我遇到了有关我的 Fragment 和与之交互的 Activity 的问题:
2020-03-08 19:47:43.864 29471-29471/? I/roid.calculato: Not late-enabling -Xcheck:jni (already on)
2020-03-08 19:47:43.941 29471-29471/? E/roid.calculato: Unknown bits set in runtime_flags: 0x8000
2020-03-08 19:47:43.942 29471-29471/? W/roid.calculato: Unexpected CPU variant for X86 using defaults: x86
2020-03-08 19:47:44.252 29471-29471/fr.android.calculator W/RenderThread: type=1400 audit(0.0:145): avc: denied { write } for name="property_service" dev="tmpfs" ino=23 scontext=u:r:untrusted_app:s0:c133,c256,c512,c768 tcontext=u:object_r:property_socket:s0 tclass=sock_file permissive=0 app=fr.android.calculator
2020-03-08 19:47:44.260 29471-29507/fr.android.calculator D/libEGL: Emulator has host GPU support, qemu.gles is set to 1.
2020-03-08 19:47:44.261 29471-29507/fr.android.calculator W/libc: Unable to set property "qemu.gles" to "1": connection failed; errno=13 (Permission denied)
2020-03-08 19:47:44.305 29471-29507/fr.android.calculator D/libEGL: loaded /vendor/lib/egl/libEGL_emulation.so
2020-03-08 19:47:44.314 29471-29507/fr.android.calculator D/libEGL: loaded /vendor/lib/egl/libGLESv1_CM_emulation.so
2020-03-08 19:47:44.323 29471-29507/fr.android.calculator D/libEGL: loaded /vendor/lib/egl/libGLESv2_emulation.so
2020-03-08 19:47:44.484 29471-29471/fr.android.calculator W/roid.calculato: Accessing hidden method Landroid/view/View;->computeFitSystemWindows(Landroid/graphics/Rect;Landroid/graphics/Rect;)Z (greylist, reflection, allowed)
2020-03-08 19:47:44.485 29471-29471/fr.android.calculator W/roid.calculato: Accessing hidden method Landroid/view/ViewGroup;->makeOptionalFitsSystemWindows()V (greylist, reflection, allowed)
2020-03-08 19:47:44.563 29471-29471/fr.android.calculator D/AndroidRuntime: Shutting down VM
2020-03-08 19:47:44.566 29471-29471/fr.android.calculator E/AndroidRuntime: FATAL EXCEPTION: main
Process: fr.android.calculator, PID: 29471
java.lang.RuntimeException: Unable to start activity ComponentInfo{fr.android.calculator/fr.android.calculator.Activities.CalculatorSecondActivity}: android.view.InflateException: Binary XML file line #8 in fr.android.calculator:layout/activity_calculator_second: Binary XML file line #13 in fr.android.calculator:layout/content_calculator_second: Error inflating class fragment
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3270)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3409)
at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:83)
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2016)
at android.os.Handler.dispatchMessage(Handler.java:107)
at android.os.Looper.loop(Looper.java:214)
at android.app.ActivityThread.main(ActivityThread.java:7356)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:930)
Caused by: android.view.InflateException: Binary XML file line #8 in fr.android.calculator:layout/activity_calculator_second: Binary XML file line #13 in fr.android.calculator:layout/content_calculator_second: Error inflating class fragment
Caused by: android.view.InflateException: Binary XML file line #13 in fr.android.calculator:layout/content_calculator_second: Error inflating class fragment
Caused by: java.lang.NullPointerException
at java.lang.VMClassLoader.findLoadedClass(Native Method)
at java.lang.ClassLoader.findLoadedClass(ClassLoader.java:738)
at java.lang.ClassLoader.loadClass(ClassLoader.java:363)
at java.lang.ClassLoader.loadClass(ClassLoader.java:312)
at android.app.Fragment.instantiate(Fragment.java:536)
at android.app.FragmentContainer.instantiate(FragmentContainer.java:53)
at android.app.FragmentManagerImpl.onCreateView(FragmentManager.java:3553)
at android.app.FragmentController.onCreateView(FragmentController.java:104)
at android.app.Activity.onCreateView(Activity.java:6948)
at androidx.fragment.app.FragmentActivity.onCreateView(FragmentActivity.java:338)
at android.view.LayoutInflater.tryCreateView(LayoutInflater.java:1069)
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:997)
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:961)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:1123)
at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:1084)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:1126)
at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:1084)
