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。