基于Android 实现图片平移、缩放、旋转同时进行

前言

之前因为项目需求，其中使用到了图片的单击显示取消，图片平移缩放功能，昨天突然想再加上图片的旋转功能，在网上看了很多相关的例子，可是没看到能同时实现我想要的功能的。

需求：

（1）图片平移、缩放、旋转等一系列操作后，图片需要自动居中显示。

（2）图片旋转后选自动水平显示或者垂直显示

（3）图片在放大缩小的同时都能旋转

demo实现部分效果截图

demo主要代码

java

mainactivity.java
package com.practice.noyet.rotatezoomimageview;
import android.app.activity;
import android.graphics.bitmap;
import android.graphics.bitmapfactory;
import android.graphics.matrix;
import android.graphics.pointf;
import android.graphics.rectf;
import android.os.asynctask;
import android.os.bundle;
import android.util.displaymetrics;
import android.view.motionevent;
import android.view.view;
import android.widget.imageview;
import com.ypy.eventbus.eventbus;
import java.io.file;
import java.math.bigdecimal;
/**
* package: com.practice.noyet.rotatezoomimageview
* created by noyet on 2015/11/11.
*/
public class mainactivity extends activity implements view.ontouchlistener {
  private imageview mimageview;
  private pointf point0 = new pointf();
  private pointf pointm = new pointf();
  private final int none = 0;
  /**
   * 平移
   */
  private final int drag = 1;
  /**
   * 旋转、缩放
   */
  private final int zoom = 2;
  /**
   * 设定事件模式
   */
  private int mode = none;
  /**
   * 图片缩放矩阵
   */
  private matrix matrix = new matrix();
  /**
   * 保存触摸前的图片缩放矩阵
   */
  private matrix savedmatrix = new matrix();
  /**
   * 保存触点移动过程中的图片缩放矩阵
   */
  private matrix matrix1 = new matrix();
  /**
   * 屏幕高度
   */
  private int displayheight;
  /**
   * 屏幕宽度
   */
  private int displaywidth;
  /**
   * 最小缩放比例
   */
  protected float minscale = 1f;
  /**
   * 最大缩放比例
   */
  protected float maxscale = 3f;
  /**
   * 当前缩放比例
   */
  protected float currentscale = 1f;
  /**
   * 多点触摸2个触摸点间的起始距离
   */
  private float olddist;
  /**
   * 多点触摸时图片的起始角度
   */
  private float oldrotation = 0;
  /**
   * 旋转角度
   */
  protected float rotation = 0;
  /**
   * 图片初始宽度
   */
  private int imgwidth;
  /**
   * 图片初始高度
   */
  private int imgheight;
  /**
   * 设置单点触摸退出图片显示时，单点触摸的灵敏度（可针对不同手机单独设置）
   */
  protected final int move_max = 2;
  /**
   * 单点触摸时手指触发的‘motionevent.action_move'次数
   */
  private int fingernummove = 0;
  private bitmap bm;
  /**
   * 保存matrix缩放比例
   */
  private float matrixscale= 1;
  /*private string imagepath;*/
  /**
   * 显示被存入缓存中的网络图片
   *
   * @param event 观察者事件
   */
  public void oneventmainthread(customeventbus event) {
    if (event == null) {
      return;
    }
    if (event.type == customeventbus.eventtype.show_picture) {
      bm = (bitmap) event.obj;
      showimage();
    }
  }
  @override
  protected void oncreate(bundle savedinstancestate) {
    super.oncreate(savedinstancestate);
    setcontentview(r.layout.activity_main);
    initdata();
  }
  public void initdata() {
    // todo auto-generated method stub
    bm = bitmapfactory.decoderesource(getresources(), r.drawable.alipay);
    displaymetrics dm = getresources().getdisplaymetrics();
    displaywidth = dm.widthpixels;
    displayheight = dm.heightpixels;
    mimageview = (imageview) findviewbyid(r.id.image_view);
    mimageview.setontouchlistener(this);
    showimage();
    //显示网络图片时使用
    /*file file = mainapplication.getinstance().getimagecache()
        .getdiskcache().get(图片路径);
    if (!file.exists()) {
      toast.maketext(this, "图片路径错误", toast.length_short).show();
    } else {
      new mytask().execute(file);
    }*/
  }
  @override
  public boolean ontouch(view view, motionevent event) {
    imageview imageview = (imageview) view;
