Android - java.lang.NullPointerException 文件：PhoneWindow.java [重复]

Question

我关注了ViewPager FragmentPagerAdapter Nullpointer，但没有任何帮助。任何解决方案将不胜感激。请注意，我只从支持库中导入了类。

import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;
import android.support.v4.view.ViewPager.OnPageChangeListener;

这是我在 Splunk Mint 中收到的崩溃日志

java.lang.NullPointerException 在 android.support.v4.app.BackStackRecord.doAddOp(BackStackRecord.java:416) 在 android.support.v4.app.BackStackRecord.add(BackStackRecord.java:411) 在 android.support.v4.app.FragmentPagerAdapter.instantiateItem(FragmentPagerAdapter.java:99) 在 android.support.v4.view.ViewPager.addNewItem(ViewPager.java:837) 在 android.support.v4.view.ViewPager.populate(ViewPager.java:987) 在 android.support.v4.view.ViewPager.populate(ViewPager.java:919) 在 android.support.v4.view.ViewPager.onMeasure(ViewPager.java:1441) 在 android.view.View.measure(View.java:15575) 在 android.widget.LinearLayout.measureVertical(LinearLayout.java:833) 在 android.widget.LinearLayout.onMeasure(LinearLayout.java:574) 在 android.view.View.measure(View.java:15575) 在 android.widget.RelativeLayout.measureChildHorizo​​ntal(RelativeLayout.java:617) 在 android.widget.RelativeLayout.onMeasure(RelativeLayout.java:399) 在 android.view.View.measure(View.java:15575) 在 android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5107) 在 android.widget.FrameLayout.onMeasure(FrameLayout.java:310) 在 android.view.View.measure(View.java:15575) 在 android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5107) 在 android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1396) 在 android.widget.LinearLayout.measureVertical(LinearLayout.java:681) 在 android.widget.LinearLayout.onMeasure(LinearLayout.java:574) 在 android.view.View.measure(View.java:15575) 在 android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5107) 在 android.widget.FrameLayout.onMeasure(FrameLayout.java:310) 在 com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2423) 在 android.view.View.measure(View.java:15575) 在 android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:2031) 在 android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1249) 在 android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1425) 在 android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1142) 在 android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:4724) 在 android.view.Choreographer$CallbackRecord.run(Choreographer.java:725) 在 android.view.Choreographer.doCallbacks(Choreographer.java:555) 在 android.view.Choreographer.doFrame(Choreographer.java:525) 在 android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:711) 在 android.os.Handler.handleCallback(Handler.java:615) 在 android.os.Handler.dispatchMessage(Handler.java:92) 在 android.os.Looper.loop(Looper.java:137) 在 android.app.ActivityThread.main(ActivityThread.java:4947) 在 java.lang.reflect.Method.invokeNative(Native Method) 在 java.lang.reflect.Method.invoke(Method.java:511) 在 com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1038) 在 com.android.internal.os.ZygoteInit.main(ZygoteInit.java:805) 在 dalvik.system.NativeStart.main(Native Method)

这是我的 FragmentPagerAdapter 的代码。

private class MyPageAdapter extends FragmentPagerAdapter {

/**
 * Instantiates a new my page adapter.
 *
 * @param fm the fm
 */
public MyPageAdapter(FragmentManager fm) {
    super(fm);
}

/* (non-Javadoc)
 * @see android.support.v4.app.FragmentPagerAdapter#getItem(int)
 */
@Override
public Fragment getItem(int position) {
    Fragment fragment = null;
    try {
        TypedArray a = null, b = null;
        int attributeResourceId = 0, attributeStepsId = 0;

        switch (currentLocale.toString().trim()) {
        // if (currentLocale.toString().trim().equals("ar")) {
        case "ar":
            if (position == 0) {
                if (Util.getSharedPref(WizardHelpActivity.this).getInt("Theme", ConstantData.AppTheme.Dark.getValue()) == ConstantData.AppTheme.Dark.getValue()) {
                    a = getTheme().obtainStyledAttributes(R.style.Dark, new int[] { R.attr.wizard2 });
                    b = getTheme().obtainStyledAttributes(R.style.Dark, new int[] { R.attr.step1 });

