Android下拉刷新上拉加载控件，对所有View通用！

叁歲伎倆 2024-02-17 17:29 25阅读 0赞

前面写过一篇关于下拉刷新控件的博客[下拉刷新控件终结者：PullToRefreshLayout][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。

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：

![SouthEast][]

ListView：

![SouthEast 1][]

GridView：

![SouthEast 2][]

ExpandableListView：

![SouthEast 3][]

ScrollView：

![SouthEast 4][]

WebView：

![SouthEast 5][]

ImageView：

![SouthEast 6][]

TextView：

![SouthEast 7][]

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：

**\[java\]** [view plain][] [copy][view plain]

1.  **package** com.jingchen.pulltorefresh.pullableview; 
2.  
3.  **public****interface** Pullable 
4.  \{ 
5.  /\*\*
6.   \* 判断是否可以下拉，如果不需要下拉功能可以直接return false
7.   \* 
8.   \* @return true如果可以下拉否则返回false
9.   \*/
10. **boolean** canPullDown(); 
11. 
12. /\*\*
13.  \* 判断是否可以上拉，如果不需要上拉功能可以直接return false
14.  \* 
15.  \* @return true如果可以上拉否则返回false
16.  \*/
17. **boolean** canPullUp(); 
18. \}

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：

**\[java\]** [view plain][] [copy][view plain]

1. **package** com.jingchen.pulltorefresh; 
2. 
3. **import** java.util.Timer; 
4. **import** java.util.TimerTask; 
5. 
6. **import** android.content.Context; 
7. **import** android.graphics.Canvas; 
8. **import** android.graphics.LinearGradient; 
9. **import** android.graphics.Paint; 
10. **import** android.graphics.Paint.Style; 
11. **import** android.graphics.RectF; 
12. **import** android.graphics.Shader.TileMode; 
13. **import** android.os.Handler; 
14. **import** android.os.Message; 
15. **import** android.util.AttributeSet; 
16. **import** android.util.Log; 
17. **import** android.view.MotionEvent; 
18. **import** android.view.View; 
19. **import** android.view.ViewGroup; 
20. **import** android.view.animation.AnimationUtils; 
21. **import** android.view.animation.LinearInterpolator; 
22. **import** android.view.animation.RotateAnimation; 
23. **import** android.widget.RelativeLayout; 
24. **import** android.widget.TextView; 
25. 
26. **import** com.jingchen.pulltorefresh.pullableview.Pullable; 
27. 
28. /\*\*
29. \* 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），
30. \* 还有一个上拉头
31. \* 
32. \* @author 陈靖
33. \*/
34. **public****class** PullToRefreshLayout **extends** RelativeLayout 
35. \{ 
36. **public****static****final** String TAG = "PullToRefreshLayout"; 
37. // 初始状态
38. **public****static****final****int** INIT = 0; 
39. // 释放刷新
40. **public****static****final****int** RELEASE\_TO\_REFRESH = 1; 
41. // 正在刷新
42. **public****static****final****int** REFRESHING = 2; 
43. // 释放加载
44. **public****static****final****int** RELEASE\_TO\_LOAD = 3; 
45. // 正在加载
46. **public****static****final****int** LOADING = 4; 
47. // 操作完毕
48. **public****static****final****int** DONE = 5; 
49. // 当前状态
50. **private****int** state = INIT; 
51. // 刷新回调接口
52. **private** OnRefreshListener mListener; 
53. // 刷新成功
54. **public****static****final****int** SUCCEED = 0; 
55. // 刷新失败
56. **public****static****final****int** FAIL = 1; 
57. // 按下Y坐标，上一个事件点Y坐标
