Android 手势滑动，多点触摸放大缩小图片

效果展示:

基本思路：

     <1>首先写一个图片控制类ImageControl，实现对图片控制的的基本操作，我们的图片控制类ImageControl是继承自ImageView自定义的视图；

     <2>再写一个测试用的布局，这里就要用到自定义的ImageView;

     <3>编写测试类ImageViewActivity，写onTouchEvent（）方法；

图片控制类ImageControl:

package com.basecontrol.view;

import android.content.Context; 
import android.graphics.Bitmap; 
import android.graphics.Matrix; 
import android.util.AttributeSet; 
import android.util.FloatMath; 
import android.view.MotionEvent; 
import android.widget.ImageView;

public class ImageControl extends ImageView {

    public ImageControl(Context context) { 
        super(context); 
    } 
    public ImageControl(Context context, AttributeSet attrs) { 
        super(context, attrs); 
    } 
    public ImageControl(Context context, AttributeSet attrs, int defStyle) { 
        super(context, attrs, defStyle); 
    } 
    
    Matrix imgMatrix=null;//定义图片的变换矩阵 
    
    static final int DOUBLE_CLICK_TIME_SPACE=300;//双击时间间隔 
    static final int DOUBLE_POINT_DISTANCE =10;// 两点放大两点间最小间距  
    static final int NONE = 0; 
    private int mode=NONE;//当前模式 
    static final int DRAG=1; 
    static final int ZOOM = 2; // 放大缩小操作  
    
    float bigScale=3f;//默认放大倍数 
    Boolean isBig=false;//是否放大 
    long lastClickTime =0;//单击时间 
    float startDistance;//两点触摸两点距离 
    float endDistance;//多点触摸两点距离 
    
    float topHeight;//状态栏高度和标题栏高度 
    Bitmap primaryBitmap=null; 
    
    float contentW;//屏幕内容区宽度 
    float contentH;//屏幕内容区高度 
    
    float primaryW;//原图宽度 
    float primaryH;//原图高度 
    
    float scale; // 适合屏幕缩放倍数  
    Boolean isMoveX = true; // 是否允许在X轴拖动  
    Boolean isMoveY = true; // 是否允许在Y轴拖动  
    float startX;  
    float startY;  
    float endX;  
    float endY;  
    float subX;  
    float subY;  
    float limitX1;  
    float limitX2;  
    float limitY1;  
    float limitY2;  
    ICustomMethod mCustomMethod=null; 
    /** 
     * @param bitmap 要显示的图片 
     * @param contentW 内容区域宽度 
     * @param contentH 内容区域高度 
     * @param topHeight 状态栏高度和标题栏高度之和 
     * @param iCustomMethod 
     */ 
    public void imageInit(Bitmap bitmap,int contentW,int contentH,int topHeight,ICustomMethod iCustomMethod) 
    { 
        this.primaryBitmap=bitmap; 
        this.contentW=contentH; 
        this.contentH=contentH; 
        this.topHeight=topHeight; 
        mCustomMethod=iCustomMethod; 
        primaryW=primaryBitmap.getWidth(); 
        primaryH=primaryBitmap.getHeight(); 
        float scaleX=(float)contentW/primaryW; 
        float scaleY=(float)contentH/primaryH; 
        scale=scaleX<scaleY?scaleX:scaleY; 
        if (scale<1&&1/scale<bigScale) 
        { 
            bigScale=(float)(1/scale+0.5); 
        } 
        
        imgMatrix=new Matrix(); 
        subX = (contentW-primaryW*scale)/2; 
        subY=(contentH-primaryH*scale)/2; 
        this.setImageBitmap(primaryBitmap); 
        this.setScaleType(ScaleType.MATRIX); 
        imgMatrix.postScale(scale, scale); 
        imgMatrix.postTranslate(subX,subY); 
        this.setImageMatrix(imgMatrix); 
    } 
    /** 
     * 按下操作 
     * @param event 
     */ 
    public void mouseDown(MotionEvent event) 
    { 
        mode=NONE; 
        startX=event.getRawX(); 
        startY=event.getRawY(); 
        if (event.getPointerCount()==1) 
        { 
            //如果两次时间间隔小于一定值，则默认为双击事件 
            if (event.getEventTime()-lastClickTime<DOUBLE_CLICK_TIME_SPACE) 
            { 
                changeSize(startX,startY); 
            } 
            else if (isBig) 
            { 
                mode=DRAG; 
            } 
        } 
        lastClickTime=event.getEventTime(); 
    } 
    /** 
     * 非第一个点按下操作 
     * @param event 
     */ 
    public void mousePointDown(MotionEvent event) 
    { 
        startDistance=getDistance(event); 
        if (startDistance > DOUBLE_POINT_DISTANCE) {  
            mode = ZOOM;  
        } else {  
            mode = NONE;  
        }  
    } 
     public void mouseMove(MotionEvent event) 
     {  
        if ((mode == DRAG) && (isMoveX || isMoveY)) {  
            float[] XY = getTranslateXY(imgMatrix);  
            float transX = 0;  
            float transY = 0;  
            if (isMoveX) {  
                endX = event.getRawX();  
                transX = endX - startX;  
                if ((XY[0] + transX) <= limitX1) {  
                    transX = limitX1 - XY[0];  
                }  
                if ((XY[0] + transX) >= limitX2) {  
                    transX = limitX2 - XY[0];  
                }  
            }  
            if (isMoveY) {  
                endY = event.getRawY();  
                transY = endY - startY;  
                if ((XY[1] + transY) <= limitY1) {  
                    transY = limitY1 - XY[1];  
                }  
                if ((XY[1] + transY) >= limitY2) {  
                    transY = limitY2 - XY[1];  
                }  
            }  
  
