程序没错但是不能运行！！！急救
package cn.mypackage3;import android.app.Activity;
import android.widget.Button;
import android.os.Bundle;
import android.os.Handler;
import android.view.View.OnClickListener;
import android.view.View;
public class HandleActivity extends Activity {
/** Called when the activity is first created. */
private Button startButton=null,endButton=null;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
startButton=(Button)findViewById(R.id.startButton);
startButton.setText(R.string.start);
endButton=(Button)findViewById(R.id.endButton);
endButton.setText(R.string.end);
startButton.setOnClickListener(new StartButtonListener());
endButton.setOnClickListener(new EndButtonListener());
}
class StartButtonListener implements OnClickListener{
public void onClick(View view){
handler.post(runnable);
}
}
class EndButtonListener implements OnClickListener{
public void onClick(View view){
handler.removeCallbacks(runnable);
}
}
Handler handler=new Handler();
Runnable runnable=new Runnable(){
public void run(){
System.out.println("go");
handler.postDelayed(runnable, 3000);
}}
;
} --------------------编程问答-------------------- 为什么不能运行呢，应该有错误信息吧？？ --------------------编程问答-------------------- --------------------编程问答-------------------- 错误信息有，但是看不懂！！！
--------------------编程问答-------------------- 07-21 11:36:02.980: ERROR/Zygote(33): setreuid() failed. errno: 2
07-21 11:36:02.980: ERROR/Zygote(33): setreuid() failed. errno: 17
07-21 11:36:02.980: ERROR/BatteryService(41): usbOnlinePath not found
07-21 11:36:02.980: ERROR/BatteryService(41): batteryVoltagePath not found
07-21 11:36:02.980: ERROR/BatteryService(41): batteryTemperaturePath not found
07-21 11:36:02.980: ERROR/Su易做图ceFlinger(41): Couldn't open /sys/power/wait_for_fb_sleep or /sys/power/wait_for_fb_wake
07-21 11:36:26.773: ERROR/EventHub(41): could not get driver version for /dev/input/mouse0, Not a typewriter
07-21 11:36:26.773: ERROR/EventHub(41): could not get driver version for /dev/input/mice, Not a typewriter
07-21 11:36:27.132: ERROR/System(41): Failure starting core service
07-21 11:36:27.132: ERROR/System(41): java.lang.SecurityException
07-21 11:36:27.132: ERROR/System(41): at android.os.BinderProxy.transact(Native Method)
07-21 11:36:27.132: ERROR/System(41): at android.os.ServiceManagerProxy.addService(ServiceManagerNative.java:146)
07-21 11:36:27.132: ERROR/System(41): at android.os.ServiceManager.addService(ServiceManager.java:72)
07-21 11:36:27.132: ERROR/System(41): at com.android.server.ServerThread.run(SystemServer.java:184)
07-21 11:36:28.612: ERROR/SoundPool(41): error loading /system/media/audio/ui/Effect_Tick.ogg
07-21 11:36:28.612: ERROR/SoundPool(41): error loading /system/media/audio/ui/KeypressStandard.ogg
07-21 11:36:28.612: ERROR/SoundPool(41): error loading /system/media/audio/ui/KeypressSpacebar.ogg
07-21 11:36:28.612: ERROR/SoundPool(41): error loading /system/media/audio/ui/KeypressDelete.ogg
07-21 11:36:28.624: ERROR/SoundPool(41): error loading /system/media/audio/ui/KeypressReturn.ogg
07-21 11:36:31.543: ERROR/ThrottleService(41): Could not open GPS configuration file /etc/gps.conf
07-21 11:36:33.804: ERROR/logwrapper(138): executing /system/bin/tc failed: No such file or directory
07-21 11:36:33.843: ERROR/logwrapper(139): executing /system/bin/tc failed: No such file or directory
07-21 11:36:33.883: ERROR/logwrapper(140): executing /system/bin/tc failed: No such file or directory
07-21 11:36:55.664: ERROR/HierarchicalStateMachine(41): TetherMaster - unhandledMessage: msg.what=3
07-21 11:37:25.974: ERROR/AndroidRuntime(284): FATAL EXCEPTION: main
