imageloader+scaleimageview+viewpager结合异步加载图片的图片浏览功能

imageloader+scaleimageview+viewpager组合异步加载图片的图片浏览功能

       在qq空间或者微信朋友圈里  看到图片总会点击图片进行查看，图片放大缩小功能包括通过手势放大缩小旋转以及双击放大缩小，并且可以左右滑动看到前一张图片或者后一张图片，需要该功能的话，这篇文章或许可以给你帮助。

       众所周知，imageloader异步加载图片，不仅可以快速加载图片，而且还可以将图片保存到sdk缓存中，因此下载图片用imageloader即可，如有不懂的，可简单看下我的这篇文章http://blog.csdn.net/u012303938/article/details/46330123，scaleimageview网上流行的一个继续于imageview的封装可以放大缩小的view，viewpager是可以实现左右滑动v4jar包中的类。

       demo下载地址http://download.csdn.net/detail/u012303938/8764507

       本demo实现了一个简单的相册功能，点击相册，异步加载所有图片，点击图片查看，左右滑动上下张，可手势放大缩小查看的图片。

      上代码

       BaseAvtivity

       

package com.example.image;

import android.app.Activity;
import android.os.Bundle;
import android.view.Window;

public abstract class BaseActivity extends Activity{
	protected void onCreate(Bundle savedInstanceState,int layoutResID) {
		// TODO Auto-generated method stub
		super.onCreate(savedInstanceState);
		this.requestWindowFeature(Window.FEATURE_NO_TITLE);
		setContentView(layoutResID);
		findView();
		addListenr();
	}
 public abstract void findView();
 public abstract void addListenr();
}

   主要的mianactivti继承与baseactivity

   

package com.example.image;


import java.util.ArrayList;
import java.util.HashMap;
import java.util.Map;




import com.nostra13.universalimageloader.core.ImageLoader;

import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.view.View.OnClickListener;
import android.widget.AdapterView;
import android.widget.BaseAdapter;
import android.widget.Button;
import android.widget.GridView;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.AdapterView.OnItemClickListener;

public class MainActivity extends BaseActivity {
	private Button btn_dl,tv_left;
	private ListView lv;
	private Context context;
	private TextView tv_tt;
	private ArrayList<Map<String, Object>> list=new ArrayList<Map<String,Object>>();
	String[] imageUrls = new String[] {
			"http://file.bmob.cn/M00/D9/44/oYYBAFSGZlyAXZjwAAC5ynS9Zww4985471",
			"http://file.bmob.cn/M00/D8/8F/oYYBAFSFh_WAB_uIAAB4PTlS6rI0966668",};
@Override
protected void onCreate(Bundle savedInstanceState) {
	// TODO Auto-generated method stub
	super.onCreate(savedInstanceState,R.layout.activity_main);
	loadData();
}
	private void loadData() {
	// TODO Auto-generated method stub
		for(int i=0;i<imageUrls.length;i++){
			Map<String, Object> map=new HashMap<String, Object>();
			map.put("text", "我的相册"+i+"张");
			list.add(map);
		}
		MyAdapter adapter=new MyAdapter();
		lv.setAdapter(adapter);
		lv.setOnItemClickListener(new OnItemClickListener() {

			public void onItemClick(AdapterView<?> arg0, View arg1, int arg2,
					long arg3) {
				// TODO Auto-generated method stub
				startActivity(new Intent(context,PhotoGlDetail.class));
			}
		});
}
	@Override
	public void findView() {
		// TODO Auto-generated method stub
		context=this;
		lv=(ListView) findViewById(R.id.lv);
	}

