首页 文章 精选 留言 我的

【移动开发】Android中图片的多点触控和缩放

2017-11-07 622

   前几天做项目用到相机拍照，之后能对图片进行缩放，拖拽，在此我将其单独抽取出来，后面用到时直接拿来用就行了！

效果图：

174133817.png

  注：这里不仅能按钮缩放，还能多点触摸缩放和拖拽功能！

1.布局：

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
<? xml  version = "1.0"  encoding = "UTF-8" ?>
< FrameLayout  xmlns:android = "http://schemas.android.com/apk/res/android"
     android:id = "@+id/flayout_img_display"
     android:layout_width = "fill_parent"
     android:layout_height = "fill_parent"
     android:orientation = "vertical"  >
     < LinearLayout
         android:id = "@+id/linearLayout_img_display"
         android:layout_width = "fill_parent"
         android:layout_height = "fill_parent"
         android:layout_gravity = "center"
         android:gravity = "center"  >
         < ImageView
             android:id = "@+id/img_display"
             android:layout_width = "fill_parent"
             android:layout_height = "wrap_content"
             android:paddingBottom = "5.0dip"
             android:paddingTop = "5.0dip"
             android:scaleType = "matrix"  />
     </ LinearLayout >
     < RelativeLayout
         android:id = "@+id/relativeLayout1"
         android:layout_width = "fill_parent"
         android:layout_height = "wrap_content"  >
         < Button
             android:id = "@+id/btn_min"
             android:layout_width = "wrap_content"
             android:layout_height = "wrap_content"
             android:layout_alignParentBottom = "true"
             android:layout_alignParentLeft = "true"
             android:enabled = "false"
             android:text = "缩小"  />
         < Button
             android:id = "@+id/btn_out"
             android:layout_width = "wrap_content"
             android:layout_height = "wrap_content"
             android:layout_alignParentBottom = "true"
             android:layout_alignParentRight = "true"
             android:text = "放大"  />
     </ RelativeLayout >
</ FrameLayout >

2.就一个类：

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
import  android.app.Activity;
import  android.content.Intent;
import  android.graphics.Bitmap;
import  android.graphics.BitmapFactory;
import  android.graphics.Matrix;
import  android.graphics.PointF;
import  android.os.Bundle;
import  android.util.FloatMath;
import  android.util.Log;
import  android.view.MotionEvent;
import  android.view.View;
import  android.view.View.OnClickListener;
import  android.view.View.OnTouchListener;
import  android.widget.Button;
import  android.widget.FrameLayout;
import  android.widget.ImageView;
import  android.widget.LinearLayout;
/**
  * 缩放图片界面
  * @author ZHF
  *
  */
public  class  MainActivity  extends  Activity {
     public  static  final  String TAG =  "ImgDisplayActivity" ;
     //控件声明
     private  Button btnZoomin, btnZoomout;
     private  ImageView imgDisPlay;
     private  LinearLayout lLayoutDisplay;
     private  FrameLayout fLayoutDisplay;
                                                                                                            
     private  Bitmap bitmap;
                                                                                                            
     private  int  imgId =  0 ;
     private  double  scale_in =  0.8 ; //缩小比例
     private  double  scale_out =  1.25 ; //放大比例
                                                                                                            
     private  float  scaleWidth =  1 ;
     private  float  scaleHeight =  1 ;
     //模式：0：什么都不干；1：拖拽； 2：缩放
     public  static  final  int  NONE =  0 ;
     public  static  final  int  DRAG =  1 ;
     public  static  final  int  ZOOM =  2 ;
     //声明触发的事件模式
     private  int  mode = NONE;
                                                                                                            
     private  Matrix matrix;    //矩阵
     private  Matrix currMatrix;  //当前矩阵
                                                                                                            
     private  PointF starPoint;
     private  PointF midPoint;
                                                                                                            
     private  float  startDistance;
                                                                                                            
     @Override
     protected  void  onCreate(Bundle savedInstanceState) {
         super .onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);
         //初始化
         fLayoutDisplay = (FrameLayout) findViewById(R.id.flayout_img_display);
         lLayoutDisplay = (LinearLayout) findViewById(R.id.linearLayout_img_display);
         imgDisPlay = (ImageView) findViewById(R.id.img_display);
         btnZoomin = (Button) findViewById(R.id.btn_min);
         btnZoomout = (Button) findViewById(R.id.btn_out);
                                                                                                                
                                                                                                                
         matrix =  new  Matrix();  //保存拖拽变化
         currMatrix =  new  Matrix(); // 当前的
         starPoint =  new  PointF(); //开始点的位置
                                                                                                                
