转：http://blog.csdn.net/huyiyang2010/article/details/18712997转：

Android单张图片查看、单指移动、双指缩放、双击最大化或最小化

标签：android图片移动imageviewbitmap 2014-01-23 20:05 4308人阅读 评论(6) 收藏 举报 分类： Android

版权声明：本文为博主原创文章，未经博主允许不得转载。

Android平台上查看单张图片时，通常情况下需要实现图片查看、单指移动、双指缩放、双击最大化或最小化功能。

目前网络上的实现方式，都没有将此功能封装为类，零落在类和xml文件中，代码难以阅读，功能难以复用。

为此，我专门写了一个类做此功能。此类唯一的缺点是没有实现回弹动画。不说废话了，上代码。

代码如下：

[java] view plain copy

1. packagecom.example.test;
3. importandroid.content.Context;
4. importandroid.graphics.Bitmap;
5. importandroid.graphics.Canvas;
6. importandroid.graphics.Matrix;
7. importandroid.graphics.PointF;
8. importandroid.graphics.drawable.BitmapDrawable;
9. importandroid.util.AttributeSet;
10. importandroid.util.FloatMath;
11. importandroid.util.Log;
12. importandroid.view.MotionEvent;
13. importandroid.widget.ImageView;
15. publicclassTouchImageViewextendsImageView{
17. privatePointFdown=newPointF();
18. privatePointFmid=newPointF();
19. <precode_snippet_id="168679"snippet_file_name="blog_20140123_1_7635608"name="code"class="java"><precode_snippet_id="168679"snippet_file_name="blog_20140123_1_7635608"name="code"class="java">privatefloatoldDist=1f;
20. privateMatrixmatrix=newMatrix();
21. privateMatrixpreMatrix=newMatrix();
22. privateMatrixsavedMatrix=newMatrix();
24. privatestaticfinalintNONE=0;
25. privatestaticfinalintDRAG=1;
26. privatestaticfinalintZOOM=2;
27. privateintmode=NONE;
29. privatebooleanisBig=false;
31. privateintwidthScreen;
32. privateintheightScreen;
34. privateinttouchImgWidth;
35. privateinttouchImgHeight;
37. privatefloatdefaultScale;
39. privatelonglastClickTime=0;
41. privateBitmaptouchImg=null;
43. privatestaticfinalintDOUBLE_CLICK_TIME_SPACE=300;
44. privatestaticfinalintDOUBLE_POINT_DISTANCE=10;
45. privatestaticfloatMAX_SCALE=3.0f;
47. publicTouchImageView(Contextcontext){
48. super(context);
49. }
51. publicTouchImageView(Contextcontext,AttributeSetattrs){
52. super(context,attrs);
53. }
55. publicTouchImageView(Contextcontext,AttributeSetattrs,intdefStyleAttr){
56. super(context,attrs,defStyleAttr);
57. }
59. publicvoidinitImageView(intscreenWidth,intscreenHeight){
60. widthScreen=screenWidth;
61. heightScreen=screenHeight;
63. touchImg=((BitmapDrawable)getDrawable()).getBitmap();
64. touchImgWidth=touchImg.getWidth();
65. touchImgHeight=touchImg.getHeight();
66. floatscaleX=(float)widthScreen/touchImgWidth;
67. floatscaleY=(float)heightScreen/touchImgHeight;
68. defaultScale=scaleX<scaleY?scaleX:scaleY;
70. floatsubX=(widthScreen-touchImgWidth*defaultScale)/2;
71. floatsubY=(heightScreen-touchImgHeight*defaultScale)/2;
72. setScaleType(ScaleType.MATRIX);
73. preMatrix.reset();
74. preMatrix.postScale(defaultScale,defaultScale);
75. preMatrix.postTranslate(subX,subY);
76. matrix.set(preMatrix);
77. invalidate();
78. }
80. @Override
81. protectedvoidonDraw(Canvascanvas){
82. if(null!=touchImg){
83. canvas.save();
84. canvas.drawBitmap(touchImg,matrix,null);
85. canvas.restore();
86. }
87. }
89. @Override
