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我正在尝试创建一个简单的应用程序,它只做一项简单的工作:我按“启动服务”按钮,Toast 出现,并且 TextView 已更改(与停止服务相同)。但是当我尝试运行应用程序时,我的 LogCat 中出现一堆错误,并且我的应用程序停止工作。
这是activity_main.xml代码:
<RelativeLayout 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:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".ServiceInterface" >
<TextView
android:id="@+id/tvResults"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:layout_centerVertical="true" />
<TextView
android:id="@+id/tvHeader"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:layout_marginTop="19dp"
android:text="Service Example"
android:textSize="20dp" />
<Button
android:id="@+id/bStart"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@+id/tvHeader"
android:layout_centerHorizontal="true"
android:layout_marginTop="38dp"
android:text="Start Service" />
<Button
android:id="@+id/bStop"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignRight="@+id/bStart"
android:layout_below="@+id/bStart"
android:text="Stop Service" />
</RelativeLayout>
我的 list 代码:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.serviceexample"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="17" />
<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name="com.example.serviceexample.ServiceInterface"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<service android:name="com.example.serviceexample.ServiceExecution" >
</service>
</application>
</manifest>
服务接口(interface)类:
package com.example.serviceexample;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;
public class ServiceInterface extends Activity implements OnClickListener {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Declare buttons for Start and Stop
Button startService = (Button) findViewById(R.id.bStart);
Button stopService = (Button) findViewById(R.id.bStop);
// Initialize serviceStatus text field in display
TextView tv = (TextView) findViewById(R.id.tvResults);
tv.setText("Service not Running");
// Set listeners for buttons
startService.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
// Start the Service
Intent startService = new Intent(ServiceInterface.this,
ServiceExecution.class);
startService(startService);
// Display Service running message
TextView start = (TextView) findViewById(R.id.tvResults);
start.setText("Service is running");
}
});
stopService.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
// Start the Service
Intent stopService = new Intent(ServiceInterface.this,
ServiceExecution.class);
startService(stopService);
// Display Service running message
TextView stop = (TextView) findViewById(R.id.tvResults);
stop.setText("Service stopped");
}
});
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
}
}
服务执行类:
package com.example.serviceexample;
import android.app.Service;
import android.content.Context;
import android.content.Intent;
import android.os.Handler;
import android.os.HandlerThread;
import android.os.IBinder;
import android.os.Looper;
import android.os.Message;
import android.widget.Toast;
public class ServiceExecution extends Service {
// Declare variables for Looper and ServiceHandler
private Looper mServiceLooper;
private ServiceHandler mServiceHandler;
// Handler that receives messages from the thread
public class ServiceHandler extends Handler {
// Create a constructor for class.
// Run once on creation of handler object.
public ServiceHandler(Looper looper) {
// Override super class to use looper provided
super(looper);
}
// Handler receives message and carries out the work of the service
public void handleMessage(Message msg) {
// Wait before toasting message appears
// to give the Service Started message time to display
for (int i = 0; i <= 30; i++) {
try {
Thread.sleep(100);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
// Toast service message