            imgMatrix.postTranslate(transX, transY);  
            startX = endX;  
            startY = endY;  
            this.setImageMatrix(imgMatrix);  
        } else if (mode == ZOOM && event.getPointerCount() > 1) {  
            endDistance = getDistance(event);  
            float dif = endDistance - startDistance;  
            if (Math.abs(endDistance - startDistance) > DOUBLE_POINT_DISTANCE) {  
                if (isBig) {  
                    if (dif < 0) {  
                        changeSize(0, 0);  
                        mode = NONE;  
                    }  
                } else if (dif > 0) {  
                    float x = event.getX(0) / 2 + event.getX(1) / 2;  
                    float y = event.getY(0) / 2 + event.getY(1) / 2;  
                    changeSize(x, y);  
                    mode = NONE;  
                }  
            }  
        }  
    } 
     /** 
      * 鼠标抬起事件 
      */ 
    public void mouseUp() 
    {  
        mode = NONE;  
    }  
    private void changeSize(float x, float y) {  
        if (isBig) {  
            // 如果处于最大状态，则还原  
            imgMatrix.reset();  
            imgMatrix.postScale(scale, scale);  
            imgMatrix.postTranslate(subX, subY);  
            isBig = false;  
        } else {  
            imgMatrix.postScale(bigScale, bigScale); // 在原有矩阵后乘放大倍数  
            float transX = -((bigScale - 1) * x);  
            float transY = -((bigScale - 1) * (y - topHeight)); // (bigScale-1)(y-statusBarHeight-subY)+2*subY;  
            float currentWidth = primaryW * scale * bigScale; // 放大后图片大小  
            float currentHeight = primaryH * scale * bigScale;  
            // 如果图片放大后超出屏幕范围处理  
            if (currentHeight > contentH) {  
                limitY1 = -(currentHeight - contentH); // 平移限制  
                limitY2 = 0;  
                isMoveY = true; // 允许在Y轴上拖动  
                float currentSubY = bigScale * subY; // 当前平移距离  
                // 平移后，内容区域上部有空白处理办法  
                if (-transY < currentSubY) {  
                    transY = -currentSubY;  
                }  
                // 平移后，内容区域下部有空白处理办法  
                if (currentSubY + transY < limitY1) {  
                    transY = -(currentHeight + currentSubY - contentH);  
                }  
            } else {  
                // 如果图片放大后没有超出屏幕范围处理，则不允许拖动  
                isMoveY = false;  
            }  
  
            if (currentWidth > contentW) {  
                limitX1 = -(currentWidth - contentW);  
                limitX2 = 0;  
                isMoveX = true;  
                float currentSubX = bigScale * subX;  
                if (-transX < currentSubX) {  
                    transX = -currentSubX;  
                }  
                if (currentSubX + transX < limitX1) {  
                    transX = -(currentWidth + currentSubX - contentW);  
                }  
            } else {  
                isMoveX = false;  
            }  
  
            imgMatrix.postTranslate(transX, transY);  
            isBig = true;  
        }  
  
        this.setImageMatrix(imgMatrix);  
        if (mCustomMethod != null) {  
            mCustomMethod.customMethod(isBig);  
        }  
    }  
    /** 
     * 获取变换矩阵中X轴偏移量和Y轴偏移量 
     * @param matrix 
     * @return 
     */ 
    private float[] getTranslateXY(Matrix matrix) 
    {  
        float[] values = new float[9];  
        matrix.getValues(values);  
        float[] floats = new float[2];  
        floats[0] = values[Matrix.MTRANS_X];  
        floats[1] = values[Matrix.MTRANS_Y];  
        return floats;  
    } 
    /** 
     * 获取两点间距离 
     * @param event 
     * @return 
     */ 
    private float getDistance(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);  
    }  
    /** 
     * 用户自定义方法 
     * @author AILALA 
     */ 
    public interface ICustomMethod 
    { 
        public void customMethod(Boolean currentStatus); 
    } 
}