90. publicbooleanonTouchEvent(MotionEventevent){
91. switch(event.getAction()&MotionEvent.ACTION_MASK){
92. caseMotionEvent.ACTION_DOWN:
93. mode=DRAG;
94. down.x=event.getX();
95. down.y=event.getY();
96. savedMatrix.set(matrix);
98. if(event.getEventTime()-lastClickTime<DOUBLE_CLICK_TIME_SPACE){
99. changeSize(event.getX(),event.getY());
100. }
101. lastClickTime=event.getEventTime();
102. break;
103. caseMotionEvent.ACTION_POINTER_DOWN:
104. oldDist=spacing(event);
105. if(oldDist>DOUBLE_POINT_DISTANCE){
106. mode=ZOOM;
107. //oldRotation=rotation(event);
108. savedMatrix.set(matrix);
109. midPoint(mid,event);
110. }
111. break;
112. caseMotionEvent.ACTION_MOVE:
113. if(mode==ZOOM){
114. floatnewDist=spacing(event);
115. floatscale=newDist/oldDist;
116. if(scale>1.01||scale<0.99){
117. preMatrix.set(savedMatrix);
118. preMatrix.postScale(scale,scale,mid.x,mid.y);//缩放
119. if(canZoom()){
120. matrix.set(preMatrix);
121. invalidate();
122. }
123. }
124. }elseif(mode==DRAG){
125. if(1.0f<distance(event,down)){
126. preMatrix.set(savedMatrix);
128. preMatrix.postTranslate(event.getX()-down.x,0);
129. if(event.getX()>down.x){
130. if(canDrag(DRAG_RIGHT)){
131. savedMatrix.set(preMatrix);
132. }else{
133. preMatrix.set(savedMatrix);
134. }
135. }else{
136. if(canDrag(DRAG_LEFT)){
137. savedMatrix.set(preMatrix);
138. }else{
139. preMatrix.set(savedMatrix);
140. }
141. }
142. preMatrix.postTranslate(0,event.getY()-down.y);
143. if(event.getY()>down.y){
144. if(canDrag(DRAG_DOWN)){
145. savedMatrix.set(preMatrix);
146. }else{
147. preMatrix.set(savedMatrix);
148. }
149. }else{
150. if(canDrag(DRAG_TOP)){
151. savedMatrix.set(preMatrix);
152. }else{
153. preMatrix.set(savedMatrix);
154. }
155. }
157. matrix.set(preMatrix);
158. invalidate();
159. down.x=event.getX();
160. down.y=event.getY();
161. savedMatrix.set(matrix);
162. }
163. }
164. break;
165. caseMotionEvent.ACTION_UP:
166. mode=NONE;
167. springback();
168. break;
169. caseMotionEvent.ACTION_POINTER_UP:
170. mode=NONE;
171. break;
172. }
173. returntrue;
174. }
176. privatevoidspringback(){
177. preMatrix.set(matrix);
178. float[]x=newfloat[4];
179. float[]y=newfloat[4];
180. getFourPoint(x,y);
181. if(x[1]-x[0]>widthScreen){
182. if(x[0]>0){
183. preMatrix.postTranslate(-x[0],0);
184. matrix.set(preMatrix);
185. invalidate();
186. }elseif(x[1]<widthScreen){
187. preMatrix.postTranslate(widthScreen-x[1],0);
188. matrix.set(preMatrix);
189. invalidate();
190. }
191. }elseif(x[1]-x[0]<widthScreen-1f){
192. preMatrix.postTranslate((widthScreen-(x[1]-x[0]))/2-x[0],0);
193. matrix.set(preMatrix);
194. invalidate();
195. }
197. if(y[2]-y[0]>heightScreen){
198. if(y[0]>0){
199. preMatrix.postTranslate(0,-y[0]);
200. matrix.set(preMatrix);
201. invalidate();
202. }elseif(y[2]<heightScreen){
203. preMatrix.postTranslate(0,heightScreen-y[2]);
204. matrix.set(preMatrix);
205. invalidate();
206. }
207. }elseif(y[2]-y[0]<heightScreen-1f){
208. preMatrix.postTranslate(0,(heightScreen-(y[2]-y[0]))/2