58. **private****float** downY, lastY; 
59. 
60. // 下拉的距离。注意：pullDownY和pullUpY不可能同时不为0
61. **public****float** pullDownY = 0; 
62. // 上拉的距离
63. **private****float** pullUpY = 0; 
64. 
65. // 释放刷新的距离
66. **private****float** refreshDist = 200; 
67. // 释放加载的距离
68. **private****float** loadmoreDist = 200; 
69. 
70. **private** MyTimer timer; 
71. // 回滚速度
72. **public****float** MOVE\_SPEED = 8; 
73. // 第一次执行布局
74. **private****boolean** isLayout = **false**; 
75. // 在刷新过程中滑动操作
76. **private****boolean** isTouch = **false**; 
77. // 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
78. **private****float** radio = 2; 
79. 
80. // 下拉箭头的转180°动画
81. **private** RotateAnimation rotateAnimation; 
82. // 均匀旋转动画
83. **private** RotateAnimation refreshingAnimation; 
84. 
85. // 下拉头
86. **private** View refreshView; 
87. // 下拉的箭头
88. **private** View pullView; 
89. // 正在刷新的图标
90. **private** View refreshingView; 
91. // 刷新结果图标
92. **private** View refreshStateImageView; 
93. // 刷新结果：成功或失败
94. **private** TextView refreshStateTextView; 
95. 
96. // 上拉头
97. **private** View loadmoreView; 
98. // 上拉的箭头
99. **private** View pullUpView; 
100. // 正在加载的图标
101. **private** View loadingView; 
102. // 加载结果图标
103. **private** View loadStateImageView; 
104. // 加载结果：成功或失败
105. **private** TextView loadStateTextView; 
106. 
107. // 实现了Pullable接口的View
108. **private** View pullableView; 
109. // 过滤多点触碰
110. **private****int** mEvents; 
111. // 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
112. **private****boolean** canPullDown = **true**; 
113. **private****boolean** canPullUp = **true**; 
114. 
115. /\*\*
116. \* 执行自动回滚的handler
117. \*/
118. Handler updateHandler = **new** Handler() 
119. \{ 
120. 
121. @Override
122. **public****void** handleMessage(Message msg) 
123. \{ 
124. // 回弹速度随下拉距离moveDeltaY增大而增大
125. MOVE\_SPEED = (**float**) (8 \+ 5 \* Math.tan(Math.PI / 2
126. / getMeasuredHeight() \* (pullDownY + Math.abs(pullUpY)))); 
127. **if** (!isTouch) 
128. \{ 
129. // 正在刷新，且没有往上推的话则悬停，显示"正在刷新..."
130. **if** (state == REFRESHING && pullDownY <= refreshDist) 
131. \{ 
132. pullDownY = refreshDist; 
133. timer.cancel(); 
134. \} **else****if** (state == LOADING && -pullUpY <= loadmoreDist) 
135. \{ 
136. pullUpY = -loadmoreDist; 
137. timer.cancel(); 
138. \} 
139. 
140. \} 
141. **if** (pullDownY > 0) 
142. pullDownY -= MOVE\_SPEED; 
143. **else****if** (pullUpY < 0) 
144. pullUpY += MOVE\_SPEED; 
145. **if** (pullDownY < 0) 
146. \{ 
147. // 已完成回弹
148. pullDownY = 0; 
149. pullView.clearAnimation(); 
150. // 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
151. **if** (state != REFRESHING && state != LOADING) 
152. changeState(INIT); 
153. timer.cancel(); 
154. \} 
155. **if** (pullUpY > 0) 
156. \{ 
157. // 已完成回弹
158. pullUpY = 0; 
159. pullUpView.clearAnimation(); 
160. // 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
161. **if** (state != REFRESHING && state != LOADING) 
162. changeState(INIT); 
163. timer.cancel(); 
164. \} 
165. // 刷新布局,会自动调用onLayout
166. requestLayout(); 
167. \} 
