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【转】android奇效之可伸缩View带互相挤压效果-初级篇

热度：84   发布时间：2016-04-28 07:30:22.0
【转】android特效之可伸缩View带互相挤压效果--初级篇

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转自：http://blog.csdn.net/manymore13/article/details/12799061

本次我要向大家介绍一个Android特效，这个特效也是我在某款软件中看到的，至于软件叫什么，我今天就不说

它的名字。我就不免费为它做广告了。微笑

好了，我来上一张动态效果图 在下面，屏幕小的请往下拉。

我不知道原软件是怎么个实现法，在这里我只是说说我的实现方法，代码可能不太好，这只是本人的一个idea 原理很简单！

? ? ??特效实现原理：

改变按钮的宽度，每次当你点击按钮时，只有两个按钮改变宽度，一个变长，一个变短，只是这个变化是慢慢

进行，不是秒变的，你懂的，这就是动画效果。你点击短的按钮后会渐渐地变长，长的按钮会随着被压缩，其他按钮宽度不变。

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我写这篇文章想起到一个抛砖引玉的效果，希望读者看了这篇文章后继续写个更好的文章。当然你不要忘记我啊，

记得要与我和大家分享。

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?下面是本次Demo运行后的效果图：

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可以看到view被挤压的效果，点击短的view会慢慢长大。在短的view慢慢长大的同时，最长的view会慢慢缩小，而且每次动画结束后都

