您好,我是Android开发的初学者。 我在MainActivity中遇到了空指针异常。 (我知道有关此主题的问题很多,但没有任何具体帮助我的东西)
> 07-05 05:23:00.407 3229-3229/package.name E/AndroidRuntime: FATAL EXCEPTION: main
Process: my.package.name, PID: 3229
java.lang.RuntimeException: Unable to start activity ComponentInfo{my.package.name/my.package.name.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.Spinner.setSelection(int)' on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2817)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2892)
at android.app.ActivityThread.-wrap11(Unknown Source:0)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1593)
at android.os.Handler.dispatchMessage(Handler.java:105)
at android.os.Looper.loop(Looper.java:164)
at android.app.ActivityThread.main(ActivityThread.java:6541)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:240)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:767)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.Spinner.setSelection(int)' on a null object reference
at graphicstool.battlegrounnd.gfx.MainActivity.revertConfig(MainActivity.java:235)
at graphicstool.battlegrounnd.gfx.MainActivity.onCreate(MainActivity.java:377)
at android.app.Activity.performCreate(Activity.java:6975)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1213)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2770)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2892)
at android.app.ActivityThread.-wrap11(Unknown Source:0)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1593)
at android.os.Handler.dispatchMessage(Handler.java:105)
at android.os.Looper.loop(Looper.java:164)
at android.app.ActivityThread.main(ActivityThread.java:6541)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:240)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:767)
请参阅上述错误。 这是我的特定错误代码
private void revertConfig() {
SharedPreferences sharedPreferences = getSharedPreferences(getPackageName(), 0);
this.sprGraphicsQuality.setSelection(sharedPreferences.getInt("sprGraphicsQuality", 0));
}
protected void onCreate(Bundle bundle) {
super.onCreate(bundle);
setContentView(R.layout.activity_main);
verifyStoragePermissions(this);
Spinner sprGraphicsQuality =(Spinner) findViewById(R.id.sprGraphicsQuality);
ArrayAdapter adapter = createFromResource(this, R.array.qualitysetting, R.layout.activity_main);
adapter.setDropDownViewResource(R.layout.activity_main);
sprGraphicsQuality.setAdapter(adapter);
revertConfig();
在这件事上请帮助我。 让我知道您是否需要更多详细信息。