168. 
169. \}; 
170. 
171. **public****void** setOnRefreshListener(OnRefreshListener listener) 
172. \{ 
173. mListener = listener; 
174. \} 
175. 
176. **public** PullToRefreshLayout(Context context) 
177. \{ 
178. **super**(context); 
179. initView(context); 
180. \} 
181. 
182. **public** PullToRefreshLayout(Context context, AttributeSet attrs) 
183. \{ 
184. **super**(context, attrs); 
185. initView(context); 
186. \} 
187. 
188. **public** PullToRefreshLayout(Context context, AttributeSet attrs, **int** defStyle) 
189. \{ 
190. **super**(context, attrs, defStyle); 
191. initView(context); 
192. \} 
193. 
194. **private****void** initView(Context context) 
195. \{ 
196. timer = **new** MyTimer(updateHandler); 
197. rotateAnimation = (RotateAnimation) AnimationUtils.loadAnimation( 
198. context, R.anim.reverse\_anim); 
199. refreshingAnimation = (RotateAnimation) AnimationUtils.loadAnimation( 
200. context, R.anim.rotating); 
201. // 添加匀速转动动画
202. LinearInterpolator lir = **new** LinearInterpolator(); 
203. rotateAnimation.setInterpolator(lir); 
204. refreshingAnimation.setInterpolator(lir); 
205. \} 
206. 
207. **private****void** hide() 
208. \{ 
209. timer.schedule(5); 
210. \} 
211. 
212. /\*\*
213. \* 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
214. \*/
215. /\*\*
216. \* @param refreshResult
217. \* PullToRefreshLayout.SUCCEED代表成功，PullToRefreshLayout.FAIL代表失败
218. \*/
219. **public****void** refreshFinish(**int** refreshResult) 
220. \{ 
221. refreshingView.clearAnimation(); 
222. refreshingView.setVisibility(View.GONE); 
223. **switch** (refreshResult) 
224. \{ 
225. **case** SUCCEED: 
226. // 刷新成功
227. refreshStateImageView.setVisibility(View.VISIBLE); 
228. refreshStateTextView.setText(R.string.refresh\_succeed); 
229. refreshStateImageView 
230. .setBackgroundResource(R.drawable.refresh\_succeed); 
231. **break**; 
232. **case** FAIL: 
233. **default**: 
234. // 刷新失败
235. refreshStateImageView.setVisibility(View.VISIBLE); 
236. refreshStateTextView.setText(R.string.refresh\_fail); 
237. refreshStateImageView 
238. .setBackgroundResource(R.drawable.refresh\_failed); 
239. **break**; 
240. \} 
241. // 刷新结果停留1秒
242. **new** Handler() 
243. \{ 
244. @Override
245. **public****void** handleMessage(Message msg) 
246. \{ 
247. changeState(DONE); 
248. hide(); 
249. \} 
250. \}.sendEmptyMessageDelayed(0, 1000); 
251. \} 
252. 
253. /\*\*
254. \* 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
255. \* 
256. \* @param refreshResult
257. \* PullToRefreshLayout.SUCCEED代表成功，PullToRefreshLayout.FAIL代表失败
258. \*/
259. **public****void** loadmoreFinish(**int** refreshResult) 
260. \{ 
261. loadingView.clearAnimation(); 
262. loadingView.setVisibility(View.GONE); 
263. **switch** (refreshResult) 
264. \{ 
265. **case** SUCCEED: 
266. // 加载成功
267. loadStateImageView.setVisibility(View.VISIBLE); 
268. loadStateTextView.setText(R.string.load\_succeed); 
269. loadStateImageView.setBackgroundResource(R.drawable.load\_succeed); 
270. **break**; 
271. **case** FAIL: 
