Android之关于手势操作图片的缩放与移动

在Android中实现手势对于图片的操作，首先需要对MotionEvent以及Matrix两个类有所了解实现对手势的识别以及图片变动的操作。
在实现该功能时候需要在xml中要将图片的缩放格式改成Matrix才行.

下面代码主要实现两个demo，一个是关于matrix的简单测试以及图片的手势缩放与移动demo.。。

XML代码如下：

<?xml version="1.0" encoding="UTF-8"?>      <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_height="fill_parent" android:layout_width="fill_parent" android:id="@+id/linearLayout1" android:weightSum="1">          <ImageView android:layout_width="wrap_content" android:id="@+id/imag" android:layout_height="wrap_content" android:src="@drawable/a"          android:layout_gravity="center"          android:scaleType="matrix"          ></ImageView>          <ImageView android:layout_width="wrap_content"                   android:id="@+id/imag1"           android:scaleType="matrix"          android:layout_height="wrap_content"></ImageView>      </LinearLayout>

实现代码：    package hfut.gmm;    import android.app.Activity;  import android.content.Context;  import android.graphics.Bitmap;  import android.graphics.BitmapFactory;  import android.graphics.Canvas;  import android.graphics.Color;  import android.graphics.Matrix;  import android.graphics.Paint;  import android.graphics.PointF;  import android.os.Bundle;  import android.util.DisplayMetrics;  import android.util.FloatMath;  import android.util.Log;  import android.view.GestureDetector;  import android.view.MotionEvent;  import android.view.View;  import android.view.GestureDetector.OnGestureListener;  import android.view.View.OnTouchListener;  import android.view.animation.AnimationUtils;  import android.widget.ImageView;    public class Img_control extends Activity implements OnTouchListener {//implements OnTouchListener {      private ImageView imgview;      private ImageView img;               private Matrix matrix=new Matrix();      private Matrix savedMatrix=new Matrix();            static final int NONE = 0;        static final int DRAG = 1;        static final int ZOOM = 2;        int mode = NONE;          // Remember some things for zooming        PointF start = new PointF();        PointF mid = new PointF();        float oldDist = 1f;              //private GestureDetector gesture;   @Override   protected void onCreate(Bundle savedInstanceState) {    // TODO Auto-generated method stub    super.onCreate(savedInstanceState);    this.setContentView(R.layout.img_control);    imgview=(ImageView)this.findViewById(R.id.imag1);    imgview.setAnimation(AnimationUtils.loadAnimation(this, R.anim.newanim));            img=(ImageView)this.findViewById(R.id.imag);    Matrix mt=img.getImageMatrix();     //mt.postRotate(30);    mt.postScale(0.5f,0.5f);mt.postScale(1.5f,1.5f);    mt.postRotate(30, 130, 100);       mt.postTranslate(100, 10);        img.setImageMatrix(mt);           //imgview.setLongClickable(true);        imgview.setImageBitmap(BitmapFactory.decodeResource(this.getResources(), R.drawable.a));    imgview.setOnTouchListener(this);    imgview.setLongClickable(true);       }   private float spacing(MotionEvent event) {            float x = event.getX(0) - event.getX(1);            float y = event.getY(0) - event.getY(1);            return FloatMath.sqrt(x * x + y * y);    }               private void midPoint(PointF point, MotionEvent event) {            float x = event.getX(0) + event.getX(1);            float y = event.getY(0) + event.getY(1);            point.set(x / 2, y / 2);    }     @Override   public boolean onTouch(View v, MotionEvent event) {    // TODO Auto-generated method stub    /*    Log.d("Infor", "类别:"+event.getAction());    Log.d("Infor", "mask:"+event.getActionMasked());    Log.d("Infor", "index:"+event.getActionIndex());    Log.d("Infor", "points:"+event.getPointerCount());*/       Log.d("Infor", "size:"+event.getSize());       if(event.getActionMasked()==MotionEvent.ACTION_POINTER_UP)        Log.d("Infor", "多点操作");       switch(event.getActionMasked()){       case MotionEvent.ACTION_DOWN:          matrix.set(imgview.getImageMatrix());          savedMatrix.set(matrix);          start.set(event.getX(),event.getY());          Log.d("Infor", "触摸了...");          mode=DRAG;             break;       case MotionEvent.ACTION_POINTER_DOWN:  //多点触控         oldDist=this.spacing(event);           if(oldDist>10f){         Log.d("Infor", "oldDist"+oldDist);            savedMatrix.set(matrix);         midPoint(mid,event);         mode=ZOOM;           }           break;       case MotionEvent.ACTION_POINTER_UP:        mode=NONE;           break;       case MotionEvent.ACTION_MOVE:        if(mode==DRAG){         //此实现图片的拖动功能...         matrix.set(savedMatrix);            matrix.postTranslate(event.getX()-start.x, event.getY()-start.y);        }            else if(mode==ZOOM){// 此实现图片的缩放功能...         float newDist=spacing(event);         if(newDist>10){          matrix.set(savedMatrix);          float scale=newDist/oldDist;          matrix.postScale(scale, scale, mid.x, mid.y);                 }            }        break;       }       imgview.setImageMatrix(matrix);    return false;   }   }

运行结果如下：