import android.app.Activity;  
                                    
import android.graphics.Bitmap;  
                                    
import android.graphics.BitmapFactory;  
                                    
import android.graphics.Matrix;  
                                    
import android.graphics.PointF;  
                                    
import android.hardware.SensorManager;  
                                    
import android.os.Bundle;  
                                    
import android.util.FloatMath;  
                                    
import android.util.Log;  
                                    
import android.view.MotionEvent;  
                                    
import android.view.View;  
                                    
import android.view.View.OnClickListener;  
                                    
import android.view.View.OnTouchListener;  
                                    
import android.widget.Button;  
                                    
import android.widget.ImageView;  
                                    
 
                                    
public class Touch extends Activity implements OnTouchListener, OnClickListener {  
                                    
 private static final String TAG = "Touch" ;  
                                    
 
                                    
 // These matrices will be used to move and zoom image  
                                    
 Matrix matrix = new Matrix();  
                                    
 Matrix savedMatrix = new Matrix();  
                                    
 PointF start = new PointF();  
                                    
 PointF mid = new PointF();  
                                    
 float oldDist;  
                                    
 private ImageView view;  
                                    
 private Button zoomIn, zoomOut;  
                                    
 //button zoom  
                                    
 private float scaleWidth = 1;  
                                    
 private float scaleHeight = 1;  
                                    
 private Bitmap bmp, zoomedBMP;  
                                    
 private int zoom_level = 0;  
                                    
 private static final double ZOOM_IN_SCALE = 1.25;//放大系数  
                                    
 private static final double ZOOM_OUT_SCALE = 0.8;//缩小系数  
                                    
 // 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;  
                                    
 
                                    
 @Override  
                                    
 public void onCreate(Bundle savedInstanceState) {  
                                    
   super.onCreate(savedInstanceState);  
                                    
   setContentView(R.layout.main);  
                                    
   //放大按钮  
                                    
   zoomIn = (Button) findViewById(R.id.zoom_in);  
                                    
   //缩小按钮  
                                    
   zoomOut = (Button) findViewById(R.id.zoom_out);  
                                    
   zoomIn.setOnClickListener(this);  
                                    
   zoomOut.setOnClickListener(this);  
                                    
   view = (ImageView) findViewById(R.id.imageView);  
                                    
   view.setOnTouchListener(this);  
                                    
   //取得drawable中图片，放大，缩小，多点触摸的作用对象  
                                    
   bmp = BitmapFactory.decodeResource(Touch.this.getResources(), R.drawable.butterfly);  
                                    
 
                                    
       }  
                                    
 
                                    
 public boolean onTouch(View v, MotionEvent event) {  
                                    
// Handle touch events here...  
                                    
ImageView view = (ImageView) v;  
                                    
 
                                    
// Handle touch events here...  
                                    
switch (event.getAction() & MotionEvent.ACTION_MASK) {  
                                    
//设置拖拉模式  
                                    
case MotionEvent.ACTION_DOWN:  
                                    
savedMatrix.set(matrix);  
                                    
start.set(event.getX(), event.getY());  
                                    
Log.d(TAG, "mode=DRAG" );  
                                    
mode = DRAG;  
                                    
break;  
                                    
 
                                    
case MotionEvent.ACTION_UP:  
                                    
case MotionEvent.ACTION_POINTER_UP:  
                                    
mode = NONE;  
                                    
Log.d(TAG, "mode=NONE" );  
                                    
break;  
                                    
//设置多点触摸模式  
                                    
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;  
                                    
//若为DRAG模式，则点击移动图片  
                                    
case MotionEvent.ACTION_MOVE:  
                                    
if (mode == DRAG) {  
                                    
matrix.set(savedMatrix);  
                                    
// 设置位移  
                                    
matrix.postTranslate(event.getX() - start.x,  
                                    
event.getX() - start.x);  
                                    
}  
                                    
//若为ZOOM模式，则多点触摸缩放  
                                    
else if (mode == ZOOM) {  
                                    
float newDist = spacing(event);  
                                    
Log.d(TAG, "newDist=" + newDist);  
                                    
if (newDist > 10f) {  
                                    
matrix.set(savedMatrix);  
                                    
float scale = newDist / oldDist;  
                                    
//设置缩放比例和图片中点位置  
                                    
matrix.postScale(scale, scale, mid.x, mid.y);  
                                    
}  
                                    
}  
                                    
break;  
                                    
}  
                                    
 
                                    
// Perform the transformation  
                                    
view.setImageMatrix(matrix);  
                                    
 
                                    
return true; // indicate event was handled  
                                    
 }  
                                    
//计算移动距离  
                                    
 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);  
                                    
 }  
                                    
//计算中点位置  
                                    
 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);  
                                    
 }  
                                    
 
                                    
//放大，缩小按钮点击事件  
                                    
@Override  
                                    
public void onClick(View v) {  
                                    
    if(v == zoomIn){  
                                    
        enlarge();  
                                    
    }else if (v == zoomOut) {  
                                    
        small();  
                                    
    }  
                                    
}  
                                    
 
                                    
//按钮点击缩小函数  
                                    
private void small() {  
                                    
int bmpWidth = bmp.getWidth();  
                                    
int bmpHeight = bmp.getHeight();  
                                    
 
                                    
scaleWidth = (float) (scaleWidth * ZOOM_OUT_SCALE);  
                                    
scaleHeight = (float) (scaleHeight * ZOOM_OUT_SCALE);  
                                    
 
                                    
Matrix matrix = new Matrix();  
                                    
matrix.postScale(scaleWidth, scaleHeight);  
                                    
zoomedBMP = Bitmap.createBitmap(bmp, 0, 0, bmpWidth, bmpHeight, matrix,  
                                    
true);  
                                    
view.setImageBitmap(zoomedBMP);  
                                    
}  
                                    
 
                                    
//按钮点击放大函数  
                                    
private void enlarge() {  
                                    
    try {  
                                    
        int bmpWidth = bmp.getWidth();  
                                    
        int bmpHeight = bmp.getHeight();  
                                    
 
                                    
        scaleWidth = (float) (scaleWidth * ZOOM_IN_SCALE);  
                                    
        scaleHeight = (float) (scaleHeight * ZOOM_IN_SCALE);  
                                    
 
                                    
        Matrix matrix = new Matrix();  
                                    
        matrix.postScale(scaleWidth, scaleHeight);  
                                    
        zoomedBMP = Bitmap.createBitmap(bmp, 0, 0, bmpWidth, bmpHeight, matrix,  
                                    
                true);  
                                    
        view.setImageBitmap(zoomedBMP);  
                                    
    } catch (Exception e) {  
                                    
        //can't zoom because of memory issue, just ignore, no big deal  
                                    
    }  
                                    
}  
                                    
}
                                

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