Context context = getApplicationContext();
Toast toast = Toast.makeText(context, "Service Message!!!",
Toast.LENGTH_LONG);
toast.show();
}
}
@Override
public IBinder onBind(Intent arg0) {
// TODO Auto-generated method stub
return null;
}
// Create a thread and service handler with a looper
public void OnCreate() {
super.onCreate();
// Create a Thread with a Looper
HandlerThread thread = new HandlerThread("ServiceStartArguments",
android.os.Process.THREAD_PRIORITY_BACKGROUND);
thread.start();
// Get the threads looper
mServiceLooper = thread.getLooper();
// Create a service handler
mServiceHandler = new ServiceHandler(mServiceLooper);
}
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
// Get message from message pool using handler
Message msg = mServiceHandler.obtainMessage();
// Set start ID in message
msg.arg1 = startId;
// Send msg to start job
mServiceHandler.sendMessage(msg);
// Toast message Started Service
Context context = getApplicationContext();
Toast toast = Toast.makeText(context, "Service Started!!!",
Toast.LENGTH_LONG);
toast.show();
// Start a Sticky
return START_STICKY;
}
public void OnDestroy() {
super.onDestroy();
// Toast Service Stopped
Context context = getApplicationContext();
Toast toast = Toast.makeText(context, "Service Stopped!!!",
Toast.LENGTH_LONG);
toast.show();
}
}
我只是不知道我的代码出了什么问题。希望有人能看到我的失败。感谢你们的帮助:)
编辑。我得到的错误:
06-16 17:28:28.406: E/Trace(619): error opening trace file: No such file or directory (2)
06-16 17:28:31.496: E/AndroidRuntime(619): FATAL EXCEPTION: main
06-16 17:28:31.496: E/AndroidRuntime(619): java.lang.RuntimeException: Unable to start service com.example.serviceexample.ServiceExecution@4120a190 with Intent { cmp=com.example.serviceexample/.ServiceExecution }: java.lang.NullPointerException
06-16 17:28:31.496: E/AndroidRuntime(619): at android.app.ActivityThread.handleServiceArgs(ActivityThread.java:2507)
06-16 17:28:31.496: E/AndroidRuntime(619): at android.app.ActivityThread.access$1900(ActivityThread.java:130)
06-16 17:28:31.496: E/AndroidRuntime(619): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1292)
06-16 17:28:31.496: E/AndroidRuntime(619): at android.os.Handler.dispatchMessage(Handler.java:99)
06-16 17:28:31.496: E/AndroidRuntime(619): at android.os.Looper.loop(Looper.java:137)
06-16 17:28:31.496: E/AndroidRuntime(619): at android.app.ActivityThread.main(ActivityThread.java:4745)
06-16 17:28:31.496: E/AndroidRuntime(619): at java.lang.reflect.Method.invokeNative(Native Method)
06-16 17:28:31.496: E/AndroidRuntime(619): at java.lang.reflect.Method.invoke(Method.java:511)
06-16 17:28:31.496: E/AndroidRuntime(619): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
06-16 17:28:31.496: E/AndroidRuntime(619): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
06-16 17:28:31.496: E/AndroidRuntime(619): at dalvik.system.NativeStart.main(Native Method)
06-16 17:28:31.496: E/AndroidRuntime(619): Caused by: java.lang.NullPointerException
06-16 17:28:31.496: E/AndroidRuntime(619): at com.example.serviceexample.ServiceExecution.onStartCommand(ServiceExecution.java:78)
06-16 17:28:31.496: E/AndroidRuntime(619): at android.app.ActivityThread.handleServiceArgs(ActivityThread.java:2490)
06-16 17:28:31.496: E/AndroidRuntime(619): ... 10 more
06-16 17:28:43.035: E/Trace(639): error opening trace file: No such file or directory (2)
06-16 17:28:43.096: E/AndroidRuntime(639): FATAL EXCEPTION: main
06-16 17:28:43.096: E/AndroidRuntime(639): java.lang.RuntimeException: Unable to start service com.example.serviceexample.ServiceExecution@411ecd30 with Intent { cmp=com.example.serviceexample/.ServiceExecution }: java.lang.NullPointerException
06-16 17:28:43.096: E/AndroidRuntime(639): at android.app.ActivityThread.handleServiceArgs(ActivityThread.java:2507)
