空指针异常，android.widget.Tablayout.getChildAt（int）

【空指针异常，android.widget.Tablayout.getChildAt（int）】将相本无种，男儿当自强。这篇文章主要讲述空指针异常，android.widget.Tablayout.getChildAt（int）相关的知识，希望能为你提供帮助。
我是android开发的新手，当我点击我的应用程序时它停止工作，因为它无法破坏表格布局......................... .................................................. .................................................. .................................................. ........................这是我在调试器控制台中得到的

E/AndroidRuntime: FATAL EXCEPTION: main Process: com.mohannad.athkarapp, PID: 7139 java.lang.RuntimeException: Unable to destroy activity{com.mohannad.athkarapp/com.mohannad.athkar`enter code here`app.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'android.view.View android.widget.TableLayout.getChildAt(int)' on a null object reference at android.app.ActivityThread.performDestroyActivity(ActivityThread.java:4203)

这是我的代码：

public class tab2fragment extends Fragment { public static TableLayout tableLayout; public static TableRow tableRow; public static TextView id0Count; public static TextView id1Count; public static TextView id2Count; public static TextView id3Count; public static TextView id4Count; public tab2fragment() { // Required empty public constructor }@Override public void onActivityCreated(Bundle savedInstanceState) { super.onActivityCreated(savedInstanceState); refreshF(); }@Override public void onStart() { super.onStart(); refreshF(); }public void refreshF(){tableLayout = (TableLayout) getActivity().findViewById(R.id.ourTable); tableRow = (TableRow) tableLayout.getChildAt(1); id0Count = (TextView) tableRow.getChildAt(0); tableRow = (TableRow) tableLayout.getChildAt(2); id1Count = (TextView) tableRow.getChildAt(0); tableRow = (TableRow) tableLayout.getChildAt(3); id2Count = (TextView) tableRow.getChildAt(0); tableRow = (TableRow) tableLayout.getChildAt(4); id3Count = (TextView) tableRow.getChildAt(0); tableRow = (TableRow) tableLayout.getChildAt(5); id4Count = (TextView) tableRow.getChildAt(0); MainActivity.CountZ1= getActivity().getSharedPreferences(MainActivity.zekr1,0); MainActivity.CountZ2 = getActivity().getSharedPreferences(MainActivity.zekr2,0); MainActivity.CountZ3 = getActivity().getSharedPreferences(MainActivity.zekr3,0); MainActivity.CountZ4 = getActivity().getSharedPreferences(MainActivity.zekr4,0); MainActivity.CountZ5 = getActivity().getSharedPreferences(MainActivity.zekr5,0); id0Count.setText(""+MainActivity.CountZ1.getInt(MainActivity.zekr1,0)); id1Count.setText(""+MainActivity.CountZ2.getInt(MainActivity.zekr2,0)); id2Count.setText(""+MainActivity.CountZ3.getInt(MainActivity.zekr3,0)); id3Count.setText(""+MainActivity.CountZ4.getInt(MainActivity.zekr4,0)); id3Count.setText(""+MainActivity.CountZ5.getInt(MainActivity.zekr5,0)); } @Override public void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState); }@Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { // Inflate the layout for this fragment return inflater.inflate(R.layout.tab2fragment, container, false); } @Override public void onResume() {super.onResume(); refreshF(); }@Override public void onDetach() { super.onDetach(); refreshF(); }