	@Override
	public void addListenr() {
		// TODO Auto-generated method stub
		
	}
	 private class MyAdapter extends BaseAdapter{
	
	class HolderView {
		public ImageView imageView1;
		public TextView textView1;
	}
	
	public int getCount() {
		// TODO Auto-generated method stub
		return list.size();
	}

	public Object getItem(int arg0) {
		// TODO Auto-generated method stub
		return list.get(arg0);
	}

	public long getItemId(int arg0) {
		// TODO Auto-generated method stub
		return arg0;
	}

	public View getView(int position, View converView, ViewGroup arg2) {
		// TODO Auto-generated method stub
		HolderView holderView=null;
		if(converView==null){
			holderView=new HolderView();
			converView=View.inflate(context, R.layout.photo_item, null);
			holderView.textView1=(TextView) converView.findViewById(R.id.textView1);
			holderView.imageView1=(ImageView) converView.findViewById(R.id.imageView1);
			converView.setTag(holderView);
		}else{
			holderView=(HolderView) converView.getTag();
		}
		holderView.textView1.setText(list.get(position).get("text").toString());
		ImageLoader.getInstance().displayImage(imageUrls[position], holderView.imageView1);
		return converView;
	}
   }


}

Tapplication继承的application

  

package com.example.image;

import java.io.File;

import com.nostra13.universalimageloader.cache.disc.impl.UnlimitedDiscCache;
import com.nostra13.universalimageloader.core.DisplayImageOptions;
import com.nostra13.universalimageloader.core.ImageLoader;
import com.nostra13.universalimageloader.core.ImageLoaderConfiguration;
import com.nostra13.universalimageloader.core.assist.QueueProcessingType;
import com.nostra13.universalimageloader.core.display.RoundedBitmapDisplayer;
import com.nostra13.universalimageloader.utils.StorageUtils;

import android.app.Application;
import android.content.Context;

public class TAppliacation extends Application{
	@Override
	public void onCreate() {
		// TODO Auto-generated method stub
		super.onCreate();
		File cacheDir = StorageUtils.getOwnCacheDirectory(getApplicationContext(), "imageloader/Cache");
		
		DisplayImageOptions defaultOptions = new DisplayImageOptions
				.Builder()
		.showImageForEmptyUri(R.drawable.ic_empty) 
		.showImageOnFail(R.drawable.ic_error) 
		.cacheInMemory(true)
		.cacheOnDisc(true)
		.considerExifParams(true)
		.build();
		ImageLoaderConfiguration config = new ImageLoaderConfiguration
				.Builder(getApplicationContext())
		.discCache(new UnlimitedDiscCache(cacheDir))
		.defaultDisplayImageOptions(defaultOptions)
		.discCacheSize(50 * 1024 * 1024)//
		.discCacheFileCount(100)//
		.threadPriority(Thread.NORM_PRIORITY - 2)
		.denyCacheImageMultipleSizesInMemory()
		.tasksProcessingOrder(QueueProcessingType.LIFO)
		.writeDebugLogs()
		.build();
		ImageLoader.getInstance().init(config);
	}

	
}

   异步加载所有图片phtogldetail

   

package com.example.image;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.Map;

import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.BaseAdapter;
import android.widget.GridView;
import android.widget.ImageView;

import com.nostra13.universalimageloader.core.DisplayImageOptions;
import com.nostra13.universalimageloader.core.ImageLoader;
import com.nostra13.universalimageloader.core.display.RoundedBitmapDisplayer;