                                                                                                                
         btnZoomin.setOnClickListener( new  OnClickListener() {
             @Override
             public  void  onClick(View v) {
                 zoomIn();
             }
         });
         btnZoomout.setOnClickListener( new  OnClickListener() {
             @Override
             public  void  onClick(View v) {
                 zoomOut(); //放大
             }
         });
                                                                                                                
         imgDisPlay.setImageResource(R.drawable.img);
         //给图片绑定监听器哦
         imgDisPlay.setOnTouchListener( new  ImageViewOnTouchListener());
                                                                                                                
     }
                                                                                                            
     /**放大操作**/
     private  void  zoomOut() {
         reSizeBmp(scale_out);
         btnZoomin.setEnabled( true );
     }
                                                                                                            
     /**缩小操作**/
     private  void  zoomIn() {
         reSizeBmp(scale_in);
     }
                                                                                                            
     /**接收传入的缩放比例实现缩放**/
     private  void  reSizeBmp( double  scale) {
         //缩放比例
         scaleWidth = ( float ) (scaleWidth * scale);
         scaleHeight = ( float ) (scaleHeight * scale);
                                                                                                                
         Matrix matrix =  new  Matrix();
         matrix.postScale(scaleWidth, scaleHeight);  //设计缩放比例
                                                                                                                
         imgDisPlay.setImageMatrix(matrix);
     }
                                                                                                            
     /**计算触摸实现缩放**/
     final  class  ImageViewOnTouchListener  implements  OnTouchListener{
         @Override
         public  boolean  onTouch(View v, MotionEvent event) {
                                                                                                                    
             switch  (event.getAction() & MotionEvent.ACTION_MASK) {
             case  MotionEvent.ACTION_DOWN:   //一只手指按下
                 Log.i(TAG, "一只手指按下" );
                 currMatrix.set(matrix);
                 starPoint.set(event.getX(), event.getY());
                                                                                                                        
                 mode = DRAG;
                 break ;
             case  MotionEvent.ACTION_POINTER_DOWN:  //如果有一只手指按下屏幕，后续又有一个手指按下     // 两只手指按下
                 Log.i(TAG, "又有一只手指按下" );
                                                                                                                        
                 startDistance = distance(event); //记下两点的距离
                 Log.i(TAG, startDistance+ "" );
                                                                                                                        
                 if (startDistance > 5f) {   //两个手指之间的最小距离像素大于5，认为是多点触摸
                     mode = ZOOM;
                     currMatrix.set(matrix);
                                                                                                                            
                     midPoint = getMidPoint(event);  //记下两个点之间的中心点
                                                                                                                            
                 }
                                                                                                                        
                 break ;
                                                                                                                        
             case  MotionEvent.ACTION_MOVE:
                                                                                                                        
                 if (mode == DRAG) {   //拖拽模式
                     Log.i(TAG, "一只手指在拖拽" );
                                                                                                                            
                     //开始--》结束点的距离
                     float  dx = event.getX() - starPoint.x;
                     float  dy = event.getY() - starPoint.y;
                                                                                                                            
                     matrix.set(currMatrix);
                     matrix.postTranslate(dx, dy); //移动到指定点：矩阵移动比例；eg:缩放有缩放比例
                 }  else  if (mode == ZOOM) {   //缩放模式
                     Log.i(TAG, "正在缩放" );
                                                                                                                            
                     float  distance = distance(event);   //两点之间的距离
                     if (distance > 5f) {
                         matrix.set(currMatrix);
                         float  cale = distance / startDistance;
                         matrix.preScale(cale, cale, midPoint.x, midPoint.y);   //进行比例缩放
                     }
                 }
                 break ;
                                                                                                                        
             case  MotionEvent.ACTION_UP:  //最后一只手指离开屏幕后触发此事件
             case  MotionEvent.ACTION_POINTER_UP:  //一只手指离开屏幕，但还有一只手指在上面会触此事件
                 //什么都没做
                 mode = NONE;
                 break ;
             default :
                 break ;
             }
                                                                                                                    
             imgDisPlay.setImageMatrix(matrix);
                                                                                                                    
             //两只手指的缩放
             return  true ;
         }
     }
                                                                                                            
     /**计算两点之间的距离像素**/
     private  float  distance(MotionEvent e) {
                                                                                                                
         float  eX = e.getX( 1 ) - e.getX( 0 );   //后面的点坐标 - 前面点的坐标
         float  eY = e.getY( 1 ) - e.getY( 0 );
         return  FloatMath.sqrt(eX * eX + eY * eY);
     }
                                                                                                            
     /**计算两点之间的中心点**/
     private  PointF getMidPoint(MotionEvent event) {
                                                                                                                
         float  x = (event.getX( 1 ) - event.getX( 0 )) /  2 ;
         float  y = (event.getY( 1 ) - event.getY( 0 )) /  2 ;
         return  new  PointF(x,y);
     }
}


    ok！主要的算法就在ImageViewOnTouchListener监听器当中，要考虑那三种情况（缩放、拖拽、什么都不干），另外需要注意的就是，单个手指和两个以上手指的情况。