06-16 17:28:43.096: E/AndroidRuntime(639): at android.app.ActivityThread.access$1900(ActivityThread.java:130)
06-16 17:28:43.096: E/AndroidRuntime(639): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1292)
06-16 17:28:43.096: E/AndroidRuntime(639): at android.os.Handler.dispatchMessage(Handler.java:99)
06-16 17:28:43.096: E/AndroidRuntime(639): at android.os.Looper.loop(Looper.java:137)
06-16 17:28:43.096: E/AndroidRuntime(639): at android.app.ActivityThread.main(ActivityThread.java:4745)
06-16 17:28:43.096: E/AndroidRuntime(639): at java.lang.reflect.Method.invokeNative(Native Method)
06-16 17:28:43.096: E/AndroidRuntime(639): at java.lang.reflect.Method.invoke(Method.java:511)
06-16 17:28:43.096: E/AndroidRuntime(639): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
06-16 17:28:43.096: E/AndroidRuntime(639): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
06-16 17:28:43.096: E/AndroidRuntime(639): at dalvik.system.NativeStart.main(Native Method)
06-16 17:28:43.096: E/AndroidRuntime(639): Caused by: java.lang.NullPointerException
06-16 17:28:43.096: E/AndroidRuntime(639): at com.example.serviceexample.ServiceExecution.onStartCommand(ServiceExecution.java:78)
06-16 17:28:43.096: E/AndroidRuntime(639): at android.app.ActivityThread.handleServiceArgs(ActivityThread.java:2490)
06-16 17:28:43.096: E/AndroidRuntime(639): ... 10 more
06-16 17:30:04.816: E/Trace(678): error opening trace file: No such file or directory (2)
06-16 17:30:35.025: E/AndroidRuntime(678): FATAL EXCEPTION: main
06-16 17:30:35.025: E/AndroidRuntime(678): java.lang.RuntimeException: Unable to start service com.example.serviceexample.ServiceExecution@4120beb8 with Intent { cmp=com.example.serviceexample/.ServiceExecution }: java.lang.NullPointerException
06-16 17:30:35.025: E/AndroidRuntime(678): at android.app.ActivityThread.handleServiceArgs(ActivityThread.java:2507)
06-16 17:30:35.025: E/AndroidRuntime(678): at android.app.ActivityThread.access$1900(ActivityThread.java:130)
06-16 17:30:35.025: E/AndroidRuntime(678): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1292)
06-16 17:30:35.025: E/AndroidRuntime(678): at android.os.Handler.dispatchMessage(Handler.java:99)
06-16 17:30:35.025: E/AndroidRuntime(678): at android.os.Looper.loop(Looper.java:137)
06-16 17:30:35.025: E/AndroidRuntime(678): at android.app.ActivityThread.main(ActivityThread.java:4745)
06-16 17:30:35.025: E/AndroidRuntime(678): at java.lang.reflect.Method.invokeNative(Native Method)
06-16 17:30:35.025: E/AndroidRuntime(678): at java.lang.reflect.Method.invoke(Method.java:511)
06-16 17:30:35.025: E/AndroidRuntime(678): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
06-16 17:30:35.025: E/AndroidRuntime(678): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
06-16 17:30:35.025: E/AndroidRuntime(678): at dalvik.system.NativeStart.main(Native Method)
06-16 17:30:35.025: E/AndroidRuntime(678): Caused by: java.lang.NullPointerException
06-16 17:30:35.025: E/AndroidRuntime(678): at com.example.serviceexample.ServiceExecution.onStartCommand(ServiceExecution.java:78)
06-16 17:30:35.025: E/AndroidRuntime(678): at android.app.ActivityThread.handleServiceArgs(ActivityThread.java:2490)
06-16 17:30:35.025: E/AndroidRuntime(678): ... 10 more
06-16 17:30:42.326: E/Trace(693): error opening trace file: No such file or directory (2)
06-16 17:30:42.386: E/AndroidRuntime(693): FATAL EXCEPTION: main
06-16 17:30:42.386: E/AndroidRuntime(693): java.lang.RuntimeException: Unable to start service com.example.serviceexample.ServiceExecution@411e5150 with Intent { cmp=com.example.serviceexample/.ServiceExecution }: java.lang.NullPointerException
06-16 17:30:42.386: E/AndroidRuntime(693): at android.app.ActivityThread.handleServiceArgs(ActivityThread.java:2507)
06-16 17:30:42.386: E/AndroidRuntime(693): at android.app.ActivityThread.access$1900(ActivityThread.java:130)
06-16 17:30:42.386: E/AndroidRuntime(693): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1292)
06-16 17:30:42.386: E/AndroidRuntime(693): at android.os.Handler.dispatchMessage(Handler.java:99)
06-16 17:30:42.386: E/AndroidRuntime(693): at android.os.Looper.loop(Looper.java:137)
06-16 17:30:42.386: E/AndroidRuntime(693): at android.app.ActivityThread.main(ActivityThread.java:4745)
06-16 17:30:42.386: E/AndroidRuntime(693): at java.lang.reflect.Method.invokeNative(Native Method)
06-16 17:30:42.386: E/AndroidRuntime(693): at java.lang.reflect.Method.invoke(Method.java:511)
06-16 17:30:42.386: E/AndroidRuntime(693): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
06-16 17:30:42.386: E/AndroidRuntime(693): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
06-16 17:30:42.386: E/AndroidRuntime(693): at dalvik.system.NativeStart.main(Native Method)
06-16 17:30:42.386: E/AndroidRuntime(693): Caused by: java.lang.NullPointerException
06-16 17:30:42.386: E/AndroidRuntime(693): at com.example.serviceexample.ServiceExecution.onStartCommand(ServiceExecution.java:78)
06-16 17:30:42.386: E/AndroidRuntime(693): at android.app.ActivityThread.handleServiceArgs(ActivityThread.java:2490)
06-16 17:30:42.386: E/AndroidRuntime(693): ... 10 more
06-16 17:33:04.446: E/Trace(753): error opening trace file: No such file or directory (2)
06-16 17:33:33.108: E/AndroidRuntime(753): FATAL EXCEPTION: main
06-16 17:33:33.108: E/AndroidRuntime(753): java.lang.RuntimeException: Unable to start service com.example.serviceexample.ServiceExecution@41205498 with Intent { cmp=com.example.serviceexample/.ServiceExecution }: java.lang.NullPointerException
06-16 17:33:33.108: E/AndroidRuntime(753): at android.app.ActivityThread.handleServiceArgs(ActivityThread.java:2507)
06-16 17:33:33.108: E/AndroidRuntime(753): at android.app.ActivityThread.access$1900(ActivityThread.java:130)
06-16 17:33:33.108: E/AndroidRuntime(753): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1292)
06-16 17:33:33.108: E/AndroidRuntime(753): at android.os.Handler.dispatchMessage(Handler.java:99)
06-16 17:33:33.108: E/AndroidRuntime(753): at android.os.Looper.loop(Looper.java:137)
06-16 17:33:33.108: E/AndroidRuntime(753): at android.app.ActivityThread.main(ActivityThread.java:4745)
06-16 17:33:33.108: E/AndroidRuntime(753): at java.lang.reflect.Method.invokeNative(Native Method)
06-16 17:33:33.108: E/AndroidRuntime(753): at java.lang.reflect.Method.invoke(Method.java:511)
06-16 17:33:33.108: E/AndroidRuntime(753): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
06-16 17:33:33.108: E/AndroidRuntime(753): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
06-16 17:33:33.108: E/AndroidRuntime(753): at dalvik.system.NativeStart.main(Native Method)
06-16 17:33:33.108: E/AndroidRuntime(753): Caused by: java.lang.NullPointerException
06-16 17:33:33.108: E/AndroidRuntime(753): at com.example.serviceexample.ServiceExecution.onStartCommand(ServiceExecution.java:78)
06-16 17:33:33.108: E/AndroidRuntime(753): at android.app.ActivityThread.handleServiceArgs(ActivityThread.java:2490)
06-16 17:33:33.108: E/AndroidRuntime(753): ... 10 more
06-16 17:33:41.275: E/Trace(768): error opening trace file: No such file or directory (2)
06-16 17:33:41.335: E/AndroidRuntime(768): FATAL EXCEPTION: main
06-16 17:33:41.335: E/AndroidRuntime(768): java.lang.RuntimeException: Unable to start service com.example.serviceexample.ServiceExecution@411e7bc8 with Intent { cmp=com.example.serviceexample/.ServiceExecution }: java.lang.NullPointerException
06-16 17:33:41.335: E/AndroidRuntime(768): at android.app.ActivityThread.handleServiceArgs(ActivityThread.java:2507)
06-16 17:33:41.335: E/AndroidRuntime(768): at android.app.ActivityThread.access$1900(ActivityThread.java:130)
