 
   return false; 
 } 
 
 @Override 
 public boolean canPullUp() 
 { 
  if (getScrollY() >= (getChildAt(0).getHeight() - getMeasuredHeight())) 
   return true; 
  else 
   return false; 
 } 
 
} 

PullableWebView:


package com.jingchen.pulltorefresh.pullableview; 
 
import android.content.Context; 
import android.util.AttributeSet; 
import android.webkit.WebView; 
 
public class PullableWebView extends WebView implements Pullable 
{ 
 
 public PullableWebView(Context context) 
 { 
  super(context); 
 } 
 
 public PullableWebView(Context context, AttributeSet attrs) 
 { 
  super(context, attrs); 
 } 
 
 public PullableWebView(Context context, AttributeSet attrs, int defStyle) 
 { 
  super(context, attrs, defStyle); 
 } 
 
 @Override 
 public boolean canPullDown() 
 { 
  if (getScrollY() == 0) 
   return true; 
  else 
   return false; 
 } 
 
 @Override 
 public boolean canPullUp() 
 { 
  if (getScrollY() >= getContentHeight() * getScale() 
    - getMeasuredHeight()) 
   return true; 
  else 
   return false; 
 } 
} 

ImageView和TextView就不贴了,我直接在方法里返回了true。
 



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