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;

/**
 * 基类Fragment
 */
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();

}

  protected void lazyLoad() {
    if (!isPrepared || !isVisible || !isFirst) {
      return;
    }
    Log.d("TAG", getClass().getName() + "->initData()");
    initData();
    isFirst = false;
  }