带有 SharedPreferences 的 MainActivity 上的 NullPointerException，空对象引用上的“boolean java.lang.String.equals(java.lang.Object)”

问题描述 投票：0回答：1

所以我有一个使用

SharedPreferences
的类，在用户登录时我存储的
SharedPreferences
中，为此我有一个名为
checkLog
的方法，默认情况下设置“NoLog”，如果还有其他事情的话将向用户介绍 MainMenu 片段。我还有一个 
checkIntents
方法，当我从另一个片段启动 MainActivity 来传递一些数据时使用该方法（是的，我主要使用片段）。

代码通常可以正常工作，但在某些情况下会抛出 

NullPointerException: 'boolean java.lang.String.equals(java.lang.Object)' on a null object reference
。

代码：

package com.apple.fitinsights;

import android.content.Context;
import android.content.SharedPreferences;
import android.os.Bundle;

import androidx.appcompat.app.AppCompatActivity;
import androidx.fragment.app.Fragment;
import androidx.fragment.app.FragmentManager;
import androidx.fragment.app.FragmentTransaction;

import com.apple.fitinsights.intro.Intro_1;
import com.apple.fitinsights.mainPage.PreMainPage;

import java.util.Objects;

public class MainActivity extends AppCompatActivity {
    String checkLogTxt,checkIntents;
    SharedPreferences sharedPreferences;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        sharedPreferences = this.getPreferences(Context.MODE_PRIVATE);
        checkIntents = "";
        checkLogTxt = "";
        checkLog();
        checkIntents();
        if (!Objects.equals(checkLogTxt, "NoLog")) {
            replaceFragment(new PreMainPage());
        }

        else if (checkLogTxt.equals("NoLog")) {
            replaceFragment(new Intro_1());
        }

        if (checkIntents.equals("forTask")) {
            replaceFragment(new PreMainPage());
        }
    }

    public void checkLog() {
        String def = "NoLog";
        checkLogTxt = sharedPreferences.getString("UserLog",def);
    }

    public void checkIntents () {
        if (getIntent().getExtras() != null) {
            checkIntents = getIntent().getExtras().getString("ForTask");
        }
    }

    public  void replaceFragment(Fragment fragment) {
        FragmentManager fragmentManager = getSupportFragmentManager();
        FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
        fragmentTransaction.setCustomAnimations(R.anim.slide_in,R.anim.slide_out);
        fragmentTransaction.replace(R.id.fragment,fragment);
        fragmentTransaction.commit();
    }


}

Stacktrace（来自 Crashlytics）：

Fatal Exception: java.lang.RuntimeException: Unable to start activity ComponentInfo{com.apple.fitinsights/com.apple.fitinsights.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'boolean java.lang.String.equals(java.lang.Object)' on a null object reference
       at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3897)
       at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:4043)
       at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:101)
       at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
       at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
       at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2437)
       at android.os.Handler.dispatchMessage(Handler.java:106)
       at android.os.Looper.loopOnce(Looper.java:211)
       at android.os.Looper.loop(Looper.java:300)
       at android.app.ActivityThread.main(ActivityThread.java:8294)
       at java.lang.reflect.Method.invoke(Method.java)
       at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:580)
       at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1028)

Caused by java.lang.NullPointerException: Attempt to invoke virtual method 'boolean java.lang.String.equals(java.lang.Object)' on a null object reference
       at com.apple.fitinsights.MainActivity.onCreate(MainActivity.java:89)
       at android.app.Activity.performCreate(Activity.java:8538)
       at android.app.Activity.performCreate(Activity.java:8502)
       at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1437)
       at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3878)
       at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:4043)
       at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:101)
       at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
       at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
       at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2437)
       at android.os.Handler.dispatchMessage(Handler.java:106)
       at android.os.Looper.loopOnce(Looper.java:211)
       at android.os.Looper.loop(Looper.java:300)
       at android.app.ActivityThread.main(ActivityThread.java:8294)
       at java.lang.reflect.Method.invoke(Method.java)
       at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:580)
       at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1028)


