Java 如何修复空指针异常Firebase Auth
我试图用FirebaseAuth从当前经过身份验证的用户检索并显示用户名,但应用程序因NullPointerException而崩溃 我尝试在控制台中显示user.getDisplayName()的值,其值不为NullJava 如何修复空指针异常Firebase Auth,java,android,firebase,firebaseui,Java,Android,Firebase,Firebaseui,我试图用FirebaseAuth从当前经过身份验证的用户检索并显示用户名,但应用程序因NullPointerException而崩溃 我尝试在控制台中显示user.getDisplayName()的值,其值不为Null ImageView profilePicView=findviewbyd(R.id.profile\u pic); TextView-nameView=findviewbyd(R.id.name); TextView emailView=findviewbyd(R.id.emai
ImageView profilePicView=findviewbyd(R.id.profile\u pic);
TextView-nameView=findviewbyd(R.id.name);
TextView emailView=findviewbyd(R.id.email);
FirebaseUser=FirebaseAuth.getInstance().getCurrentUser();
如果(用户!=null){
if(user.getDisplayName()!=null){
System.out.println(“------------------------------用户显示名称:“+user.getDisplayName());
nameView.setText(user.getDisplayName());
}
if(user.getEmail()!=null){
emailView.setText(user.getEmail());
}
if(user.getPhotoUrl()!=null){
用(这个)滑翔
.load(user.getPhotoUrl())
.进入(个人资料视图);
}
}
这是堆栈错误
I/System.out: ------------------------------user display name : Mohammed Elmahdi Bechlaghem
D/AndroidRuntime: Shutting down VM
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.megadevbrain.ranahna, PID: 20913
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.megadevbrain.ranahna/com.megadevbrain.ranahna.Navigation}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.TextView.setText(java.lang.CharSequence)' on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3121)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3264)
at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:78)
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:108)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:68)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1955)
at android.os.Handler.dispatchMessage(Handler.java:106)
at android.os.Looper.loop(Looper.java:214)
at android.app.ActivityThread.main(ActivityThread.java:7076)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:965)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.TextView.setText(java.lang.CharSequence)' on a null object reference
at com.megadevbrain.ranahna.Navigation.onCreate(Navigation.java:52)
at android.app.Activity.performCreate(Activity.java:7327)
at android.app.Activity.performCreate(Activity.java:7318)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1275)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3101)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3264)
at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:78)
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:108)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:68)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1955)
at android.os.Handler.dispatchMessage(Handler.java:106)
at android.os.Looper.loop(Looper.java:214)
at android.app.ActivityThread.main(ActivityThread.java:7076)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:965)
I/Process: Sending signal. PID: 20913 SIG: 9
Process 20913 terminated.
空指针尝试说您的Textview为空。这可能是因为findviewbyid与XML上的正确ID不匹配。确保您的id与XML和.Java文件匹配,您必须在调用对象的方法中使用线程。nameView或emailView变量为空。请检查R.id.name和R.id.email是否为当前视图xml中的有效文本视图。确保您的
xml
中有idname
的testview
。或者发布你的xml
文件。这非常有用,我使用的是导航抽屉,没有“getHeaderView(0).findViewById(R.id.profile_pic)”,完全错过了它,谢谢你的帮助。