实现在Android通过手势实现的缩放处理
今天在源码天堂安卓源码频道网站那里下载一个特效功能，实现在Android通过手势实现的缩放处理，喜欢的朋友可以研究一下吧。
import android.app.Activity;import android.content.Context;import android.graphics.Canvas;import android.graphics.Color;import android.graphics.Paint;import android.os.Bundle;import android.util.DisplayMetrics;import android.view.MotionEvent;import android.view.View;/** * ... * * @author vlinux * */public class MultiTouchTestActivity extends Activity {/** Called when the activity is first created. */@Overridepublic void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);// setContentView(R.layout.main);View view = new MultiTouchView(this);setContentView(view);}class MultiTouchView extends View {private float x1;private float y1;private float x2;private float y2;public MultiTouchView(Context context) {super(context);// TODO Auto-generated constructor stub}@Overridepublic boolean onTouchEvent(MotionEvent event) {// TODO Auto-generated method stubfloat size = event.getSize();int szi = (int) size;int dxi = szi >> 12;int dyit = ((1 << 12) - 1);int dyi = szi & dyit;DisplayMetrics metrics = getResources().getDisplayMetrics();float dx = metrics.widthPixels * dxi / (float) dyit;float dy = metrics.heightPixels * dyi / (float) dyit;x1 = event.getX();y1 = event.getY();x2 = x1 + dx;y2 = y1 + dy;invalidate();return true;}@Overrideprotected void onDraw(Canvas canvas) {// TODO Auto-generated method stubsuper.onDraw(canvas);float r = (float) Math.sqrt((x1 - x2) * (x1 - x2) + (y1 - y2)* (y1 - y2)) / 2;r = 50 >= r ? 50 : r;Paint paint = new Paint();paint.setColor(Color.BLUE);canvas.drawCircle(x1, y1, r, paint);}}}