/*
 * @author CarrayDraw
 * @time 2015-6-1
 * 照片详细
 */
public class PhotoGlDetail extends BaseActivity{
	private ArrayList<Map<String, Object>> list=new ArrayList<Map<String,Object>>();
	private GridView gridView1;
	private Context context;
	private ArrayList<byte[]> lbyte=new ArrayList<byte[]>();
	DisplayImageOptions options;
	//private NormalLoadPictrue loadPictrue;
	public static String[] imageUrls = new String[] {
			"http://file.bmob.cn/M00/D8/8F/oYYBAFSFh_WAB_uIAAB4PTlS6rI0966668",
			"http://file.bmob.cn/M00/D7/56/oYYBAFSBhJSAIdIJAACoNxTDcM44444974",
			"http://file.bmob.cn/M00/D9/45/oYYBAFSGZvKAdpqWAACKHHYyClU0459660",
			"http://file.bmob.cn/M00/D9/45/oYYBAFSGZreAEyRSAADfcLFM62U5428980",
			"http://file.bmob.cn/M00/D9/44/oYYBAFSGZlyAXZjwAAC5ynS9Zww4985471",
			"http://file.bmob.cn/M00/D9/44/oYYBAFSGZYqAUYxAAADSNZMdbOs5036914",
			"http://file.bmob.cn/M00/D9/43/oYYBAFSGZRCATj2XAADDaZB1Nbo6433800",
			"http://file.bmob.cn/M00/D9/41/oYYBAFSGZJKAWXyDAADPOI8iH6Q3523485",
			"http://file.bmob.cn/M00/D8/8F/oYYBAFSFiE6AbAu2AACfguCRGHY3486277",
			"http://file.bmob.cn/M00/D7/57/oYYBAFSBhd-Aa1IiAAC86WAfmc89917549",
			"http://file.bmob.cn/M00/D7/55/oYYBAFSBgiKAC2aGAAC4We1hZmk1405980",
			"http://file.bmob.cn/M00/D7/56/oYYBAFSBgrmAXQ8BAAD665llCTc5545260",
			"http://file.bmob.cn/M00/D7/56/oYYBAFSBg-CAePQKAAC38mflwMY8903422"};
  @Override
protected void onCreate(Bundle savedInstanceState) {
	// TODO Auto-generated method stub
	super.onCreate(savedInstanceState,R.layout.photodetail);
	options = new DisplayImageOptions.Builder()
	.showImageOnLoading(R.drawable.ic_launcher)
	.showImageForEmptyUri(R.drawable.ic_empty)
	.showImageOnFail(R.drawable.ic_error).cacheInMemory(true)
	.cacheOnDisc(true).considerExifParams(true)
	.displayer(new RoundedBitmapDisplayer(20)).build();
	loadData();
}
	private void loadData() {
	// TODO Auto-generated method stub
	for(int i=0;i<imageUrls.length;i++){
		Map<String, Object> map=new HashMap<String, Object>();
		map.put("img", imageUrls[i]);
		list.add(map);
	}
	MyAdapter adapter=new MyAdapter();
	gridView1.setAdapter(adapter);
	gridView1.setOnItemClickListener(new OnItemClickListener() {

		@Override
		public void onItemClick(AdapterView<?> arg0, View arg1, int position,
				long arg3) {
			// TODO Auto-generated method stub
			Intent intent=new Intent(context,HeadPortrait.class);
			intent.putExtra("bitmap", lbyte);
			intent.putExtra("pos", position);
			startActivity(intent);
		}
	});
}
	@Override
	public void findView() {
		// TODO Auto-generated method stub
		context=this;
	//	loadPictrue=new NormalLoadPictrue();
		gridView1=(GridView) findViewById(R.id.gridView1);
		
		
	}

	
	 private class MyAdapter extends BaseAdapter{

	

			 
			class HolderView {
				public ImageView imageView1;
			}
			

			public int getCount() {
				// TODO Auto-generated method stub
				return list.size();
			}

			public Object getItem(int arg0) {
				// TODO Auto-generated method stub
				return list.get(arg0);
			}

			public long getItemId(int arg0) {
				// TODO Auto-generated method stub
				return arg0;
			}

			public View getView(final int position, View converView, ViewGroup arg2) {
				// TODO Auto-generated method stub
				HolderView holderView=null;
				if(converView==null){
					holderView=new HolderView();
					converView=View.inflate(context,R.layout.photodetail_item, null);
					holderView.imageView1=(ImageView) converView.findViewById(R.id.imageView1);
					converView.setTag(holderView);
				}else{
					holderView=(HolderView) converView.getTag();
				}
				//loadPictrue.getPicture(imageUrls[position], holderView.imageView1);
				ImageLoader.getInstance().displayImage(imageUrls[position], holderView.imageView1,options);
				
