Question

打开应用程序后，它将成功打开并运行我们的“ MenuActivity.java”。但是，当我们单击一个按钮以启动单独的活动“ MainActivity.java”时，该应用程序不会崩溃，也不会跟踪堆栈或其他任何东西。这是MenuActivity


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_menu);

        Button button = findViewById(R.id.buttonDiceRoller);
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent intent = new Intent(MenuActivity.this, MainActivity.class);
                startActivity(intent);
                finish();
            }
        });
    }
}

这是MainActivity的开始


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Toolbar toolbar = findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

这是我们的android清单文件

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.cs125final">

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity
            android:name=".MenuActivity"
            android:label="@string/app_name"
            android:theme="@style/AppTheme.NoActionBar">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity
            android:name=".MainActivity"
            android:label="CS125Final" >
        </activity>
    </application>

</manifest>

这是应用程序在运行时的外观。 If you want to view it not really necesarry

然后，当您单击diceRoller按钮时，该应用程序将关闭，并且屏幕上显示“您的应用程序不断停止”。

为什么会这样？大型logcat：

2019-12-09 17:37:53.628 12050-12050/com.example.cs125final E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.example.cs125final, PID: 12050
    java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.cs125final/com.example.cs125final.MainActivity}: 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: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: 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:345)
        at androidx.appcompat.app.AppCompatActivity.setSupportActionBar(AppCompatActivity.java:130)
        at com.example.cs125final.MainActivity.onCreate(MainActivity.java:25)
        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) 
        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) 
2019-12-09 17:37:53.636 12050-12050/com.example.cs125final I/Process: Sending signal. PID: 12050 SIG: 9

Answer 1

两个主题都必须设置为

android:theme="@style/AppTheme.NoActionBar"

Answer 2

以您的样式，以这种方式定义父项

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

startActivity（intent）;似乎总是使应用崩溃

2 个答案: