Java Android开发-意图

我最近开始在API版本16（4.1）上开发Android。根据developer.android.com上提供的教程，我开始开发这个应用程序，它教会了我如何使用意图。问题是，一旦我的应用程序加载到模拟器上，它就会显示应用程序必须关闭的错误。我将给出我的xml代码。有人能告诉我哪里出了问题吗？谢谢

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent" 
android:orientation="horizontal">


<EditText
    android:id="@+id/et1"
    android:layout_width="0dp"
    android:layout_height="wrap_content"
    android:hint="Edit text"
    android:layout_weight="1"
    tools:ignore="HardcodedText" />

<Button
    android:id="@+id/b1"
    android:layout_width="wrap_content"
    android:layout_height="40dp"
    android:text="Press"
    android:onClick="sendMessage"
    tools:ignore="HardcodedText" />

</LinearLayout>

日志如下所示

09-26 19:35:03.880: E/Trace(615): error opening trace file: No such file or directory     (2)
09-26 19:35:04.430: D/AndroidRuntime(615): Shutting down VM
09-26 19:35:04.430: W/dalvikvm(615): threadid=1: thread exiting with uncaught exception  (group=0x40a13300)
09-26 19:35:04.471: E/AndroidRuntime(615): FATAL EXCEPTION: main
09-26 19:35:04.471: E/AndroidRuntime(615): java.lang.RuntimeException: Unable to     instantiate activity ComponentInfo{com.learn.training1/com.learn.training1.Training1}:     java.lang.NullPointerException
 09-26 19:35:04.471: E/AndroidRuntime(615):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1983)
09-26 19:35:04.471: E/AndroidRuntime(615):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2084)
09-26 19:35:04.471: E/AndroidRuntime(615):  at android.app.ActivityThread.access$600(ActivityThread.java:130)
09-26 19:35:04.471: E/AndroidRuntime(615):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1195)
09-26 19:35:04.471: E/AndroidRuntime(615):  at android.os.Handler.dispatchMessage(Handler.java:99)
09-26 19:35:04.471: E/AndroidRuntime(615):  at android.os.Looper.loop(Looper.java:137)
09-26 19:35:04.471: E/AndroidRuntime(615):  at android.app.ActivityThread.main(ActivityThread.java:4745)
09-26 19:35:04.471: E/AndroidRuntime(615):  at java.lang.reflect.Method.invokeNative(Native Method)
09-26 19:35:04.471: E/AndroidRuntime(615):  at java.lang.reflect.Method.invoke(Method.java:511)
09-26 19:35:04.471: E/AndroidRuntime(615):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
09-26 19:35:04.471: E/AndroidRuntime(615):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
09-26 19:35:04.471: E/AndroidRuntime(615):  at dalvik.system.NativeStart.main(Native Method)
09-26 19:35:04.471: E/AndroidRuntime(615): Caused by: java.lang.NullPointerException
09-26 19:35:04.471: E/AndroidRuntime(615):  at android.app.Activity.findViewById(Activity.java:1825)
09-26 19:35:04.471: E/AndroidRuntime(615):  at com.learn.training1.Training1.<init>(Training1.java:15)
09-26 19:35:04.471: E/AndroidRuntime(615):  at java.lang.Class.newInstanceImpl(Native Method)
09-26 19:35:04.471: E/AndroidRuntime(615):  at java.lang.Class.newInstance(Class.java:1319)
09-26 19:35:04.471: E/AndroidRuntime(615):  at android.app.Instrumentation.newActivity(Instrumentation.java:1053)
09-26 19:35:04.471: E/AndroidRuntime(615):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1974)
09-26 19:35:04.471: E/AndroidRuntime(615):  ... 11 more
09-26 19:35:32.352: I/Process(615): Sending signal. PID: 615 SIG: 9
09-26 19:39:22.460: E/Trace(664): error opening trace file: No such file or directory (2)
09-26 19:39:22.820: D/AndroidRuntime(664): Shutting down VM
09-26 19:39:22.820: W/dalvikvm(664): threadid=1: thread exiting with uncaught exception (group=0x40a13300)
09-26 19:39:22.846: E/AndroidRuntime(664): FATAL EXCEPTION: main
