android canvas 绘制网格 并添加格子点击事件_canvas 网格点击

实现： 

import android.app.Activity;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.RectF;
import android.support.constraint.ConstraintLayout;
import android.util.AttributeSet;
import android.util.DisplayMetrics;
import android.view.MotionEvent;
import android.view.View;
import android.widget.LinearLayout;
 
 
 
public class BGNet extends View {
    private Context context;
    private Paint paint;
    private Path path;
    private int dmWidth;
    private int dmHeight;
    private String TAG="BGNet";
 
    public BGNet(Context context) {
        super(context);
        this.context=context;
        init();
    }
 
    public BGNet(Context context,AttributeSet attrs) {
        super(context, attrs);
        this.context=context;
        init();
    }
 
    public BGNet(Context context,AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        this.context=context;
        init();
    }
 
    private void init(){
        DisplayMetrics displayMetrics = new DisplayMetrics();
        ((Activity)context).getWindowManager().getDefaultDisplay().getRealMetrics(displayMetrics);
        dmWidth=displayMetrics.widthPixels;
        dmHeight=displayMetrics.heightPixels;
 
        paint=new Paint();
        paint.setAntiAlias(true);
        paint.setColor(Color.RED);
        paint.setStrokeWidth(3f);
        paint.setStyle(Paint.Style.STROKE);
 
        path=new Path();
 
        invalidate();
    }
 
    float allSpell=0;
    float top=200;
    int partCount=9;
 
 
 
    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        LogTools.i(TAG, "onDraw==");
 
        //绘制网格
        top=(dmHeight-dmWidth)/2;
        allSpell=0;
        float spell=(float) dmWidth/(float) partCount;
        for(int i=0;i<=partCount;i++){
            canvas.drawLine(1.5f, allSpell+top, dmWidth, allSpell+top, paint);//横向
            float vX= i==0 ? 1.5f : (i==partCount ? allSpell-1.5f : allSpell);
            canvas.drawLine(vX, top, vX, dmWidth+top, paint);//纵向
            allSpell+=spell;
        }
 
        if(downRectF!=null){
            Paint downRectFPaint=new Paint();
            downRectFPaint.setColor(Color.RED);
            downRectFPaint.setAntiAlias(true);
            downRectFPaint.setStyle(Paint.Style.FILL);
            canvas.drawRect(downRectF, downRectFPaint);
        }
 
 
    }
 
    RectF downRectF;
    @Override
    public boolean onTouchEvent(MotionEvent event) {
        switch (event.getAction()){
                        case MotionEvent.ACTION_DOWN:
                int c=0;
                float downX=event.getRawX();
                float downY=event.getRawY();
 
 
                    float spell=((float) dmWidth/(float) partCount);
                    float initX=spell;
                    float initY=top+spell;
 
                while (initX<=dmWidth && initY<=dmHeight-top && downY<=dmHeight-top && downY>=top){
                    c++;
 
                    if(initX<downX){
                        initX+=spell;
                    }
 
                    if(initY<downY){
                        initY+=spell;
                    }
                    LogTools.i(TAG, "c=="+c+",initX="+initX+",initY="+initY+",downX="+downX+",downY="+downY+",spell="+spell+",top="+top);
                    if(downX>= initX-spell && downX<=initX && downY>=initY-spell && downY<=initY){
 
                        downRectF=new RectF(initX-spell,initY-spell,initX,initY);
                        invalidate();
 
                        LogTools.i(TAG, "down==row=="+initX/spell+",columns="+(initY-top)/spell);
                        break;
                    }
 
                }
 
                break;
            case MotionEvent.ACTION_MOVE:
                break;
            case MotionEvent.ACTION_UP:
                break;
        }
 
 
        return super.onTouchEvent(event);
    }
 
 
 
 
//    @Override
//    protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
//        super.onLayout(changed, left, top, right, bottom);
//
//        LogTools.i(TAG,"onLayout="+changed);
//    }
//
    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        LogTools.i(TAG,"onMeasure=w="+getMeasuredWidth()+",h="+getMeasuredHeight());
    }
}