所以情况就是这样： 启动时会显示一个启动画面（同时在顶部显示位置请求）并启动计时器，经过一段时间后，它会移动到MainActivity。如果我允许使用该位置（当启动画面在backgorund中时），它在进入MainActivity时会崩溃。但是，如果我等到允许该位置直到显示MainActivity，则不会崩溃。
此错误仅在安装后第一次应用应用时生成。我第二次尝试复制错误，它没有显示（但可能是因为我没有提出允许我的职位的问题？）
我不知道错误的位置，并且错误日志没有告诉我错误被触发的代码到底在哪里？
这是logcat的错误：
12-05 23:19:35.670 19723-19723/se.dxapps.skidspar.beta E/AndroidRuntime: FATAL EXCEPTION: main
Process: se.dxapps.skidspar.beta, PID: 19723
java.lang.RuntimeException: Unable to stop activity {se.dxapps.skidspar.beta/se.dxapps.skidspar.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.view.View.clearAccessibilityFocus()' on a null object reference
at android.app.ActivityThread.performStopActivityInner(ActivityThread.java:3962)
at android.app.ActivityThread.handleStopActivity(ActivityThread.java:4011)
at android.app.ActivityThread.-wrap25(ActivityThread.java)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1542)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:241)
at android.app.ActivityThread.main(ActivityThread.java:6274)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.view.View.clearAccessibilityFocus()' on a null object reference
at android.view.ViewGroup.removeViewInternal(ViewGroup.java:4706)
at android.view.ViewGroup.removeViewAt(ViewGroup.java:4665)
at android.support.v4.app.FragmentManagerImpl.moveFragmentToExpectedState(FragmentManager.java:1762)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1819)
at android.support.v4.app.FragmentManagerImpl.dispatchStateChange(FragmentManager.java:3227)
at android.support.v4.app.FragmentManagerImpl.dispatchStop(FragmentManager.java:3204)
at android.support.v4.app.FragmentController.dispatchStop(FragmentController.java:236)
at android.support.v4.app.FragmentActivity.onStop(FragmentActivity.java:597)
at android.support.v7.app.AppCompatActivity.onStop(AppCompatActivity.java:183)
at android.app.Instrumentation.callActivityOnStop(Instrumentation.java:1290)
at android.app.Activity.performStop(Activity.java:6895)
at android.app.ActivityThread.performStopActivityInner(ActivityThread.java:3959)
at android.app.ActivityThread.handleStopActivity(ActivityThread.java:4011)
at android.app.ActivityThread.-wrap25(ActivityThread.java)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1542)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:241)
at android.app.ActivityThread.main(ActivityThread.java:6274)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)
这是＆＃34;部分＆＃34; MainActivity代码（由于正文中有字符限制）
public class MainActivity extends AppCompatActivity implements TabListener, LocationListener {
private static final String TAG = "lol";
private static int ACTIVITY_SETTINGS = 4;
private static MapsearchFragment mMapFragment;
private static ListsearchFragment mListFragment;
private static ListFavoritesFragment mFavFragment;
SearchView mSearchView = null;
/**
* The {@link android.support.v4.view.PagerAdapter} that will provide fragments for each of the
* three primary sections of the app. We use a {@link android.support.v4.app.FragmentPagerAdapter}
* derivative, which will keep every loaded fragment in memory. If this becomes too memory
* intensive, it may be best to switch to a {@link android.support.v4.app.FragmentStatePagerAdapter}.
*/
AppSectionsPagerAdapter mAppSectionsPagerAdapter;
/**
* The {@link ViewPager} that will display the three primary sections of the app, one at a
* time.
*/
ViewPager mViewPager;
private int defaultShowAge = 7;
private boolean defaultShowPref = true;
private DrawerLayout mDrawerLayout;
private ListView mDrawerList;
private ActionBarDrawerToggle mDrawerToggle;
private CharSequence mDrawerTitle;
private CharSequence mTitle;
private WebView adView;
private Toolbar toolbar;
private LocationManager locationManager;
private Skidspar skidspar;
private String prop_firstLaunch = "firstLaunch";
private PropertyStorage propertyStorage;
private AdHelper adHelper;
// private GifImageView gifImageView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Crittercism.initialize(getApplicationContext(), "52a2321a8b2e331d0f000003");
setContentView(R.layout.activity_main);
//final ActionBar actionBar = getActionBar();
// Create the adapter that will return a fragment for each of the three primary sections
// of the app.
adView = ReviveAdHelper.getAdView(findViewById(R.id.reviveAdFooter));
adView.loadUrl(ReviveAdHelper.footerAdUrl);
mAppSectionsPagerAdapter = new AppSectionsPagerAdapter(getSupportFragmentManager(), getResources());
//Location listener stuff.
locationManager = (LocationManager) this.getSystemService(Context.LOCATION_SERVICE);
MyLog.d("Skidspar", "onCreate");
skidspar = (Skidspar) getApplicationContext();
skidspar.setMyMain(this);
/* augustw */
if (PermissionRequest.execute(this)) //else -> efterfrågar permissions och kör onRequestPermissionsResult() istället.
invokeLocationManagement();
//adHelper = new AdHelper(this, (GifImageView) findViewById(R.id.adview), skidspar.getDefaultTracker());
if (hasGPSPermission()) {
if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
// TODO: Consider calling
// ActivityCompat#requestPermissions
// here to request the missing permissions, and then overriding
// public void onRequestPermissionsResult(int requestCode, String[] permissions,
// int[] grantResults)
// to handle the case where the user grants the permission. See the documentation
// for ActivityCompat#requestPermissions for more details.
