有时,当我运行我的应用程序时,它会给我一个错误,如下所示:
Exception in thread "main" java.lang.NullPointerException
at com.example.myproject.Book.getTitle(Book.java:16)
at com.example.myproject.Author.getBookTitles(Author.java:25)
at com.example.myproject.Bootstrap.main(Bootstrap.java:14)
人们将此称为"堆栈跟踪".什么是堆栈跟踪？有什么能告诉我程序中发生的错误？
关于这个问题 - 我经常看到一个问题,一个新手程序员"得到一个错误",他们只是粘贴他们的堆栈跟踪和一些随机的代码块,而不了解堆栈跟踪是什么或如何使用它.这个问题旨在作为新手程序员的参考,他们可能需要帮助来理解堆栈跟踪的价值.
我试图在控制台输出中调查项目构建错误,如下所示:
:myapp:processDebugResources FAILED
FAILURE: Build failed with an exception.
* What went wrong:
Execution failed for task ':app:processDebugResources'.
...
...
* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output.
我怀疑它与资源未找到错误有关.我的问题是,在IDE级别,我如何添加--stacktrace或--debug选项,以便它可以为我调试生成更多信息？
我在Windows 7上使用Android Studio 2.0.在构建我的Android项目时,我收到以下错误:
:app:transformResourcesWithMergeJavaResForDebug FAILED
FAILURE: Build failed with an exception.
* What went wrong:
Execution failed for task ':app:transformResourcesWithMergeJavaResForDebug'.
> com.android.build.api.transform.TransformException: com.android.builder.packaging.DuplicateFileException: Duplicate files copied in APK com/google/appengine/repackaged/org/apache/commons/codec/language/bm/sep_approx_spanish.txt
File1: C:\Users\USER\.gradle\caches\modules-2\files-2.1\com.google.appengine\appengine-api-1.0-sdk\1.9.28\e92c18272b555027d9ec666e7a89162f10638314\appengine-api-1.0-sdk-1.9.28.jar
File2: C:\Users\USER\.gradle\caches\modules-2\files-2.1\com.google.appengine\appengine-endpoints\1.9.28\bf2e8a74bd28e388b3487fc78a0c7adfa592fd5d\appengine-endpoints-1.9.28.jar`
我一直在挖掘几个小时,看不到任何导致这种情况的事情.我在我的主目录中删除了.gradle,但它只是重建它.有谁知道是什么原因造成的？
全程输出:
Executing tasks: [:app:clean, :app:generateDebugSources, :app:mockableAndroidJar, :app:prepareDebugUnitTestDependencies, :app:generateDebugAndroidTestSources, :app:assembleDebug]
Configuration on demand is an incubating feature.
WARNING: Dependency org.apache.httpcomponents:httpclient:4.0.1 is ignored for debug as it may be conflicting with the internal version provided by Android.
In case of problem, please repackage it with jarjar to …当我尝试在Android Studio上运行App时出现此错误:
错误:任务':app:transformClassesWithDexForAvsDebug'的执行失败.com.android.build.api.transform.TransformException:com.android.ide.common.process.ProcessException:org.gradle.process.internal.ExecException:进程'命令'C:\ Program Files\Android\Android Studio\jre\bin\java.exe''以非零退出值2结束
添加multiDexEnabled true没有解决问题.
这些是gradle文件:
的build.gradle(模块:应用):
apply plugin: 'android-sdk-manager'
apply plugin: 'com.android.application'
apply plugin: 'jp.leafytree.android-scala'
apply plugin: 'android-apt'
apply plugin: 'hugo'
apply plugin: 'com.mutualmobile.gradle.plugins.dexinfo'
apply from: 'config/quality.gradle'
repositories {
flatDir {
dirs 'libs'
}
}
android {
//Trigger the licenseFormat task at least once in any compile phase
applicationVariants.all { variant ->
variant.javaCompiler.dependsOn(rootProject.licenseFormat)
}
compileSdkVersion rootProject.ext.compileSdkVersion
buildToolsVersion rootProject.ext.buildToolsVersion
defaultConfig {
multiDexEnabled true
minSdkVersion rootProject.ext.minSdkVersion
targetSdkVersion rootProject.ext.targetSdkVersion
versionCode System.getenv("BUILD_NUMBER") as Integer ?: 99999
versionName rootProject.ext.majorVersion …我得到的错误是这样的:
FAILED
FAILURE: Build failed with an exception.
* What went wrong:
Execution failed for task ':app:processDebugResources'.
> com.android.ide.common.process.ProcessException: org.gradle.process.internal.ExecException: Process 'command 'C:\Users\bliss_000\AppData\Local\Android\Sdk\build-tools\23.0.3\aapt.exe'' finished with non-zero exit value 1
* Try:
Run with --info or --debug option to get more log output.
* Exception is:
org.gradle.api.tasks.TaskExecutionException: Execution failed for task ':app:processDebugResources'.
at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeActions(ExecuteActionsTaskExecuter.java:69)
at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.execute(ExecuteActionsTaskExecuter.java:46)
at org.gradle.api.internal.tasks.execution.PostExecutionAnalysisTaskExecuter.execute(PostExecutionAnalysisTaskExecuter.java:35)
at org.gradle.api.internal.tasks.execution.SkipUpToDateTaskExecuter.execute(SkipUpToDateTaskExecuter.java:66)
at org.gradle.api.internal.tasks.execution.ValidatingTaskExecuter.execute(ValidatingTaskExecuter.java:58)
at org.gradle.api.internal.tasks.execution.SkipEmptySourceFilesTaskExecuter.execute(SkipEmptySourceFilesTaskExecuter.java:52)
at org.gradle.api.internal.tasks.execution.SkipTaskWithNoActionsExecuter.execute(SkipTaskWithNoActionsExecuter.java:52)
at org.gradle.api.internal.tasks.execution.SkipOnlyIfTaskExecuter.execute(SkipOnlyIfTaskExecuter.java:53)
at org.gradle.api.internal.tasks.execution.ExecuteAtMostOnceTaskExecuter.execute(ExecuteAtMostOnceTaskExecuter.java:43)
at org.gradle.execution.taskgraph.DefaultTaskGraphExecuter$EventFiringTaskWorker.execute(DefaultTaskGraphExecuter.java:203)
at org.gradle.execution.taskgraph.DefaultTaskGraphExecuter$EventFiringTaskWorker.execute(DefaultTaskGraphExecuter.java:185)
at org.gradle.execution.taskgraph.AbstractTaskPlanExecutor$TaskExecutorWorker.processTask(AbstractTaskPlanExecutor.java:66)
at org.gradle.execution.taskgraph.AbstractTaskPlanExecutor$TaskExecutorWorker.run(AbstractTaskPlanExecutor.java:50)
at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor.process(DefaultTaskPlanExecutor.java:25)
at …