272. **default**: 
273. // 加载失败
274. loadStateImageView.setVisibility(View.VISIBLE); 
275. loadStateTextView.setText(R.string.load\_fail); 
276. loadStateImageView.setBackgroundResource(R.drawable.load\_failed); 
277. **break**; 
278. \} 
279. // 刷新结果停留1秒
280. **new** Handler() 
281. \{ 
282. @Override
283. **public****void** handleMessage(Message msg) 
284. \{ 
285. changeState(DONE); 
286. hide(); 
287. \} 
288. \}.sendEmptyMessageDelayed(0, 1000); 
289. \} 
290. 
291. **private****void** changeState(**int** to) 
292. \{ 
293. state = to; 
294. **switch** (state) 
295. \{ 
296. **case** INIT: 
297. // 下拉布局初始状态
298. refreshStateImageView.setVisibility(View.GONE); 
299. refreshStateTextView.setText(R.string.pull\_to\_refresh); 
300. pullView.clearAnimation(); 
301. pullView.setVisibility(View.VISIBLE); 
302. // 上拉布局初始状态
303. loadStateImageView.setVisibility(View.GONE); 
304. loadStateTextView.setText(R.string.pullup\_to\_load); 
305. pullUpView.clearAnimation(); 
306. pullUpView.setVisibility(View.VISIBLE); 
307. **break**; 
308. **case** RELEASE\_TO\_REFRESH: 
309. // 释放刷新状态
310. refreshStateTextView.setText(R.string.release\_to\_refresh); 
311. pullView.startAnimation(rotateAnimation); 
312. **break**; 
313. **case** REFRESHING: 
314. // 正在刷新状态
315. pullView.clearAnimation(); 
316. refreshingView.setVisibility(View.VISIBLE); 
317. pullView.setVisibility(View.INVISIBLE); 
318. refreshingView.startAnimation(refreshingAnimation); 
319. refreshStateTextView.setText(R.string.refreshing); 
320. **break**; 
321. **case** RELEASE\_TO\_LOAD: 
322. // 释放加载状态
323. loadStateTextView.setText(R.string.release\_to\_load); 
324. pullUpView.startAnimation(rotateAnimation); 
325. **break**; 
326. **case** LOADING: 
327. // 正在加载状态
328. pullUpView.clearAnimation(); 
329. loadingView.setVisibility(View.VISIBLE); 
330. pullUpView.setVisibility(View.INVISIBLE); 
331. loadingView.startAnimation(refreshingAnimation); 
332. loadStateTextView.setText(R.string.loading); 
333. **break**; 
334. **case** DONE: 
335. // 刷新或加载完毕，啥都不做
336. **break**; 
337. \} 
338. \} 
339. 
340. /\*\*
341. \* 不限制上拉或下拉
342. \*/
343. **private****void** releasePull() 
344. \{ 
345. canPullDown = **true**; 
346. canPullUp = **true**; 
347. \} 
348. 
349. /\*
350. \* （非 Javadoc）由父控件决定是否分发事件，防止事件冲突
351. \* 
352. \* @see android.view.ViewGroup\#dispatchTouchEvent(android.view.MotionEvent)
353. \*/
354. @Override
355. **public****boolean** dispatchTouchEvent(MotionEvent ev) 
356. \{ 
357. **switch** (ev.getActionMasked()) 
358. \{ 
359. **case** MotionEvent.ACTION\_DOWN: 
360. downY = ev.getY(); 
361. lastY = downY; 
362. timer.cancel(); 
363. mEvents = 0; 
364. releasePull(); 
365. **break**; 
366. **case** MotionEvent.ACTION\_POINTER\_DOWN: 
367. **case** MotionEvent.ACTION\_POINTER\_UP: 
368. // 过滤多点触碰
369. mEvents = -1; 
370. **break**; 
371. **case** MotionEvent.ACTION\_MOVE: 
372. **if** (mEvents == 0) 
373. \{ 
374. **if** (((Pullable) pullableView).canPullDown() && canPullDown 
375. && state != LOADING) 
376. \{ 
377. // 可以下拉，正在加载时不能下拉