209. -y[0]);
210. matrix.set(preMatrix);
211. invalidate();
212. }
213. }
215. privatevoidgetFourPoint(float[]x,float[]y){
216. float[]f=newfloat[9];
217. preMatrix.getValues(f);
218. //图片4个顶点的坐标
219. x[0]=f[Matrix.MSCALE_X]*0+f[Matrix.MSKEW_X]*0
220. +f[Matrix.MTRANS_X];
221. y[0]=f[Matrix.MSKEW_Y]*0+f[Matrix.MSCALE_Y]*0
222. +f[Matrix.MTRANS_Y];
223. x[1]=f[Matrix.MSCALE_X]*touchImg.getWidth()+f[Matrix.MSKEW_X]*0
224. +f[Matrix.MTRANS_X];
225. y[1]=f[Matrix.MSKEW_Y]*touchImg.getWidth()+f[Matrix.MSCALE_Y]*0
226. +f[Matrix.MTRANS_Y];
227. x[2]=f[Matrix.MSCALE_X]*0+f[Matrix.MSKEW_X]
228. *touchImg.getHeight()+f[Matrix.MTRANS_X];
229. y[2]=f[Matrix.MSKEW_Y]*0+f[Matrix.MSCALE_Y]
230. *touchImg.getHeight()+f[Matrix.MTRANS_Y];
231. x[3]=f[Matrix.MSCALE_X]*touchImg.getWidth()+f[Matrix.MSKEW_X]
232. *touchImg.getHeight()+f[Matrix.MTRANS_X];
233. y[3]=f[Matrix.MSKEW_Y]*touchImg.getWidth()+f[Matrix.MSCALE_Y]
234. *touchImg.getHeight()+f[Matrix.MTRANS_Y];
235. }
237. privatefinalstaticintDRAG_LEFT=0;
238. privatefinalstaticintDRAG_RIGHT=1;
239. privatefinalstaticintDRAG_TOP=2;
240. privatefinalstaticintDRAG_DOWN=3;
242. privatebooleancanDrag(finalintdirection){
243. float[]x=newfloat[4];
244. float[]y=newfloat[4];
245. getFourPoint(x,y);
247. //出界判断
248. if((x[0]>0||x[2]>0||x[1]<widthScreen||x[3]<widthScreen)
249. &&(y[0]>0||y[1]>0||y[2]<heightScreen||y[3]<heightScreen)){
250. returnfalse;
251. }
252. if(DRAG_LEFT==direction){
253. //左移出界判断
254. if(x[1]<widthScreen||x[3]<widthScreen){
255. returnfalse;
256. }
257. }elseif(DRAG_RIGHT==direction){
258. //右移出界判断
259. if(x[0]>0||x[2]>0){
260. returnfalse;
261. }
262. }elseif(DRAG_TOP==direction){
263. //上移出界判断
264. if(y[2]<heightScreen||y[3]<heightScreen){
265. returnfalse;
266. }
267. }elseif(DRAG_DOWN==direction){
268. //下移出界判断
269. if(y[0]>0||y[1]>0){
270. returnfalse;
271. }
272. }else{
273. returnfalse;
274. }
275. returntrue;
276. }
278. privatebooleancanZoom(){
279. float[]x=newfloat[4];
280. float[]y=newfloat[4];
281. getFourPoint(x,y);
282. //图片现宽度
283. doublewidth=Math.sqrt((x[0]-x[1])*(x[0]-x[1])+(y[0]-y[1])
284. *(y[0]-y[1]));
285. doubleheight=Math.sqrt((x[0]-x[2])*(x[0]-x[2])+(y[0]-y[2])
286. *(y[0]-y[2]));
287. //缩放比率判断
288. if(width<touchImgWidth*defaultScale-1
289. ||width>touchImgWidth*MAX_SCALE+1){
290. returnfalse;
291. }
293. //出界判断
294. if(width<widthScreen&&height<heightScreen){
295. returnfalse;
296. }
297. returntrue;
298. }
300. //触碰两点间距离
301. privatestaticfloatspacing(MotionEventevent){
302. floatx=event.getX(0)-event.getX(1);
303. if(x<0){
304. x=-x;
305. }
306. floaty=event.getY(0)-event.getY(1);
307. if(y<0){
308. y=-y;
309. }
310. returnFloatMath.sqrt(x*x+y*y);
311. }
313. //取手势中心点
314. privatestaticvoidmidPoint(PointFpoint,MotionEventevent){
315. floatx=event.getX(0)+event.getX(1);
316. floaty=event.getY(0)+event.getY(1);
317. point.set(x/2,y/2);
318. }
320. //取两点之间的距离
321. privatestaticfloatdistance(MotionEventpoint2,PointFpoint1){
