Java 带有Intent/IntentService的Android空指针异常
我的应用程序因返回以下堆栈跟踪而崩溃:Java 带有Intent/IntentService的Android空指针异常,java,android,Java,Android,我的应用程序因返回以下堆栈跟踪而崩溃: java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.example.**REDACTED**.copyright/com.example.**REDACTED**.copyright.MainActivity}: java.lang.NullPointerException 07-21 22:26:18.499 E/AndroidRuntime(15933
java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.example.**REDACTED**.copyright/com.example.**REDACTED**.copyright.MainActivity}: java.lang.NullPointerException
07-21 22:26:18.499 E/AndroidRuntime(15933): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2128)
07-21 22:26:18.499 E/AndroidRuntime(15933): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2252)
07-21 22:26:18.499 E/AndroidRuntime(15933): at android.app.ActivityThread.access$800(ActivityThread.java:139)
07-21 22:26:18.499 E/AndroidRuntime(15933): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1200)
07-21 22:26:18.499 E/AndroidRuntime(15933): at android.os.Handler.dispatchMessage(Handler.java:102)
07-21 22:26:18.499 E/AndroidRuntime(15933): at android.os.Looper.loop(Looper.java:136)
07-21 22:26:18.499 E/AndroidRuntime(15933): at android.app.ActivityThread.main(ActivityThread.java:5103)
07-21 22:26:18.499 E/AndroidRuntime(15933): at java.lang.reflect.Method.invokeNative(Native Method)
07-21 22:26:18.499 E/AndroidRuntime(15933): at java.lang.reflect.Method.invoke(Method.java:515)
07-21 22:26:18.499 E/AndroidRuntime(15933): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:790)
07-21 22:26:18.499 E/AndroidRuntime(15933): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:606)
07-21 22:26:18.499 E/AndroidRuntime(15933): at dalvik.system.NativeStart.main(Native Method)
07-21 22:26:18.499 E/AndroidRuntime(15933): Caused by: java.lang.NullPointerException
07-21 22:26:18.499 E/AndroidRuntime(15933): at android.content.ContextWrapper.getPackageName(ContextWrapper.java:135)
07-21 22:26:18.499 E/AndroidRuntime(15933): at android.content.ComponentName.<init>(ComponentName.java:77)
07-21 22:26:18.499 E/AndroidRuntime(15933): at android.content.Intent.<init>(Intent.java:3834)
07-21 22:26:18.499 E/AndroidRuntime(15933): at com.example.**REDACTED**.copyright.MainActivity.<init>(MainActivity.java:31)
07-21 22:26:18.499 E/AndroidRuntime(15933): at java.lang.Class.newInstanceImpl(Native Method)
07-21 22:26:18.499 E/AndroidRuntime(15933): at java.lang.Class.newInstance(Class.java:1208)
07-21 22:26:18.499 E/AndroidRuntime(15933): at android.app.Instrumentation.newActivity(Instrumentation.java:1061)
07-21 22:26:18.499 E/AndroidRuntime(15933): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2119)
mServiceIntent不会再次引用,直到下列行也位于MainActivity中:
@Override
protected void onStop() {
super.onStop();
this.startService(mServiceIntent);
Log.v("MainActivity", "onStop called");
如果你需要更多的信息,我很乐意添加。提前感谢您的耐心和帮助。您应该在onStop()方法(在运行时发生)中实例化意图,而不是在编译时定义它。例如:
public class MainActivity extends Activity {
Intent mServiceIntent;
...
@Override
protected void onStop() {
super.onStop();
mServiceIntent = new Intent(this, Scan.class);
this.startService(mServiceIntent);
Log.v("MainActivity", "onStop called");
使用此代码,希望它能正常工作
Intent intent = new Intent(this, SplashScreen.class);
intent .addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(intent );
如何在
super
或setContenView
之前使用Intent
。您正在另一个函数中使用mServiceIntent
,但尚未声明变量global。显示真正符合逻辑的代码。@Gaurav可能就是这个错误。这很有效,谢谢,我能够在多个方法中使用mServiceIntent而不会崩溃。
Intent intent = new Intent(this, SplashScreen.class);
intent .addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(intent );