Android之Viewpager+Fragment实现懒加载示例

package com.yctime.truelove.fragment;import android.content.Context;import android.nfc.Tag;import android.os.Bundle;import android.support.annotation.Nullable;import android.support.v4.app.Fragment;import android.util.Log;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;public abstract class BaseFragment extends Fragment {  protected View mRootView;  public Context mContext;  protected boolean isVisible;  private boolean isPrepared;  private boolean isFirst = true;  public BaseFragment() {    // Required empty public constructor  }  @Override  public void setUserVisibleHint(boolean isVisibleToUser) {    super.setUserVisibleHint(isVisibleToUser);//    Log.d("TAG", "fragment->setUserVisibleHint");    if (getUserVisibleHint()) {      isVisible = true;      lazyLoad();    } else {      isVisible = false;      onInvisible();    }  }  @Override  public void onCreate(@Nullable Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    mContext = getActivity();    setHasOptionsMenu(true);//    Log.d("TAG", "fragment->onCreate");  }  @Override  public View onCreateView(LayoutInflater inflater, ViewGroup container,               Bundle savedInstanceState) {    if (mRootView == null) {      mRootView = initView();    }//    Log.d("TAG", "fragment->onCreateView");    return mRootView;  }  @Override  public void onActivityCreated(@Nullable Bundle savedInstanceState) {    super.onActivityCreated(savedInstanceState);//    Log.d("TAG", "fragment->onActivityCreated");    isPrepared = true;    lazyLoad();  }  protected void lazyLoad() {    if (!isPrepared || !isVisible || !isFirst) {      return;    }    Log.d("TAG", getClass().getName() + "->initData()");    initData();    isFirst = false;  }  //do something  protected void onInvisible() {  }  public abstract View initView();  public abstract void initData();}