手势图片

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;

    }  

}