}

public class MainActivity extends AppCompatActivity { public static final String switchp = "Switchpref"; public static final String radio = "radioPref"; public static final String zekr1 = "MyPrefsFileZ1"; public static final String zekr2 = "MyPrefsFileZ2"; public static final String zekr3 = "MyPrefsFileZ3"; public static final String zekr4 = "MyPrefsFileZ4"; public static final String zekr5 = "MyPrefsFileZ5"; public static SharedPreferences CountZ1; public static SharedPreferences CountZ2; public static SharedPreferences CountZ3; public static SharedPreferences CountZ4; public static SharedPreferences CountZ5; public static SharedPreferences switchStatus; public static SharedPreferences radStatus; @Override public void onBackPressed() { super.onBackPressed(); finish(); }@Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); ViewPager viewPager = (ViewPager) findViewById(R.id.pager); ViewPagerAdapter adapter = new ViewPagerAdapter(getSupportFragmentManager()); // Add Fragments to adapter one by one adapter.addFragment(new tab1fragment(), "???????"); adapter.addFragment(new tab2fragment(), "?????"); adapter.addFragment(new tab3fragment(), "?????????"); viewPager.setAdapter(adapter); TabLayout tabLayout = (TabLayout) findViewById(R.id.tabs); tabLayout.setupWithViewPager(viewPager); }public void zerothat(View view) { TextView v= findViewById(R.id.textcount); tab1fragment.spinner = (Spinner) findViewById(R.id.spinner); doVibrate(200); SharedPreferences.Editor editor1= MainActivity.CountZ1.edit(); SharedPreferences.Editor editor2= MainActivity.CountZ2.edit(); SharedPreferences.Editor editor3= MainActivity.CountZ3.edit(); SharedPreferences.Editor editor4= MainActivity.CountZ4.edit(); SharedPreferences.Editor editor5= MainActivity.CountZ5.edit(); int pos=tab1fragment.spinner.getSelectedItemPosition(); switch (pos){ case 0:tab1fragment.count1=0; tab2fragment.id0Count.setText(""+0); editor1= MainActivity.CountZ1.edit(); editor1.putInt(MainActivity.zekr1,0); editor1.commit(); v= findViewById(R.id.textcount); v.setText(""+MainActivity.CountZ1.getInt(MainActivity.zekr1,0)); break; case 1: tab1fragment.count2=0; tab2fragment.id1Count.setText(""+0); editor2= MainActivity.CountZ2.edit(); editor2.putInt(MainActivity.zekr2,0); editor2.commit(); v= findViewById(R.id.textcount); v.setText(""+MainActivity.CountZ2.getInt(MainActivity.zekr2,0)); break; case 2: tab1fragment.count3=0; tab2fragment.id2Count.setText(""+0); editor3= MainActivity.CountZ3.edit(); editor3.putInt(MainActivity.zekr3,0); editor3.commit(); v= findViewById(R.id.textcount); v.setText(""+MainActivity.CountZ3.getInt(MainActivity.zekr3,0)); break; case 3: tab1fragment.count4=0; tab2fragment.id3Count.setText(""+0); editor4= MainActivity.CountZ4.edit(); editor4.putInt(MainActivity.zekr4,0); editor4.commit(); v= findViewById(R.id.textcount); v.setText(""+MainActivity.CountZ4.getInt(MainActivity.zekr4,0)); break; case 4: tab1fragment.count5=0; tab2fragment.id4Count.setText(""+0); editor5= MainActivity.CountZ5.edit(); editor5.putInt(MainActivity.zekr5,0); editor5.commit(); v= findViewById(R.id.textcount); v.setText(""+MainActivity.CountZ5.getInt(MainActivity.zekr5,0)); break; }}// Adapter for the viewpager using FragmentPagerAdapter class ViewPagerAdapter extends FragmentPagerAdapter { private final List< Fragment> mFragmentList = new ArrayList< > (); private final List< String> mFragmentTitleList = new ArrayList< > (); public ViewPagerAdapter(FragmentManager manager) { super(manager); }@Override public Fragment getItem(int position) { return mFragmentList.get(position); }@Override public int getCount() { return mFragmentList.size(); }public void addFragment(Fragment fragment, String title) { mFragmentList.add(fragment); mFragmentTitleList.add(title); }@Override public CharSequence getPageTitle(int position) { return mFragmentTitleList.get(position); } } void doVibrate(Integer num){ Vibrator x = (Vibrator) getSystemService(this.VIBRATOR_SERVICE); x.vibrate(num); }

}
答案我提供了一种快速解决方案，但我也建议你浏览片段和活动生命周期的Android基础知识。

tableLayout = (TableLayout) getActivity().findViewById(R.id.ourTable); if(tableLayout != null ){ tableRow = (TableRow) tableLayout.getChildAt(1); id0Count = (TextView) tableRow.getChildAt(0); tableRow = (TableRow) tableLayout.getChildAt(2); id1Count = (TextView) tableRow.getChildAt(0); tableRow = (TableRow) tableLayout.getChildAt(3); id2Count = (TextView) tableRow.getChildAt(0); tableRow = (TableRow) tableLayout.getChildAt(4); id3Count = (TextView) tableRow.getChildAt(0); tableRow = (TableRow) tableLayout.getChildAt(5); id4Count = (TextView) tableRow.getChildAt(0); MainActivity.CountZ1= getActivity().getSharedPreferences(MainActivity.zekr1,0); MainActivity.CountZ2 = getActivity().getSharedPreferences(MainActivity.zekr2,0); MainActivity.CountZ3 = getActivity().getSharedPreferences(MainActivity.zekr3,0); MainActivity.CountZ4 = getActivity().getSharedPreferences(MainActivity.zekr4,0); MainActivity.CountZ5 = getActivity().getSharedPreferences(MainActivity.zekr5,0); id0Count.setText(""+MainActivity.CountZ1.getInt(MainActivity.zekr1,0)); id1Count.setText(""+MainActivity.CountZ2.getInt(MainActivity.zekr2,0)); id2Count.setText(""+MainActivity.CountZ3.getInt(MainActivity.zekr3,0)); id3Count.setText(""+MainActivity.CountZ4.getInt(MainActivity.zekr4,0)); id3Count.setText(""+MainActivity.CountZ5.getInt(MainActivity.zekr5,0)); }

下面的代码没有任何意义。