                } else {
                    a = getTheme().obtainStyledAttributes(R.style.Light, new int[] { R.attr.wizard2 });
                    b = getTheme().obtainStyledAttributes(R.style.Light, new int[] { R.attr.step1 });
                }
                attributeResourceId = a.getResourceId(0, 0);
                attributeStepsId = b.getResourceId(0, 0);
                a.recycle();
                fragment = WizardHelpPageFragment.getInstance(attributeResourceId, R.string.wizard_help_step1_title, R.string.activity_wizard_help_step2_line2, attributeStepsId);
            } else if (position == 1) {
                if (Util.getSharedPref(WizardHelpActivity.this).getInt("Theme", ConstantData.AppTheme.Dark.getValue()) == ConstantData.AppTheme.Dark.getValue()) {
                    a = getTheme().obtainStyledAttributes(R.style.Dark, new int[] { R.attr.wizard1 });
                    b = getTheme().obtainStyledAttributes(R.style.Dark, new int[] { R.attr.step2 });
                } else {
                    a = getTheme().obtainStyledAttributes(R.style.Light, new int[] { R.attr.wizard1 });
                    b = getTheme().obtainStyledAttributes(R.style.Light, new int[] { R.attr.step2 });
                }
                attributeResourceId = a.getResourceId(0, 0);
                attributeStepsId = b.getResourceId(0, 0);
                a.recycle();

                fragment = WizardHelpPageFragment.getInstance(attributeResourceId, R.string.wizard_help_step2_title, R.string.activity_wizard_help_step1_line2, attributeStepsId);
            }

            else if (position == 2) {
                if (Util.getSharedPref(WizardHelpActivity.this).getInt("Theme", ConstantData.AppTheme.Dark.getValue()) == ConstantData.AppTheme.Dark.getValue()) {
                    a = getTheme().obtainStyledAttributes(R.style.Dark, new int[] { R.attr.wizard3_ar });

                    b = getTheme().obtainStyledAttributes(R.style.Dark, new int[] { R.attr.step3 });
                } else {
                    a = getTheme().obtainStyledAttributes(R.style.Light, new int[] { R.attr.wizard3_ar });

                    b = getTheme().obtainStyledAttributes(R.style.Light, new int[] { R.attr.step3 });
                }
                attributeResourceId = a.getResourceId(0, 0);
                attributeStepsId = b.getResourceId(0, 0);
                a.recycle();

                fragment = WizardHelpPageFragment.getInstance(attributeResourceId, R.string.wizard_help_step3_title, R.string.activity_wizard_help_step3_line2, attributeStepsId);
            }

            else if (position == 3) {
                if (Util.getSharedPref(WizardHelpActivity.this).getInt("Theme", ConstantData.AppTheme.Dark.getValue()) == ConstantData.AppTheme.Dark.getValue()) {
                    a = getTheme().obtainStyledAttributes(R.style.Dark, new int[] { R.attr.wizard4_ar });
                    b = getTheme().obtainStyledAttributes(R.style.Dark, new int[] { R.attr.step4 });
                } else {
                    a = getTheme().obtainStyledAttributes(R.style.Light, new int[] { R.attr.wizard4_ar });
                    b = getTheme().obtainStyledAttributes(R.style.Light, new int[] { R.attr.step4 });
                }
                attributeResourceId = a.getResourceId(0, 0);

                attributeStepsId = b.getResourceId(0, 0);
                a.recycle();
                fragment = WizardHelpPageFragment.getInstance(attributeResourceId, R.string.wizard_help_step4_title, R.string.activity_wizard_help_step4_line2, attributeStepsId);
            }
            else {
                if (Util.getSharedPref(WizardHelpActivity.this).getInt("Theme", ConstantData.AppTheme.Dark.getValue()) == ConstantData.AppTheme.Dark.getValue()) {
                    a = getTheme().obtainStyledAttributes(R.style.Dark, new int[] { R.attr.wizard1 });
                    b = getTheme().obtainStyledAttributes(R.style.Dark, new int[] { R.attr.step1 });
                } else {
                    a = getTheme().obtainStyledAttributes(R.style.Light, new int[] { R.attr.wizard1 });
                    b = getTheme().obtainStyledAttributes(R.style.Light, new int[] { R.attr.step1 });
                }
                attributeResourceId = a.getResourceId(0, 0);
                attributeStepsId = b.getResourceId(0, 0);
                a.recycle();
                fragment = WizardHelpPageFragment.getInstance(attributeResourceId, R.string.wizard_help_step1_title, R.string.activity_wizard_help_step1_line2, attributeStepsId);
            }
            // } else {
            break;
        case "en":
            if (position == 0) {
                if (Util.getSharedPref(WizardHelpActivity.this).getInt("Theme", ConstantData.AppTheme.Dark.getValue()) == ConstantData.AppTheme.Dark.getValue()) {
                    a = getTheme().obtainStyledAttributes(R.style.Dark, new int[] { R.attr.wizard2 });

                    b = getTheme().obtainStyledAttributes(R.style.Dark, new int[] { R.attr.step1 });
                } else {
                    a = getTheme().obtainStyledAttributes(R.style.Light, new int[] { R.attr.wizard2 });

                    b = getTheme().obtainStyledAttributes(R.style.Light, new int[] { R.attr.step1 });
                }
                attributeResourceId = a.getResourceId(0, 0);
                attributeStepsId = b.getResourceId(0, 0);
                a.recycle();
                fragment = WizardHelpPageFragment.getInstance(attributeResourceId, R.string.wizard_help_step1_title, R.string.activity_wizard_help_step2_line2, attributeStepsId);
            } else if (position == 1) {
                if (Util.getSharedPref(WizardHelpActivity.this).getInt("Theme", ConstantData.AppTheme.Dark.getValue()) == ConstantData.AppTheme.Dark.getValue()) {
                    a = getTheme().obtainStyledAttributes(R.style.Dark, new int[] { R.attr.wizard1 });

                    b = getTheme().obtainStyledAttributes(R.style.Dark, new int[] { R.attr.step2 });
                } else {
                    a = getTheme().obtainStyledAttributes(R.style.Light, new int[] { R.attr.wizard1 });

                    b = getTheme().obtainStyledAttributes(R.style.Light, new int[] { R.attr.step2 });
                }
                attributeResourceId = a.getResourceId(0, 0);
                attributeStepsId = b.getResourceId(0, 0);
                a.recycle();
                fragment = WizardHelpPageFragment.getInstance(attributeResourceId, R.string.wizard_help_step2_title, R.string.activity_wizard_help_step1_line2, attributeStepsId);
            }

            else if (position == 2) {
                if (Util.getSharedPref(WizardHelpActivity.this).getInt("Theme", ConstantData.AppTheme.Dark.getValue()) == ConstantData.AppTheme.Dark.getValue()) {
                    a = getTheme().obtainStyledAttributes(R.style.Dark, new int[] { R.attr.wizard3 });
                    b = getTheme().obtainStyledAttributes(R.style.Dark, new int[] { R.attr.step3 });
                } else {
                    a = getTheme().obtainStyledAttributes(R.style.Light, new int[] { R.attr.wizard3 });
                    b = getTheme().obtainStyledAttributes(R.style.Light, new int[] { R.attr.step3 });
                }
                attributeResourceId = a.getResourceId(0, 0);
                attributeStepsId = b.getResourceId(0, 0);
                a.recycle();
                fragment = WizardHelpPageFragment.getInstance(attributeResourceId, R.string.wizard_help_step3_title, R.string.activity_wizard_help_step3_line2, attributeStepsId);
            }

            else if (position == 3) {
                if (Util.getSharedPref(WizardHelpActivity.this).getInt("Theme", ConstantData.AppTheme.Dark.getValue()) == ConstantData.AppTheme.Dark.getValue()) {
                    a = getTheme().obtainStyledAttributes(R.style.Dark, new int[] { R.attr.wizard4 });
                    b = getTheme().obtainStyledAttributes(R.style.Dark, new int[] { R.attr.step4 });
                } else {
                    a = getTheme().obtainStyledAttributes(R.style.Light,

                    new int[] { R.attr.wizard4 });

                    b = getTheme().obtainStyledAttributes(R.style.Light, new int[] { R.attr.step4 });
                }
                attributeResourceId = a.getResourceId(0, 0);
                attributeStepsId = b.getResourceId(0, 0);
                a.recycle();
                fragment = WizardHelpPageFragment.getInstance(attributeResourceId, R.string.wizard_help_step4_title, R.string.activity_wizard_help_step4_line2, attributeStepsId);
            }

            else {
                if (Util.getSharedPref(WizardHelpActivity.this).getInt("Theme", ConstantData.AppTheme.Dark.getValue()) == ConstantData.AppTheme.Dark.getValue()) {
                    a = getTheme().obtainStyledAttributes(R.style.Dark, new int[] { R.attr.wizard1 });

                    b = getTheme().obtainStyledAttributes(R.style.Dark, new int[] { R.attr.step1 });

                } else {
                    a = getTheme().obtainStyledAttributes(R.style.Light, new int[] { R.attr.wizard1 });

                    b = getTheme().obtainStyledAttributes(R.style.Light, new int[] { R.attr.step1 });
                }
                attributeResourceId = a.getResourceId(0, 0);
                attributeStepsId = b.getResourceId(0, 0);
                a.recycle();
                fragment = WizardHelpPageFragment.getInstance(attributeResourceId, R.string.wizard_help_step1_title, R.string.activity_wizard_help_step1_line2, attributeStepsId);
            }
            break;
        case "hi":
            if (position == 0) {
                if (Util.getSharedPref(WizardHelpActivity.this).getInt("Theme", ConstantData.AppTheme.Dark.getValue()) == ConstantData.AppTheme.Dark.getValue()) {
                    a = getTheme().obtainStyledAttributes(R.style.Dark, new int[] { R.attr.wizard2 });
                    b = getTheme().obtainStyledAttributes(R.style.Dark, new int[] { R.attr.step1 });

                } else {
                    a = getTheme().obtainStyledAttributes(R.style.Light, new int[] { R.attr.wizard2 });
                    b = getTheme().obtainStyledAttributes(R.style.Light, new int[] { R.attr.step1 });
                }
                attributeResourceId = a.getResourceId(0, 0);
                attributeStepsId = b.getResourceId(0, 0);
                a.recycle();

                fragment = WizardHelpPageFragment.getInstance(attributeResourceId, R.string.wizard_help_step1_title, R.string.activity_wizard_help_step2_line2, attributeStepsId);
            } else if (position == 1) {
                if (Util.getSharedPref(WizardHelpActivity.this).getInt("Theme", ConstantData.AppTheme.Dark.getValue()) == ConstantData.AppTheme.Dark.getValue()) {
                    a = getTheme().obtainStyledAttributes(R.style.Dark, new int[] { R.attr.wizard1 });
                    b = getTheme().obtainStyledAttributes(R.style.Dark, new int[] { R.attr.step2 });
                } else {
                    a = getTheme().obtainStyledAttributes(R.style.Light, new int[] { R.attr.wizard1 });
                    b = getTheme().obtainStyledAttributes(R.style.Light, new int[] { R.attr.step2 });
                }
                attributeResourceId = a.getResourceId(0, 0);
                attributeStepsId = b.getResourceId(0, 0);
                a.recycle();

                fragment = WizardHelpPageFragment.getInstance(attributeResourceId, R.string.wizard_help_step2_title, R.string.activity_wizard_help_step1_line2, attributeStepsId);
            }

            else if (position == 2) {
                if (Util.getSharedPref(WizardHelpActivity.this).getInt("Theme", ConstantData.AppTheme.Dark.getValue()) == ConstantData.AppTheme.Dark.getValue()) {
                    a = getTheme().obtainStyledAttributes(R.style.Dark, new int[] { R.attr.wizard3_hi });

                    b = getTheme().obtainStyledAttributes(R.style.Dark, new int[] { R.attr.step3 });
                } else {
                    a = getTheme().obtainStyledAttributes(R.style.Light, new int[] { R.attr.wizard3_hi });

                    b = getTheme().obtainStyledAttributes(R.style.Light, new int[] { R.attr.step3 });
                }
                attributeResourceId = a.getResourceId(0, 0);
                attributeStepsId = b.getResourceId(0, 0);
                a.recycle();

                fragment = WizardHelpPageFragment.getInstance(attributeResourceId, R.string.wizard_help_step3_title, R.string.activity_wizard_help_step3_line2, attributeStepsId);
            }

            else if (position == 3) {
                if (Util.getSharedPref(WizardHelpActivity.this).getInt("Theme", ConstantData.AppTheme.Dark.getValue()) == ConstantData.AppTheme.Dark.getValue()) {
                    a = getTheme().obtainStyledAttributes(R.style.Dark, new int[] { R.attr.wizard4_hi });
                    b = getTheme().obtainStyledAttributes(R.style.Dark, new int[] { R.attr.step4 });
                } else {
                    a = getTheme().obtainStyledAttributes(R.style.Light, new int[] { R.attr.wizard4_hi });
                    b = getTheme().obtainStyledAttributes(R.style.Light, new int[] { R.attr.step4 });
                }
                attributeResourceId = a.getResourceId(0, 0);

                attributeStepsId = b.getResourceId(0, 0);
                a.recycle();
                fragment = WizardHelpPageFragment.getInstance(attributeResourceId, R.string.wizard_help_step4_title, R.string.activity_wizard_help_step4_line2, attributeStepsId);
            }