06-16 17:33:41.335: E/AndroidRuntime(768): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1292)
06-16 17:33:41.335: E/AndroidRuntime(768): at android.os.Handler.dispatchMessage(Handler.java:99)
06-16 17:33:41.335: E/AndroidRuntime(768): at android.os.Looper.loop(Looper.java:137)
06-16 17:33:41.335: E/AndroidRuntime(768): at android.app.ActivityThread.main(ActivityThread.java:4745)
06-16 17:33:41.335: E/AndroidRuntime(768): at java.lang.reflect.Method.invokeNative(Native Method)
06-16 17:33:41.335: E/AndroidRuntime(768): at java.lang.reflect.Method.invoke(Method.java:511)
06-16 17:33:41.335: E/AndroidRuntime(768): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
06-16 17:33:41.335: E/AndroidRuntime(768): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
06-16 17:33:41.335: E/AndroidRuntime(768): at dalvik.system.NativeStart.main(Native Method)
06-16 17:33:41.335: E/AndroidRuntime(768): Caused by: java.lang.NullPointerException
06-16 17:33:41.335: E/AndroidRuntime(768): at com.example.serviceexample.ServiceExecution.onStartCommand(ServiceExecution.java:78)
06-16 17:33:41.335: E/AndroidRuntime(768): at android.app.ActivityThread.handleServiceArgs(ActivityThread.java:2490)
06-16 17:33:41.335: E/AndroidRuntime(768): ... 10 more
06-16 17:35:05.576: E/Trace(838): error opening trace file: No such file or directory (2)
06-16 17:35:17.266: E/AndroidRuntime(838): FATAL EXCEPTION: main
06-16 17:35:17.266: E/AndroidRuntime(838): java.lang.RuntimeException: Unable to start service com.example.serviceexample.ServiceExecution@41207c10 with Intent { cmp=com.example.serviceexample/.ServiceExecution }: java.lang.NullPointerException
06-16 17:35:17.266: E/AndroidRuntime(838): at android.app.ActivityThread.handleServiceArgs(ActivityThread.java:2507)
06-16 17:35:17.266: E/AndroidRuntime(838): at android.app.ActivityThread.access$1900(ActivityThread.java:130)
06-16 17:35:17.266: E/AndroidRuntime(838): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1292)
06-16 17:35:17.266: E/AndroidRuntime(838): at android.os.Handler.dispatchMessage(Handler.java:99)
06-16 17:35:17.266: E/AndroidRuntime(838): at android.os.Looper.loop(Looper.java:137)
06-16 17:35:17.266: E/AndroidRuntime(838): at android.app.ActivityThread.main(ActivityThread.java:4745)
06-16 17:35:17.266: E/AndroidRuntime(838): at java.lang.reflect.Method.invokeNative(Native Method)
06-16 17:35:17.266: E/AndroidRuntime(838): at java.lang.reflect.Method.invoke(Method.java:511)
06-16 17:35:17.266: E/AndroidRuntime(838): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
06-16 17:35:17.266: E/AndroidRuntime(838): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
06-16 17:35:17.266: E/AndroidRuntime(838): at dalvik.system.NativeStart.main(Native Method)
06-16 17:35:17.266: E/AndroidRuntime(838): Caused by: java.lang.NullPointerException
06-16 17:35:17.266: E/AndroidRuntime(838): at com.example.serviceexample.ServiceExecution.onStartCommand(ServiceExecution.java:78)
06-16 17:35:17.266: E/AndroidRuntime(838): at android.app.ActivityThread.handleServiceArgs(ActivityThread.java:2490)
06-16 17:35:17.266: E/AndroidRuntime(838): ... 10 more
06-16 17:35:24.806: E/Trace(852): error opening trace file: No such file or directory (2)
06-16 17:35:24.857: E/AndroidRuntime(852): FATAL EXCEPTION: main
06-16 17:35:24.857: E/AndroidRuntime(852): java.lang.RuntimeException: Unable to start service com.example.serviceexample.ServiceExecution@411ea5b8 with Intent { cmp=com.example.serviceexample/.ServiceExecution }: java.lang.NullPointerException
06-16 17:35:24.857: E/AndroidRuntime(852): at android.app.ActivityThread.handleServiceArgs(ActivityThread.java:2507)
06-16 17:35:24.857: E/AndroidRuntime(852): at android.app.ActivityThread.access$1900(ActivityThread.java:130)
