ViewPager不设置预加载和Fragment只加载一次

今日写了一个 ViewPager 和 Fragment 配合使用，达到 ViewPager 不设置预加载（也就是一次只加载一个）和 Fragment 懒加载（也就是只加载一次）。通俗的说就是滑动或点击哪个便加载哪个，并且加载过的不再加载。

/**
 * Automatically generated file. DO NOT MODIFY
 */
package com.example.qd.fragmentdemo;

public final class BuildConfig {
  public static final boolean DEBUG = Boolean.parseBoolean（“true“）;
  public static final String APPLICATION_ID = “com.example.qd.fragmentdemo“;
  public static final String BUILD_TYPE = “debug“;
  public static final String FLAVOR = ““;
  public static final int VERSION_CODE = 1;
  public static final String VERSION_NAME = “1.0“;
}

 属性            大小     日期    时间   名称
----------- ---------  ---------- -----  ----
     目录           0  2018-11-26 11:27  FragmentDemo\
     文件         127  2018-11-26 11:22  FragmentDemo\.gitignore
     目录           0  2018-11-26 11:23  FragmentDemo\.gradle\
     目录           0  2018-11-26 11:45  FragmentDemo\.gradle\4.1\
     目录           0  2018-11-26 11:23  FragmentDemo\.gradle\4.1\fileChanges\
     文件           1  2018-11-26 15:17  FragmentDemo\.gradle\4.1\fileChanges\last-build.bin
     目录           0  2018-11-26 11:45  FragmentDemo\.gradle\4.1\fileContent\
     文件          17  2018-11-26 15:17  FragmentDemo\.gradle\4.1\fileContent\fileContent.lock
     目录           0  2018-11-26 11:23  FragmentDemo\.gradle\4.1\fileHashes\
     文件      161333  2018-11-26 15:17  FragmentDemo\.gradle\4.1\fileHashes\fileHashes.bin
     文件          17  2018-11-26 15:17  FragmentDemo\.gradle\4.1\fileHashes\fileHashes.lock
     文件       20027  2018-11-26 11:45  FragmentDemo\.gradle\4.1\fileHashes\resourceHashesCache.bin
     目录           0  2018-11-26 11:45  FragmentDemo\.gradle\4.1\javaCompile\
     文件      814415  2018-11-26 15:17  FragmentDemo\.gradle\4.1\javaCompile\classAnalysis.bin
     文件      335013  2018-11-26 11:45  FragmentDemo\.gradle\4.1\javaCompile\jarAnalysis.bin
     文件          17  2018-11-26 15:17  FragmentDemo\.gradle\4.1\javaCompile\javaCompile.lock
     文件      392359  2018-11-26 15:17  FragmentDemo\.gradle\4.1\javaCompile\taskHistory.bin
     文件       20968  2018-11-26 15:17  FragmentDemo\.gradle\4.1\javaCompile\taskJars.bin
     目录           0  2018-11-26 11:23  FragmentDemo\.gradle\4.1\taskHistory\
     文件     1392706  2018-11-26 15:17  FragmentDemo\.gradle\4.1\taskHistory\fileSnapshots.bin
     文件       51245  2018-11-26 15:17  FragmentDemo\.gradle\4.1\taskHistory\taskHistory.bin
     文件          17  2018-11-26 15:17  FragmentDemo\.gradle\4.1\taskHistory\taskHistory.lock
     目录           0  2018-11-26 11:23  FragmentDemo\.gradle\buildOutputCleanup\
     文件           0  2018-11-26 11:23  FragmentDemo\.gradle\buildOutputCleanup\built.bin
     文件          51  2018-11-26 11:23  FragmentDemo\.gradle\buildOutputCleanup\cache.properties
     文件           2  2018-11-26 15:17  FragmentDemo\.gradle\buildOutputCleanup\cache.properties.lock
     目录           0  2018-11-26 15:34  FragmentDemo\.idea\
     文件         626  2018-11-26 11:23  FragmentDemo\.idea\gradle.xml
     目录           0  2018-11-26 11:28  FragmentDemo\.idea\libraries\
     文件         233  2018-11-26 11:25  FragmentDemo\.idea\libraries\android_android_26.xml
     文件         533  2018-11-26 11:25  FragmentDemo\.idea\libraries\android_arch_core_common_1_0_0_jar.xml
............此处省略1386个文件信息