Java Android处理程序链NullPointerException
我正试图通过Java Android处理程序链NullPointerException,java,android,multithreading,android-handler,Java,Android,Multithreading,Android Handler,我正试图通过处理程序在活动-服务-线程之间创建通信活动启动启动线程的服务线程向服务器发送请求，等待应答并通过处理程序将其重新发送到服务（正常工作）。但是当我尝试从服务的处理程序向活动发送消息时，应用程序以NullPointerException关闭。我做错了什么 基于 我的活动 public class ActivityLogin extends Activity{ public static LoginHandler loginHandler = null; public
处理程序在活动
-服务
-线程
之间创建通信<代码>活动线程的服务
<代码>线程处理程序将其重新发送到服务
（正常工作）。但是当我尝试从服务
的处理程序
向活动
发送消息时，应用程序以NullPointerException关闭。我做错了什么
基于
我的活动
public class ActivityLogin extends Activity{
public static LoginHandler loginHandler = null;
public static class LoginHandler extends Handler {
private WeakReference<ActivityLogin> target = null;
LoginHandler(ActivityLogin target) {
this.target = new WeakReference<ActivityLogin>(target);
}
public void setTarget(ActivityLogin target) {
this.target.clear();
this.target = new WeakReference<ActivityLogin>(target);
}
@Override
public void handleMessage(Message msg) {
ActivityLogin activity = this.target.get();
if(activity == null) return;
String response = msg.getData().getString("RESPONSE");
System.err.println("RESPONSE "+response);
}
}
@Override
protected void onCreate(Bundle savedInstanceState) {
Log.d("TAG","---------------------APP STARTED---------------------");
super.onCreate(savedInstanceState);
setContentView(R.layout.layout_login);
if(loginHandler == null) loginHandler = new LoginHandler(this);
else loginHandler.setTarget(this);
}
public void onLogin(View v){
JsonUser user = new JsonUser();
user.login = "Name";
user.password = "Pazzword";
user.device = "4567-753-5768-2343";
Intent intent = new Intent(this,ComService.class);
intent.putExtra("DATA_KEY", new Gson().toJson(user));
this.startService(intent);
}
}
更新
04-15 18:36:35.292 24524-24524/com.example.test E/Trace﹕ error opening trace file: No such file or directory (2)
04-15 18:36:35.332 24524-24524/com.example.test D/TAG﹕ ---------------------APP STARTED---------------------
04-15 18:36:35.462 24524-24524/com.example.test D/libEGL﹕ loaded /system/lib/egl/libEGL_mali.so
04-15 18:36:35.462 24524-24524/com.example.test D/libEGL﹕ loaded /system/lib/egl/libGLESv1_CM_mali.so
04-15 18:36:35.462 24524-24524/com.example.test D/libEGL﹕ loaded /system/lib/egl/libGLESv2_mali.so
04-15 18:36:35.492 24524-24524/com.example.test D/OpenGLRenderer﹕ Enabling debug mode 0
04-15 18:36:36.442 24554-24554/com.example.test:background E/Trace﹕ error opening trace file: No such file or directory (2)
04-15 18:36:36.682 24554-24567/com.example.test:background W/System.err﹕ {"status":{"success":false,"message":"some_text"},"result":null}
04-15 18:36:36.682 24554-24554/com.example.test:background D/AndroidRuntime﹕ Shutting down VM
04-15 18:36:36.682 24554-24554/com.example.test:background W/dalvikvm﹕ threadid=1: thread exiting with uncaught exception (group=0x41712300)
04-15 18:36:36.682 24554-24554/com.example.test:background E/AndroidRuntime﹕ FATAL EXCEPTION: main
java.lang.NullPointerException
at com.example.test.ComService$ServiceHandler.handleMessage(ComService.java:31)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:4745)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
at dalvik.system.NativeStart.main(Native Method)
AndroidManifext.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.test"
android:versionCode="1"
android:versionName="1.0">
<uses-sdk android:minSdkVersion="14"/>
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.CAMERA" />
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.WAKE_LOCK" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-feature android:name="android.hardware.camera" android:required="true" />
<application android:label="@string/app_name" android:icon="@drawable/ic_launcher"
android:theme="@android:style/Theme.Holo.Light.NoActionBar.Fullscreen">
<activity android:name=".ActivityLogin"
android:label="@string/app_name"
android:windowSoftInputMode="stateHidden"
android:theme="@android:style/Theme.Holo.Light.NoActionBar.Fullscreen">
<intent-filter>
<action android:name="android.intent.action.MAIN"/>
<category android:name="android.intent.category.LAUNCHER"/>
</intent-filter>
</activity>
<service android:name=".ComService"
android:exported="false"
android:process=":background"
/>
</application>
</manifest>
总之，我从我的应用程序中删除了服务。安卓服务
是癌症肿瘤，线程没有好处。这只是我的意见。请发布异常的完整stacktrace和异常和声明的stacktrace。这不是您应该采用的实现服务到活动通信的方式。看一看消息或阅读有关服务绑定的信息。非常有趣！您可以执行活动服务线程活动，但不能执行活动服务线程服务活动。
04-15 18:36:35.292 24524-24524/com.example.test E/Trace﹕ error opening trace file: No such file or directory (2)
04-15 18:36:35.332 24524-24524/com.example.test D/TAG﹕ ---------------------APP STARTED---------------------
04-15 18:36:35.462 24524-24524/com.example.test D/libEGL﹕ loaded /system/lib/egl/libEGL_mali.so
04-15 18:36:35.462 24524-24524/com.example.test D/libEGL﹕ loaded /system/lib/egl/libGLESv1_CM_mali.so
04-15 18:36:35.462 24524-24524/com.example.test D/libEGL﹕ loaded /system/lib/egl/libGLESv2_mali.so
04-15 18:36:35.492 24524-24524/com.example.test D/OpenGLRenderer﹕ Enabling debug mode 0
04-15 18:36:36.442 24554-24554/com.example.test:background E/Trace﹕ error opening trace file: No such file or directory (2)
04-15 18:36:36.682 24554-24567/com.example.test:background W/System.err﹕ {"status":{"success":false,"message":"some_text"},"result":null}
04-15 18:36:36.682 24554-24554/com.example.test:background D/AndroidRuntime﹕ Shutting down VM
04-15 18:36:36.682 24554-24554/com.example.test:background W/dalvikvm﹕ threadid=1: thread exiting with uncaught exception (group=0x41712300)
04-15 18:36:36.682 24554-24554/com.example.test:background E/AndroidRuntime﹕ FATAL EXCEPTION: main
java.lang.NullPointerException
at com.example.test.ComService$ServiceHandler.handleMessage(ComService.java:31)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:4745)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
at dalvik.system.NativeStart.main(Native Method)
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.test"
android:versionCode="1"
android:versionName="1.0">
<uses-sdk android:minSdkVersion="14"/>
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.CAMERA" />
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.WAKE_LOCK" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-feature android:name="android.hardware.camera" android:required="true" />
<application android:label="@string/app_name" android:icon="@drawable/ic_launcher"
android:theme="@android:style/Theme.Holo.Light.NoActionBar.Fullscreen">
<activity android:name=".ActivityLogin"
android:label="@string/app_name"
android:windowSoftInputMode="stateHidden"
android:theme="@android:style/Theme.Holo.Light.NoActionBar.Fullscreen">
<intent-filter>
<action android:name="android.intent.action.MAIN"/>
<category android:name="android.intent.category.LAUNCHER"/>
</intent-filter>
</activity>
<service android:name=".ComService"
android:exported="false"
android:process=":background"
/>
</application>
</manifest>