闪退的软件，根本不知道怎么办

问题遇到的现象和发生背景

这个软件是闪退王，

遇到的现象和发生背景，请写出第一个错误信息

Anonymous new View.OnClickListener() can be replaced with lambda

用代码块功能插入代码，请勿粘贴截图。 不用代码块回答率下降 50%

package com.itheima.sixyao;

import static com.itheima.sixyao.R.drawable.yy1;
import static com.itheima.sixyao.R.drawable.yy2;
import static com.itheima.sixyao.R.drawable.yy4;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;

import java.util.Random;

public class MainActivity extends AppCompatActivity {
    static int ss;
    static int bb=0;
    Button b1,b2;
    ImageView i1 ,i2,i3,i4,i5,i6;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);


        i1.findViewById(R.id.i1);
        i2.findViewById(R.id.i2);
        i3.findViewById(R.id.i3);
        i4.findViewById(R.id.i4);
        i5.findViewById(R.id.i5);
        i6.findViewById(R.id.i6);

        b1.findViewById(R.id.b1);
        b2.findViewById(R.id.b2);
        b1.setOnClickListener (new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                runOnUiThread(new Runnable() {
                    @Override
                    public void run() {


                        bb = bb + 1;
                        b1.setBackgroundColor(getResources().getColor(R.color.purple_200));


                        Random f = new Random();
                        ss = f.nextInt(4);
                        if (bb % 6 == 1) {
                            if (ss == 0) {
                                i1.setBackground(getResources().getDrawable(yy1));
                            }
                            if (ss == 1) {

                                i1.setBackground(getResources().getDrawable(yy2));

                            }
                            if (ss == 2) {

                                i1.setBackground(getResources().getDrawable(R.drawable.yy3));

                            }

                            if (ss == 3) {

                                i1.setBackground(getResources().getDrawable(yy4));

                            }
                        }


                        if (bb % 6 == 2) {
                            if (ss == 0) {
                                i2.setBackground(getResources().getDrawable(yy1));
                            }
                            if (ss == 1) {

                                i2.setBackground(getResources().getDrawable(yy2));

                            }
                            if (ss == 2) {

                                i2.setBackground(getResources().getDrawable(R.drawable.yy3));

                            }

                            if (ss == 3) {

                                i2.setBackground(getResources().getDrawable(yy4));

                            }
                        }


                        if (bb % 6 == 3) {
                            if (ss == 0) {
                                i3.setBackground(getResources().getDrawable(yy1));
                            }
                            if (ss == 1) {

                                i3.setBackground(getResources().getDrawable(yy2));

                            }
                            if (ss == 2) {

                                i3.setBackground(getResources().getDrawable(R.drawable.yy3));

                            }

                            if (ss == 3) {

                                i3.setBackground(getResources().getDrawable(yy4));

                            }
                        }


                        if (bb % 6 == 4) {
                            if (ss == 0) {
                                i4.setBackground(getResources().getDrawable(yy1));
                            }
                            if (ss == 1) {

                                i4.setBackground(getResources().getDrawable(yy2));

                            }
                            if (ss == 2) {

                                i4.setBackground(getResources().getDrawable(R.drawable.yy3));

                            }

                            if (ss == 3) {

                                i4.setBackground(getResources().getDrawable(yy4));

                            }
                        }


                        if (bb % 6 == 5) {
                            if (ss == 0) {
                                i5.setBackground(getResources().getDrawable(yy1));
                            }
                            if (ss == 1) {

                                i5.setBackground(getResources().getDrawable(yy2));

                            }
                            if (ss == 2) {

                                i5.setBackground(getResources().getDrawable(R.drawable.yy3));

                            }

                            if (ss == 3) {

                                i5.setBackground(getResources().getDrawable(R.drawable.yy4));

                            }
                        }


                        if (bb % 6 == 0) {
                            if (ss == 0) {
                                i6.setBackground(getResources().getDrawable(yy1));
                            }
                            if (ss == 1) {

                                i6.setBackground(getResources().getDrawable(yy2));

                            }
                            if (ss == 2) {

                                i6.setBackground(getResources().getDrawable(R.drawable.yy3));

                            }

                            if (ss == 3) {

                                i6.setBackground(getResources().getDrawable(yy4));

                            }
                        }


                    }


            });

                }
        });

        b2.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                b2.setBackgroundColor(getResources().getColor(R.color.purple_200));

            }
        });



    }
}

运行结果及详细报错内容

闪退

我的解答思路和尝试过的方法，不写自己思路的，回答率下降 60%

我好像觉得这是因为UI不能被主线程操作

我想要达到的结果，如果你需要快速回答，请尝试 “付费悬赏”

能实现六爻占卜的功能

代码有点小问题，也提示你了Anonymous new View.OnClickListener() can be replaced with lambda,意思就是让你将 b1.setOnClickListener (new View.OnClickListener() {xxxx}换成lambda表达式来写
b1.setOnclicklistener(view
->
xxxx);
这是jdk1.8出现的新特性，匿名内部类用lambda表达式来写