MultiTouch ---- multi-touch, scaling images, changing image positions,

MultiTouch ---- multi-touch, scaling images, changing image positions,

Today's mobile phones support multi-touch functions (images can be scaled and positions can be changed). But how can we use hardware to implement this function?

Follow me to learn this function

International practice: first DEMO free: http://download.csdn.net/detail/cnwutianhao/9443667

Example image:

 

I recorded it with Genymotion, but it didn't work as well as the multi-touch display on the real machine. You can run the program on the real machine and enjoy the multi-touch function. (Note: The Genymotion multi-touch shortcut is ctrl + move the cursor up and down)

Code implementation:

Layout file activtiy_main.xml

 

 1     <?xml version="1.0" encoding="utf-8"?>   2     <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"   3         xmlns:tools="http://schemas.android.com/tools"   4         android:layout_width="match_parent"   5         android:layout_height="match_parent"   6         tools:context="com.cnwuth.mutiltouch.MainActivity">   7        8         <ImageView   9             android:id="@+id/iv"  10             android:layout_width="match_parent"  11             android:layout_height="match_parent"  12             android:scaleType="matrix"  13             android:src="@mipmap/ic_launcher"/>  14       15     </RelativeLayout>  

 

MainActivity. java

 

1 package com. cnwuth. mutiltouch; 2 3 import android. graphics. matrix; 4 import android. graphics. pointF; 5 import android. support. v7.app. appCompatActivity; 6 import android. OS. bundle; 7 import android. view. motionEvent; 8 import android. view. view; 9 import android. widget. imageView; 10 11 public class MainActivity extends AppCompatActivity implements View. onTouchListener {12 13 private ImageView mImageView; 14 15 // scaling Control 16 private Matrix mMatrix = new Matrix (); 17 private Matrix savedMatrix = new Matrix (); 18 19 // indicate 20 private static final int NONE = 0; 21 private static final int DRAG = 1; 22 private static final int ZOOM = 2; 23 private int mode = NONE; 24 25 // defines the point of the first press, the focus of the two touchpoints, and the distance between the two fingers that have an accident: 26 private PointF startPoint = new PointF (); 27 private PointF midPoint = new PointF (); 28 private float oriDis = 1f; 29 30 @ Override 31 protected void onCreate (Bundle savedInstanceState) {32 super. onCreate (savedInstanceState); 33 setContentView (R. layout. activity_main); 34 mImageView = (ImageView) findViewById (R. id. iv); 35 mImageView. setOnTouchListener (this); 36} 37 38 @ Override 39 public boolean onTouch (View v, MotionEvent event) {40 ImageView view = (ImageView) v; 41 switch (event. getAction () & MotionEvent. ACTION_MASK) 42 {43 // 44 case MotionEvent. ACTION_DOWN: 45 mMatrix. set (view. getImageMatrix (); 46 savedMatrix. set (mMatrix); 47 startPoint. set (event. getX (), event. getY (); 48 mode = DRAG; 49 break; 50 // double-finger 51 case MotionEvent. ACTION_POINTER_DOWN: 52 oriDis = distance (event); 53 if (oriDis> 10f) 54 {55 savedMatrix. set (mMatrix); 56 midPoint = middle (event); 57 mode = ZOOM; 58} 59 break; 60 // open 61 case MotionEvent by finger. ACTION_UP: 62 case MotionEvent. ACTION_POINTER_UP: 63 mode = NONE; 64 break; 65 // single-finger sliding event 66 case MotionEvent. ACTION_MOVE: 67 if (mode = DRAG) 68 {69 // is a finger dragging 70 mMatrix. set (savedMatrix); 71 mMatrix. postTranslate (event. getX ()-startPoint. x, event. getY ()-startPoint. y); 72} 73 else if (mode = ZOOM) 74 {75 // two fingers slide 76 float newDist = distance (event); 77 if (newDist> 10f) 78 {79 mMatrix. set (savedMatrix); 80 float scale = newDist/oriDis; 81 mMatrix. postScale (scale, scale, midPoint. x, midPoint. y); 82} 83} 84 break; 85} 86 // set the Matrix 87 view of ImageView. setImageMatrix (mMatrix); 88 return true; 89} 90 91 // calculate the distance between two touch points 92 private float distance (MotionEvent event) {93 float x = event. getX (0)-event. getX (1); 94 float y = event. getY (0)-event. getY (1); 95 return (float) Math. sqrt (x * x + y * y); 96} 97 98 // calculate the midpoint 99 private PointF middle (MotionEvent event) {100 float x = event. getX (0) + event. getX (1); 101 float y = event. getY (0) + event. getY (1); 102 return new PointF (x/2, y/2); 103} 104}

 

(Note: The environment must run in Android Studio and the SDK is updated to the latest version. Otherwise, an error will occur)

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