九宮格的算法

創建九宮格的uibutton方法

    int y = 0;
    int x = 0;
    //重寫FreeButton的title跟image的方法（九宮格排列）
    for(int i=0;i<9;i++){
        UIbutton*btn1=[UIbutton buttonWithType:UIButtonTypeCustom];
        if(i%3==0&&i>0){
            y+=f/3;
            x=0;
        }
        btn1.tag=i;
        btn1.frame=CGRectMake(x,y,SCREEN_WIDTH/3,f/3);
        [btn1 setTitle:self.arr[i] forState:0];
        btn1.titleLabel.textAlignment=NSTextAlignmentCenter;
        [btn1 setTitleColor:[UIColor lightGrayColor] forState:0];
        btn1.titleLabel.font=[UIFont systemFontOfSize:16];
        [btn1 setImage:[UIImage imageNamed:self.imgarr[i]] forState:0];
        [btn1 addTarget:self action:@selector(onClick:) forControlEvents:1<<6];
        [scrollView addSubview:btn1];
        x+=SCREEN_WIDTH/3;
    }

SCREEN_WIDTH 是個宏， 定義屏幕寬度