如何在 Android 中正确隐藏活动标题

Question

 @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        requestWindowFeature(Window.FEATURE_NO_TITLE);
        setContentView(R.layout.activity_main);
}

crashes my app with the error

android.util.AndroidRuntimeException: requestFeature() must be called before adding content

I know I have to request window feature before setting the content view and that's what I'm doing. Why is the error still there?

My Acitivty extends AppCompatActivity and is declared in manifest like this:

 <activity
            android:name=".activity.CameraActivity"
            android:label="@string/title_activity_camera"
            android:theme="@style/Theme.AppCompat.Light.Dialog"></activity>

EDIT full stack trace:

Process: irisrecognition.example.com.irisrecognition, PID: 29756
 java.lang.RuntimeException: Unable to start activity ComponentInfo{irisrecognition.example.com.irisrecognition/irisrecognition.example.com.irisrecognition.activity.CameraActivity}: android.util.AndroidRuntimeException: requestFeature() must be called before adding content
     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2693)
     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2758)
     at android.app.ActivityThread.access$900(ActivityThread.java:177)
     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1448)
     at android.os.Handler.dispatchMessage(Handler.java:102)
     at android.os.Looper.loop(Looper.java:145)
     at android.app.ActivityThread.main(ActivityThread.java:5942)
     at java.lang.reflect.Method.invoke(Native Method)
     at java.lang.reflect.Method.invoke(Method.java:372)
     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1400)
     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1195)
  Caused by: android.util.AndroidRuntimeException: requestFeature() must be called before adding content
     at com.android.internal.policy.impl.PhoneWindow.requestFeature(PhoneWindow.java:359)
     at android.app.Activity.requestWindowFeature(Activity.java:3785)
     at irisrecognition.example.com.irisrecognition.activity.CameraActivity.onCreate(CameraActivity.java:56)
     at android.app.Activity.performCreate(Activity.java:6289)
     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1119)
     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2646)
     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2758) 
     at android.app.ActivityThread.access$900(ActivityThread.java:177) 
     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1448) 
     at android.os.Handler.dispatchMessage(Handler.java:102) 
     at android.os.Looper.loop(Looper.java:145) 
     at android.app.ActivityThread.main(ActivityThread.java:5942) 
     at java.lang.reflect.Method.invoke(Native Method) 
     at java.lang.reflect.Method.invoke(Method.java:372) 
     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1400) 
     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1195) 

Answer 1

You must call requestFeature before super.onCreate. it's necessary to call requestFeature() before super.onCreate() replace your code with

@Override
    protected void onCreate(Bundle savedInstanceState) {
        requestWindowFeature(Window.FEATURE_NO_TITLE);            
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
}

Answer 2

call requestWindowFeature before super.onCreate

@Override
    protected void onCreate(Bundle savedInstanceState) {
        requestWindowFeature(Window.FEATURE_NO_TITLE);
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
}

Answer 3

you can try this:

<style name="Theme.AppCompat.Light.NoActionBar.FullScreen" parent="@style/Theme.AppCompat.Light">
    <item name="windowNoTitle">true</item>
    <item name="windowActionBar">false</item>
    <item name="android:windowFullscreen">true</item>
    <item name="android:windowContentOverlay">@null</item>
</style>

I hope this will help you.