Question

我试图解决它，但我无法做任何事情，我总是得到NPE即使尝试和捕获，我不知道还有什么要做，请一些帮助，

删除npe的正确方法是什么？我该怎么办？

try{
    if(user.isEmailVerified()){
      Log.d(TAG, "onComplete: success. email is verified.");
      Intent intent = new Intent(LoginActivity.this, HomeActivity.class);
      startActivity(intent);
    } else {
      Toast.makeText(mContext, "Email is not verified \n check your email inbox.", Toast.LENGTH_SHORT).show();
      mProgressbar.setVisibility(View.GONE);
      mPleaseWait.setVisibility(View.GONE);
      mAuth.signOut();
    }
} catch (NullPointerException e){
    Log.e(TAG, "onComplete: NullPointerException: " + e.getMessage() );
}

当我删除进度条时程序被执行但后来我在logcat中得到了所有这些...

02-18 21:03:17.670 1492-1492/? E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.togo.plgl.togo, PID: 1492
        java.lang.RuntimeException: Unable to start activity ComponentInfo{com.togo.plgl.togo/com.togo.plgl.togo.Home.HomeActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'void com.ittianyu.bottomnavigationviewex.BottomNavigationViewEx.enableAnimation(boolean)' on a null object reference
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2793)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2864)
        at android.app.ActivityThread.-wrap12(ActivityThread.java)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1567)
        at android.os.Handler.dispatchMessage(Handler.java:105)
        at android.os.Looper.loop(Looper.java:156)
        at android.app.ActivityThread.main(ActivityThread.java:6523)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:942)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:832)
    Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void com.ittianyu.bottomnavigationviewex.BottomNavigationViewEx.enableAnimation(boolean)' on a null object reference
        at com.togo.plgl.togo.utils.BottomNavigationViewHelper.setupBottomNavigationView(BottomNavigationViewHelper.java:26)
        at com.togo.plgl.togo.Home.HomeActivity.setupBottomNavigationView(HomeActivity.java:95)
        at com.togo.plgl.togo.Home.HomeActivity.onCreate(HomeActivity.java:51)
        at android.app.Activity.performCreate(Activity.java:6915)
        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1123)
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2746)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2864) 
        at android.app.ActivityThread.-wrap12(ActivityThread.java) 
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1567) 
        at android.os.Handler.dispatchMessage(Handler.java:105) 
        at android.os.Looper.loop(Looper.java:156) 
        at android.app.ActivityThread.main(ActivityThread.java:6523) 
        at java.lang.reflect.Method.invoke(Native Method) 
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:942) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:832) 
02-18 21:03:17.683 1492-1492/? I/Process: Sending signal. PID: 1492 SIG: 9

Answer 1

在这种情况下尝试捕获会阻止您的应用程序崩溃。这只是一个Lint警告。

如果要删除警告。首先检查变量user是否为空。

if (user == null){
    // show error
    return;
}
// your code

Answer 2

在调用isEmailverified之前检查用户。用户可能为null，因此当您尝试在null上调用一个方法时，编译器将通过空指针异常。

尝试if（user！= Null和user.isEmailVerified）

Answer 3

如果您使用mAuth记录用户，可以尝试

{
    "First":  [
                  0,
                  0
              ]
}

或

# Re-convert: $tempObj.First then *directly* contains the input array
#             (there is no .Value property anymore).
$tempObj = $json | ConvertFrom-Json

# Construct a new hashtable...
$List2 = @{ First = $tempObj.First }
# ... and convert it to JSON.
$List2 | ConvertTo-Json

在您要求方法

if(mAuth.getCurrentUser() != null) {

//do your stuff
if(user.isEmailVerified()){ ...}

}

之前

因此，您可以保证在请求用户信息之前已连接用户

我怎样才能解决这个问题？ “方法调用'isEmailVerified'可能会产生'java.lang.NullPointerException'”

3 个答案: