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Java 尝试调用虚拟方法';void android.view.view.setAnimation(android.view.animation.animation)和#x27;关于空对象引用_Java_Android_Android Animation_Android Menu - Fatal编程技术网

Java 尝试调用虚拟方法';void android.view.view.setAnimation(android.view.animation.animation)和#x27;关于空对象引用

Java 尝试调用虚拟方法';void android.view.view.setAnimation(android.view.animation.animation)和#x27;关于空对象引用,java,android,android-animation,android-menu,Java,Android,Android Animation,Android Menu,我有通知菜单图标。我需要在调用onCreateOptions菜单()时设置动画 在实施过程中,我一直面临如下问题: Attempt to invoke virtual method 'void android.view.View.setAnimation(android.view.animation.Animation)' on a null object reference. Java代码: private Animation animation; @Override public bo

我有通知菜单图标。我需要在调用
onCreateOptions菜单()
时设置动画

在实施过程中,我一直面临如下问题:

Attempt to invoke virtual method 'void 
android.view.View.setAnimation(android.view.animation.Animation)' on a 
null object reference.
Java代码:

private Animation animation;
@Override
public boolean onCreateOptionsMenu(Menu menu) {
    getMenuInflater().inflate(R.menu.home_screen,menu);

    animation = 
 AnimationUtils.loadAnimation(getApplicationContext(),R.anim.notify);

menu.findItem(R.id.notifications).getActionView().setAnimation(animation);

    return super.onCreateOptionsMenu(menu);
}
home_screen.xml:

 <?xml version="1.0" encoding="utf-8"?>
 <menu xmlns:android="http://schemas.android.com/apk/res/android"
 xmlns:app="http://schemas.android.com/apk/res-auto">
 <item
    android:id="@+id/notifications"
    android:title="@string/action_settings"
    app:showAsAction="ifRoom"
    android:icon="@drawable/notifications"/>
  </menu>

notify.xml:

 <?xml version="1.0" encoding="utf-8"?>
 <rotate xmlns:android="http://schemas.android.com/apk/res/android"
android:fromDegrees="0"
android:toDegrees="180"
android:pivotX="50%"
android:pivotY="50%"
android:duration="500"
android:interpolator="@android:anim/accelerate_interpolator" />

请告诉我解决问题的方法。 提前感谢。

根据答案,您需要先设置动作视图。并尝试将用户图像视图作为自定义动作视图来设置菜单项的动画,以获取更多参考