问题
I am developing a library that uses Data Binding to process attributes in a Layout's Views (I won't develop as it is irrelevant to this issue).
As the applications should be able to specify their own layout, I am trying to leverage the resource prioritization mechanism:
In cases where a resource ID is defined in both the application and the library, the tools ensure that the resource declared in the application gets priority and that the resource in the library module is not compiled into the application
apk. This gives your application the flexibility to either use or redefine any resource behaviors or values that are defined in any library.
This works fine as long as the application's layout contains exactly as many views than the library's. However, when I add more views to the application's layout, the following exception happens at runtime when inflating the layout:
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.plnech.example, PID: 31773
java.lang.ArrayIndexOutOfBoundsException: length=2; index=2
at android.databinding.ViewDataBinding.mapBindings(ViewDataBinding.java:938)
at android.databinding.ViewDataBinding.mapBindings(ViewDataBinding.java:995)
at android.databinding.ViewDataBinding.mapBindings(ViewDataBinding.java:568)
at com.plnech.library.databinding.HitsItemBinding.<init>(HitsItemBinding.java:23)
at com.plnech.library.databinding.HitsItemBinding.bind(HitsItemBinding.java:102)
at android.databinding.DataBinderMapper.getDataBinder(DataBinderMapper.java:11)
at android.databinding.DataBindingUtil.bind(DataBindingUtil.java:185)
at android.databinding.DataBindingUtil.inflate(DataBindingUtil.java:120)
at android.databinding.DataBindingUtil.inflate(DataBindingUtil.java:88)
at com.plnech.library.helper.databinding.ResultsAdapter.onCreateViewHolder(ResultsAdapter.java:36)
at com.plnech.library.helper.databinding.ResultsAdapter.onCreateViewHolder(ResultsAdapter.java:21)
at android.support.v7.widget.RecyclerView$Adapter.createViewHolder(RecyclerView.java:5482)
at android.support.v7.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:4707)
at android.support.v7.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:4617)
at android.support.v7.widget.LinearLayoutManager$LayoutState.next(LinearLayoutManager.java:1994)
at android.support.v7.widget.LinearLayoutManager.layoutChunk(LinearLayoutManager.java:1390)
at android.support.v7.widget.LinearLayoutManager.fill(LinearLayoutManager.java:1353)
at android.support.v7.widget.LinearLayoutManager.onLayoutChildren(LinearLayoutManager.java:574)
at android.support.v7.widget.RecyclerView.dispatchLayoutStep2(RecyclerView.java:3028)
at android.support.v7.widget.RecyclerView.onMeasure(RecyclerView.java:2625)
at android.view.View.measure(View.java:18788)
at android.widget.RelativeLayout.measureChild(RelativeLayout.java:676)
at android.widget.RelativeLayout.onMeasure(RelativeLayout.java:479)
at android.view.View.measure(View.java:18788)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5951)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:194)
at android.support.v7.widget.ContentFrameLayout.onMeasure(ContentFrameLayout.java:135)
at android.view.View.measure(View.java:18788)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5951)
at android.support.v7.widget.ActionBarOverlayLayout.onMeasure(ActionBarOverlayLayout.java:391)
at android.view.View.measure(View.java:18788)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5951)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:194)
at android.view.View.measure(View.java:18788)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5951)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1465)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:748)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:630)
at android.view.View.measure(View.java:18788)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5951)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:194)
at com.android.internal.policy.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2643)
at android.view.View.measure(View.java:18788)
at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:2100)
at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1216)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1452)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1107)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:6013)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:858)
at android.view.Choreographer.doCallbacks(Choreographer.java:670)
at android.view.Choreographer.doFrame(Choreographer.java:606)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:844)
at android.os.Handler.handleCallback
It seems that as the library's layout has only 1 item, the generated bindings are stored in a array of length=1, and then accessed at index 2 as the application's layout has 2 items. But if the prioritization is done at compile-time, shouldn't the bindings be generated with the application's layout?
Likewise, when the application's layout has less Views than the library's, I get this exception when inflating the layout:
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.plnech.example, PID: 14269
java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.TextView.setTag(java.lang.Object)' on a null object reference
at com.plnech.library.databinding.HitsItemBinding.<init>(HitsItemBinding.java:31)
at com.plnech.library.databinding.HitsItemBinding.bind(HitsItemBinding.java:118)
at android.databinding.DataBinderMapper.getDataBinder(DataBinderMapper.java:11)
at android.databinding.DataBindingUtil.bind(DataBindingUtil.java:185)
at android.databinding.DataBindingUtil.inflate(DataBindingUtil.java:120)
at android.databinding.DataBindingUtil.inflate(DataBindingUtil.java:88)
at com.plnech.library.helper.databinding.ResultsAdapter.onCreateViewHolder(ResultsAdapter.java:36)
at com.plnech.library.helper.databinding.ResultsAdapter.onCreateViewHolder(ResultsAdapter.java:21)
at android.support.v7.widget.RecyclerView$Adapter.createViewHolder(RecyclerView.java:5482)
at android.support.v7.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:4707)
at android.support.v7.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:4617)
at android.support.v7.widget.LinearLayoutManager$LayoutState.next(LinearLayoutManager.java:1994)
at android.support.v7.widget.LinearLayoutManager.layoutChunk(LinearLayoutManager.java:1390)
at android.support.v7.widget.LinearLayoutManager.fill(LinearLayoutManager.java:1353)
at android.support.v7.widget.LinearLayoutManager.onLayoutChildren(LinearLayoutManager.java:574)
at android.support.v7.widget.RecyclerView.dispatchLayoutStep2(RecyclerView.java:3028)
at android.support.v7.widget.RecyclerView.onMeasure(RecyclerView.java:2625)
at android.view.View.measure(View.java:18788)
at android.widget.RelativeLayout.measureChild(RelativeLayout.java:676)
at android.widget.RelativeLayout.onMeasure(RelativeLayout.java:479)
at android.view.View.measure(View.java:18788)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5951)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:194)
at android.support.v7.widget.ContentFrameLayout.onMeasure(ContentFrameLayout.java:135)
at android.view.View.measure(View.java:18788)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5951)
at android.support.v7.widget.ActionBarOverlayLayout.onMeasure(ActionBarOverlayLayout.java:391)
at android.view.View.measure(View.java:18788)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5951)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:194)
at android.view.View.measure(View.java:18788)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5951)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1465)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:748)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:630)
at android.view.View.measure(View.java:18788)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5951)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:194)
at com.android.internal.policy.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2643)
at android.view.View.measure(View.java:18788)
at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:2100)
at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1216)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1452)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1107)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:6013)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:858)
at android.view.Choreographer.doCallbacks(Choreographer.java:670)
at android.view.Choreographer.doFrame(Choreographer.java:606)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:844)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:148)
Is there a way to use data binding and still allow an application to redefine a bound resource with a different amount of Views?
来源：https://stackoverflow.com/questions/37213375/is-it-possible-to-redefine-a-librarys-databinding-resource