mPresenter 空指针问题

mny459 commented 5 years ago

Look at here

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Environment

[x] MVPArms Version: 2.5.0
[x] AndroidStudio Version: 3.3.1
[x] Gradle Plugin Version: 4.10.1
[x] Target Android Version: 28
[x] Device Model: 红米Note 4、三星 SM G965F、小米6等

Bug Description:

首先这个Bug我自己没有复现出来，但是在同事的手机上面出现过一次，在Bugly上也出现过多次，就是在 Fragment 中的 mPresenter 为空了。项目中引入了 Fragmentation ，所以重写了Fragment，在项目中将mPresenter 置空的操作只有如下代码，将从原来的onDestory 提前到了 onDestroyView，（不确定是不是因为这个的原因，因为自己想尽办法了，还是没有复现，也就是说我自己运行是正常的）：

    @Override
    public void onDestroyView() {
        if (mPresenter != null) {
            mPresenter.onDestroy();//释放资源
        }
        this.mPresenter = null;
        super.onDestroyView();
    }

Related Code:

报错代码

     @Override
    public void initData(@Nullable Bundle savedInstanceState) {
       // 省略其他初始化代码
        mPresenter.initHomeDevice();
    }

Bug Log:

Stack trace:  
java.lang.NullPointerException: Attempt to invoke virtual method 'void com.包名省略.mvp.presenter.DeviceOperationPresenter.f()' on a null object reference
  at com.包名省略.mvp.ui.fragment.devices.DeviceOperationFragment.initData(DeviceOperationFragment.java:179)
  at com.jess.arms.base.a.g.b(FragmentDelegateImpl.java:74)
  at com.jess.arms.b.g.onFragmentActivityCreated(FragmentLifecycle.java:85)
  at android.support.v4.app.FragmentManagerImpl.dispatchOnFragmentActivityCreated(FragmentManager.java:3490)
  at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1445)
  at android.support.v4.app.FragmentManagerImpl.moveFragmentToExpectedState(FragmentManager.java:1752)
  at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1821)
  at android.support.v4.app.BackStackRecord.executePopOps(BackStackRecord.java:855)
  at android.support.v4.app.FragmentManagerImpl.executeOps(FragmentManager.java:2592)
  at android.support.v4.app.FragmentManagerImpl.executeOpsTogether(FragmentManager.java:2382)
  at android.support.v4.app.FragmentManagerImpl.removeRedundantOperationsAndExecute(FragmentManager.java:2337)
  at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:2244)
  at android.support.v4.app.FragmentManagerImpl.executePendingTransactions(FragmentManager.java:783)
  at android.support.v4.app.FragmentationMagician$4.run(FragmentationMagician.java:134)
  at android.support.v4.app.FragmentationMagician.hookStateSaved(FragmentationMagician.java:194)
  at android.support.v4.app.FragmentationMagician.executePendingTransactionsAllowingStateLoss(FragmentationMagician.java:131)
  at me.yokeyword.fragmentation.k$15.a(TransactionDelegate.java:172)
  at me.yokeyword.fragmentation.b.b.a(ActionQueue.java:53)
  at me.yokeyword.fragmentation.b.b.b(ActionQueue.java:45)
  at me.yokeyword.fragmentation.b.b.a(ActionQueue.java:17)
  at me.yokeyword.fragmentation.b.b$1.run(ActionQueue.java:37)
  at android.os.Handler.handleCallback(Handler.java:792)
  at android.os.Handler.dispatchMessage(Handler.java:98)
  at android.os.Looper.loop(Looper.java:176)
  at android.app.ActivityThread.main(ActivityThread.java:6701)
  at java.lang.reflect.Method.invoke(Native Method)
  at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:246)
  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:783)

Others:

问了群友，有的说是Dagger2注入的问题，我看了一下代码实在 onCreate 里面注入的，initData实在 onActivityCreate调用的，所以我觉得应该是已经注入的了,以下是相关源码

    // Dagger 依赖注入
    @Override
    public void onCreate(@Nullable Bundle savedInstanceState) {
        if (iFragment.useEventBus())//如果要使用eventbus请将此方法返回true
            EventBusManager.getInstance().register(mFragment);//注册到事件主线
        iFragment.setupFragmentComponent(ArmsUtils.obtainAppComponentFromContext(mFragment.getActivity()));
    }
   //  调用initData
  @Override
    public void onActivityCreate(@Nullable Bundle savedInstanceState) {
        iFragment.initData(savedInstanceState);
    }

子类实现注入方法：

    @Override
    public void setupFragmentComponent(@NonNull AppComponent appComponent) {
        DaggerDeviceOperationComponent //如找不到该类,请编译一下项目
                .builder()
                .appComponent(appComponent)
                .deviceOperationModule(new DeviceOperationModule(this))
                .build()
                .inject(this);
    }

麻烦作者帮忙看一下了，感激不尽