我正在开发一个从网络服务器获取 JSON 然后在图表中显示数据的 Android 应用程序。
这是日志猫，谁能解释一下错误是什么？
10-28 02:30:01.653: D/gralloc_goldfish(5043): Emulator without GPU emulation detected.
10-28 02:30:04.393: D/AndroidRuntime(5043): Shutting down VM
10-28 02:30:04.393: W/dalvikvm(5043): threadid=1: thread exiting with uncaught exception (group=0x409961f8)
10-28 02:30:04.433: E/AndroidRuntime(5043): FATAL EXCEPTION: main
10-28 02:30:04.433: E/AndroidRuntime(5043): java.lang.IllegalStateException: Could not execute method of the activity
10-28 02:30:04.433: E/AndroidRuntime(5043): at android.view.View$1.onClick(View.java:3039)
10-28 02:30:04.433: E/AndroidRuntime(5043): at android.view.View.performClick(View.java:3480)
10-28 02:30:04.433: E/AndroidRuntime(5043): at android.view.View$PerformClick.run(View.java:13983)
10-28 02:30:04.433: E/AndroidRuntime(5043): at android.os.Handler.handleCallback(Handler.java:605)
10-28 02:30:04.433: E/AndroidRuntime(5043): at android.os.Handler.dispatchMessage(Handler.java:92)
10-28 02:30:04.433: E/AndroidRuntime(5043): at android.os.Looper.loop(Looper.java:137)
10-28 02:30:04.433: E/AndroidRuntime(5043): at android.app.ActivityThread.main(ActivityThread.java:4340)
10-28 02:30:04.433: E/AndroidRuntime(5043): at java.lang.reflect.Method.invokeNative(Native Method)
10-28 02:30:04.433: E/AndroidRuntime(5043): at java.lang.reflect.Method.invoke(Method.java:511)
10-28 02:30:04.433: E/AndroidRuntime(5043): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
10-28 02:30:04.433: E/AndroidRuntime(5043): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
10-28 02:30:04.433: E/AndroidRuntime(5043): at dalvik.system.NativeStart.main(Native Method)
10-28 02:30:04.433: E/AndroidRuntime(5043): Caused by: java.lang.reflect.InvocationTargetException
10-28 02:30:04.433: E/AndroidRuntime(5043): at java.lang.reflect.Method.invokeNative(Native Method)
10-28 02:30:04.433: E/AndroidRuntime(5043): at java.lang.reflect.Method.invoke(Method.java:511)
10-28 02:30:04.433: E/AndroidRuntime(5043): at android.view.View$1.onClick(View.java:3034)
10-28 02:30:04.433: E/AndroidRuntime(5043): ... 11 more
10-28 02:30:04.433: E/AndroidRuntime(5043): Caused by: java.lang.NullPointerException
10-28 02:30:04.433: E/AndroidRuntime(5043): at android.graph.LineGraph.getIntent(LineGraph.java:27)
10-28 02:30:04.433: E/AndroidRuntime(5043): at android.graph.GraphAChartEngineActivity.lineGraphHandler(GraphAChartEngineActivity.java:35)
10-28 02:30:04.433: E/AndroidRuntime(5043): ... 14 more
10-28 02:30:07.945: I/Process(5043): Sending signal. PID: 5043 SIG: 9