java.lang.NullPointerException:attempt在Android2.1.3中对空对象调用虚拟'void android.widget.TextView.setTest‘
它显示了仿真器播放时出现的错误。
无法启动活动ComponentInfo{com.nehagupta.braintrainer/com.nehagupta.braintrainer.MainActivity}：java.lang.NullPointerException:尝试在android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2723) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2784) at android.app.ActivityThread.-wrap12(ActivityThread.java) at android.app上调用空对象引用上的虚拟方法‘android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2784)’.ActivityThread$H.handleMessage(ActivityThread.java:1523) at android.os.Handler.dispatchMessage(Handler.java:102) at android.os.Looper.loop(Looper.java:163) at android.app.ActivityThread.main(ActivityThread.java:6238) at java.lang.reflect.Method.invoke(原生方法) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:933) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:823)引起的: com.nehagupta.braintrainer.MainActivity.generateQuestion(MainActivity.java:36)：试图在com.nehagupta.braintrainer.MainActivity.generateQuestion(MainActivity.java:36) at com.nehagupta.braintrainer.MainActivity.onCreate(MainActivity.java:90) at android.app.Activity.performCreate(Activity.java:6857) at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1119) at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1119)上调用空对象引用上的虚拟方法‘android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1119)’.app.ActivityThread.performLaunchActivity(ActivityThread.java:2676) .再来9个 无法启动活动ComponentInfo{com.nehagupta.braintrainer/com.nehagupta.braintrainer.MainActivity}：java.lang.NullPointerException:尝试在android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2723) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2784) at android.app.ActivityThread.-wrap12(ActivityThread.java) at android.app上调用空对象引用上的虚拟方法‘android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2784)’.ActivityThread$H.handleMessage(ActivityThread.java:1523) at android.os.Handler.dispatchMessage(Handler.java:102) at android.os.Looper.loop(Looper.java:163) at android.app.ActivityThread.main(ActivityThread.java:6238) at java.lang.reflect.Method.invoke(原生方法) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:933) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:823)引起的: com.nehagupta.braintrainer.MainActivity.generateQuestion(MainActivity.java:36)：试图在com.nehagupta.braintrainer.MainActivity.generateQuestion(MainActivity.java:36) at com.nehagupta.braintrainer.MainActivity.onCreate(MainActivity.java:90) at android.app.Activity.performCreate(Activity.java:6857) at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1119) at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1119)上调用空对象引用上的虚拟方法‘android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1119)’.app.ActivityThread.performLaunchActivity(ActivityThread.java:2676) .再来9个
回答 2
Stack Overflow用户
发布于 2019-07-17 17:11:05
我认为你必须初始化你的TextView。
如果您正在活动，请将代码放在onCreate方法的下面。
TextView myTextView = findViewById(R.id.your_text_view_id);或者，如果您使用的是Fragment，那么在onCreateView中插入以下一行：
TextView myTextView = view.findViewById(R.id.text_view_id);Stack Overflow用户
发布于 2019-07-17 17:21:20
在上下文中初始化视图ID时，检查视图ID是否与您在layout.xml文件中定义的相同。
https://stackoverflow.com/questions/57080989
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