07-21 11:37:25.974: ERROR/AndroidRuntime(284): java.lang.RuntimeException: Unable to start activity ComponentInfo{cn.mypackage3/cn.mypackage3.HandleActivity}: java.lang.NullPointerException
07-21 11:37:25.974: ERROR/AndroidRuntime(284): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663)
07-21 11:37:25.974: ERROR/AndroidRuntime(284): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
07-21 11:37:25.974: ERROR/AndroidRuntime(284): at android.app.ActivityThread.access$2300(ActivityThread.java:125)
07-21 11:37:25.974: ERROR/AndroidRuntime(284): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
07-21 11:37:25.974: ERROR/AndroidRuntime(284): at android.os.Handler.dispatchMessage(Handler.java:99)
07-21 11:37:25.974: ERROR/AndroidRuntime(284): at android.os.Looper.loop(Looper.java:123)
07-21 11:37:25.974: ERROR/AndroidRuntime(284): at android.app.ActivityThread.main(ActivityThread.java:4627)
07-21 11:37:25.974: ERROR/AndroidRuntime(284): at java.lang.reflect.Method.invokeNative(Native Method)
07-21 11:37:25.974: ERROR/AndroidRuntime(284): at java.lang.reflect.Method.invoke(Method.java:521)
07-21 11:37:25.974: ERROR/AndroidRuntime(284): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
07-21 11:37:25.974: ERROR/AndroidRuntime(284): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
07-21 11:37:25.974: ERROR/AndroidRuntime(284): at dalvik.system.NativeStart.main(Native Method)
07-21 11:37:25.974: ERROR/AndroidRuntime(284): Caused by: java.lang.NullPointerException
07-21 11:37:25.974: ERROR/AndroidRuntime(284): at cn.mypackage3.HandleActivity.onCreate(HandleActivity.java:18)
07-21 11:37:25.974: ERROR/AndroidRuntime(284): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
07-21 11:37:25.974: ERROR/AndroidRuntime(284): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)
07-21 11:37:25.974: ERROR/AndroidRuntime(284): ... 11 more
--------------------编程问答-------------------- 麻烦各位了，在这谢过了，谢谢，谢谢，谢谢。。。。。 --------------------编程问答-------------------- 我运行了下你这些代码没错呀，你看下main.xml有没有错哦
--------------------编程问答--------------------
我没用main.xml，我自己新建了一个result.xml,我用的它！！！ --------------------编程问答-------------------- 空指针异常 看看是不是R.id.endButton R.id.startButton 都是在main.xml定义的吗 不是就错了. --------------------编程问答-------------------- startButton.setText(R.string.start);
这行应该是第18行，就这行报空
1，检查下string.xml中是否有名为start的字符串
2，检查main.xml中startButton是否给了id --------------------编程问答-------------------- 07-21 11:37:25.974: ERROR/AndroidRuntime(284): Caused by: java.lang.NullPointerException
07-21 11:37:25.974: ERROR/AndroidRuntime(284): at cn.mypackage3.HandleActivity.onCreate(HandleActivity.java:18)
18行，空指针异常，我数了一哈，好像是这句错了
startButton.setText(R.string.start); --------------------编程问答--------------------
setContentView(R.layout.main);
到底用result 还是main --------------------编程问答--------------------
main和result都用！！！ --------------------编程问答--------------------
我在result.xml中定义的值在R.java中都有更新，我想应该没事！！！应该可以用，而不用main.xml。 --------------------编程问答--------------------
你用的是setContentView(R.layout.main);findViewById(id) id是要在main.xml定义的才行，要不然findViewById会返回null，你后面的操作就会报空指针异常了 --------------------编程问答-------------------- 学习一下！ --------------------编程问答-------------------- startButton=(Button)findViewById(R.id.startButton);
应该是main中没有id为startButton，检查看是不是拼写错误 --------------------编程问答--------------------
楼上正解。我也遇到过同样的问题。 --------------------编程问答--------------------
查看下R.java文件中，id是否都给全了！确认button按钮在main.xml文件布局文件中。再次build项目运行下看看 --------------------编程问答-------------------- 学习中。。。。 --------------------编程问答-------------------- 按照你的代码测试了一篇，没有发现错误，我在想你是不是将AndroidManifest.xml文件的内容改动了导致的。 --------------------编程问答--------------------
有可能
补充：移动开发 , Android