378. // 对实际滑动距离做缩小，造成用力拉的感觉
379. pullDownY = pullDownY + (ev.getY() - lastY) / radio; 
380. **if** (pullDownY < 0) 
381. \{ 
382. pullDownY = 0; 
383. canPullDown = **false**; 
384. canPullUp = **true**; 
385. \} 
386. **if** (pullDownY > getMeasuredHeight()) 
387. pullDownY = getMeasuredHeight(); 
388. **if** (state == REFRESHING) 
389. \{ 
390. // 正在刷新的时候触摸移动
391. isTouch = **true**; 
392. \} 
393. \} **else****if** (((Pullable) pullableView).canPullUp() && canPullUp 
394. && state != REFRESHING) 
395. \{ 
396. // 可以上拉，正在刷新时不能上拉
397. pullUpY = pullUpY + (ev.getY() - lastY) / radio; 
398. **if** (pullUpY > 0) 
399. \{ 
400. pullUpY = 0; 
401. canPullDown = **true**; 
402. canPullUp = **false**; 
403. \} 
404. **if** (pullUpY < -getMeasuredHeight()) 
405. pullUpY = -getMeasuredHeight(); 
406. **if** (state == LOADING) 
407. \{ 
408. // 正在加载的时候触摸移动
409. isTouch = **true**; 
410. \} 
411. \} **else**
412. releasePull(); 
413. \} **else**
414. mEvents = 0; 
415. lastY = ev.getY(); 
416. // 根据下拉距离改变比例
417. radio = (**float**) (2 \+ 2 \* Math.tan(Math.PI / 2 / getMeasuredHeight() 
418. \* (pullDownY + Math.abs(pullUpY)))); 
419. requestLayout(); 
420. **if** (pullDownY <= refreshDist 
421. && (state == RELEASE\_TO\_REFRESH || state == DONE)) \{ 
422. // 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
423. changeState(INIT); 
424. \} 
425. **if** (pullDownY >= refreshDist && (state == INIT || state == DONE)) \{ 
426. // 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
427. changeState(RELEASE\_TO\_REFRESH); 
428. \} 
429. // 下面是判断上拉加载的，同上，注意pullUpY是负值
430. **if** (-pullUpY <= loadmoreDist 
431. && (state == RELEASE\_TO\_LOAD || state == DONE)) \{ 
432. changeState(INIT); 
433. \} 
434. **if** (-pullUpY >= loadmoreDist && (state == INIT || state == DONE)) \{ 
435. changeState(RELEASE\_TO\_LOAD); 
436. \} 
437. // 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 +
438. // Math.abs(pullUpY))就可以不对当前状态作区分了
439. **if** ((pullDownY + Math.abs(pullUpY)) > 8) 
440. \{ 
441. // 防止下拉过程中误触发长按事件和点击事件
442. ev.setAction(MotionEvent.ACTION\_CANCEL); 
443. \} 
444. **break**; 
445. **case** MotionEvent.ACTION\_UP: 
446. **if** (pullDownY > refreshDist || -pullUpY > loadmoreDist) 
447. // 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
448. isTouch = **false**; 
449. **if** (state == RELEASE\_TO\_REFRESH) 
450. \{ 
451. changeState(REFRESHING); 
452. // 刷新操作
453. **if** (mListener != **null**) 
454. mListener.onRefresh(**this**); 
455. \} **else****if** (state == RELEASE\_TO\_LOAD) 
456. \{ 
457. changeState(LOADING); 
458. // 加载操作
459. **if** (mListener != **null**) 
460. mListener.onLoadMore(**this**); 
461. \} 
462. hide(); 
463. **default**: 
464. **break**; 
465. \} 
466. // 事件分发交给父类
467. **super**.dispatchTouchEvent(ev); 
468. **return****true**; 
469. \} 
470. 
471. **private****void** initView() 
472. \{ 
473. // 初始化下拉布局
474. pullView = refreshView.findViewById(R.id.pull\_icon); 
475. refreshStateTextView = (TextView) refreshView 
476. .findViewById(R.id.state\_tv); 