源码下载:http://down.51cto.com/data/876165





     本文转自zhf651555765 51CTO博客，原文链接：http://blog.51cto.com/smallwoniu/1252191，如需转载请自行联系原作者




上一篇 下一篇
优秀的个人博客,低调大师

微信关注我们

原文链接：https://yq.aliyun.com/articles/471631

转载内容版权归作者及来源网站所有！

低调大师中文资讯倾力打造互联网数据资讯、行业资源、电子商务、移动互联网、网络营销平台。持续更新报道IT业界、互联网、市场资讯、驱动更新,是最及时权威的产业资讯及硬件资讯报道平台。

网络安全 - Harden CISCO Devices

Introduction 介绍 This document lists all the option that is recommended to help you secure your CISCO IOS system devices,which increases the overall security of your network 这篇文档包含了建议你使用的一些安全选项，旨在帮助你加强使用 CISCO IOS 系统的设备的安全性，从整体上整体加强网路安全。 service sequence-numbers Each system status messages logged in the system logging process have a sequence reference number applied. This command makes that number visible by displaying it with the message. The sequence number is displayed as the first part of the...
2017-11-07
708
上一篇

【移动开发】Android中异步加载数据（二）AsyncTask异步更新界面

今天介绍第二种异步更新界面的方式：AsyncTask 官方文档： AsyncTask enables proper and easyuse of the UI thread. This class allows to perform background operations and publish results on the UI thread without having to manipulate threads and/or handlers. AsyncTask能够更恰当和更简单的去使用UI线程。这个类允许执行后台操作和展现结果在UI线程上，无需操纵线程和/或处理程序。AsyncTask的内部实现是一个线程池，每个后台任务会提交到线程池中的线程执行，然后使用Thread+Handler的方式调用回调函数。 1.AsyncTask抽象出后台线程运行的五个状态： 分别是：1、准备运行，2、正在后台运行，3、进度更新，4、完成后台任务，5、取消任务，对于这五个阶段，AsyncTask提供了五个回调函数： 1、准备运行：onPreExecute(),该回调函数在任务被执行...
2017-11-07
673
下一篇

相关文章

发表评论

资源下载

更多资源
腾讯云软件源

腾讯云软件源

为解决软件依赖安装时官方源访问速度慢的问题，腾讯云为一些软件搭建了缓存服务。您可以通过使用腾讯云软件源站来提升依赖包的安装速度。为了方便用户自由搭建服务架构，目前腾讯云软件源站支持公网访问和内网访问。

时间: 2026-04-11 大小: 1MB 下载: 9次
Spring

Spring

Spring框架（Spring Framework）是由Rod Johnson于2002年提出的开源Java企业级应用框架，旨在通过使用JavaBean替代传统EJB实现方式降低企业级编程开发的复杂性。该框架基于简单性、可测试性和松耦合性设计理念，提供核心容器、应用上下文、数据访问集成等模块，支持整合Hibernate、Struts等第三方框架，其适用范围不仅限于服务器端开发，绝大多数Java应用均可从中受益。

时间: 2025-12-17 大小: 5MB 下载: 1次
Sublime Text

Sublime Text

Sublime Text具有漂亮的用户界面和强大的功能，例如代码缩略图，Python的插件，代码段等。还可自定义键绑定，菜单和工具栏。Sublime Text 的主要功能包括：拼写检查，书签，完整的 Python API ， Goto 功能，即时项目切换，多选择，多窗口等等。Sublime Text 是一个跨平台的编辑器，同时支持Windows、Linux、Mac OS X等操作系统。

时间: 2025-12-03 大小: 9.84MB 下载: 39次
WebStorm

WebStorm

WebStorm 是jetbrains公司旗下一款JavaScript 开发工具。目前已经被广大中国JS开发者誉为“Web前端开发神器”、“最强大的HTML5编辑器”、“最智能的JavaScript IDE”等。与IntelliJ IDEA同源，继承了IntelliJ IDEA强大的JS部分的功能。

时间: 2025-12-13 大小: 249.54MB 下载: 22次
手机查看

扫码在手机上查看文章

扫描二维码，手机阅读更方便

热门标签
DeepSeek Jdk25 OpenAi HarmonyOS6 Nacos3 SpringBoot4 SpringCloud Docker Kubernetes Service Mesh Redis Gemini3 Rocky

欢迎您来访！

登录后，您将获得更多功能！
热门文章
联系我们

有任何问题或合作意向欢迎联系我们

Email: 99873273@qq.com

QQ: 99873273

用户登录
用户注册