				

				
				return converView;
			}
		   }


	@Override
	public void addListenr() {
		// TODO Auto-generated method stub
		
	}
}

     查看图片的类   headportrail

   

package com.example.image;


import java.io.File;
import java.util.ArrayList;

import com.nostra13.universalimageloader.cache.disc.DiscCacheAware;
import com.nostra13.universalimageloader.core.ImageLoader;
import com.nostra13.universalimageloader.core.assist.DiscCacheUtil;

import android.app.Activity;
import android.content.Intent;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Bundle;
import android.os.Environment;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.view.PagerAdapter;
import android.support.v4.view.ViewPager;
import android.support.v4.view.ViewPager.OnPageChangeListener;
import android.util.Log;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.TextView;
/*
 * @author CrrayDraw
 * @time 2015-6-1
 * 查看图片
 */
public class HeadPortrait extends Activity implements OnPageChangeListener{
	
	private ViewPager viewPager;
	private TextView textView;
	
@Override
protected void onCreate(Bundle savedInstanceState) {
	// TODO Auto-generated method stub
	super.onCreate(savedInstanceState);
	setContentView(R.layout.aaa);
	textView=(TextView) findViewById(R.id.textView);
	viewPager=(ViewPager) findViewById(R.id.viewPager);
	Intent intent = getIntent();
	if (intent != null)
	{
		
		int  currentPos=intent.getIntExtra("pos", 0);
		MyAdapter adapter=new MyAdapter();
		viewPager.setAdapter(adapter);
		viewPager.setCurrentItem(currentPos);
		viewPager.setEnabled(false);
		viewPager.setOnPageChangeListener(this);
		textView.setText(currentPos+"/"+PhotoGlDetail.imageUrls.length);
		
	}
	
	
}
   class MyAdapter extends PagerAdapter{

	@Override
	public int getCount() {
		// TODO Auto-generated method stub
		return PhotoGlDetail.imageUrls.length;
	}

	@Override
	public void destroyItem(ViewGroup container, int position, Object object) {
		// TODO Auto-generated method stub
		View view=(View) object;
		container.removeView(view);
	}

	@Override
	public Object instantiateItem(ViewGroup container, int position) {
		// TODO Auto-generated method stub
		Bitmap bitmap =null;
		File file=DiscCacheUtil.findInCache(PhotoGlDetail.imageUrls[position], ImageLoader.getInstance().getDiscCache() );
		if(file.exists()){
			bitmap= BitmapFactory.decodeFile(file.getPath());
		}
		if(bitmap==null){
			Log.i("values", "i:"+position);
			bitmap=BitmapFactory.decodeResource(getResources(), R.drawable.ic_empty);
		}
		Log.i("values", "iiiii:"+position);
		View view=View.inflate(HeadPortrait.this, R.layout.img_frag, null);
		ScaleImageView imageView=(ScaleImageView) view.findViewById(R.id.img);
		imageView.setImageBitmap(bitmap);
		container.addView(imageView);
		return view;
	}

	@Override
	public boolean isViewFromObject(View agr0, Object arg1) {
		// TODO Auto-generated method stub
	
		return agr0==arg1;
	}


	   
   }
public void onPageScrollStateChanged(int arg0) {
	// TODO Auto-generated method stub
	
}
public void onPageScrolled(int arg0, float arg1, int arg2) {
	// TODO Auto-generated method stub
	
}
public void onPageSelected(int currentPos) {
	// TODO Auto-generated method stub
	textView.setText((currentPos+1)+"/"+PhotoGlDetail.imageUrls.length);
}
public String getpaths(String url){
	String urlPath=url.substring(url.indexOf("/")+1);
	
	
	
	return url;
	
