java.lang.IllegalStateException: Required view 'nav' with ID 2131558567 for field

java.lang.IllegalStateException: Required view 'nav' with ID 2131558567 for field 'mAHBottomNavigation' was not found. If this view is optional add '@Nullable' (fields) or '@Optional' (methods) annotation.

原因：BaseActivity忘记加这一行：this.setContentView(this.getLayoutId());

@Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); // 设置不能横屏，防止生命周期的改变 setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_NOSENSOR); this.setContentView(this.getLayoutId());//缺少这一行 ButterKnife.bind(this);//绑定ButterKnife mContext = this; this.initView(); this.initData(); this.initEvent(); Timber.tag(TAG).i("-->onCreate()"); } /** * 获取布局id * * @return */ protected abstract int getLayoutId();