09-26 19:39:22.846: E/AndroidRuntime(664): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.learn.training1/com.learn.training1.Training1}: java.lang.NullPointerException
 09-26 19:39:22.846: E/AndroidRuntime(664):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1983)
09-26 19:39:22.846: E/AndroidRuntime(664):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2084)
09-26 19:39:22.846: E/AndroidRuntime(664):  at android.app.ActivityThread.access$600(ActivityThread.java:130)
09-26 19:39:22.846: E/AndroidRuntime(664):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1195)
09-26 19:39:22.846: E/AndroidRuntime(664):  at android.os.Handler.dispatchMessage(Handler.java:99)
09-26 19:39:22.846: E/AndroidRuntime(664):  at android.os.Looper.loop(Looper.java:137)
09-26 19:39:22.846: E/AndroidRuntime(664):  at android.app.ActivityThread.main(ActivityThread.java:4745)
09-26 19:39:22.846: E/AndroidRuntime(664):  at java.lang.reflect.Method.invokeNative(Native Method)
09-26 19:39:22.846: E/AndroidRuntime(664):  at java.lang.reflect.Method.invoke(Method.java:511)
09-26 19:39:22.846: E/AndroidRuntime(664):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
09-26 19:39:22.846: E/AndroidRuntime(664):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
09-26 19:39:22.846: E/AndroidRuntime(664):  at dalvik.system.NativeStart.main(Native Method)
09-26 19:39:22.846: E/AndroidRuntime(664): Caused by: java.lang.NullPointerException
09-26 19:39:22.846: E/AndroidRuntime(664):  at android.app.Activity.findViewById(Activity.java:1825)
09-26 19:39:22.846: E/AndroidRuntime(664):  at com.learn.training1.Training1.<init>(Training1.java:15)
09-26 19:39:22.846: E/AndroidRuntime(664):  at java.lang.Class.newInstanceImpl(Native Method)
09-26 19:39:22.846: E/AndroidRuntime(664):  at java.lang.Class.newInstance(Class.java:1319)
09-26 19:39:22.846: E/AndroidRuntime(664):  at android.app.Instrumentation.newActivity(Instrumentation.java:1053)
09-26 19:39:22.846: E/AndroidRuntime(664):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1974)
09-26 19:39:22.846: E/AndroidRuntime(664):  ... 11 more
09-26 19:40:29.130: E/Trace(712): error opening trace file: No such file or directory (2)
09-26 19:40:29.431: D/dalvikvm(712): newInstance failed: Lcom/learn/training1/Training1; not accessible to Landroid/app/Instrumentation;
09-26 19:40:29.431: D/AndroidRuntime(712): Shutting down VM
09-26 19:40:29.431: W/dalvikvm(712): threadid=1: thread exiting with uncaught exception (group=0x40a13300)
09-26 19:40:29.461: E/AndroidRuntime(712): FATAL EXCEPTION: main
09-26 19:40:29.461: E/AndroidRuntime(712): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.learn.training1/com.learn.training1.Training1}: java.lang.IllegalAccessException: access to class not allowed
09-26 19:40:29.461: E/AndroidRuntime(712):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1983)
09-26 19:40:29.461: E/AndroidRuntime(712):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2084)
09-26 19:40:29.461: E/AndroidRuntime(712):  at android.app.ActivityThread.access$600(ActivityThread.java:130)
09-26 19:40:29.461: E/AndroidRuntime(712):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1195)
09-26 19:40:29.461: E/AndroidRuntime(712):  at android.os.Handler.dispatchMessage(Handler.java:99)
09-26 19:40:29.461: E/AndroidRuntime(712):  at android.os.Looper.loop(Looper.java:137)
09-26 19:40:29.461: E/AndroidRuntime(712):  at android.app.ActivityThread.main(ActivityThread.java:4745)
