public class MainActivity extends FragmentActivity {

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main_activity);
    Button btn = findViewById(R.id.button1);
    btn.setOnClickListener(v -> {
        with();
        try {
            Thread.sleep(4000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        with();
    });
}

public void with() {
    FragmentManager fm = this.getSupportFragmentManager();
    Fragment fragment = fm.findFragmentByTag("abc");
    if (fragment == null) {
        Log.i("hunter", "这一行执行了两次");
        fragment = new Fragment();
        fm.beginTransaction().add(fragment, "abc").commitAllowingStateLoss();
    }
}

}

老师，上面的代码new Fragment()怎么执行了两次，第一次添加Fragment的时候设置了tag呀