DefaultDispatcher-worker-2:
       at jdk.internal.misc.Unsafe.park(Unsafe.java)
       at java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:376)
       at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.park(CoroutineScheduler.java:292)
       at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.tryPark(CoroutineScheduler.java:292)
       at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.runWorker(CoroutineScheduler.java:292)
       at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.run(CoroutineScheduler.java:292)

pool-11-thread-1:
       at jdk.internal.misc.Unsafe.park(Unsafe.java)
       at java.util.concurrent.locks.LockSupport.park(LockSupport.java:341)
       at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionNode.block(AbstractQueuedSynchronizer.java:506)
       at java.util.concurrent.ForkJoinPool.unmanagedBlock(ForkJoinPool.java:3466)
       at java.util.concurrent.ForkJoinPool.managedBlock(ForkJoinPool.java:3437)
       at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:1623)
       at java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:435)
       at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1071)
       at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1131)
       at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:644)
       at java.lang.Thread.run(Thread.java:1012)

Firebase Background Thread #2:
       at jdk.internal.misc.Unsafe.park(Unsafe.java)
       at java.util.concurrent.locks.LockSupport.park(LockSupport.java:341)
       at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionNode.block(AbstractQueuedSynchronizer.java:506)
       at java.util.concurrent.ForkJoinPool.unmanagedBlock(ForkJoinPool.java:3466)
       at java.util.concurrent.ForkJoinPool.managedBlock(ForkJoinPool.java:3437)
       at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:1623)
       at java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:435)
       at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1071)
       at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1131)
       at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:644)
       at com.google.firebase.concurrent.CustomThreadFactory.lambda$newThread$0(CustomThreadFactory.java:193)
       at java.lang.Thread.run(Thread.java:1012)

DefaultDispatcher-worker-3:
       at jdk.internal.misc.Unsafe.park(Unsafe.java)
       at java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:376)
       at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.park(CoroutineScheduler.java:292)
       at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.tryPark(CoroutineScheduler.java:292)
       at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.runWorker(CoroutineScheduler.java:292)
       at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.run(CoroutineScheduler.java:292)

Firebase Blocking Thread #1:
       at java.net.SocketInputStream.socketRead0(SocketInputStream.java)
       at java.net.SocketInputStream.socketRead(SocketInputStream.java:118)
       at java.net.SocketInputStream.read(SocketInputStream.java:173)
       at java.net.SocketInputStream.read(SocketInputStream.java:143)
       at com.android.org.conscrypt.ConscryptEngineSocket$SSLInputStream.readFromSocket(ConscryptEngineSocket.java:983)
       at com.android.org.conscrypt.ConscryptEngineSocket$SSLInputStream.processDataFromSocket(ConscryptEngineSocket.java:947)
       at com.android.org.conscrypt.ConscryptEngineSocket$SSLInputStream.-$$Nest$mprocessDataFromSocket()
       at com.android.org.conscrypt.ConscryptEngineSocket.doHandshake(ConscryptEngineSocket.java:236)
       at com.android.org.conscrypt.ConscryptEngineSocket.startHandshake(ConscryptEngineSocket.java:218)
       at com.android.okhttp.internal.io.RealConnection.connectTls(RealConnection.java:196)
       at com.android.okhttp.internal.io.RealConnection.connectSocket(RealConnection.java:153)
       at com.android.okhttp.internal.io.RealConnection.connect(RealConnection.java:116)
       at com.android.okhttp.internal.http.StreamAllocation.findConnection(StreamAllocation.java:186)
       at com.android.okhttp.internal.http.StreamAllocation.findHealthyConnection(StreamAllocation.java:128)
       at com.android.okhttp.internal.http.StreamAllocation.newStream(StreamAllocation.java:97)
       at com.android.okhttp.internal.http.HttpEngine.connect(HttpEngine.java:289)
       at com.android.okhttp.internal.http.HttpEngine.sendRequest(HttpEngine.java:232)
       at com.android.okhttp.internal.huc.HttpURLConnectionImpl.execute(HttpURLConnectionImpl.java:465)
       at com.android.okhttp.internal.huc.HttpURLConnectionImpl.connect(HttpURLConnectionImpl.java:131)
       at com.android.okhttp.internal.huc.HttpURLConnectionImpl.getOutputStream(HttpURLConnectionImpl.java:262)
       at com.android.okhttp.internal.huc.DelegatingHttpsURLConnection.getOutputStream(DelegatingHttpsURLConnection.java:219)
       at com.android.okhttp.internal.huc.HttpsURLConnectionImpl.getOutputStream(HttpsURLConnectionImpl.java:30)
       at com.google.firebase.installations.remote.FirebaseInstallationServiceClient.writeRequestBodyToOutputStream(FirebaseInstallationServiceClient.java)
       at com.google.firebase.installations.remote.FirebaseInstallationServiceClient.writeFIDCreateRequestBodyToOutputStream(FirebaseInstallationServiceClient.java:39)
       at com.google.firebase.installations.remote.FirebaseInstallationServiceClient.createFirebaseInstallation(FirebaseInstallationServiceClient.java:215)
       at com.google.firebase.installations.FirebaseInstallations.registerFidWithServer(FirebaseInstallations.java:215)
       at com.google.firebase.installations.FirebaseInstallations.doNetworkCallIfNecessary(FirebaseInstallations.java:94)
       at com.google.firebase.installations.FirebaseInstallations.lambda$doRegistrationOrRefresh$3(FirebaseInstallations.java:94)
       at com.google.firebase.concurrent.SequentialExecutor$1.run(SequentialExecutor.java:8)
       at com.google.firebase.concurrent.SequentialExecutor$QueueWorker.workOnQueue(SequentialExecutor.java:76)
       at com.google.firebase.concurrent.SequentialExecutor$QueueWorker.run(SequentialExecutor.java:12)
       at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
       at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:644)
       at com.google.firebase.concurrent.CustomThreadFactory.lambda$newThread$0(CustomThreadFactory.java:193)
       at java.lang.Thread.run(Thread.java:1012)