}
}

      网上流行的scaleimageview

   

package com.example.image;




import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Matrix;
import android.graphics.PointF;
import android.graphics.RectF;
import android.graphics.drawable.Drawable;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.widget.ImageView;

/**
 * 来自网络：图片缩放控件（支持缩放、拖动双击旋转）<br>
 * 
 * @author kymjs (https://github.com/kymjs)
 */
public class ScaleImageView extends ImageView {

    public enum ImageState {
        NONE, // 初始状
        DRAG, // 拖动
        ZOOM, // 缩放
        ROTATE, // 旋转
        ZOOM_OR_ROTATE // 缩放或旋
    }

    private ImageState mode = ImageState.NONE;

    static final float MAX_SCALE = 2.5f;

    private float imageW; // 图片宽度
    private float imageH; // 图片高度
    private float rotatedImageW;
    private float rotatedImageH;
    private float viewW;
    private float viewH;

    private final Matrix matrix = new Matrix();
    private final Matrix savedMatrix = new Matrix();

    private final PointF pA = new PointF();
    private final PointF pB = new PointF();
    private final PointF mid = new PointF();
    private final PointF lastClickPos = new PointF();

    private long lastClickTime = 0; // 上次点击时间（用于计算双击）
    private double rotation = 0.0;
    private float dist = 1f; // 两点间距

    private boolean canRotate = true; // 是否启旋转图片功
    private boolean canDoubleClick = true; // 是否启双击缩放功

    public void setCanDoubleClick(boolean canDoubleClick) {
        this.canDoubleClick = canDoubleClick;
    }

    public boolean canDoubleClick() {
        return canDoubleClick;
    }

    public void setCanRotate(boolean canRotate) {
        this.canRotate = canRotate;
    }

    public boolean canRotate() {
        return canRotate;
    }

    public ScaleImageView(Context context) {
        super(context);
        initView();
    }

    public ScaleImageView(Context context, AttributeSet attrs) {
        super(context, attrs);
        initView();
    }

    public ScaleImageView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        initView();
    }

    /**
     * 初始化控
     */
    private void initView() {
        setScaleType(ImageView.ScaleType.MATRIX);
    }

    @Override
    public void setImageBitmap(Bitmap bm) {
        super.setImageBitmap(bm);
        setImageWidthHeight();
    }

    @Override
    public void setImageDrawable(Drawable drawable) {
        super.setImageDrawable(drawable);
        setImageWidthHeight();
    }

    @Override
    public void setImageResource(int resId) {
        super.setImageResource(resId);
        setImageWidthHeight();
    }

    private void setImageWidthHeight() {
        Drawable d = getDrawable();
        if (d == null) {
            return;
        }
        imageW = rotatedImageW = d.getIntrinsicWidth();
        imageH = rotatedImageH = d.getIntrinsicHeight();
        initImage();
    }

    /**
     * 图片大小改变时回
     */
    @Override
    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
        super.onSizeChanged(w, h, oldw, oldh);
        viewW = w;
        viewH = h;
        if (oldw == 0) { // 如果图片还没有计算大
            initImage();
        } else {
            fixScale(); // 固定大小
            fixTranslation();
            setImageMatrix(matrix);
        }
    }

    /**
     * 首次加载，初始化图片控件
     */
    private void initImage() {
        if (viewW <= 0 || viewH <= 0 || imageW <= 0 || imageH <= 0) {
            return;
        }
        mode = ImageState.NONE;
        matrix.setScale(0, 0);
        fixScale();
        fixTranslation();
        setImageMatrix(matrix);
    }

