[移动开发]android studio 用为什么模拟器运行app时就闪退了？

?代码如下：?

package com.example.myapplication;

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

import androidx.appcompat.app.AppCompatActivity;

public class MainActivity extends AppCompatActivity {

    private Button button;
    private ImageView imageView1,imageView2;
    private int count;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_fl);

        button = (Button)findViewById(R.id.button);
        imageView1 = (ImageView)findViewById(R.id.imageView);
        imageView2 = (ImageView)findViewById(R.id.imageView);

        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                if(count % 2 == 0){
                    imageView1.setVisibility(View.VISIBLE);
                    imageView2.setVisibility(View.INVISIBLE);
                }else{
                    imageView1.setVisibility(View.INVISIBLE);
                    imageView2.setVisibility(View.VISIBLE);
                }
                count++;
            }
        });
    }
}