ScionFrontendApi:
       at jdk.internal.misc.Unsafe.park(Unsafe.java)
       at java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:252)
       at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awaitNanos(AbstractQueuedSynchronizer.java:1672)
       at java.util.concurrent.LinkedBlockingQueue.poll(LinkedBlockingQueue.java:460)
       at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1070)
       at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1131)
       at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:644)
       at java.lang.Thread.run(Thread.java:1012)

Timer-1:
       at java.lang.Object.wait(Object.java)
       at java.lang.Object.wait(Object.java:386)
       at java.lang.Object.wait(Object.java:524)
       at java.util.TimerThread.mainLoop(Timer.java:534)
       at java.util.TimerThread.run(Timer.java:513)

Timer-0:
       at java.lang.Object.wait(Object.java)
       at java.lang.Object.wait(Object.java:386)
       at java.lang.Object.wait(Object.java:524)
       at java.util.TimerThread.mainLoop(Timer.java:534)
       at java.util.TimerThread.run(Timer.java:513)

Firebase Background Thread #1:
       at jdk.internal.misc.Unsafe.park(Unsafe.java)
       at java.util.concurrent.locks.LockSupport.park(LockSupport.java:341)
       at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionNode.block(AbstractQueuedSynchronizer.java:506)
       at java.util.concurrent.ForkJoinPool.unmanagedBlock(ForkJoinPool.java:3466)
       at java.util.concurrent.ForkJoinPool.managedBlock(ForkJoinPool.java:3437)
       at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:1623)
       at java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:435)
       at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1071)
       at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1131)
       at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:644)
       at com.google.firebase.concurrent.CustomThreadFactory.lambda$newThread$0(CustomThreadFactory.java:193)
       at java.lang.Thread.run(Thread.java:1012)

