我尝试在我的应用程序上使用底部导航，但是它不起作用，并且应用程序崩溃。 这是我的主要活动：
public static String getStringFromSubscription(Subscription subscription) throws MbException {
Marshaller marshaller;
StringWriter stringWriter = new StringWriter();
try {
marshaller = JAXBContext.newInstance("com.myhealth.com").createMarshaller();
marshaller.setProperty(Marshaller.JAXB_FRAGMENT, true);
marshaller.setProperty("com.sun.xml.bind.xmlDeclaration", Boolean.FALSE);
marshaller.marshal(subscription, stringWriter);
} catch (Exception e) {
throw new MbException(e);
}
return stringWriter;
}
这是我的xml文件：
package com.example.testing;
import android.support.annotation.NonNull;
import android.support.design.widget.BottomNavigationView;
import android.support.v4.app.Fragment;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.MenuItem;
public class MainActivity extends AppCompatActivity implements BottomNavigationView.OnNavigationItemSelectedListener {
@Override
protected void onCreate (Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
loadFragment(new HomeFragment());
BottomNavigationView navigation = findViewById(R.id.navigation);
navigation.setOnNavigationItemSelectedListener(this);
}
public boolean onNavigationItemSelected(@NonNull MenuItem item) {
Fragment fragment = null;
switch (item.getItemId()) {
case R.id.homePage:
fragment = new HomeFragment();
break;
case R.id.chat:
fragment = new ChatFragment();
break;
}
return loadFragment(fragment);
}
private boolean loadFragment(Fragment fragment) {
if (fragment != null) {
getSupportFragmentManager()
.beginTransaction()
.replace(R.id.fragment_container, fragment)
.commit();
return true;
}
return false;
}
}
此外，我为导航创建了两个片段，它们都具有相同的xml和类代码
片段xml：
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.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/container"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<FrameLayout
android:id="@+id/fragment_container"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginBottom="56dp"
android:text="@string/title_home"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<android.support.design.widget.BottomNavigationView
android:id="@+id/navigation"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginStart="0dp"
android:layout_marginEnd="0dp"
android:background="?android:attr/windowBackground"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:menu="@menu/menu_nav" />
</android.support.constraint.ConstraintLayout>
片段类：
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:layout_centerVertical="true"
android:text="Home"
android:textAppearance="@style/Base.TextAppearance.AppCompat.Large" />
</RelativeLayout>
我还将此代码添加到了build.gradle
package com.example.testing;
public class HomeFragment extends Fragment {
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
return inflater.inflate(R.layout.fragment_home, null);
}
}
但是我在logcat中得到了什么：
implementation 'com.android.support:design:28.0.0'
请帮助
HERE是菜单xml：
--------- beginning of crash
2019-04-05 21:55:34.150 3169-3169/com.example.testing E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.testing, PID: 3169
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.testing/com.example.testing.MainActivity}: android.view.InflateException: Binary XML file line #20: Binary XML file line #20: Error inflating class android.support.design.widget.BottomNavigationView
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2778)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2856)
at android.app.ActivityThread.-wrap11(Unknown Source:0)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1589)
at android.os.Handler.dispatchMessage(Handler.java:106)
at android.os.Looper.loop(Looper.java:164)
at android.app.ActivityThread.main(ActivityThread.java:6494)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:438)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:807)
Caused by: android.view.InflateException: Binary XML file line #20: Binary XML file line #20: Error inflating class android.support.design.widget.BottomNavigationView
Caused by: android.view.InflateException: Binary XML file line #20: Error inflating class android.support.design.widget.BottomNavigationView
Caused by: java.lang.reflect.InvocationTargetException
at java.lang.reflect.Constructor.newInstance0(Native Method)
at java.lang.reflect.Constructor.newInstance(Constructor.java:334)
at android.view.LayoutInflater.createView(LayoutInflater.java:647)
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:790)
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:730)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:863)
at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:824)
at android.view.LayoutInflater.inflate(LayoutInflater.java:515)
at android.view.LayoutInflater.inflate(LayoutInflater.java:423)
at android.view.LayoutInflater.inflate(LayoutInflater.java:374)
at android.support.v7.app.AppCompatDelegateImpl.setContentView(AppCompatDelegateImpl.java:469)
at android.support.v7.app.AppCompatActivity.setContentView(AppCompatActivity.java:140)
at com.example.testing.MainActivity.onCreate(MainActivity.java:15)
at android.app.Activity.performCreate(Activity.java:7009)
at android.app.Activity.performCreate(Activity.java:7000)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1214)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2731)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2856)
at android.app.ActivityThread.-wrap11(Unknown Source:0)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1589)
at android.os.Handler.dispatchMessage(Handler.java:106)
at android.os.Looper.loop(Looper.java:164)
at android.app.ActivityThread.main(ActivityThread.java:6494)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:438)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:807)
Caused by: android.view.InflateException: Couldn't resolve menu item onClick handler chat in class com.example.testing.MainActivity
at android.support.v7.view.SupportMenuInflater$InflatedOnMenuItemClickListener.<init>(SupportMenuInflater.java:254)
at android.support.v7.view.SupportMenuInflater$MenuState.setItem(SupportMenuInflater.java:482)
at android.support.v7.view.SupportMenuInflater$MenuState.addItem(SupportMenuInflater.java:530)
at android.support.v7.view.SupportMenuInflater.parseMenu(SupportMenuInflater.java:206)
at android.support.v7.view.SupportMenuInflater.inflate(SupportMenuInflater.java:128)
at android.support.design.widget.BottomNavigationView.inflateMenu(BottomNavigationView.java:252)
at android.support.design.widget.BottomNavigationView.<init>(BottomNavigationView.java:187)
2019-04-05 21:55:34.152 3169-3169/com.example.testing E/AndroidRuntime: at android.support.design.widget.BottomNavigationView.<init>(BottomNavigationView.java:114)
... 26 more
Caused by: java.lang.NoSuchMethodException: chat [interface android.view.MenuItem]
at java.lang.Class.getMethod(Class.java:2068)
at java.lang.Class.getMethod(Class.java:1690)
at android.support.v7.view.SupportMenuInflater$InflatedOnMenuItemClickListener.<init>(SupportMenuInflater.java:250)
... 33 more
答案 0 :(得分：0)
Caused by: android.view.InflateException: Couldn't resolve menu item onClick handler chat in class com.example.testing.MainActivity
删除点击次数
答案 1 :(得分：0)
问题出在菜单XML文件中的这一行-
android:onClick="chat"
这试图引用方法public void chat(View)，该方法将处理菜单项的click事件。但是，您的活动中没有定义此类方法，因此应用程序崩溃，因为它找不到所需的方法。与其他菜单项相同，除了它崩溃之前甚至还没有崩溃。
解决方案？由于您已经为底部导航菜单实现了OnClick，因此请从菜单项中删除onClick属性。