322. floatx=point1.x-point2.getX();
323. if(x<0){
324. x=-x;
325. }
326. floaty=point1.y-point2.getY();
327. if(y<0){
328. y=-y;
329. }
330. returnFloatMath.sqrt(x*x+y*y);
331. }
333. privatevoidchangeSize(floatx,floaty){
334. if(isBig){
335. floatsubX=(widthScreen-touchImgWidth*defaultScale)/2;
336. floatsubY=(heightScreen-touchImgHeight*defaultScale)/2;
337. preMatrix.reset();
338. preMatrix.postScale(defaultScale,defaultScale);
339. preMatrix.postTranslate(subX,subY);
340. matrix.set(preMatrix);
341. invalidate();
343. isBig=false;
344. }else{
345. floattransX=(widthScreen-touchImgWidth*MAX_SCALE)/2;
346. floattransY=(heightScreen-touchImgHeight*MAX_SCALE)/2;
347. preMatrix.reset();
348. preMatrix.postScale(MAX_SCALE,MAX_SCALE);
349. preMatrix.postTranslate(transX,transY);
350. matrix.set(preMatrix);
351. invalidate();
353. isBig=true;
354. }
355. }
356. }
357. </pre>
358. <pre></pre>
359. <pre></pre>
360. <p></p>
361. <pre></pre>
362. <pre></pre>
363. <p><br>
364. </p>
365. <p><br>
366. </p>
367. <p></p>
368. <p>测试代码如下：</p>
369. <p><br>
370. </p>
371. <p>activity_main.xml文件：</p>
372. <p></p>
373. <precode_snippet_id="168679"snippet_file_name="blog_20140123_2_8257273"name="code"class="html"><LinearLayoutxmlns:android="http://schemas.android.com/apk/res/android"
374. xmlns:tools="http://schemas.android.com/tools"
375. android:id="@+id/layout_id"
376. android:layout_width="match_parent"
377. android:layout_height="match_parent"
378. tools:context=".MainActivity">
380. <com.example.test.TouchImageView
381. android:id="@+id/img_id"
382. android:layout_width="400dip"
383. android:layout_height="800dip"
384. android:src="@drawable/banner"
385. android:scaleType="fitCenter"/>
387. </LinearLayout>
388. </pre><br>
389. <p><br>
390. </p>
391. <p>MainActivity.java文件：</p>
392. <p></p>
393. <p></p>
394. <precode_snippet_id="168679"snippet_file_name="blog_20140123_3_2367928"name="code"class="java">packagecom.example.test;
396. importandroid.app.Activity;
397. importandroid.os.Bundle;
398. importandroid.util.DisplayMetrics;
399. importandroid.view.Menu;
400. importandroid.view.ViewTreeObserver.OnGlobalLayoutListener;
401. importandroid.widget.LinearLayout;
403. publicclassMainActivityextendsActivity{
405. privateTouchImageViewimgView;
407. @Override
408. protectedvoidonCreate(BundlesavedInstanceState){
409. super.onCreate(savedInstanceState);
410. setContentView(R.layout.activity_main);
412. DisplayMetricsdm=newDisplayMetrics();
413. getWindowManager().getDefaultDisplay().getMetrics(dm);
415. TouchImageViewimgView=(TouchImageView)findViewById(R.id.img_id);
416. imgView.initImageView(dm.widthPixels,dm.heightPixels-80);
417. }
419. @Override
420. publicbooleanonCreateOptionsMenu(Menumenu){
421. //Inflatethemenu;thisaddsitemstotheactionbarifitispresent.
422. getMenuInflater().inflate(R.menu.main,menu);
423. returntrue;
424. }
426. }
427. </pre><br>
428. <br>
429. <p></p>
431. </pre>

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