android.app.IActivityManager$Stub$Proxy.getContentProvider(IActivityManager.java:5899)
       at android.app.ActivityThread.acquireProvider(ActivityThread.java:7408)
       at android.app.ContextImpl$ApplicationContentResolver.acquireUnstableProvider(ContextImpl.java:3465)
       at android.content.ContentResolver.acquireUnstableProvider(ContentResolver.java:2526)
       at android.content.ContentResolver.query(ContentResolver.java:1203)
       at android.content.ContentResolver.query(ContentResolver.java:1151)
       at android.content.ContentResolver.query(ContentResolver.java:1107)
       at m.oz.a(:com.google.android.gms.dynamite_measurementdynamite@[email protected] (190400-0):12)
       at m.pe.a(:com.google.android.gms.dynamite_measurementdynamite@[email protected] (190400-0):1)
       at m.pu.b(:com.google.android.gms.dynamite_measurementdynamite@[email protected] (190400-0):332)
       at m.qo.a(:com.google.android.gms.dynamite_measurementdynamite@[email protected] (190400-0):3)
       at m.gi.a(:com.google.android.gms.dynamite_measurementdynamite@[email protected] (190400-0):9)
       at m.jv.b(:com.google.android.gms.dynamite_measurementdynamite@[email protected] (190400-0):69)
       at m.jv.a(:com.google.android.gms.dynamite_measurementdynamite@[email protected] (190400-0):2)
       at m.kl.av(:com.google.android.gms.dynamite_measurementdynamite@[email protected] (190400-0):43)
       at m.kx.p(:com.google.android.gms.dynamite_measurementdynamite@[email protected] (190400-0):5)
       at m.ku.run(:com.google.android.gms.dynamite_measurementdynamite@[email protected] (190400-0):64)
       at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:487)
       at java.util.concurrent.FutureTask.run(FutureTask.java:264)
       at m.kq.run(:com.google.android.gms.dynamite_measurementdynamite@[email protected] (190400-0):48)

OkHttp ConnectionPool:
       at java.lang.Object.wait(Object.java)
       at com.android.okhttp.ConnectionPool$1.run(ConnectionPool.java:106)
       at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
       at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:644)
       at java.lang.Thread.run(Thread.java:1012)

FinalizerDaemon:
       at java.lang.Object.wait(Object.java)
       at java.lang.Object.wait(Object.java:386)
       at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:210)
       at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:231)
       at java.lang.Daemons$FinalizerDaemon.runInternal(Daemons.java:309)
       at java.lang.Daemons$Daemon.run(Daemons.java:145)
       at java.lang.Thread.run(Thread.java:1012)

DefaultDispatcher-worker-1:
       at jdk.internal.misc.Unsafe.park(Unsafe.java)
       at java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:376)
       at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.park(CoroutineScheduler.java:292)
       at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.tryPark(CoroutineScheduler.java:292)
       at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.runWorker(CoroutineScheduler.java:292)
       at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.run(CoroutineScheduler.java:292)

FramePolicy:
       at android.os.MessageQueue.nativePollOnce(MessageQueue.java)
       at android.os.MessageQueue.next(MessageQueue.java:341)
       at android.os.Looper.loopOnce(Looper.java:169)
       at android.os.Looper.loop(Looper.java:300)
       at android.os.HandlerThread.run(HandlerThread.java:67)

com.google.firebase.crashlytics.startup1:
       at jdk.internal.misc.Unsafe.park(Unsafe.java)
       at java.util.concurrent.locks.LockSupport.park(LockSupport.java:341)
       at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionNode.block(AbstractQueuedSynchronizer.java:506)
       at java.util.concurrent.ForkJoinPool.unmanagedBlock(ForkJoinPool.java:3466)
       at java.util.concurrent.ForkJoinPool.managedBlock(ForkJoinPool.java:3437)
       at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:1623)
       at java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:435)
       at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1071)
       at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1131)
       at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:644)
       at com.google.firebase.crashlytics.internal.common.ExecutorUtils$1$1.onRun(ExecutorUtils.java:2)
       at com.google.firebase.crashlytics.internal.common.BackgroundPriorityRunnable.run(BackgroundPriorityRunnable.java:5)
       at java.lang.Thread.run(Thread.java:1012)

