Java 从活动启动库存主屏幕时强制关闭

我试图从一个活动启动股票主屏幕，但它一直强制关闭。到目前为止，我有一个活动显示已安装房屋的列表。用户可以选择一个，它将启动选择的主屏幕。这对已安装的家庭来说效果很好，但当我选择预装的家庭时，它将强制关闭

这是我用来开始活动的东西。我为我的设备提供了库存主页的packagename

Intent startMain = getPackageManager().getLaunchIntentForPackage("com.android.launcher");
startMain.addCategory(Intent.CATEGORY_HOME);
startMain.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(startMain);

任何帮助都会很棒，因为我不明白为什么这对大多数家庭有效，但对其他家庭无效

日志类别：

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如果您想返回主屏幕，为什么不直接调用finish；？用户选择要启动的主屏幕，而不是默认屏幕。因此，基本上，我试图启动任何主屏幕，即使它没有设置为默认主屏幕。

02-01 20:26:46.144: E/AndroidRuntime(7432): FATAL EXCEPTION: main
02-01 20:26:46.144: E/AndroidRuntime(7432): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.calsto.lockscreen/com.calsto.HomeWizard.NanohaLauncher}: java.lang.NullPointerException
02-01 20:26:46.144: E/AndroidRuntime(7432):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1956)
02-01 20:26:46.144: E/AndroidRuntime(7432):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1981)
02-01 20:26:46.144: E/AndroidRuntime(7432):     at android.app.ActivityThread.access$600(ActivityThread.java:123)
02-01 20:26:46.144: E/AndroidRuntime(7432):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1147)
02-01 20:26:46.144: E/AndroidRuntime(7432):     at android.os.Handler.dispatchMessage(Handler.java:99)
02-01 20:26:46.144: E/AndroidRuntime(7432):     at android.os.Looper.loop(Looper.java:137)
02-01 20:26:46.144: E/AndroidRuntime(7432):     at android.app.ActivityThread.main(ActivityThread.java:4424)
02-01 20:26:46.144: E/AndroidRuntime(7432):     at java.lang.reflect.Method.invokeNative(Native Method)
02-01 20:26:46.144: E/AndroidRuntime(7432):     at java.lang.reflect.Method.invoke(Method.java:511)
02-01 20:26:46.144: E/AndroidRuntime(7432):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:787)
02-01 20:26:46.144: E/AndroidRuntime(7432):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:554)
02-01 20:26:46.144: E/AndroidRuntime(7432):     at dalvik.system.NativeStart.main(Native Method)
02-01 20:26:46.144: E/AndroidRuntime(7432): Caused by: java.lang.NullPointerException
02-01 20:26:46.144: E/AndroidRuntime(7432):     at android.app.Instrumentation.execStartActivity(Instrumentation.java:1378)
02-01 20:26:46.144: E/AndroidRuntime(7432):     at android.app.Activity.startActivityForResult(Activity.java:3190)
02-01 20:26:46.144: E/AndroidRuntime(7432):     at android.app.Activity.startActivity(Activity.java:3297)
02-01 20:26:46.144: E/AndroidRuntime(7432):     at com.calsto.HomeWizard.NanohaLauncher.onCreate(NanohaLauncher.java:233)
02-01 20:26:46.144: E/AndroidRuntime(7432):     at android.app.Activity.performCreate(Activity.java:4465)
02-01 20:26:46.144: E/AndroidRuntime(7432):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1049)
02-01 20:26:46.144: E/AndroidRuntime(7432):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1920)
02-01 20:26:46.144: E/AndroidRuntime(7432):     ... 11 more