477. refreshingView = refreshView.findViewById(R.id.refreshing\_icon); 
478. refreshStateImageView = refreshView.findViewById(R.id.state\_iv); 
479. // 初始化上拉布局
480. pullUpView = loadmoreView.findViewById(R.id.pullup\_icon); 
481. loadStateTextView = (TextView) loadmoreView 
482. .findViewById(R.id.loadstate\_tv); 
483. loadingView = loadmoreView.findViewById(R.id.loading\_icon); 
484. loadStateImageView = loadmoreView.findViewById(R.id.loadstate\_iv); 
485. \} 
486. 
487. @Override
488. **protected****void** onLayout(**boolean** changed, **int** l, **int** t, **int** r, **int** b) 
489. \{ 
490. **if** (!isLayout) 
491. \{ 
492. // 这里是第一次进来的时候做一些初始化
493. refreshView = getChildAt(0); 
494. pullableView = getChildAt(1); 
495. loadmoreView = getChildAt(2); 
496. isLayout = **true**; 
497. initView(); 
498. refreshDist = ((ViewGroup) refreshView).getChildAt(0) 
499. .getMeasuredHeight(); 
500. loadmoreDist = ((ViewGroup) loadmoreView).getChildAt(0) 
501. .getMeasuredHeight(); 
502. \} 
503. // 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
504. refreshView.layout(0, 
505. (**int**) (pullDownY + pullUpY) - refreshView.getMeasuredHeight(), 
506. refreshView.getMeasuredWidth(), (**int**) (pullDownY + pullUpY)); 
507. pullableView.layout(0, (**int**) (pullDownY + pullUpY), 
508. pullableView.getMeasuredWidth(), (**int**) (pullDownY + pullUpY) 
509. \+ pullableView.getMeasuredHeight()); 
510. loadmoreView.layout(0, 
511. (**int**) (pullDownY + pullUpY) + pullableView.getMeasuredHeight(), 
512. loadmoreView.getMeasuredWidth(), 
513. (**int**) (pullDownY + pullUpY) + pullableView.getMeasuredHeight() 
514. \+ loadmoreView.getMeasuredHeight()); 
515. \} 
516. 
517. **class** MyTimer 
518. \{ 
519. **private** Handler handler; 
520. **private** Timer timer; 
521. **private** MyTask mTask; 
522. 
523. **public** MyTimer(Handler handler) 
524. \{ 
525. **this**.handler = handler; 
526. timer = **new** Timer(); 
527. \} 
528. 
529. **public****void** schedule(**long** period) 
530. \{ 
531. **if** (mTask != **null**) 
532. \{ 
533. mTask.cancel(); 
534. mTask = **null**; 
535. \} 
536. mTask = **new** MyTask(handler); 
537. timer.schedule(mTask, 0, period); 
538. \} 
539. 
540. **public****void** cancel() 
541. \{ 
542. **if** (mTask != **null**) 
543. \{ 
544. mTask.cancel(); 
545. mTask = **null**; 
546. \} 
547. \} 
548. 
549. **class** MyTask **extends** TimerTask 
550. \{ 
551. **private** Handler handler; 
552. 
553. **public** MyTask(Handler handler) 
554. \{ 
555. **this**.handler = handler; 
556. \} 
557. 
558. @Override
559. **public****void** run() 
560. \{ 
561. handler.obtainMessage().sendToTarget(); 
562. \} 
563. 
564. \} 
565. \} 
566. 
567. /\*\*
568. \* 刷新加载回调接口
569. \* 
570. \* @author chenjing
571. \* 
572. \*/
573. **public****interface** OnRefreshListener 
574. \{ 
575. /\*\*
576. \* 刷新操作
577. \*/
578. **void** onRefresh(PullToRefreshLayout pullToRefreshLayout); 
579. 
580. /\*\*
581. \* 加载操作
582. \*/
583. **void** onLoadMore(PullToRefreshLayout pullToRefreshLayout); 
584. \} 
585. 
586. \}