    /**
     * 设置matrix，记录当前图片大
     */
    private void fixScale() {
        float p[] = new float[9];
        matrix.getValues(p);
        float curScale = Math.abs(p[0]) + Math.abs(p[1]);
        float minScale = Math.min(viewW / rotatedImageW, viewH / rotatedImageH);
        if (curScale < minScale) {
            if (curScale > 0) {
                double scale = minScale / curScale;
                p[0] = (float) (p[0] * scale);
                p[1] = (float) (p[1] * scale);
                p[3] = (float) (p[3] * scale);
                p[4] = (float) (p[4] * scale);
                matrix.setValues(p);
            } else {
                matrix.setScale(minScale, minScale);
            }
        }
    }

    /**
     * 大缩放
     */
    private float maxPostScale() {
        float p[] = new float[9];
        matrix.getValues(p);
        float curScale = Math.abs(p[0]) + Math.abs(p[1]);

        float minScale = Math.min(viewW / rotatedImageW, viewH / rotatedImageH);
        float maxScale = Math.max(minScale, MAX_SCALE);
        return maxScale / curScale;
    }

    /**
     * 移动matrix
     */
    private void fixTranslation() {
        RectF rect = new RectF(0, 0, imageW, imageH);
        matrix.mapRect(rect);

        float height = rect.height();
        float width = rect.width();

        float deltaX = 0, deltaY = 0;

        if (width < viewW) {
            deltaX = (viewW - width) / 2 - rect.left;
        } else if (rect.left > 0) {
            deltaX = -rect.left;
        } else if (rect.right < viewW) {
            deltaX = viewW - rect.right;
        }

        if (height < viewH) {
            deltaY = (viewH - height) / 2 - rect.top;
        } else if (rect.top > 0) {
            deltaY = -rect.top;
        } else if (rect.bottom < viewH) {
            deltaY = viewH - rect.bottom;
        }
        matrix.postTranslate(deltaX, deltaY);
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        switch (event.getAction() & MotionEvent.ACTION_MASK) {
        // 主点按下 ：记录当前matrix，以及初始化按下坐标、图片状
        case MotionEvent.ACTION_DOWN:
            savedMatrix.set(matrix);
            pA.set(event.getX(), event.getY());
            pB.set(event.getX(), event.getY());
            mode = ImageState.DRAG;
            break;
        // 副点按下 ：如果间距大10，记录此时matrix，以及两点的坐标、图片状
        case MotionEvent.ACTION_POINTER_DOWN:
            if (event.getActionIndex() > 1) // 超过两个点返
                break;
            dist = spacing(event.getX(0), event.getY(0), event.getX(1),
                    event.getY(1));
            if (dist > 10f) { // 如果连续两点距离大于10，则判定为多点模
                savedMatrix.set(matrix);
                pA.set(event.getX(0), event.getY(0));
                pB.set(event.getX(1), event.getY(1));
                mid.set((event.getX(0) + event.getX(1)) / 2,
                        (event.getY(0) + event.getY(1)) / 2);
                mode = ImageState.ZOOM_OR_ROTATE;
            }
            break;

        // 主点或负点抬
        case MotionEvent.ACTION_UP:
        case MotionEvent.ACTION_POINTER_UP:
            if (mode == ImageState.DRAG) {
                if (spacing(pA.x, pA.y, pB.x, pB.y) < 50) {
                    long now = System.currentTimeMillis();
                    if (now - lastClickTime < 500
                            && spacing(pA.x, pA.y, lastClickPos.x,
                                    lastClickPos.y) < 50) {
                        doubleClick(pA.x, pA.y);
                        now = 0;
                    }
                    lastClickPos.set(pA);
                    lastClickTime = now;
                }
            } else if (mode == ImageState.ROTATE) {
                int level = (int) Math.floor((rotation + Math.PI / 4)
                        / (Math.PI / 2));
                if (level == 4)
                    level = 0;
                matrix.set(savedMatrix);
                matrix.postRotate(90 * level, mid.x, mid.y);
                if (level == 1 || level == 3) {
                    float tmp = rotatedImageW;
                    rotatedImageW = rotatedImageH;
                    rotatedImageH = tmp;
                    fixScale();
                }
                fixTranslation();
                setImageMatrix(matrix);
            }
            mode = ImageState.NONE;
            break;

