Android graphics画图的点击事件处理

packagecom.jacp.test;
importAndroid.app.Activity;
importAndroid.content.Context;
importAndroid.graphics.Canvas;
importAndroid.graphics.Color;
importAndroid.graphics.Paint;
importAndroid.graphics.Rect;
importAndroid.graphics.RectF;
importAndroid.os.Bundle;
importAndroid.util.DisplayMetrics;
importAndroid.view.MotionEvent;
importAndroid.view.View;
importAndroid.widget.Toast;
publicclassDrawSimpleCircleextendsActivity{
publicvoidonCreate(BundlesavedInstanceState){
super.onCreate(savedInstanceState);
DisplayMetricsmetrics=newDisplayMetrics();
this.getWindowManager().getDefaultDisplay().getMetrics(metrics);
//屏幕的分辨率
intwidth=metrics.widthPixels;
intheight=metrics.heightPixels;
setContentView(newMyCircle(this,width,height));
}
classMyCircleextendsView{
privateContextcontext;
/**
*屏幕的宽
*/
privateintwidth;
/**
*屏幕的高
*/
privateintheight;
/**
*颜色区分区域
*/
privateint[]colors=newint[]{Color.BLACK,Color.BLUE,Color.CYAN,
Color.GREEN,Color.GRAY,Color.MAGENTA,Color.RED,Color.LTGRAY};
privateString[]colorStrs=newString[]{
"黑色","蓝色","青绿色","绿色","灰色","洋红色","红色","浅灰色"};
/**
*大园半径
*/
privatefloatbigR;
/**
*小圆半径
*/
privatefloatlitterR;
/**
*屏幕中间点的X坐标
*/
privatefloatcenterX;
/**
*屏幕中间点的Y坐标
*/
privatefloatcenterY;
publicMyCircle(Contextcontext,intwidth,intheight){
super(context);
this.context=context;
this.width=width;
this.height=height;
setFocusable(true);
System.out.println("width="+width+"<---->height="+height);
//设置两个圆的半径
bigR=(width-20)/2;
litterR=bigR/2;
centerX=width/2;
centerY=height/2;
}
@Override
protectedvoidonDraw(Canvascanvas){
//画背景颜色
Paintbg=newPaint();
bg.setColor(Color.WHITE);
RectbgR=newRect(0,0,width,height);
canvas.drawRect(bgR,bg);
floatstart=0F;
Paintpaint=newPaint(Paint.ANTI_ALIAS_FLAG);
for(inti=0;i<4;i++){
//注意一定要先画大圆，再画小圆，不然看不到效果，小圆在下面会被大圆覆盖
//画大圆
RectFbigOval=newRectF(centerX-bigR,centerY-bigR,
centerX+bigR,centerY+bigR);
paint.setColor(colors[i]);
canvas.drawArc(bigOval,start,90,true,paint);
//画小圆
RectFlitterOval=newRectF(centerX-litterR,centerY-litterR,
centerX+litterR,centerY+litterR);
paint.setColor(colors[i+2]);
canvas.drawArc(litterOval,start,90,true,paint);
start+=90F;
}
super.onDraw(canvas);
}
@Override
publicbooleanonTouchEvent(MotionEventevent){
//获取点击屏幕时的点的坐标
floatx=event.getX();
floaty=event.getY();
whichCircle(x,y);
returnsuper.onTouchEvent(event);
}
/**
*确定点击的点在哪个圆内
*@paramx
*@paramy
*/
privatevoidwhichCircle(floatx,floaty){
//将屏幕中的点转换成以屏幕中心为原点的坐标点
floatmx=x-centerX;
floatmy=y-centerY;
floatresult=mx*mx+my*my;
StringBuildertip=newStringBuilder();
tip.append("您点击了");
//高中的解析几何
if(result<=litterR*litterR){//点击的点在小圆内
tip.append("小圆的");
tip.append(colorStrs[whichZone(mx,my)+2]);
tip.append("区域");
}elseif(result<=bigR*bigR){//点击的点在大圆内
tip.append("大圆的");
tip.append(colorStrs[whichZone(mx,my)]);
tip.append("区域");
}else{//点不在作作区域
tip.append("作用区域以外的区域");
}
Toast.makeText(context,tip,Toast.LENGTH_SHORT).show();
}
/**
*判断点击了圆的哪个区域
*@paramx
*@paramy
*@return
*/
privateintwhichZone(floatx,floaty){
//简单的象限点处理
//第一象限在右下角，第二象限在左下角，代数里面的是逆时针，这里是顺时针
if(x>0&&y>0){
return0;
}elseif(x>0&&y<0){
return3;
}elseif(x<0&&y<0){
return2;
}elseif(x<0&&y>0){
return1;
}
return-1;
}
}
}

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