Android应用REST API重复调用排查：主界面非首次加载缓慢

问题背景 #

主界面除首次加载外，其余加载耗时都很长，Logcat显示加载数据的REST API被多次调用。

已排查的原因 #

• 怀疑存在循环代码，观察数据时修改变量意外触发数据重新加载，但通过CPU Profiler分析，数据从父Fragment到子Fragment的流转正常。
• 怀疑多个Fragment实例调用API：
  • 在Fragment的Observer中添加日志代码：

    reportGroupVM.selectedReport.observe(viewLifecycleOwner, Observer {
        binding.tvTitle.text = it.title
        LogUtil.d("EnergyConsumptionFrag", this@EnergyConsumptionFragment.toString())
        energyConsumptionVM.getSpecificReport(it.entityLinkContainer?.self?.href)
    })
    

  • 日志输出显示存在多个不同ID的Fragment实例：

    2023-09-22 21:27:21.180  6992-6992  EnergyConsumptionFrag   dev.packagename                      D  EnergyConsumptionFragment{49abc22} (ab026b8f-bfe8-4587-8d4b-d451e46bea13) id=0x7f0a0211 EnergyConsumptionFragment}
    2023-09-22 21:27:21.195  6992-6992  EnergyConsumptionFrag   dev.packagename                      D  EnergyConsumptionFragment{b12d8ca} (7a6776a6-824a-45d6-af2c-8c17207c1a43) id=0x7f0a0211 EnergyConsumptionFragment}
    2023-09-22 21:27:21.210  6992-6992  EnergyConsumptionFrag   dev.packagename                      D  EnergyConsumptionFragment{96a67d1} (6f4d5392-8971-4906-9af7-94b5bf9df8fb) id=0x7f0a0211 EnergyConsumptionFragment}
    2023-09-22 21:27:21.225  6992-6992  EnergyConsumptionFrag   dev.packagename                      D  EnergyConsumptionFragment{ff4a010} (45c24f6f-3ed6-4a75-ab08-d46f08523775) id=0x7f0a0211 EnergyConsumptionFragment}
    

  • 生成该Fragment的唯一代码位置：

    loadFragment(EnergyConsumptionFragment())
    
    private fun loadFragment(fragment: Fragment) {
        val transaction = childFragmentManager.beginTransaction()
    
        if (!fragment.isAdded) {
            transaction.add(R.id.layout_report, fragment, fragment.javaClass.simpleName)
        } else {
            //transaction.replace(R.id.layout_report, fragment, fragment.javaClass.simpleName)
        }
    
        transaction.commit()
    }
    

    这段代码逻辑看似无问题。

提问 #

还有哪些可能的原因需要排查？该如何调试这个问题？

内容的提问来源于stack exchange，提问作者ryannmahajan