测试布局：

<?xml version="1.0" encoding="utf-8"?> 
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent" > 
    
    <com.basecontrol.view.ImageControl 
        android:id="@+id/common_imageview_imageControll" 
        android:layout_width="fill_parent" 
        android:layout_height="fill_parent" 
        android:src="@drawable/ic_launcher"/>

    <LinearLayout 
        android:id="@+id/common_iamgeview_llTitle" 
        android:layout_width="wrap_content" 
        android:layout_height="wrap_content" 
        android:layout_alignParentLeft="true" 
        android:layout_alignParentTop="true" > 
  
        <TextView 
            android:id="@+id/common_imageview_title" 
            android:layout_width="fill_parent" 
            android:layout_height="wrap_content" 
            android:text="报告"/> 
    </LinearLayout> 
</RelativeLayout>

测试的Activity:

package com.basecontrol.ui;

import com.basecontrol.view.ImageControl; 
import com.basecontrol.view.ImageControl.ICustomMethod; 
import com.example.basecontrol.R; 
import android.app.Activity; 
import android.graphics.Bitmap; 
import android.graphics.Rect; 
import android.graphics.drawable.BitmapDrawable; 
import android.os.Bundle; 
import android.view.MotionEvent; 
import android.view.View; 
import android.widget.LinearLayout; 
import android.widget.TextView; 
import android.widget.Toast;

public class ImageViewActivity extends Activity 
{

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
        super.onCreate(savedInstanceState); 
        setContentView(R.layout.bc_common_image_view); 
        findView(); 
    } 
    
    public void onWindowFocusChanged(boolean hasFocus) 
    { 
        super.onWindowFocusChanged(hasFocus); 
        init(); 
    }; 
    
    ImageControl imgControl; 
    LinearLayout llTitle; 
    TextView tvTitle; 
    private void findView() 
    { 
        imgControl=(ImageControl) findViewById(R.id.common_imageview_imageControll); 
        llTitle=(LinearLayout) findViewById(R.id.common_iamgeview_llTitle); 
        tvTitle=(TextView) findViewById(R.id.common_imageview_title); 
    } 
    
    private void init() { 
        tvTitle.setText("图片测试");  
        // 这里可以为imgcontrol的图片路径动态赋值  
        // ............  
          
        Bitmap bmp;  
        if (imgControl.getDrawingCache() != null) {  
            bmp = Bitmap.createBitmap(imgControl.getDrawingCache());  
        } else {  
            bmp = ((BitmapDrawable)imgControl.getDrawable()).getBitmap();  
        }  
        Rect frame = new Rect();  
        getWindow().getDecorView().getWindowVisibleDisplayFrame(frame);  
        int statusBarHeight = frame.top;  
        int screenW = this.getWindowManager().getDefaultDisplay().getWidth();  
        int screenH = this.getWindowManager().getDefaultDisplay().getHeight()  
                - statusBarHeight;  
        if (bmp != null) {  
            imgControl.imageInit(bmp, screenW, screenH, statusBarHeight,  
                    new ICustomMethod() {  
                        @Override 
                        public void customMethod(Boolean currentStatus) {  
                            // 当图片处于放大或缩小状态时，控制标题是否显示  
                            if (currentStatus) {  
                                llTitle.setVisibility(View.GONE);  
                            } else {  
                                llTitle.setVisibility(View.VISIBLE);  
                            }  
                        } 
                    });  
        }  
        else  
        {  
            Toast.makeText(ImageViewActivity.this, "图片加载失败，请稍候再试！", Toast.LENGTH_SHORT)  
                    .show();  
        }  
  
    } 
    @Override 
    public boolean onTouchEvent(MotionEvent event) { 
        switch (event.getAction()&MotionEvent.ACTION_MASK) { 
        case MotionEvent.ACTION_DOWN: 
            imgControl.mouseDown(event); 
            break; 
        case MotionEvent.ACTION_POINTER_DOWN: 
            imgControl.mousePointDown(event); 
            break; 
        case MotionEvent.ACTION_MOVE: 
            imgControl.mouseMove(event); 
            break; 
        case MotionEvent.ACTION_UP: 
            imgControl.mouseUp(); 
            break; 
        } 
        return super.onTouchEvent(event); 
    } 
}

嗯，就酱…………