有一个最长的view 。我这里所说的view在本次Demo中是按钮，当然你也可以换成其他的控件，或者是ViewGroup的子类也行。

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[java]?view plaincopyprint?
  1. public?class?PinchActivity?extends?Activity?implements?View.OnClickListener?{??
  2. ??
  3. ????private?final?static?String?TAG?=?"MainActivity";??
  4. ??????
  5. ????//?屏幕宽度??
  6. ????private?int?screentWidth?=?0;??
  7. ??????
  8. ????//?View可伸展最长的宽度??
  9. ????private?int?maxWidth;??
  10. ??????
  11. ????//?View可伸展最小宽度??
  12. ????private?int?minWidth;??
  13. ??????
  14. ????//?当前点击的View??
  15. ????private?View?currentView;??
  16. ??????
  17. ????//?显示最长的那个View??
  18. ????private?View?preView;??
  19. ??????
  20. ????//?主布局ViewGroup??
  21. ????private?LinearLayout?mainContain;??
  22. ??????
  23. ????//?标识符?动画是否结束??
  24. ????private?boolean?animationIsEnd?=?true;??
  25. ??????
  26. ????//?变大操作??
  27. ????private?static?final?int?OPE_BIG?=?1;??
  28. ??????
  29. ????//?变小操作??
  30. ????private?static?final?int?OPE_SMALL?=?2;??
  31. ??????
  32. ????//?当前操作?-1表示无效操作??
  33. ????private?int?currentOpe?=?-1;??
  34. ??????
  35. ????//?前进的步伐距离??
  36. ????private?static?final?int?STEP?=?10;??
  37. ??
  38. ????@Override??
  39. ????protected?void?onCreate(Bundle?savedInstanceState)???
  40. ????{??
  41. ??
  42. ????????super.onCreate(savedInstanceState);??
  43. ??????????
  44. ????????setContentView(R.layout.activity_main);??
  45. ??
  46. ????????initCommonData();??
  47. ??????????
  48. ????????initViewData();??
  49. ??????????
  50. ????????measureWidth(screentWidth);???
  51. ??
  52. ????}??
  53. ??
  54. ????private?void?initViewData()?{??
  55. ??
  56. ????????mainContain?=?(LinearLayout)?this.findViewById(R.id.main_contain);??
  57. ????????View?child;??
  58. ????????int?childCount?=?mainContain.getChildCount();??
  59. ????????for?(int?i?=?0;?i?<?childCount;?i++)?{??
  60. ????????????child?=?mainContain.getChildAt(i);??
  61. ????????????child.setOnClickListener(this);??
  62. ????????}??
  63. ????}??
  64. ??????
  65. ????private?void?initCommonData()??
  66. ????{??
  67. ????????DisplayMetrics?metric?=?new?DisplayMetrics();??
  68. ????????getWindowManager().getDefaultDisplay().getMetrics(metric);??
  69. ????????screentWidth?=?metric.widthPixels;?//?屏幕宽度（像素）??
  70. ????}??
  71. ??
  72. ??
  73. ????private?void?setCurrentViewParams()?{??
  74. ??
  75. ????????if?(currentView?==?null)?{??
  76. ????????????return;??
  77. ????????}??
  78. ????????LayoutParams?params?=?currentView.getLayoutParams();??
  79. ????????if?(params?==?null)?{??
  80. ????????????return;??
  81. ????????}??
  82. ????????int?realWidth?=?params.width;??
  83. ????????int?nextWidth?=?0;??
  84. ????????if?(currentOpe?==?OPE_BIG)?{??
  85. ????????????nextWidth?=?realWidth?+?STEP;??
  86. ????????}?else?if?(currentOpe?==?OPE_SMALL)?{??
  87. ????????????nextWidth?=?realWidth?-?STEP;??
  88. ????????}??
  89. ????????if?(nextWidth?>?maxWidth)?{??
  90. ????????????nextWidth?=?maxWidth;??
  91. ????????}?else?if?(nextWidth?<?minWidth)?{??
  92. ????????????nextWidth?=?minWidth;??
  93. ????????}??
  94. ????????params.width?=?nextWidth;??
  95. ????????currentView.setLayoutParams(params);??
  96. ????????if?(nextWidth?==?maxWidth?||?nextWidth?==?minWidth)?{??
  97. ????????????animationIsEnd?=?true;??
  98. ????????????onOffClickable();??
  99. ????????????stopAnimation();??
  100. ????????????return;??
  101. ????????}??
  102. ????????mHandler.sendEmptyMessageDelayed(1,?20);??
  103. ????}??
  104. ??
  105. ????//?初始化宽度?测量max?min?长度??
  106. ????private?void?measureWidth(int?screenWidth)?{??
  107. ??????????
  108. ????????int?halfWidth?=?screenWidth?/?2;??
  109. ????????maxWidth?=?halfWidth?-?50;??
  110. ????????minWidth?=?(screenWidth?-?maxWidth)?/?(mainContain.getChildCount()?-?1);??
  111. ??
  112. ????????View?child;??
  113. ????????int?childCount?=?mainContain.getChildCount();??
  114. ????????for?(int?i?=?0;?i?<?childCount;?i++)?{??
  115. ????????????child?=?mainContain.getChildAt(i);??
  116. ????????????LayoutParams?params?=?child.getLayoutParams();??
  117. ????????????if?(i?==?0)?{??
  118. ????????????????preView?=?child;??
  119. ????????????????params.width?=?maxWidth;??
  120. ????????????}?else?{??
  121. ????????????????params.width?=?minWidth;??
  122. ????????????}??
  123. ??
  124. ????????????child.setLayoutParams(params);??
  125. ????????}??
  126. ????}??
  127. ??
  128. ????//?这里用handler更新界面??
  129. ????private?Handler?mHandler?=?new?Handler()?{??
  130. ??
  131. ????????@Override??
  132. ????????public?void?handleMessage(Message?msg)?{??
  133. ??
  134. ????????????if?(msg.what?==?1)?{??
  135. ????????????????setCurrentViewParams();??
  136. ????????????}???
  137. ????????}??
  138. ??
  139. ????};??
  140. ??
  141. ????//?停止动画??
  142. ????private?void?stopAnimation()?{??
  143. ????????currentOpe?=?-1;??
  144. ????????currentView?=?null;??
  145. ????}??
  146. ??
  147. ????private?void?startAnimation()?{??
  148. ??
  149. ????????if?(currentView?==?null?||?currentOpe?==?-1)?{??
  150. ????????????Log.d(TAG,?"无效动画");??
  151. ????????????return;??
  152. ????????}??
  153. ??????????
  154. ????????animationIsEnd?=?false;??
  155. ????????onOffClickable();??
  156. ????????mHandler.sendEmptyMessage(1);??
  157. ????}??
  158. ??
  159. ????@Override??
  160. ????public?void?onClick(View?v)?{??
  161. ??????????
  162. ????????int?id?=?v.getId();??
  163. ??????????
  164. ????????switch?(id)?{??
  165. ??????????
  166. ????????case?R.id.btnOne:??
  167. ????????????currentView?=?mainContain.getChildAt(0);??
  168. ????????????break;??
  169. ????????case?R.id.btnTwo:??
  170. ????????????currentView?=?mainContain.getChildAt(1);??
  171. ????????????break;??
  172. ????????case?R.id.btnThree:??
  173. ????????????currentView?=?mainContain.getChildAt(2);??
  174. ????????????break;??
  175. ????????case?R.id.btnFour:??
  176. ????????????currentView?=?mainContain.getChildAt(3);??
  177. ????????????break;??
  178. ????????}??
  179. ??
  180. ????????Log.i(TAG,?((Button)?currentView).getText().toString()?+?"?click");??
  181. ??????????
  182. ????????if?(currentView?!=?null?&&?animationIsEnd)?{??
  183. ??????????????
  184. ????????????int?currentViewWidth?=?currentView.getWidth();??
  185. ??????????????
  186. ????????????if?(currentViewWidth?==?maxWidth)?{??
  187. ????????????????currentOpe?=?OPE_SMALL;??
  188. ????????????}?else?{??
  189. ????????????????currentOpe?=?OPE_BIG;??
  190. ????????????}??
  191. ??????????????
  192. ????????????clickEvent(currentView);??
  193. ??????????????
  194. ????????????startAnimation();??
  195. ????????}??
  196. ??
  197. ????}??
  198. ??
  199. ????private?void?clickEvent(View?view)?{??
  200. ????????View?child;??
  201. ????????int?childCount?=?mainContain.getChildCount();??
  202. ????????for?(int?i?=?0;?i?<?childCount;?i++)?{??
  203. ????????????child?=?mainContain.getChildAt(i);??
  204. ????????????if?(preView?==?child)?{??
  205. ????????????????LinearLayout.LayoutParams?params?=?(android.widget.LinearLayout.LayoutParams)?child??
  206. ????????????????????????.getLayoutParams();??
  207. ????????????????params.weight?=?1.0f;??
  208. ????????????????child.setLayoutParams(params);??
  209. ????????????}?else?{??
  210. ????????????????LinearLayout.LayoutParams?params?=?(android.widget.LinearLayout.LayoutParams)?child??
  211. ????????????????????????.getLayoutParams();??
  212. ????????????????params.weight?=?0.0f;??
  213. ????????????????params.width?=?minWidth;??
  214. ????????????????child.setLayoutParams(params);??
  215. ????????????}??
  216. ????????}??
  217. ????????preView?=?view;??
  218. ????????printWeight();??
  219. ????}??
  220. ??
  221. ????private?void?printWeight()?{??
  222. ????????View?child;??
  223. ????????int?childCount?=?mainContain.getChildCount();??
  224. ????????for?(int?i?=?0;?i?<?childCount;?i++)?{??
  225. ????????????child?=?mainContain.getChildAt(i);??
  226. ????????????LinearLayout.LayoutParams?params?=?(android.widget.LinearLayout.LayoutParams)?child??
  227. ????????????????????.getLayoutParams();??
  228. ????????????Log.i("mm1",?((Button)?child).getText()?+?":?"?+?params.weight);??
  229. ????????}??
  230. ????}??
  231. ??????
  232. ????//???
  233. ????private?void?onOffClickable()??
  234. ????{??
  235. ????????View?child;??
  236. ????????boolean?clickable?=?animationIsEnd;??
  237. ????????int?childCount?=?mainContain.getChildCount();??
  238. ????????for?(int?i?=?0;?i?<?childCount;?i++)?{??
  239. ????????????child?=?mainContain.getChildAt(i);??
  240. ????????????child.setClickable(clickable);??
  241. ????????}??
  242. ????}??
  243. ??
  244. }??