09-26 19:40:29.461: E/AndroidRuntime(712):  at java.lang.reflect.Method.invokeNative(Native Method)
09-26 19:40:29.461: E/AndroidRuntime(712):  at java.lang.reflect.Method.invoke(Method.java:511)
09-26 19:40:29.461: E/AndroidRuntime(712):  at  com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
09-26 19:40:29.461: E/AndroidRuntime(712):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
09-26 19:40:29.461: E/AndroidRuntime(712):  at dalvik.system.NativeStart.main(Native Method)
09-26 19:40:29.461: E/AndroidRuntime(712): Caused by: java.lang.IllegalAccessException: access to class not allowed
09-26 19:40:29.461: E/AndroidRuntime(712):  at java.lang.Class.newInstanceImpl(Native Method)
09-26 19:40:29.461: E/AndroidRuntime(712):  at java.lang.Class.newInstance(Class.java:1319)
09-26 19:40:29.461: E/AndroidRuntime(712):  at android.app.Instrumentation.newActivity(Instrumentation.java:1053)
09-26 19:40:29.461: E/AndroidRuntime(712):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1974)
09-26 19:40:29.461: E/AndroidRuntime(712):  ... 11 more
09-26 19:43:52.020: E/Trace(760): error opening trace file: No such file or directory (2)
09-26 19:43:52.110: D/dalvikvm(760): newInstance failed: Lcom/learn/training1/Training1; not accessible to Landroid/app/Instrumentation;
09-26 19:43:52.110: D/AndroidRuntime(760): Shutting down VM
09-26 19:43:52.110: W/dalvikvm(760): threadid=1: thread exiting with uncaught exception (group=0x40a13300)
09-26 19:43:52.190: E/AndroidRuntime(760): FATAL EXCEPTION: main
09-26 19:43:52.190: E/AndroidRuntime(760): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.learn.training1/com.learn.training1.Training1}: java.lang.IllegalAccessException: access to class not allowed
09-26 19:43:52.190: E/AndroidRuntime(760):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1983)
09-26 19:43:52.190: E/AndroidRuntime(760):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2084)
09-26 19:43:52.190: E/AndroidRuntime(760):  at android.app.ActivityThread.access$600(ActivityThread.java:130)
09-26 19:43:52.190: E/AndroidRuntime(760):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1195)
09-26 19:43:52.190: E/AndroidRuntime(760):  at android.os.Handler.dispatchMessage(Handler.java:99)
09-26 19:43:52.190: E/AndroidRuntime(760):  at android.os.Looper.loop(Looper.java:137)
09-26 19:43:52.190: E/AndroidRuntime(760):  at android.app.ActivityThread.main(ActivityThread.java:4745)
09-26 19:43:52.190: E/AndroidRuntime(760):  at java.lang.reflect.Method.invokeNative(Native Method)
 09-26 19:43:52.190: E/AndroidRuntime(760):     at java.lang.reflect.Method.invoke(Method.java:511)
09-26 19:43:52.190: E/AndroidRuntime(760):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
09-26 19:43:52.190: E/AndroidRuntime(760):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
09-26 19:43:52.190: E/AndroidRuntime(760):  at dalvik.system.NativeStart.main(Native Method)
09-26 19:43:52.190: E/AndroidRuntime(760): Caused by: java.lang.IllegalAccessException: access to class not allowed
09-26 19:43:52.190: E/AndroidRuntime(760):  at java.lang.Class.newInstanceImpl(Native Method)
09-26 19:43:52.190: E/AndroidRuntime(760):  at java.lang.Class.newInstance(Class.java:1319)
09-26 19:43:52.190: E/AndroidRuntime(760):  at android.app.Instrumentation.newActivity(Instrumentation.java:1053)
09-26 19:43:52.190: E/AndroidRuntime(760):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1974)
09-26 19:43:52.190: E/AndroidRuntime(760):  ... 11 more
09-26 19:47:20.550: I/Process(810): Sending signal. PID: 810 SIG: 9