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：

**\[java\]** [view plain][] [copy][view plain]

1. **package** com.jingchen.pulltorefresh.pullableview; 
2. 
3. **import** android.content.Context; 
4. **import** android.util.AttributeSet; 
5. **import** android.util.Log; 
6. **import** android.widget.ListView; 
7. 
8. **public****class** PullableListView **extends** ListView **implements** Pullable 
9. \{ 
10. 
11. **public** PullableListView(Context context) 
12. \{ 
13. **super**(context); 
14. \} 
15. 
16. **public** PullableListView(Context context, AttributeSet attrs) 
17. \{ 
18. **super**(context, attrs); 
19. \} 
20. 
21. **public** PullableListView(Context context, AttributeSet attrs, **int** defStyle) 
22. \{ 
23. **super**(context, attrs, defStyle); 
24. \} 
25. 
26. @Override
27. **public****boolean** canPullDown() 
28. \{ 
29. **if** (getCount() == 0) 
30. \{ 
31. // 没有item的时候也可以下拉刷新
32. **return****true**; 
33. \} **else****if** (getFirstVisiblePosition() == 0
34. && getChildAt(0).getTop() >= 0) 
35. \{ 
36. // 滑到ListView的顶部了
37. **return****true**; 
38. \} **else**
39. **return****false**; 
40. \} 
41. 
42. @Override
43. **public****boolean** canPullUp() 
44. \{ 
45. **if** (getCount() == 0) 
46. \{ 
47. // 没有item的时候也可以上拉加载
48. **return****true**; 
49. \} **else****if** (getLastVisiblePosition() == (getCount() - 1)) 
50. \{ 
51. // 滑到底部了
52. **if** (getChildAt(getLastVisiblePosition() - getFirstVisiblePosition()) != **null**
53. && getChildAt( 
54. getLastVisiblePosition() 
55. \- getFirstVisiblePosition()).getBottom() <= getMeasuredHeight()) 
56. **return****true**; 
57. \} 
58. **return****false**; 
59. \} 
60. \}

PullableExpandableListView：

**\[java\]** [view plain][] [copy][view plain]

1. **package** com.jingchen.pulltorefresh.pullableview; 
2. 
3. **import** android.content.Context; 
4. **import** android.util.AttributeSet; 
5. **import** android.widget.ExpandableListView; 
6. 
7. **public****class** PullableExpandableListView **extends** ExpandableListView **implements**
8. Pullable 
9. \{ 
10. 
11. **public** PullableExpandableListView(Context context) 
12. \{ 
13. **super**(context); 
14. \} 
15. 
16. **public** PullableExpandableListView(Context context, AttributeSet attrs) 
17. \{ 
18. **super**(context, attrs); 
19. \} 
20. 
21. **public** PullableExpandableListView(Context context, AttributeSet attrs, 
22. **int** defStyle) 
23. \{ 
24. **super**(context, attrs, defStyle); 
25. \} 
26. 
27. @Override
28. **public****boolean** canPullDown() 
29. \{ 
30. **if** (getCount() == 0) 
31. \{ 
32. // 没有item的时候也可以下拉刷新
33. **return****true**; 
34. \} **else****if** (getFirstVisiblePosition() == 0
35. && getChildAt(0).getTop() >= 0) 
36. \{ 
37. // 滑到顶部了
38. **return****true**; 
39. \} **else**
40. **return****false**; 
41. \} 
42. 
43. @Override
44. **public****boolean** canPullUp() 
45. \{ 
46. **if** (getCount() == 0) 
47. \{ 
48. // 没有item的时候也可以上拉加载
49. **return****true**; 
50. \} **else****if** (getLastVisiblePosition() == (getCount() - 1)) 
51. \{ 
52. // 滑到底部了
53. **if** (getChildAt(getLastVisiblePosition() - getFirstVisiblePosition()) != **null**
54. && getChildAt( 
55. getLastVisiblePosition() 
56. \- getFirstVisiblePosition()).getBottom() <= getMeasuredHeight()) 
57. **return****true**; 
58. \} 
59. **return****false**; 
60. \} 
61. 
62. \}