        // 拖动
        case MotionEvent.ACTION_MOVE:
            if (mode == ImageState.ZOOM_OR_ROTATE) {
                PointF pC = new PointF(event.getX(1) - event.getX(0) + pA.x,
                        event.getY(1) - event.getY(0) + pA.y);
                double a = spacing(pB.x, pB.y, pC.x, pC.y);
                double b = spacing(pA.x, pA.y, pC.x, pC.y);
                double c = spacing(pA.x, pA.y, pB.x, pB.y);
                if (a >= 10) {
                    double cosB = (a * a + c * c - b * b) / (2 * a * c);
                    double angleB = Math.acos(cosB);
                    double PID4 = Math.PI / 4;
                    if (angleB > PID4 && angleB < 3 * PID4) {
                        mode = ImageState.ROTATE;
                        rotation = 0;
                    } else {
                        mode = ImageState.ZOOM;
                    }
                }
            }

            if (mode == ImageState.DRAG) {
                matrix.set(savedMatrix);
                pB.set(event.getX(), event.getY());
                matrix.postTranslate(event.getX() - pA.x, event.getY() - pA.y);
                fixTranslation();
                setImageMatrix(matrix);
            } else if (mode == ImageState.ZOOM) {
                float newDist = spacing(event.getX(0), event.getY(0),
                        event.getX(1), event.getY(1));
                if (newDist > 10f) {
                    matrix.set(savedMatrix);
                    float tScale = Math.min(newDist / dist, maxPostScale());
                    matrix.postScale(tScale, tScale, mid.x, mid.y);
                    fixScale();
                    fixTranslation();
                    setImageMatrix(matrix);
                }
            } else if (mode == ImageState.ROTATE) {
                if (canRotate) {
                    PointF pC = new PointF(
                            event.getX(1) - event.getX(0) + pA.x, event.getY(1)
                                    - event.getY(0) + pA.y);
                    double a = spacing(pB.x, pB.y, pC.x, pC.y);
                    double b = spacing(pA.x, pA.y, pC.x, pC.y);
                    double c = spacing(pA.x, pA.y, pB.x, pB.y);
                    if (b > 10) {
                        double cosA = (b * b + c * c - a * a) / (2 * b * c);
                        double angleA = Math.acos(cosA);
                        double ta = pB.y - pA.y;
                        double tb = pA.x - pB.x;
                        double tc = pB.x * pA.y - pA.x * pB.y;
                        double td = ta * pC.x + tb * pC.y + tc;
                        if (td > 0) {
                            angleA = 2 * Math.PI - angleA;
                        }
                        rotation = angleA;
                        matrix.set(savedMatrix);
                        matrix.postRotate((float) (rotation * 180 / Math.PI),
                                mid.x, mid.y);
                        setImageMatrix(matrix);
                    }
                }
            }
            break;
        }
        return true;
    }

    /**
     * 两点的距
     */
    private float spacing(float x1, float y1, float x2, float y2) {
        float x = x1 - x2;
        float y = y1 - y2;
        return (float) Math.sqrt(x * x + y * y);
    }

    /**
     * 双击时调
     */
    private void doubleClick(float x, float y) {
        if (canDoubleClick) {
            float p[] = new float[9];
            matrix.getValues(p);
            float curScale = Math.abs(p[0]) + Math.abs(p[1]);

            float minScale = Math.min(viewW / rotatedImageW, viewH
                    / rotatedImageH);
            if (curScale <= minScale + 0.01) { // 放大
                float toScale = Math.max(minScale, MAX_SCALE) / curScale;
                matrix.postScale(toScale, toScale, x, y);
            } else { // 缩小
                float toScale = minScale / curScale;
                matrix.postScale(toScale, toScale, x, y);
                fixTranslation();
            }
            setImageMatrix(matrix);
        }
    }
}