    switch (event.getaction() & motionevent.action_mask) {
      case motionevent.action_down:
        savedmatrix.set(matrix);
        point0.set(event.getx(), event.gety());
        mode = drag;
        system.out.println("motionevent--action_down");
        break;
      case motionevent.action_pointer_down:
        olddist = spacing(event);
        oldrotation = rotation(event);
        savedmatrix.set(matrix);
        setmidpoint(pointm, event);
        mode = zoom;
        system.out.println("motionevent--action_pointer_down---" + oldrotation);
        break;
      case motionevent.action_up:
        if (mode == drag & (fingernummove this.finish();
        }
        checkview();
        centerandrotate();
        imageview.setimagematrix(matrix);
        system.out.println("motionevent--action_up");
        fingernummove = 0;
        break;
      case motionevent.action_pointer_up:
        mode = none;
        system.out.println("motionevent--action_pointer_up");
        break;
      case motionevent.action_move:
        operatemove(event);
        imageview.setimagematrix(matrix1);
        fingernummove++;
        system.out.println("motionevent--action_move");
        break;
    }
    return true;
  }
  @override
  protected void ondestroy() {
    // todo auto-generated method stub
    super.ondestroy();
    if (bm != null & !bm.isrecycled()) {
      bm.recycle(); // 回收图片所占的内存
      system.gc(); // 提醒系统及时回收
    }
  }
  /**
   * 显示图片
   */
  private void showimage() {
    imgwidth = bm.getwidth();
    imgheight = bm.getheight();
    mimageview.setimagebitmap(bm);
    matrix.setscale(1, 1);
    centerandrotate();
    mimageview.setimagematrix(matrix);
  }
  /**
   * 触点移动时的操作
   *
   * @param event 触摸事件
   */
  private void operatemove(motionevent event) {
    matrix1.set(savedmatrix);
    switch (mode) {
      case drag:
        matrix1.posttranslate(event.getx() - point0.x, event.gety() - point0.y);
        break;
      case zoom:
        rotation = rotation(event) - oldrotation;
        float newdist = spacing(event);
        float scale = newdist / olddist;
        currentscale = (scale > 3.5f) ? 3.5f : scale;
        system.out.println("缩放倍数---" + currentscale);
        system.out.println("旋转角度---" + rotation);
        /** 縮放 */
        matrix1.postscale(currentscale, currentscale, pointm.x, pointm.y);
        /** 旋轉 */
        matrix1.postrotate(rotation, displaywidth / 2, displayheight / 2);
        break;
    }
  }
  /**
   * 两个触点的距离
   *
   * @param event 触摸事件
   * @return float
   */
  private float spacing(motionevent event) {
    float x = event.getx(0) - event.getx(1);
    float y = event.gety(0) - event.gety(1);
    return (float) math.sqrt(x * x + y * y);
  }
  /**
   * 获取旋转角度
   */
  private float rotation(motionevent event) {
    double delta_x = (event.getx(0) - event.getx(1));
    double delta_y = (event.gety(0) - event.gety(1));
    double radians = math.atan2(delta_y, delta_x);
    return (float) math.todegrees(radians);
  }
  /**
   * 两个触点的中间坐标
   *
   * @param pointm 中间坐标
   * @param event 触摸事件
   */
  private void setmidpoint(pointf pointm, motionevent event) {
    float x = event.getx(0) + event.gety(1);
    float y = event.gety(0) + event.gety(1);
    pointm.set(x / 2, y / 2);
  }
  /**
   * 检查约束条件(缩放倍数)
   */
  private void checkview() {
    if (currentscale > 1) {
      if (currentscale * matrixscale > maxscale) {
        matrix.postscale(maxscale / matrixscale, maxscale / matrixscale, pointm.x, pointm.y);
