Android手势控制实现缩放、移动图片

本文实例为大家分享了android手势控制实现缩放、移动图片的方法，供大家参考，具体内容如下

新建一个触摸监听器类

package com.liyong.btprinter; 

import android.graphics.matrix; 
import android.graphics.pointf; 
import android.util.floatmath; 
import android.view.motionevent; 
import android.view.view; 
import android.view.view.ontouchlistener; 
import android.widget.imageview; 

public class mulitpointtouchlistener implements ontouchlistener { 

private static final string tag = "touch"; 
  // these matrices will be used to move and zoom image 
  matrix matrix = new matrix(); 
  matrix savedmatrix = new matrix(); 

  // we can be in one of these 3 states 
  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; 

  @override 
  public boolean ontouch(view v, motionevent event) { 

      imageview view = (imageview) v; 
      // log.e("view_width", 
      // view.getimagematrix()..tostring()+"*"+v.getwidth()); 
      // dump touch event to log 
      dumpevent(event); 

      // handle touch events here... 
      switch (event.getaction() & motionevent.action_mask) { 
      case motionevent.action_down: 

          matrix.set(view.getimagematrix()); 
          savedmatrix.set(matrix); 
          start.set(event.getx(), event.gety()); 
          //log.d(tag, "mode=drag"); 
          mode = drag; 

          
          //log.d(tag, "mode=none"); 
          break; 
      case motionevent.action_pointer_down: 
          olddist = spacing(event); 
          //log.d(tag, "olddist=" + olddist); 
          if (olddist > 10f) { 
              savedmatrix.set(matrix); 
              midpoint(mid, event); 
              mode = zoom; 
              //log.d(tag, "mode=zoom"); 
          } 
          break; 
      case motionevent.action_up: 
      case motionevent.action_pointer_up: 
          mode = none; 
          //log.e("view.getwidth", view.getwidth() + ""); 
          //log.e("view.getheight", view.getheight() + ""); 

          break; 
      case motionevent.action_move: 
          if (mode == drag) { 
              // ... 
              matrix.set(savedmatrix); 
              matrix.posttranslate(event.getx() - start.x, event.gety() 
                      - start.y); 
          } else if (mode == zoom) { 
              float newdist = spacing(event); 
              //log.d(tag, "newdist=" + newdist); 
              if (newdist > 10f) { 
                  matrix.set(savedmatrix); 
                  float scale = newdist / olddist; 
                  matrix.postscale(scale, scale, mid.x, mid.y); 
              } 
          } 
          break; 
      } 

      view.setimagematrix(matrix); 
      return true; // indicate event was handled 
  } 

  private void dumpevent(motionevent event) { 
      string names[] = { "down", "up", "move", "cancel", "outside", 
              "pointer_down", "pointer_up", "7?", "8?", "9?" }; 
      stringbuilder sb = new stringbuilder(); 
      int action = event.getaction(); 
      int actioncode = action & motionevent.action_mask; 
      sb.append("event action_").append(names[actioncode]); 
      if (actioncode == motionevent.action_pointer_down 
              || actioncode == motionevent.action_pointer_up) { 
          sb.append("(pid ").append( 
                  action >> motionevent.action_pointer_id_shift); 
          sb.append(")"); 
      } 
      sb.append("["); 
      for (int i = 0; i < event.getpointercount(); i++) { 
          sb.append("#").append(i); 
          sb.append("(pid ").append(event.getpointerid(i)); 
          sb.append(")=").append((int) event.getx(i)); 
          sb.append(",").append((int) event.gety(i)); 
          if (i + 1 < event.getpointercount()) 
              sb.append(";"); 
      } 
      sb.append("]"); 
      //log.d(tag, sb.tostring()); 
  } 

  
  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); 
  } 


}

编写一个xml文件

<?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="fill_parent" 
    android:id="@+id/priviewimage" 
    android:layout_height="fill_parent" 
    android:layout_gravity="center" 
    android:scaletype="matrix" 
    > 
   </imageview> 
  </linearlayout> 

注意其中的: android:scaletype="matrix"

priviewimage.setimagebitmap(activitypreviewimage.click_bitmap); 
priviewimage=(imageview)findviewbyid(r.id.priviewimage); 
priviewimage.setontouchlistener(new mulitpointtouchlistener()); 

以上就是android手势控制缩放移动图片的全部代码，希望对大家的学习有所帮助。