懒加载fragment基类

import android.os.Bundle;
/**
 * 这是一个懒加载fragment基类
 */
public abstract class LazyBaseFragment extends BaseFragment {
    private static final String TAG = LazyBaseFragment.class.getSimpleName();
    private boolean isPrepared;

    @Override
    public void onActivityCreated(Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
        initPrepare();
    }


    /**
     * 第一次onResume中的调用onUserVisible避免操作与onFirstUserVisible操作重复
     */
    private boolean isFirstResume = true;

    @Override
    public void onResume() {
        super.onResume();
        if (isFirstResume) {
            isFirstResume = false;
            return;
        }
        if (getUserVisibleHint()) {
            onUserVisible();
        }
    }

    @Override
    public void onPause() {
        super.onPause();
        if (getUserVisibleHint()) {
            onUserInvisible();
        }
    }

    private boolean isFirstVisible = true;
    private boolean isFirstInvisible = true;

    @Override
    public void setUserVisibleHint(boolean isVisibleToUser) {
        super.setUserVisibleHint(isVisibleToUser);
        if (isVisibleToUser) {
            if (isFirstVisible) {
                isFirstVisible = false;
                initPrepare();
            } else {
                onUserVisible();
            }
        } else {
            if (isFirstInvisible) {
                isFirstInvisible = false;
                onFirstUserInvisible();
            } else {
                onUserInvisible();
            }
        }
    }

    public synchronized void initPrepare() {
        if (isPrepared) {
            onFirstUserVisible();
        } else {
            isPrepared = true;
        }
    }

    /**
     * 第一次fragment可见（进行初始化工作）
     */
    public void onFirstUserVisible() {

    }

    /**
     * fragment可见（切换回来或者onResume）
     */
    public void onUserVisible() {

    }

    /**
     * 第一次fragment不可见（不建议在此处理事件）
     */
    public void onFirstUserInvisible() {

    }

    /**
     * fragment不可见（切换掉或者onPause）
     */
    public void onUserInvisible() {

    }
}

public abstract class BaseFragment extends Fragment {
    protected View mRootView;

    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        if (getLayoutId() <= 0) {
            return super.onCreateView(inflater, container, savedInstanceState);
        }
        if (mRootView == null) {
            mRootView = inflater.inflate(getLayoutId(), container, false);
        }
        return mRootView;
    }

    @Override
    public void onViewCreated(View view, Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);
        ButterKnife.bind(this, view);
        afterCreate(savedInstanceState);
    }

    @Override
    public void onDetach() {
        super.onDetach();
        ButterKnife.unbind(this);
    }

    protected abstract int getLayoutId();

    protected abstract void afterCreate(Bundle savedInstanceState);

    /**
     * 在当前Fragment开启另外一个Fragment
     */
    protected void startFragment(Fragment fragment) {
        FragmentTransaction ft = getFragmentManager().beginTransaction();
        ft.setCustomAnimations(R.anim.in_from_right, R.anim.out_to_left);
        ft.replace(getId(), fragment);
        ft.addToBackStack(null);
        ft.commit();
    }

    @Override
    public void onResume() {
        super.onResume();
        MobclickAgent.onPageStart(getClass().getName());//友盟统计
    }

    @Override
    public void onPause() {
        super.onPause();
        MobclickAgent.onPageEnd(getClass().getName());//友盟统计
    }
}