        matrixscale = maxscale;
      } else {
        matrix.postscale(currentscale, currentscale, pointm.x, pointm.y);
        matrixscale *= currentscale;
      }
    } else {
      if (currentscale * matrixscale else {
        matrix.postscale(currentscale, currentscale, pointm.x, pointm.y);
        matrixscale *= currentscale;
      }
    }
  }
  /**
   * 图片居中显示、判断旋转角度 小于（90 * x + 45）度图片旋转（90 * x）度 大于则旋转（90 * (x+1)）
   */
  private void centerandrotate() {
    rectf rect = new rectf(0, 0, imgwidth, imgheight);
    matrix.maprect(rect);
    float width = rect.width();
    float height = rect.height();
    float dx = 0;
    float dy = 0;
    if (width 2 - width / 2 - rect.left;
    } else if (rect.left > 0) {
      dx = -rect.left;
    } else if (rect.right if (height 2 - height / 2 - rect.top;
    } else if (rect.top > 0) {
      dy = -rect.top;
    } else if (rect.bottom if (rotation != 0) {
      int rotationnum = (int) (rotation / 90);
      float rotationavai = new bigdecimal(rotation % 90).setscale(1, bigdecimal.round_half_up).floatvalue();
      float realrotation = 0;
      if (rotation > 0) {
        realrotation = rotationavai > 45 ? (rotationnum + 1) * 90 : rotationnum * 90;
      } else if (rotation 0) {
        realrotation = rotationavai 45 ? (rotationnum - 1) * 90 : rotationnum * 90;
      }
      system.out.println("realrotation: " + realrotation);
      matrix.postrotate(realrotation, displaywidth / 2, displayheight / 2);
      rotation = 0;
    }
  }
  /**
   * 显示网络图片时使用
   */
  private class mytask extends asynctaskfile, file, bitmap> {
    bitmap bitmap;
    string path;
    int scale = 1;
    long size;
    @override
    protected bitmap doinbackground(file... params) {
      // todo auto-generated method stub
      try {
        size = params[0].length();
        path = params[0].getabsolutepath();
        bitmapfactory.options options = new bitmapfactory.options();
        options.injustdecodebounds = true;
        bitmapfactory.decodefile(path, options);
        scale = calculateinsamplesize(options, displaywidth,
            displayheight);
        options.injustdecodebounds = false;
        options.insamplesize = scale;
        bitmap = bitmapfactory.decodefile(path, options);
      } catch (exception e) {
        // todo auto-generated catch block
        e.printstacktrace();
      }
      return bitmap;
    }
    @override
    protected void onpostexecute(bitmap result) {
      // todo auto-generated method stub
      eventbus.getdefault().post(
          new customeventbus(customeventbus.eventtype.show_picture, result));
    }
    /**
     * 获取图片缩放比例
     *
     * @param paramoptions options
     * @param paramint1  宽
     * @param paramint2  高
     * @return int
     */
    private int calculateinsamplesize(bitmapfactory.options paramoptions,
                     int paramint1, int paramint2) {
      int i = paramoptions.outheight;
      int j = paramoptions.outwidth;
      int k = 1;
      if ((i > paramint2) || (j > paramint1)) {
        int m = math.round(i / paramint2);
        int n = math.round(j / paramint1);
        k = m return k;
    }
  }
}
customeventbus.java
package com.practice.noyet.rotatezoomimageview;
/**
* package: com.practice.noyet.rotatezoomimageview
* created by noyet on 2015/11/11.
*/
public class customeventbus {
  public eventtype type;
  public object obj;
  public customeventbus(eventtype type, object obj) {
    this.type = type;
    this.obj = obj;
  }
  enum eventtype {
    show_picture
  }
}