return;
}
if (locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER) != null) {
skidspar.setMyLocation(locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER));
}
Location wifi = locationManager.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
if (wifi != null) {
if (skidspar.getMyLocation() == null) {
skidspar.setMyLocation(wifi);
} else if (Utils.isBetterLocation(wifi, skidspar.getMyLocation())) {
skidspar.setMyLocation(wifi);
}
}
} else {
}
mTitle = mDrawerTitle = getTitle();
mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
mDrawerList = (ListView) findViewById(R.id.left_drawer);
// set a custom shadow that overlays the main content when the drawer opens
mDrawerLayout.setDrawerShadow(R.drawable.drawer_shadow, GravityCompat.START);
// set up the drawer's list view with items and click listener
mDrawerList.setAdapter(new MenuListAdapter(this, 0, 0, createMenuList()));
mDrawerList.setOnItemClickListener(new DrawerItemClickListener());
toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
mDrawerToggle = new ActionBarDrawerToggle(
this, /* host Activity */
mDrawerLayout, /* DrawerLayout object */
toolbar, /* nav drawer icon to replace 'Up' caret */
R.string.drawer_open, /* "open drawer" description */
R.string.drawer_close /* "close drawer" description */
) {
/** Called when a drawer has settled in a completely closed state. */
public void onDrawerClosed(View view) {
super.onDrawerClosed(view);
toolbar.setTitle(mTitle);
}
/** Called when a drawer has settled in a completely open state. */
public void onDrawerOpened(View drawerView) {
super.onDrawerOpened(drawerView);
toolbar.setTitle(mDrawerTitle);
}
};
// Set the drawer toggle as the DrawerListener
mDrawerLayout.setDrawerListener(mDrawerToggle);
//ViewPager stuff.
SlidingTabLayout mSlidingTabLayout = (SlidingTabLayout) findViewById(R.id.sliding_tabs);
mSlidingTabLayout.setCustomTabView(R.layout.tab_indicator, android.R.id.text1);
mSlidingTabLayout.setCustomTabColorizer(new SlidingTabLayout.TabColorizer() {
@Override
public int getIndicatorColor(int position) {
return Color.WHITE;
}
});
// Set up the ViewPager, attaching the adapter and setting up a listener for when the
// user swipes between sections.
mViewPager = (ViewPager) findViewById(R.id.view_pager);
mViewPager.setAdapter(mAppSectionsPagerAdapter);
mViewPager.addOnPageChangeListener(new ViewPager.SimpleOnPageChangeListener() {
@Override
public void onPageSelected(int position) {
// When swiping between different app sections, select the corresponding tab.
// We can also use ActionBar.Tab#select() to do this if we have a reference to the
// Tab.
// actionBar.setSelectedNavigationItem(position);
if (position == 0) {
if (mListFragment != null) {
mListFragment.refreshMyView();
}
} else if (position == 1) {
if (mMapFragment != null) {
mMapFragment.refreshMyView();
}
}
Log.d("AdHelper","Swiped");
adView.loadUrl(ReviveAdHelper.footerAdUrl);
//adHelper.generateAd();
}
});
//setSlidingTabLayoutContentDescriptions();
Resources res = getResources();
//mSlidingTabLayout.setSelectedIndicatorColors(res.getColor(R.color.tab_selected_strip));
mSlidingTabLayout.setDistributeEvenly(true);
mSlidingTabLayout.setViewPager(mViewPager);
if (mSearchView != null) {
mSearchView.setQuery("", false);
}
int shownTab = 0;
try {
shownTab = Integer.parseInt(PreferenceManager.getDefaultSharedPreferences(this).getString("pref_default_tab", "1"));
} catch (Exception e) {
shownTab = 0;
}
mViewPager.setCurrentItem(shownTab);
//adHelper.generateAd();
// gifImageView = (GifImageView) findViewById(R.id.banner);
Tracker tracker = ((Skidspar) getApplication()).getTracker(Skidspar.TrackerName.APP_TRACKER);
tracker.send(new HitBuilders.ScreenViewBuilder().setNewSession().build());
propertyStorage = new PropertyStorage(getApplicationContext());
String firstLaunch = propertyStorage.get(prop_firstLaunch);
if(firstLaunch == null){ //alltid null vid första launch iom att värdet aldrig har sparats
onFirstAppLaunch();
propertyStorage.save(prop_firstLaunch, "false");
}
}
public void onFirstAppLaunch() {
final Toast toast = Toast.makeText(getApplicationContext(), "Under inställningar kan du välja vilka anläggningar som ska visas", Toast.LENGTH_LONG);
CountDownTimer toastCountDown = new CountDownTimer(8000, 1000) {
@Override
public void onTick(long millisUntilFinished) {
toast.show();
}
@Override
public void onFinish() {
toast.cancel();
}
};
//Visa toast och starta nedräkningen
toast.show();
toastCountDown.start();
}
public void invokeLocationManagement() {
try {
tryStartLocationService();
if (locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER) != null) {
skidspar.setMyLocation(locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER));
}
Location wifi = locationManager.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
if (wifi != null) {
if (skidspar.getMyLocation() == null) {
skidspar.setMyLocation(wifi);
} else if (Utils.isBetterLocation(wifi, skidspar.getMyLocation())) {
skidspar.setMyLocation(wifi);
}
}
} catch(SecurityException ex) {
ex.printStackTrace();
}
}
答案 0 :(得分：0)
您给出的代码不完整，我们可以回答。 但是从Logcat详细介绍它显示尝试在空引用对象“上调用虚拟方法void android.view.View.clearAccessibilityFocus（）。这必须在代码行中由组成findViewById（R.id.something）如果您要添加不在当前布局中的View，则会注册错误。所以您必须指定您要调用的视图的基础查看，所以你的代码行应该像是通过View invokeTabelViewInMain调用TableLayout然后'（TableLayout）invokeTabelViewInMain.findViewwById（R.id.something）'。它会起作用。