09-26 19:35:03.880:E/Trace（615）：打开跟踪文件时出错：没有这样的文件或目录（2）
09-26 19:35:04.430:D/AndroidRuntime（615）：关闭虚拟机
09-26 19:35:04.430:W/dalvikvm（615）：threadid=1：线程以未捕获异常退出（组=0x40a13300）
09-26 19:35:04.471:E/AndroidRuntime（615）：致命异常：主
09-26 19:35:04.471:E/AndroidRuntime（615）：java.lang.RuntimeException:无法实例化活动组件信息{com.learn.training1/com.learn.training1.training1}:java.lang.NullPointerException
09-26 19:35:04.471:E/AndroidRuntime（615）：在android.app.ActivityThread.performLaunchActivity（ActivityThread.java:1983）
09-26 19:35:04.471:E/AndroidRuntime（615）：在android.app.ActivityThread.handleLaunchActivity（ActivityThread.java:2084）
09-26 19:35:04.471:E/AndroidRuntime（615）：在android.app.ActivityThread.access$600（ActivityThread.java:130）
09-26 19:35:04.471:E/AndroidRuntime（615）：在android.app.ActivityThread$H.handleMessage（ActivityThread.java:1195）
09-26 19:35:04.471:E/AndroidRuntime（615）：在android.os.Handler.dispatchMessage（Handler.java:99）上
09-26 19:35:04.471:E/AndroidRuntime（615）：在android.os.Looper.loop（Looper.java:137）
09-26 19:35:04.471:E/AndroidRuntime（615）：位于android.app.ActivityThread.main（ActivityThread.java:4745）
09-26 19:35:04.471:E/AndroidRuntime（615）：位于java.lang.reflect.Method.Invokenactive（本机方法）
09-26 19:35:04.471:E/AndroidRuntime（615）：在java.lang.reflect.Method.invoke（Method.java:511）
09-26 19:35:04.471:E/AndroidRuntime（615）：在com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run（ZygoteInit.java:786）
09-26 19:35:04.471:E/AndroidRuntime（615）：在com.android.internal.os.ZygoteInit.main（ZygoteInit.java:553）
9-26 19:35:04.471:E/AndroidRuntime（615）：在dalvik.system.NativeStart.main（本机方法）
09-26 19:35:04.471:E/AndroidRuntime（615）：由以下原因引起：java.lang.NullPointerException
09-26 19:35:04.471:E/AndroidRuntime（615）：在android.app.Activity.findViewById（Activity.java:1825）
09-26 19:35:04.471:E/AndroidRuntime（615）：在com.learn.training1.training1.（training1.java:15）
09-26 19:35:04.471:E/AndroidRuntime（615）：位于java.lang.Class.newInstanceImpl（本机方法）
09-26 19:35:04.471:E/AndroidRuntime（615）：位于java.lang.Class.newInstance（Class.java:1319）
09-26 19:35:04.471:E/AndroidRuntime（615）：在android.app.Instrumentation.newActivity（Instrumentation.java:1053）上
09-26 19:35:04.471:E/AndroidRuntime（615）：在android.app.ActivityThread.performLaunchActivity（ActivityThread.java:1974）
9-26 19:35:04.471:E/AndroidRuntime（615）：。。。还有11个
09-26 19:35:32.352:I/进程（615）：发送信号。PID:615信号：9
09-26 19:39:22.460:E/Trace（664）：打开跟踪文件时出错：没有这样的文件或目录（2）
09-26 19:39:22.820:D/AndroidRuntime（664）：关闭虚拟机
09-26 19:39:22.820:W/dalvikvm（664）：threadid=1：线程以未捕获异常退出（组=0x40a13300）
09-26 19:39:22.846:E/AndroidRuntime（664）：致命异常：main
09-26 19:39:22.846:E/AndroidRuntime（664）：java.lang.RuntimeException:无法实例化活动组件信息{com.learn.training1/com.learn.training1.training1}:java.lang.NullPointerException
09-26 19:39:22.846:E/AndroidRuntime（664）：在android.app.ActivityThread.performLaunchActivity（ActivityThread.java:1983）
09-26 19:39:22.846:E/AndroidRuntime（664）：在android.app.ActivityThread.handleLaunchActivity（ActivityThread.java:2084）
09-26 19:39:22.846:E/AndroidRuntime（664）：在android.app.ActivityThread.access$600（ActivityThread.java:130）
09-26 19:39:22.846:E/AndroidRuntime（664）：在android.app.ActivityThread$H.handleMessage（ActivityThread.java:1195）
09-26 19:39:22.846:E/AndroidRuntime（664）：位于android.os.Handler.dispatchMessage（Handler.java:99）
09-26 19:39:22.846:E/AndroidRuntime（664）：在android.os.Looper.loop（Looper.java:137）
09-26 19:39:22.846:E/AndroidRuntime（664）：位于android.app.ActivityThread.main（ActivityThread.java:4745）
09-26 19:39:22.846:E/AndroidRuntime（664）：位于java.lang.reflect.Method.Invokenactive（本机方法）
09-26 19:39:22.846:E/AndroidRuntime（664）：位于java.lang.reflect.Method.invoke（Method.java:511）
09-26 19:39:22.846:E/AndroidRuntime（664）：在com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run（ZygoteInit.java:786）
09-26 19:39:22.846:E/AndroidRuntime（664）：位于com.android.internal.os.ZygoteInit.main（ZygoteInit.java:553）
9-26 19:39:22.846:E/AndroidRuntime（664）：在dalvik.system.NativeStart.main（本机方法）
09-26 19:39:22.846:E/AndroidRuntime（664）：由以下原因引起：java.lang.NullPointerException
09-26 19:39:22.846:E/AndroidRuntime（664）：在android.app.Activity.findViewById（Activity.java:1825）
09-26 19:39:22.846:E/AndroidRuntime（664）：在com.learn.training1.training1.（training1.java:15）
09-26 19:39:22.846:E/AndroidRuntime（664）：位于java.lang.Class.newInstanceImpl（本机方法）
09-26 19:39:22.846:E/AndroidRuntime（664）：位于java.lang.Class.newInstance（Class.java:1319）
09-26 19:39:22.846:E/AndroidRuntime（664）：在android.app.Instrumentation.newActivity（Instrumentation.java:1053）上
09-26 19:39:22.846:E/AndroidRuntime（664）：在android.app.ActivityThread.performLaunchActivity（ActivityThread.java:1974）
9-26 19:39:22.846:E/AndroidRuntime（664）：。。。还有11个
09-26 19:40:29.130:E/Trace（712）：打开跟踪文件时出错：没有这样的文件或目录（2）
09-26 19:40:29.431:D/dalvikvm（712）：新实例失败：Lcom/learn/training1/training1；Landroid/app/仪器无法访问；
09-26 19:40:29.431:D/AndroidRuntime（712）：关闭
public class Training1 extends Activity {
    ...your activity code here...
}