at android.view.LayoutInflater.parseInclude(LayoutInflater.java:1263)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:1119)
at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:1084)
at android.view.LayoutInflater.inflate(LayoutInflater.java:682)
at android.view.LayoutInflater.inflate(LayoutInflater.java:534)
at android.view.LayoutInflater.inflate(LayoutInflater.java:481)
at androidx.appcompat.app.AppCompatDelegateImpl.setContentView(AppCompatDelegateImpl.java:555)
at androidx.appcompat.app.AppCompatActivity.setContentView(AppCompatActivity.java:161)
at fr.android.calculator.Activities.CalculatorSecondActivity.onCreate(CalculatorSecondActivity.java:15)
at android.app.Activity.performCreate(Activity.java:7802)
at android.app.Activity.performCreate(Activity.java:7791)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1299)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3245)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3409)
2020-03-08 19:47:44.568 29471-29471/fr.android.calculator E/AndroidRuntime: at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:83)
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2016)
at android.os.Handler.dispatchMessage(Handler.java:107)
at android.os.Looper.loop(Looper.java:214)
at android.app.ActivityThread.main(ActivityThread.java:7356)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:930)
2020-03-08 19:47:44.595 29471-29471/fr.android.calculator I/Process: Sending signal. PID: 29471 SIG: 9
这是我的 Activity :
public class CalculatorSecondActivity extends AppCompatActivity implements LowerCalculatorFragment.OnFragmentInteractionListener {
private LowerCalculatorFragment lowerCalculatorFragment;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_calculator_second);
lowerCalculatorFragment = LowerCalculatorFragment.newInstance("fragment","you");
getSupportFragmentManager().beginTransaction().add(R.id.lowerCalculator,lowerCalculatorFragment).commit();
}
@Override
public void onFragmentInteraction(Uri uri) {
}
}
这是我的 fragment :
public class LowerCalculatorFragment extends Fragment {
// TODO: Rename parameter arguments, choose names that match
// the fragment initialization parameters, e.g. ARG_ITEM_NUMBER
private static final String ARG_PARAM1 = "param1";
private static final String ARG_PARAM2 = "param2";
// TODO: Rename and change types of parameters
private String mParam1;
private String mParam2;
private OnFragmentInteractionListener mListener;
/**
* Use this factory method to create a new instance of
* this fragment using the provided parameters.
*
* @param param1 Parameter 1.
* @param param2 Parameter 2.
* @return A new instance of fragment LowerCalculatorFragment.
*/
// TODO: Rename and change types and number of parameters
public static LowerCalculatorFragment newInstance(String param1, String param2) {
LowerCalculatorFragment fragment = new LowerCalculatorFragment();
Bundle args = new Bundle();
args.putString(ARG_PARAM1, param1);
args.putString(ARG_PARAM2, param2);
fragment.setArguments(args);
return fragment;
}
public LowerCalculatorFragment() {
// Required empty public constructor
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (getArguments() != null) {
mParam1 = getArguments().getString(ARG_PARAM1);
mParam2 = getArguments().getString(ARG_PARAM2);
}
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
return inflater.inflate(R.layout.fragment_lower_calculator, container, false);
}
// TODO: Rename method, update argument and hook method into UI event
public void onButtonPressed(Uri uri) {
if (mListener != null) {
mListener.onFragmentInteraction(uri);
}
}
@Override
public void onAttach(Context context) {
super.onAttach(context);
if (context instanceof OnFragmentInteractionListener) {
mListener = (OnFragmentInteractionListener) context;
} else {
throw new RuntimeException(context.toString()
+ " must implement OnFragmentInteractionListener");
}
}
@Override
public void onDetach() {
super.onDetach();
mListener = null;
}
/**
* This interface must be implemented by activities that contain this
* fragment to allow an interaction in this fragment to be communicated
* to the activity and potentially other fragments contained in that
* activity.
* <p>
* See the Android Training lesson <a href=
* "http://developer.android.com/training/basics/fragments/communicating.html"
* >Communicating with Other Fragments</a> for more information.