?

?

改变控件的宽度或者高度：

?1.获取参数类 ?LayoutParams params =??View.getLayoutParams() ?

?2.?设置控件高度或者宽度属性?params.width 、params.height?

?3.设置完属性后不要忘记 ?view.setLayoutParams(params);

?

LayoutParams 这个类是根据你父控件来获取的，比如我代码中：

?

[java]?view plaincopyprint?
  1. LinearLayout.LayoutParams?params?=?(android.widget.LinearLayout.LayoutParams)?child.getLayoutParams();??

?

child是一个Button ，在XML中它的父控件是LinearLayout，所以我这里有上面的强转，?LinearLayout.LayoutParams 不仅有设置控件宽度和高度的属性，还有一个本次Demo重点用到的一个属性android:layout_weight?，想必大家在开发中用到这个属性的不在少数吧！

?

android:layout_weight

Indicates how much of the extra space in the LinearLayout will be allocated to the view associated with these LayoutParams. Specify 0 if the view should not be stretched. Otherwise the extra pixels will be pro-rated among all views whose weight is greater than 0.

大概意思是View根据比例享用多余空间。这个比例就是你设置的这个值的大小，如果你设置它的值为0的话，就等于你没设置这个值，不等于零的话，就按你设的比例来瓜分LinearLayout中的多余空间。具体用法有不懂的请去seach。

?

最后说一些本次Demo中主要有以下三点不足：

1. 特效动画死板，变化速度死板；

2. 特效动画不能设置动画时间，如遇到高分辨率的机型，动画时间会变长。

3. view只能水平伸缩，不能竖直伸缩。

以上三点不足将在下篇为大家解决。

好了，上述就是本次特效讲解的全部内容，有什么地方说的有误的，欢迎您指正！欢迎拍砖！欢迎留言，如对你有帮助，请不要吝惜你手中的鼠标左键，点赞一个！奋斗

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