@Inject for构造函数的问题

Question

I am new to robojuice, but i need to work on a piece of code which was already built by someone else. I am facing issue if I add an extra parameter to the constructor of a class which already has @Inject. My android application crashes giving the below error with no detail description about the issue:

"java.lang.RuntimeException: Unable to start activity ComponentInfo{com.my.app.envTest/com.my.app.navigation.NavigActivity}: com.google.inject.ConfigurationException: Guice configuration errors:"

I am sure this error is not with the activity, but with the new parameter i added to the constructor. If i remove that param it works fine.

Previously:

 @Inject
public PlotRepo(RuntimeExceptionDao<Plot, String> plotDao, RuntimeExceptionDao<LocalPlotData, Long> localPlotDataDao) {
    this.plotDao = plotDao;
    this.localPlotDataDao = localPlotDataDao;
   }

Facing issue for:

 @Inject
public PlotRepo(RuntimeExceptionDao<Plot, String> plotDao, RuntimeExceptionDao<LocalPlotData, Long> localPlotDataDao, RuntimeExceptionDao<LocalSelPlotData, Long> localSelPlotDataDao) {
    this.plotDao = plotDao;
    this.localPlotDataDao = localPlotDataDao;
    this.localSelPlotDataDao = localSelPlotDataDao;
   }

After Debugging i got this error:

1) Could not find a suitable constructor in     com.j256.ormlite.dao.RuntimeExceptionDao. Classes must have either one (and only one) constructor annotated with @Inject or a zero-argument constructor that is not private.
  at com.j256.ormlite.dao.RuntimeExceptionDao.class(Unknown Source)
  while locating     com.j256.ormlite.dao.RuntimeExceptionDao<com.myapp.s.b.sets.domain.LocalSelPlotData, java.lang.Long>
  for parameter 2 at com.tp.my.sets.PlotRepo.<init>(Unknown Source)
  while locating com.myapp.s.b.sets.PlotRepo
  for parameter 1 at com.myapp.s.b.GroupingManager.<init>(Unknown Source)
  while locating com.myapp.s.b.GroupingManager
  for field at com.myapp.s.b.navigation.NavigActivity.groupingManager(Unknown    Source)
   while locating com.myapp.s.b.navigation.NavigActivity

Not sure where I am going wrong, also could not find much help on this. Can someone help me figure out the issue.

Thanks

Answer 1

There were two things that missed in my code. My database classes were missing default constructors. Ormlite needs default constructors, which were missing in some of my classes. After that, I had missed the bindings for the Db annotated dependency like this:

    bind(new TypeLiteral<RuntimeExceptionDao<MyTable, Long>>() {}).toProvider(new DaoProvider<MyTable, Long>(MyTable.class));

After these changes the issue got fixed.

Thanks all for the help!

Answer 2

Firstly - though this does not explicitly answer your question, but cannot have those two constructors - after Type Erasure they are identical and indistinguishable.

You'd need to explicitly define classes such as

RuntimePlotExceptionDao extends RuntimeExceptionDao<Plot, String>
RuntimeLocalPlotDateExceptionDao extends RuntimeExceptionDao<LocalPlotData, Long>

Secondly - why do you want to have two @Inject constructors? Which one should the container pick when creating the object?