*/
public interface OnFragmentInteractionListener {
// TODO: Update argument type and name
void onFragmentInteraction(Uri uri);
}
}
这是我的 Activity 布局:
<?xml version="1.0" encoding="utf-8"?>
<androidx.coordinatorlayout.widget.CoordinatorLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".Activities.CalculatorSecondActivity">
<include layout="@layout/content_calculator_second"/>
</androidx.coordinatorlayout.widget.CoordinatorLayout>
我的 Activity 的内容布局:
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="@string/appbar_scrolling_view_behavior"
tools:showIn="@layout/activity_calculator_second"
tools:context=".Activities.CalculatorSecondActivity">
<FrameLayout android:layout_width="wrap_content" android:layout_height="wrap_content"
tools:ignore="MissingConstraints">
<fragment android:layout_width="match_parent" android:layout_height="match_parent"
android:id="@+id/lowerCalculator"></fragment>
</FrameLayout>
</androidx.constraintlayout.widget.ConstraintLayout>
最后是与我的 fragment 关联的布局:
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".Fragments.LowerCalculatorFragment">
<!-- TODO: Update blank fragment layout -->
<LinearLayout
android:background="@drawable/textview_border"
android:orientation="horizontal"
android:layout_width="match_parent"
android:layout_height="0dp" android:id="@+id/numberOperators">
<LinearLayout
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_margin="10dp"
android:layout_height="match_parent" android:id="@+id/numbers">
<LinearLayout
android:orientation="horizontal"
android:layout_width="match_parent"
android:layout_height="match_parent" android:layout_weight="1" android:id="@+id/SevenToPlus">
<Button
android:text="7"
android:layout_width="0dp"
android:layout_height="match_parent" android:id="@+id/button7" android:layout_weight="1"
/>
<Button
android:text="8"
android:layout_width="0dp"
android:layout_height="match_parent" android:id="@+id/button8" android:layout_weight="1"
/>
<Button
android:text="9"
android:layout_width="0dp"
android:layout_height="match_parent" android:id="@+id/button9" android:layout_weight="1"
/>
<Button
android:text="+"
android:layout_width="0dp"
android:layout_height="match_parent" android:id="@+id/buttonPlus" android:layout_weight="1"
/>
</LinearLayout>
<LinearLayout
android:orientation="horizontal"
android:layout_width="match_parent"
android:layout_height="match_parent" android:id="@+id/FourToMinus-">
<Button
android:text="4"
android:layout_width="0dp"
android:layout_height="match_parent" android:id="@+id/button4" android:layout_weight="1"
/>
<Button
android:text="5"
android:layout_width="0dp"
android:layout_height="match_parent" android:id="@+id/button5" android:layout_weight="1"
/>
<Button
android:text="6"
android:layout_width="0dp"
android:layout_height="match_parent" android:id="@+id/button6" android:layout_weight="1"
/>
<Button
android:text="-"
android:layout_width="0dp"
android:layout_height="match_parent" android:id="@+id/buttonMinus" android:layout_weight="1"
/>
</LinearLayout>
<LinearLayout
android:orientation="horizontal"
android:layout_width="match_parent"
android:layout_height="match_parent" android:layout_weight="1" android:id="@+id/OneToAsterix">
<Button
android:text="1"
android:layout_width="0dp"
android:layout_height="match_parent" android:id="@+id/button1" android:layout_weight="1"
/>
<Button
android:text="2"
android:layout_width="0dp"
android:layout_height="match_parent" android:id="@+id/button2" android:layout_weight="1"
/>
<Button
android:text="3"
android:layout_width="0dp"
android:layout_height="match_parent" android:id="@+id/button3" android:layout_weight="1"
/>
<Button
android:text="*"
android:layout_width="0dp"
android:layout_height="match_parent" android:id="@+id/buttonTimes" android:layout_weight="1"
/>
</LinearLayout>
<LinearLayout
android:orientation="horizontal"
android:layout_width="match_parent"
android:layout_height="match_parent" android:layout_weight="1" android:id="@+id/ZeroAndDivide">
<Button
android:text="0"
android:layout_width="0dp"
android:layout_height="match_parent" android:id="@+id/button0" android:layout_weight="1"
/>
<Button
android:text="/"
android:layout_width="0dp"
android:layout_height="match_parent" android:id="@+id/buttonDivide"
android:layout_weight="1"
/>
</LinearLayout>
</LinearLayout>
<LinearLayout
android:layout_margin="10dp"
android:orientation="horizontal"
android:layout_width="match_parent"
android:layout_height="match_parent" android:id="@+id/resultButton">
</LinearLayout>
</LinearLayout>
</FrameLayout>
你们能看出问题出在哪里吗？因为我不...
预先感谢您的帮助
最佳答案
您正在使用
<fragment android:layout_width="match_parent" android:layout_height="match_parent"
android:id="@+id/lowerCalculator"></fragment>
<fragment>标签必须与 android:name 一起使用或class属性指向你的类。由于您不使用其中任何一个，因此在为您的 fragment 查找空类名时会崩溃。
由于您是以编程方式添加 fragment (通过 beginTransaction() )，因此您不应该使用 <fragment>根本没有标签。相反，使用简单的 FrameLayout或者，如果您使用 Fragment 1.2.0或更高版本，您应该使用 FragmentContainerView :
<FrameLayout android:layout_width="wrap_content" android:layout_height="wrap_content"
tools:ignore="MissingConstraints">
<androidx.fragment.app.FragmentContainerView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="@+id/lowerCalculator" />
</FrameLayout>
关于java - 关于 fragment 的类膨胀错误，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/60591463/