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メインアプリで、別のアプリを実行すると、NullPointerExceptionが発生します。別のアプリを実行すると、アンドロイドでNullPointerExceptionが発生する
このlogcatここ
java.lang.RuntimeException: Unable to start activity ComponentInfo{kr.co.iosystem.blackeyeonandroid/kr.co.iosystem.blackeyeonandroid.BlackEyeActivity}:
java.lang.NullPointerException
android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2184)
android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2233)
android.app.ActivityThread.access$800(ActivityThread.java:135)
android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
android.os.Handler.dispatchMessage(Handler.java:102)
android.os.Looper.loop(Looper.java:136)
android.app.ActivityThread.main(ActivityThread.java:5001)
java.lang.reflect.Method.invokeNative(Native Method)
java.lang.reflect.Method.invoke(Method.java:515)
com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
android.app.Instrumentation.execStartActivity(Instrumentation.java:1417)
android.app.Activity.startActivityForResult(Activity.java:3424)
android.app.Activity.startActivityForResult(Activity.java:3385)
android.app.Activity.startActivity(Activity.java:3627)
android.app.Activity.startActivity(Activity.java:3595)
kr.co.iosystem.blackeyeonandroid.BlackEyeActivity.netCheckAutoUpdate(BlackEyeActivity.java:479)
kr.co.iosystem.blackeyeonandroid.BlackEyeActivity.onCreate(BlackEyeActivity.java:147)
android.app.Activity.performCreate(Activity.java:5231)
android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2148) E/AndroidRuntime(2678): ... 11 more
と私のコード。
protected static Context mainContext =null;
@Override
protected void onCreate(final Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
netCheckAutoUpdate(); //NullPointerException
}
public void netCheckAutoUpdate() {
ConnectivityManager connectivityManager = (ConnectivityManager) this.getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo ethernet = connectivityManager.getNetworkInfo(ConnectivityManager.TYPE_ETHERNET);
NetworkInfo wifi = connectivityManager.getNetworkInfo(ConnectivityManager.TYPE_WIFI);
if (wifi.isConnected()) {
Intent intent = mainContext.getPackageManager().getLaunchIntentForPackage("package name");
startActivity(intent); //NullPointerException
} else if (ethernet.isConnected()) {
Intent intent = mainContext.getPackageManager().getLaunchIntentForPackage("package name");
startActivity(intent); //NullPointerException
} else {
Intent intent = mainContext.getPackageManager().getLaunchIntentForPackage("package name");
startActivity(intent); //NullPointerException
}
}
おそらく、nullチェックを使用する必要がありますか？
これが正しい場合は、どのようにヌルチェックを使用しますか？ mainContextはグローバル変数
私は無線LANを接続します。私は、マニフェストからの適切な権限他の言葉でNullPointerExceptionが この部分
NetworkInfo wifi = connectivityManager.getNetworkInfo(ConnectivityManager.TYPE_WIFI);
if (wifi.isConnected()) {
Intent intent = mainContext.getPackageManager().getLaunchIntentForPackage("kr.co.iosystem.be_update");
startActivity(intent);
}
、
`startActivity(intent)` here occur NullPointerException.
を発生します。あなたのmainContext
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE"/>
<uses-permission android:name="android.permission.CHANGE_NETWORK_STATE"/>
<uses-permission android:name="android.permission.CHANGE_WIFI_STATE"/>