Firebase Background Thread #0:
       at jdk.internal.misc.Unsafe.park(Unsafe.java)
       at java.util.concurrent.locks.LockSupport.park(LockSupport.java:341)
       at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionNode.block(AbstractQueuedSynchronizer.java:506)
       at java.util.concurrent.ForkJoinPool.unmanagedBlock(ForkJoinPool.java:3466)
       at java.util.concurrent.ForkJoinPool.managedBlock(ForkJoinPool.java:3437)
       at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:1623)
       at java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:435)
       at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1071)
       at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1131)
       at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:644)
       at com.google.firebase.concurrent.CustomThreadFactory.lambda$newThread$0(CustomThreadFactory.java:193)
       at java.lang.Thread.run(Thread.java:1012)

GmsDynamite:
       at java.lang.Object.wait(Object.java)
       at java.lang.Object.wait(Object.java:386)
       at java.lang.Object.wait(Object.java:524)
       at com.google.android.gms.dynamite.zza.run(zza.java:12)

Firebase Background Thread #3:
       at jdk.internal.misc.Unsafe.park(Unsafe.java)
       at java.util.concurrent.locks.LockSupport.park(LockSupport.java:341)
       at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionNode.block(AbstractQueuedSynchronizer.java:506)
       at java.util.concurrent.ForkJoinPool.unmanagedBlock(ForkJoinPool.java:3466)
       at java.util.concurrent.ForkJoinPool.managedBlock(ForkJoinPool.java:3437)
       at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:1623)
       at java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:435)
       at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1071)
       at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1131)
       at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:644)
       at com.google.firebase.concurrent.CustomThreadFactory.lambda$newThread$0(CustomThreadFactory.java:193)
       at java.lang.Thread.run(Thread.java:1012)

ReferenceQueueDaemon:
       at java.lang.Object.wait(Object.java)
       at java.lang.Object.wait(Object.java:386)
       at java.lang.Object.wait(Object.java:524)
       at java.lang.Daemons$ReferenceQueueDaemon.runInternal(Daemons.java:239)
       at java.lang.Daemons$Daemon.run(Daemons.java:145)
       at java.lang.Thread.run(Thread.java:1012)

Firebase Blocking Thread #3:
       at jdk.internal.misc.Unsafe.park(Unsafe.java)
       at java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:252)
       at java.util.concurrent.SynchronousQueue$TransferStack.transfer(SynchronousQueue.java:401)
       at java.util.concurrent.SynchronousQueue.poll(SynchronousQueue.java:903)
       at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1070)
       at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1131)
       at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:644)
       at com.google.firebase.concurrent.CustomThreadFactory.lambda$newThread$0(CustomThreadFactory.java:193)
       at java.lang.Thread.run(Thread.java:1012)

FinalizerWatchdogDaemon:
       at java.lang.Object.wait(Object.java)
       at java.lang.Object.wait(Object.java:386)
       at java.lang.Object.wait(Object.java:524)
       at java.lang.Daemons$FinalizerWatchdogDaemon.sleepUntilNeeded(Daemons.java:428)
       at java.lang.Daemons$FinalizerWatchdogDaemon.runInternal(Daemons.java:408)
       at java.lang.Daemons$Daemon.run(Daemons.java:145)
       at java.lang.Thread.run(Thread.java:1012)

Crashlytics Exception Handler1:
       at dalvik.system.VMStack.getThreadStackTrace(VMStack.java)
       at java.lang.Thread.getStackTrace(Thread.java:1841)
       at java.lang.Thread.getAllStackTraces(Thread.java:1909)
       at com.google.firebase.crashlytics.internal.common.CrashlyticsReportDataCapture.populateThreadsList(CrashlyticsReportDataCapture.java:426)
       at com.google.firebase.crashlytics.internal.common.CrashlyticsReportDataCapture.populateExecutionData(CrashlyticsReportDataCapture.java:426)
       at com.google.firebase.crashlytics.internal.common.CrashlyticsReportDataCapture.populateEventApplicationData(CrashlyticsReportDataCapture.java:426)
       at com.google.firebase.crashlytics.internal.common.CrashlyticsReportDataCapture.captureEventData(CrashlyticsReportDataCapture.java:426)
       at com.google.firebase.crashlytics.internal.common.SessionReportingCoordinator.persistEvent(SessionReportingCoordinator.java:426)
       at com.google.firebase.crashlytics.internal.common.SessionReportingCoordinator.persistFatalEvent(SessionReportingCoordinator.java:426)
       at com.google.firebase.crashlytics.internal.common.CrashlyticsController$2.call(CrashlyticsController.java:426)
       at com.google.firebase.crashlytics.internal.common.CrashlyticsController$2.call(CrashlyticsController.java:426)
       at com.google.firebase.crashlytics.internal.common.CrashlyticsBackgroundWorker$3.then(CrashlyticsBackgroundWorker.java:12)
       at com.google.android.gms.tasks.zze.run(:8)
       at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
       at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:644)
       at com.google.firebase.crashlytics.internal.common.ExecutorUtils$1$1.onRun(ExecutorUtils.java:2)
       at com.google.firebase.crashlytics.internal.common.BackgroundPriorityRunnable.run(BackgroundPriorityRunnable.java:5)
       at java.lang.Thread.run(Thread.java:1012)