06-16 17:35:24.857: E/AndroidRuntime(852): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1292)
06-16 17:35:24.857: E/AndroidRuntime(852): at android.os.Handler.dispatchMessage(Handler.java:99)
06-16 17:35:24.857: E/AndroidRuntime(852): at android.os.Looper.loop(Looper.java:137)
06-16 17:35:24.857: E/AndroidRuntime(852): at android.app.ActivityThread.main(ActivityThread.java:4745)
06-16 17:35:24.857: E/AndroidRuntime(852): at java.lang.reflect.Method.invokeNative(Native Method)
06-16 17:35:24.857: E/AndroidRuntime(852): at java.lang.reflect.Method.invoke(Method.java:511)
06-16 17:35:24.857: E/AndroidRuntime(852): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
06-16 17:35:24.857: E/AndroidRuntime(852): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
06-16 17:35:24.857: E/AndroidRuntime(852): at dalvik.system.NativeStart.main(Native Method)
06-16 17:35:24.857: E/AndroidRuntime(852): Caused by: java.lang.NullPointerException
06-16 17:35:24.857: E/AndroidRuntime(852): at com.example.serviceexample.ServiceExecution.onStartCommand(ServiceExecution.java:78)
06-16 17:35:24.857: E/AndroidRuntime(852): at android.app.ActivityThread.handleServiceArgs(ActivityThread.java:2490)
06-16 17:35:24.857: E/AndroidRuntime(852): ... 10 more
最佳答案
mServiceHandler 在 onStartCommand 中为 null。尝试在该函数中初始化它。
如果添加简单的打印:
public void OnCreate() {
System.out.println("In on create");
和
public int onStartCommand(Intent intent, int flags, int startId) {
System.out.println("In onStartCommand()");
你可以很容易地看到你的程序只进入第二个函数。因此,处理程序结果仍未初始化。您可以完全摆脱 onCreate 方法并将其逻辑合并到 onStartCommand 中。
原因如下:when onCreate and onStartCommand on Service class are invoked
关于java - 服务应用程序停止工作,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/17136024/
我在Windows 10中使用一些简单的Powershell代码遇到了这个奇怪的问题,我认为这可能是我做错了,但我不是Powershell的天才。 我有这个: $ix = [System.Net.Dn
var urlsearch = "http://192.168.10.113:8080/collective-intellegence/StoreClicks?userid=" + userId +
我有一个非常奇怪的问题,过去两天一直让我抓狂。 我有一个我试图控制的串行设备(LS 100 光度计)。使用设置了正确参数的终端(白蚁),我可以发送命令(“MES”),然后是定界符(CR LF),然后我
我目前正试图让无需注册的 COM 使用 Excel 作为客户端,使用 .NET dll 作为服务器。目前,我只是试图让概念验证工作,但遇到了麻烦。 显然,当我使用 Excel 时,我不能简单地使用与可
我开发了简单的 REST API - https://github.com/pavelpetrcz/MandaysFigu - 我的问题是在本地主机上,WildFly 16 服务器的应用程序运行正常。
我遇到了奇怪的情况 - 从 Django shell 创建一些 Mongoengine 对象是成功的,但是从 Django View 创建相同的对象看起来成功,但 MongoDB 中没有出现任何数据。
我是 flask 的新手,只编写了一个相当简单的网络应用程序——没有数据库,只是一个航类搜索 API 的前端。一切正常,但为了提高我的技能,我正在尝试使用应用程序工厂和蓝图重构我的代码。让它与 pus
我的谷歌分析 JavaScript 事件在开发者控制台中运行得很好。 但是当从外部 js 文件包含在页面上时,它们根本不起作用。由于某种原因。 例如; 下面的内容将在包含在控制台中时运行。但当包含在单
这是一本名为“Node.js 8 the Right Way”的书中的任务。你可以在下面看到它: 这是我的解决方案: 'use strict'; const zmq = require('zeromq
我正在阅读文本行,并创建其独特单词的列表(在将它们小写之后)。我可以使它与 flatMap 一起工作,但不能使它与 map 的“子”流一起工作。 flatMap 看起来更简洁和“更好”,但为什么 di
我正在编写一些 PowerShell 脚本来进行一些构建自动化。我发现 here echo $? 根据前面的语句返回真或假。我刚刚发现 echo 是 Write-Output 的别名。 写主机 $?
关闭。这个问题不满足Stack Overflow guidelines .它目前不接受答案。 想改善这个问题吗?更新问题,使其成为 on-topic对于堆栈溢出。 4年前关闭。 Improve thi
我将一个工作 View Controller 类从另一个项目复制到一个新项目中。我无法在新项目中加载 View 。在旧项目中我使用了presentModalViewController。在新版本中,我
我对 javascript 很陌生,所以很难看出我哪里出错了。由于某种原因,我的功能无法正常工作。任何帮助,将不胜感激。我尝试在外部 js 文件、头部/主体中使用它们,但似乎没有任何效果。错误要么出在
我正在尝试学习Flutter中的复选框。 问题是,当我想在Scaffold(body :)中使用复选框时,它正在工作。但我想在不同的地方使用它,例如ListView中的项目。 return Cente
我们当前使用的是 sleuth 2.2.3.RELEASE,我们看不到在 http header 中传递的 userId 字段没有传播。下面是我们的代码。 BaggageField REQUEST_I
我有一个组合框,其中包含一个项目,比如“a”。我想调用该组合框的 Action 监听器,仅在手动选择项目“a”完成时才调用。我也尝试过 ItemStateChanged,但它的工作原理与 Action
你能看一下照片吗?现在,一步前我执行了 this.interrupt()。您可以看到 this.isInterrupted() 为 false。我仔细观察——“这个”没有改变。它具有相同的 ID (1
我们当前使用的是 sleuth 2.2.3.RELEASE,我们看不到在 http header 中传递的 userId 字段没有传播。下面是我们的代码。 BaggageField REQUEST_I
我正在尝试在我的网站上设置一个联系表单,当有人点击发送时,就会运行一个作业,并在该作业中向所有管理员用户发送通知。不过,我在失败的工作表中不断收到此错误: Illuminate\Database\El
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