PullableGridView：

**\[java\]** [view plain][] [copy][view plain]

1. **package** com.jingchen.pulltorefresh.pullableview; 
2. 
3. **import** android.content.Context; 
4. **import** android.util.AttributeSet; 
5. **import** android.widget.GridView; 
6. 
7. **public****class** PullableGridView **extends** GridView **implements** Pullable 
8. \{ 
9. 
10. **public** PullableGridView(Context context) 
11. \{ 
12. **super**(context); 
13. \} 
14. 
15. **public** PullableGridView(Context context, AttributeSet attrs) 
16. \{ 
17. **super**(context, attrs); 
18. \} 
19. 
20. **public** PullableGridView(Context context, AttributeSet attrs, **int** defStyle) 
21. \{ 
22. **super**(context, attrs, defStyle); 
23. \} 
24. 
25. @Override
26. **public****boolean** canPullDown() 
27. \{ 
28. **if** (getCount() == 0) 
29. \{ 
30. // 没有item的时候也可以下拉刷新
31. **return****true**; 
32. \} **else****if** (getFirstVisiblePosition() == 0
33. && getChildAt(0).getTop() >= 0) 
34. \{ 
35. // 滑到顶部了
36. **return****true**; 
37. \} **else**
38. **return****false**; 
39. \} 
40. 
41. @Override
42. **public****boolean** canPullUp() 
43. \{ 
44. **if** (getCount() == 0) 
45. \{ 
46. // 没有item的时候也可以上拉加载
47. **return****true**; 
48. \} **else****if** (getLastVisiblePosition() == (getCount() - 1)) 
49. \{ 
50. // 滑到底部了
51. **if** (getChildAt(getLastVisiblePosition() - getFirstVisiblePosition()) != **null**
52. && getChildAt( 
53. getLastVisiblePosition() 
54. \- getFirstVisiblePosition()).getBottom() <= getMeasuredHeight()) 
55. **return****true**; 
56. \} 
57. **return****false**; 
58. \} 
59. 
60. \}

PullableScrollView：

**\[java\]** [view plain][] [copy][view plain]

PullableWebView：

**\[java\]** [view plain][] [copy][view plain]

1.  **package** com.jingchen.pulltorefresh.pullableview; 
2.  
3.  **import** android.content.Context; 
4.  **import** android.util.AttributeSet; 
5.  **import** android.webkit.WebView; 
6.  
7.  **public****class** PullableWebView **extends** WebView **implements** Pullable 
8.  \{ 
9.  
10. **public** PullableWebView(Context context) 
11.  \{ 
12. **super**(context); 
13.  \} 
14. 
15. **public** PullableWebView(Context context, AttributeSet attrs) 
16.  \{ 
17. **super**(context, attrs); 
18.  \} 
19. 
20. **public** PullableWebView(Context context, AttributeSet attrs, **int** defStyle) 
21.  \{ 
22. **super**(context, attrs, defStyle); 
23.  \} 
24. 
25. @Override
26. **public****boolean** canPullDown() 
27.  \{ 
28. **if** (getScrollY() == 0) 
29. **return****true**; 
30. **else**
31. **return****false**; 
32.  \} 
33. 
34. @Override
35. **public****boolean** canPullUp() 
36.  \{ 
37. **if** (getScrollY() >= getContentHeight() \* getScale() 
38.  \- getMeasuredHeight()) 
39. **return****true**; 
40. **else**
41. **return****false**; 
42.  \} 
43. \}

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

OK了，整个demo的代码有点多，就不贴了。

[demo下载][demo]

[PullToRefreshLayout]: http://blog.csdn.net/zhongkejingwang/article/details/38340701
[SouthEast]: https://image.dandelioncloud.cn/pgy_files/images/2024/01/30/801da4bb4fd84eebb07a08a9f23b6141.png
[SouthEast 1]: https://image.dandelioncloud.cn/pgy_files/images/2024/01/30/e03fe854c11a4e2ca17c9369c7607964.png
[SouthEast 2]: https://image.dandelioncloud.cn/pgy_files/images/2024/01/30/14b8a5090b934b9d8391a5d595fad9f3.png
[SouthEast 3]: https://image.dandelioncloud.cn/pgy_files/images/2024/01/30/a32c5fc4e3784e998fe3b168d79b10f5.png
[SouthEast 4]: https://image.dandelioncloud.cn/pgy_files/images/2024/01/30/aa14575a481f471c80c9879ed3b783f9.png
[SouthEast 5]: https://image.dandelioncloud.cn/pgy_files/images/2024/01/30/7af8711676554c3693ef8036f396dd23.png
[SouthEast 6]: https://image.dandelioncloud.cn/pgy_files/images/2024/01/30/3da12bd01a544e2d948761b60ae85852.png
[SouthEast 7]: https://image.dandelioncloud.cn/pgy_files/images/2024/01/30/643339e7af5147169ca3ae029e20f029.png
[view plain]: http://blog.csdn.net/zhongkejingwang/article/details/38868463#
[demo]: http://download.csdn.net/detail/onceing/9530444