awaitEvenIfOnMainThread task continuation executor1:
       at jdk.internal.misc.Unsafe.park(Unsafe.java)
       at java.util.concurrent.locks.LockSupport.park(LockSupport.java:341)
       at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionNode.block(AbstractQueuedSynchronizer.java:506)
       at java.util.concurrent.ForkJoinPool.unmanagedBlock(ForkJoinPool.java:3466)
       at java.util.concurrent.ForkJoinPool.managedBlock(ForkJoinPool.java:3437)
       at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:1623)
       at java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:435)
       at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1071)
       at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1131)
       at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:644)
       at com.google.firebase.crashlytics.internal.common.ExecutorUtils$1$1.onRun(ExecutorUtils.java:2)
       at com.google.firebase.crashlytics.internal.common.BackgroundPriorityRunnable.run(BackgroundPriorityRunnable.java:5)
       at java.lang.Thread.run(Thread.java:1012)

launch:
       at android.os.MessageQueue.nativePollOnce(MessageQueue.java)
       at android.os.MessageQueue.next(MessageQueue.java:341)
       at android.os.Looper.loopOnce(Looper.java:169)
       at android.os.Looper.loop(Looper.java:300)
       at android.os.HandlerThread.run(HandlerThread.java:67)

pool-3-thread-1:
       at jdk.internal.misc.Unsafe.park(Unsafe.java)
       at java.util.concurrent.locks.LockSupport.park(LockSupport.java:341)
       at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionNode.block(AbstractQueuedSynchronizer.java:506)
       at java.util.concurrent.ForkJoinPool.unmanagedBlock(ForkJoinPool.java:3466)
       at java.util.concurrent.ForkJoinPool.managedBlock(ForkJoinPool.java:3437)
       at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:1623)
       at java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:435)
       at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1071)
       at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1131)
       at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:644)
       at java.lang.Thread.run(Thread.java:1012)

我已经尝试启动检查 MainActivity 中的意图和日志的字符串，正如您在代码中看到的那样，但没有成功，那么，我可以采取任何想法或措施来解决这个问题吗？我将非常感激。

java android nullpointerexception sharedpreferences
1个回答
0
投票

问题解决了，感谢 Robert 和 Computable 的建议，我可以解决问题。 有 2 个问题，

equals
命令的放置方式错误，所以我这样解决：

if (!"NoLog".equals(checkLogTxt)) {
        replaceFragment(new PreMainPage());
    }
   else if (("NoLog".equals(checkLogTxt))) {
        replaceFragment(new Intro_1());
    }

    if ("forTask".equals(checkLogTxt)) {
        replaceFragment(new PreMainPage());
    }

然后在 

checkIntents
方法中我创建了条件来控制 
NullPointerException
，这样：

 public void checkIntents () {
        if (getIntent().getExtras() != null) {
            if (getIntent().getExtras().getString("ForTask") != null) {
                checkIntents = getIntent().getExtras().getString("ForTask");
            }
            if (getIntent().getExtras().getString("ForTask") == null) {
                checkIntents = "NoTask";
            }
        }
    }

如果值为 

checkIntents
，则使 
null
=“NoTask”，这样该值就永远不会是 
null
。

最新问题
© www.soinside.com 2019 - 2024. All rights reserved.