MultiTouch ———— Multi-touch, telescopic picture, change picture position

Today's mobile phones all support multi-touch function (can be image stretching, changing position), but how do we programmers to combine the hardware to achieve this function?

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Example Picture:

I recorded with Genymotion, no real-world multi-touch display of the effect so good, we run the program on the real machine, you will experience the multi-touch function. (Note: Genymotion Multi-touch shortcut is CTRL + Drag the mouse pointer up or down.)

Specific 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"3Xmlns:tools= "Http://schemas.android.com/tools"4Android:layout_width= "Match_parent"5android:layout_height= "Match_parent"6tools:context= "Com.cnwuth.mutiltouch.MainActivity" >7       8<ImageView9Android:id= "@+id/iv"TenAndroid:layout_width= "Match_parent" Oneandroid:layout_height= "Match_parent" AAndroid:scaletype= "Matrix" -android:src= "@mipmap/ic_launcher"/> -        the</RelativeLayout>

Mainactivity.java

1      PackageCom.cnwuth.mutiltouch; 2       3     ImportAndroid.graphics.Matrix; 4     ImportAndroid.graphics.PointF; 5     Importandroid.support.v7.app.AppCompatActivity; 6     ImportAndroid.os.Bundle; 7     Importandroid.view.MotionEvent; 8     ImportAndroid.view.View; 9     ImportAndroid.widget.ImageView; Ten        One      Public classMainactivityextendsAppcompatactivityImplementsview.ontouchlistener{ A        -         PrivateImageView Mimageview;  -        the         //Zoom Control -         PrivateMatrix Mmatrix =NewMatrix ();  -         PrivateMatrix Savedmatrix =NewMatrix ();  -        +         //representations of different states -         Private Static Final intNONE = 0;  +         Private Static Final intDRAG = 1;  A         Private Static Final intZOOM = 2;  at         Private intmode =NONE;  -        -         //define the first pressed point, the focus of the two contact points, and the distance between the two fingers pressed: -         PrivatePointF StartPoint =NewPointF ();  -         PrivatePointF midpoint =NewPointF ();  -         Private floatOridis =1f;  in        - @Override to         protected voidonCreate (Bundle savedinstancestate) { +             Super. OnCreate (savedinstancestate);  - Setcontentview (R.layout.activity_main);  theMimageview =(ImageView) Findviewbyid (R.ID.IV);  *Mimageview.setontouchlistener ( This);  $         }  Panax Notoginseng        - @Override the          Public BooleanOnTouch (View V, motionevent event) { +ImageView view =(ImageView) v;  A             Switch(Event.getaction () &motionevent.action_mask) the             {   +                 //single Finger -                  CaseMotionevent.action_down: $ Mmatrix.set (View.getimagematrix ());  $ Savedmatrix.set (Mmatrix);  - Startpoint.set (Event.getx (), event.gety ());  -mode =DRAG;  the                      Break;  -                 //two fingersWuyi                  CaseMotionevent.action_pointer_down: theOridis =distance (event);  -                     if(Oridis >10f) Wu                     {   - Savedmatrix.set (Mmatrix);  AboutMidpoint =Middle (event);  $mode =ZOOM;  -                     }   -                      Break;  -                 //Finger Release A                  Casemotionevent.action_up: +                  Casemotionevent.action_pointer_up: themode =NONE;  -                      Break;  $                 //single finger swipe event the                  CaseMotionevent.action_move: the                     if(Mode = =DRAG) the                     {   the                         //is a finger-dragging - Mmatrix.set (Savedmatrix);  inMmatrix.posttranslate (Event.getx ()-Startpoint.x, event.gety ()-startpoint.y);  the                     }   the                     Else if(Mode = =ZOOM) About                     {   the                         //two finger swipe the                         floatNewdist =distance (event);  the                         if(Newdist >10f) +                         {   - Mmatrix.set (Savedmatrix);  the                             floatScale = newdist/Oridis; Bayi Mmatrix.postscale (scale, scale, midpoint.x, MIDPOINT.Y);  the                         }   the                     }   -                      Break;  -             }   the             //set the matrix for ImageView the View.setimagematrix (Mmatrix);  the             return true;  the         }   -        the         //calculates the distance between two touch points the         Private floatDistance (Motionevent event) { the             floatx = Event.getx (0)-Event.getx (1); 94             floaty = event.gety (0)-event.gety (1);  the             return(float) math.sqrt (x * x + y *y);  the         }   the       98         //calculates the midpoint of a two touch point About         PrivatePointF Middle (motionevent event) { -             floatx = Event.getx (0) + event.getx (1); 101             floaty = event.gety (0) + event.gety (1); 102             return NewPointF (X/2, Y/2); 103         }  104}

(Note: The environment needs to be run under Android Studio, and the SDK updates to the latest, otherwise there will be an error)

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MultiTouch ———— Multi-touch, telescopic picture, change picture position