当我将片段作为两个场景的根容器时。显示第一个场景1。当用户选择特定选项时,应用程序将进入第二个场景。scene2是scene1的副本,但只做了很少的修改,新的textview和button。
当用户点击按钮,我希望应用程序返回到以前的布局。我写的方法是:
public void exit(View v) {scene2.exit();}
并在按钮的onclick属性中将其名称作为参数传递。
不幸的是,我不能切换到以前的布局。系统引发以下异常:
java.lang.IllegalStateException: Could not find method exit(View) in a parent or ancestor Context for android:onClick attribute defined on view class com.google.android.material.button.MaterialButton with id 'button'
片段的java代码
public class SecondFragment extends Fragment {
private ViewGroup rootContainer;
private Scene scene1, scene2;
private Transition transitionMgr;
private SecondViewModel mViewModel;
private TextView valueView, rateView;
public static SecondFragment newInstance() {
return new SecondFragment();
}
@Override
public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container,
@Nullable Bundle savedInstanceState) {
setHasOptionsMenu(true);
View v = inflater.inflate(R.layout.root_container_fragment, container, false);
transitionMgr = TransitionInflater.from(getActivity()).inflateTransition(R.transition.transition);
rootContainer = (ViewGroup) v;
scene2 = Scene.getSceneForLayout(rootContainer, R.layout.scene2, getActivity());
scene1 = Scene.getSceneForLayout(rootContainer, R.layout.scene1, getActivity());
scene1.enter();
return v;
}
@RequiresApi(api = Build.VERSION_CODES.Q)
@Override
public void onActivityCreated(@Nullable Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
mViewModel = new ViewModelProvider(this).get(SecondViewModel.class);
mViewModel.getValueObject().observe(getViewLifecycleOwner(), valueObserver);
valueView = rootContainer.findViewById(R.id.valueView);
}
[....]
[....]
[.....]
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case R.id.one:
layoutPrepare("Dollar");
return true;
case R.id.two:
layoutPrepare("Euro");
return true;
default:
return super.onOptionsItemSelected(item);
}
}
private void layoutPrepare(String currency) {
scene2.setEnterAction(new Runnable() {
@Override
public void run() {
setHasOptionsMenu(false);
rateView = rootContainer.findViewById(R.id.rateView);
rateView.setText(String.valueOf(mViewModel.getRate(currency)));
valueView = rootContainer.findViewById(R.id.valueView);
valueView.setText(String.valueOf(mViewModel.conversion(currency)));
}
});
TransitionManager.go(scene2, transitionMgr);
}
public void exit(View v)
{
scene2.exit();
}
}
场景1和场景2的xml:
场景1:
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/main"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".SecondFragment">
<TextView
android:id="@+id/valueView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="228dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>
场景2:
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/main"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".SecondFragment">
<TextView
android:id="@+id/valueView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="464dp"
android:text="test"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.498"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<TextView
android:id="@+id/rateView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="59dp"
android:layout_marginTop="93dp"
android:text="test"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<Button
android:id="@+id/button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:onClick="exit"
android:text="Return"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.89" />
</androidx.constraintlayout.widget.ConstraintLayout>
1条答案
按热度按时间xn1cxnb41#
不确定这是否能解决你的问题,但根据tools:context
在定义哪个活动或片段类示例化了正在定义的布局时,tools:context起着主要作用。
两个xml都有工具:指向secondfragment的上下文。
因此,请尝试将布局更改为指向相应的片段。