调用startActivity()后应用程序崩溃

Question

我有一个注册的活动(RegisterActivity(，按下注册按钮后，我必须加载另一个包含许多片段的活动(MenuActivity(。问题是当我点击注册按钮时，我的应用程序崩溃了。我该怎么做？我的代码中有错误吗？如果需要，我还会发布MenuActivity和MenuFragment的.xml文件。提前感谢大家！这是我的代码：

MenuActivity.class

public class MenuActivity extends AppCompatActivity implements NavigationView.OnNavigationItemSelectedListener {
private DrawerLayout drawer;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_menu);
Toolbar toolbar = findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
drawer = findViewById(R.id.drawer_layout);
NavigationView navigationView = findViewById(R.id.nav_view);
navigationView.setNavigationItemSelectedListener(this);
ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(this, drawer, toolbar,
R.string.navigation_drawer_open, R.string.navigation_drawer_close);
drawer.addDrawerListener(toggle);
toggle.syncState();
if(savedInstanceState == null) {
getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container,
new MenuFragment()).commit();
navigationView.setCheckedItem(R.id.nav_profile);
}
}
@Override
public void onBackPressed() {
if(drawer.isDrawerOpen(GravityCompat.START)) {
drawer.closeDrawer(GravityCompat.START);
} else {
super.onBackPressed();
}
}
@Override
public boolean onNavigationItemSelected(@NonNull MenuItem item) {
switch(item.getItemId()) {
case R.id.nav_menu:
getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container,
new MenuFragment()).commit();
break;
case R.id.nav_profile:
getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container,
new ProfileFragment()).commit();
break;
case R.id.nav_send:
getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container,
new SendFragment()).commit();
break;
case R.id.nav_settings:
getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container,
new SettingsFragment()).commit();
break;
}
drawer.closeDrawer(GravityCompat.START);
return true;
}
}

RegisterActivity.class

mAuth.createUserWithEmailAndPassword(email, password).addOnCompleteListener(new OnCompleteListener<AuthResult>() {
@Override
public void onComplete(@NonNull Task<AuthResult> task) {
if(task.isSuccessful()) {
Toast.makeText(RegisterActivity.this, "User successful created", Toast.LENGTH_SHORT).show();
startActivity(new Intent(getApplicationContext(), MenuActivity.class));
//Intent intent = new Intent(getApplicationContext(), MenuActivity.class);
//intent.putExtra("fullName", fullName);
//startActivity(intent);
}
else {
Toast.makeText(RegisterActivity.this, "Error! " +
task.getException().getMessage(), Toast.LENGTH_SHORT).show();
}
}
});

这是消息错误：

E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.xxxxxxx, PID: 5790
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.xxxxxxx/com.example.xxxxxxx.activities.MenuActivity}: java.lang.IllegalStateException: This Activity already has an action bar supplied by the window decor. Do not request Window.FEATURE_SUPPORT_ACTION_BAR and set windowActionBar to false in your theme to use a Toolbar instead.
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2646)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2707)
at android.app.ActivityThread.-wrap12(ActivityThread.java)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1460)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6077)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:866)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:756)
Caused by: java.lang.IllegalStateException: This Activity already has an action bar supplied by the window decor. Do not request Window.FEATURE_SUPPORT_ACTION_BAR and set windowActionBar to false in your theme to use a Toolbar instead.
at androidx.appcompat.app.AppCompatDelegateImpl.setSupportActionBar(AppCompatDelegateImpl.java:572)
at androidx.appcompat.app.AppCompatActivity.setSupportActionBar(AppCompatActivity.java:159)
at com.example.inbioaiqua.activities.MenuActivity.onCreate(MenuActivity.java:30)
at android.app.Activity.performCreate(Activity.java:6662)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1118)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2599)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2707) 
at android.app.ActivityThread.-wrap12(ActivityThread.java) 
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1460) 
at android.os.Handler.dispatchMessage(Handler.java:102) 
at android.os.Looper.loop(Looper.java:154) 
at android.app.ActivityThread.main(ActivityThread.java:6077) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:866) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:756) 

Answer 1

欢迎使用Stackoverflow。我很乐意帮助你，但你能像处理MenuActivity.class一样，向我们提供你的崩溃错误和整个RegisterActivity.class吗？可能有很多错误和解决方案，但乍一看很难回答。

此外，在看到代码的其余部分之前，我会提出两件事。

1.延迟startActivity((与toast消息的时间长度

这将向用户显示祝酒词消息；用户被创建"；然后转到MenuActivity.class。这是一个很好的练习，因为你的Toast不会引起任何问题，或者一旦你已经上了MenuActivity就不会显示。

要做到这一点，只需使用这个：

Handler mHandler = new Handler();
mHandler.postDelayed(new Runnable() {
@Override
public void run() {
Intent intent = new Intent(RegisterActivity.this, MenuActivity.class);
startActivity(intent);
finish();
}
}, 2000);
//Toast.LENGTH_SHORT = 2000 milisec = 2 seconds
//Toast.LENGHT_LONG = 3500 milisec = 3.5 seconds

---

2.在MenuActivity.class中显示您的消息

如果您不想延迟启动活动((，您只需在注册过程结束后，在用户进入MenuActivity后显示消息即可。为此，您可以使用intet.putExtra提供用户来自RegisterActivity.class.的信息

Intent intent = new Intent(RegisterActivity.this, MenuActivity.class);
intent.putExtra("NEW_USER", true);
startActivity(intent);
finish();

然后在OnCreate中的MenuActivity.class中写下这个。

if (getIntent().hasExtra("NEW_USER") && getIntent().getBooleanExtra("NEW_USER", false)) {
Toast.makeText(getBaseContext(), "User created succesfully", Toast.LENGTH_SHORT).show();
}

---

3.使用theme.xml或styles.xml删除ActionBar

你父母的主题是什么？如果您不想要ActionBar，那么在styles.xml中的基本主题中写下两行：

<item name="windowActionBar">false</item> 
<item name="windowNoTitle">true</item>

所以你的基本主题风格应该是这样的：

<!-- Base application theme. -->
<style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar">
<!-- Customize your theme here. -->
<item name="colorPrimary">@color/colorPrimary</item>
<item name="colorPrimaryDark">@color/colorPrimaryDark</item>
<item name="colorAccent">@color/colorAccent</item>
<item name="windowActionBar">false</item>
<item name="windowNoTitle">true</item>
</style>

或者，您可以简单地将基本主题扩展为NoActionBar主题，并可能解决此问题。

<style name="NoActionBarTheme" parent="Theme.AppCompat.Light.NoActionBar">
...
</style>

---

4.在AndroidManifest.xml中检查您的应用程序和活动主题

检查您在AndroidManifest.xml中使用的主题。可能是您的主题没有指向styles.xml或theme.xml中的正确主题。这也可以为每个活动更改，所以请检查您是否在某个地方覆盖了主题。

Answer 2

尝试以下源代码

startActivity(new Intent(getActivity(), MenuActivity.class));

当您在碎片上时，getApplicationContext()不起作用。所以，你必须尝试getActivity