            else {
                if (Util.getSharedPref(WizardHelpActivity.this).getInt("Theme", ConstantData.AppTheme.Dark.getValue()) == ConstantData.AppTheme.Dark.getValue()) {
                    a = getTheme().obtainStyledAttributes(R.style.Dark, new int[] { R.attr.wizard1 });
                    b = getTheme().obtainStyledAttributes(R.style.Dark, new int[] { R.attr.step1 });
                } else {
                    a = getTheme().obtainStyledAttributes(R.style.Light, new int[] { R.attr.wizard1 });
                    b = getTheme().obtainStyledAttributes(R.style.Light, new int[] { R.attr.step1 });
                }
                attributeResourceId = a.getResourceId(0, 0);
                attributeStepsId = b.getResourceId(0, 0);
                a.recycle();
                fragment = WizardHelpPageFragment.getInstance(attributeResourceId, R.string.wizard_help_step1_title, R.string.activity_wizard_help_step1_line2, attributeStepsId);
            }
            break;
        case "ur":
            if (position == 0) {
                if (Util.getSharedPref(WizardHelpActivity.this).getInt("Theme", ConstantData.AppTheme.Dark.getValue()) == ConstantData.AppTheme.Dark.getValue()) {
                    a = getTheme().obtainStyledAttributes(R.style.Dark, new int[] { R.attr.wizard2 });
                    b = getTheme().obtainStyledAttributes(R.style.Dark, new int[] { R.attr.step1 });

                } else {
                    a = getTheme().obtainStyledAttributes(R.style.Light, new int[] { R.attr.wizard2 });
                    b = getTheme().obtainStyledAttributes(R.style.Light, new int[] { R.attr.step1 });
                }
                attributeResourceId = a.getResourceId(0, 0);
                attributeStepsId = b.getResourceId(0, 0);
                a.recycle();

                fragment = WizardHelpPageFragment.getInstance(attributeResourceId, R.string.wizard_help_step1_title, R.string.activity_wizard_help_step2_line2, attributeStepsId);
            } else if (position == 1) {
                if (Util.getSharedPref(WizardHelpActivity.this).getInt("Theme", ConstantData.AppTheme.Dark.getValue()) == ConstantData.AppTheme.Dark.getValue()) {
                    a = getTheme().obtainStyledAttributes(R.style.Dark, new int[] { R.attr.wizard1 });
                    b = getTheme().obtainStyledAttributes(R.style.Dark, new int[] { R.attr.step2 });
                } else {
                    a = getTheme().obtainStyledAttributes(R.style.Light, new int[] { R.attr.wizard1 });
                    b = getTheme().obtainStyledAttributes(R.style.Light, new int[] { R.attr.step2 });
                }
                attributeResourceId = a.getResourceId(0, 0);
                attributeStepsId = b.getResourceId(0, 0);
                a.recycle();

                fragment = WizardHelpPageFragment.getInstance(attributeResourceId, R.string.wizard_help_step2_title, R.string.activity_wizard_help_step1_line2, attributeStepsId);
            }

            else if (position == 2) {
                if (Util.getSharedPref(WizardHelpActivity.this).getInt("Theme", ConstantData.AppTheme.Dark.getValue()) == ConstantData.AppTheme.Dark.getValue()) {
                    a = getTheme().obtainStyledAttributes(R.style.Dark, new int[] { R.attr.wizard3_ur });

                    b = getTheme().obtainStyledAttributes(R.style.Dark, new int[] { R.attr.step3 });
                } else {
                    a = getTheme().obtainStyledAttributes(R.style.Light, new int[] { R.attr.wizard3_ur });

                    b = getTheme().obtainStyledAttributes(R.style.Light, new int[] { R.attr.step3 });
                }
                attributeResourceId = a.getResourceId(0, 0);
                attributeStepsId = b.getResourceId(0, 0);
                a.recycle();

                fragment = WizardHelpPageFragment.getInstance(attributeResourceId, R.string.wizard_help_step3_title, R.string.activity_wizard_help_step3_line2, attributeStepsId);
            }

            else if (position == 3) {
                if (Util.getSharedPref(WizardHelpActivity.this).getInt("Theme", ConstantData.AppTheme.Dark.getValue()) == ConstantData.AppTheme.Dark.getValue()) {
                    a = getTheme().obtainStyledAttributes(R.style.Dark, new int[] { R.attr.wizard4_ur });
                    b = getTheme().obtainStyledAttributes(R.style.Dark, new int[] { R.attr.step4 });
                } else {
                    a = getTheme().obtainStyledAttributes(R.style.Light, new int[] { R.attr.wizard4_ur });
                    b = getTheme().obtainStyledAttributes(R.style.Light, new int[] { R.attr.step4 });
                }
                attributeResourceId = a.getResourceId(0, 0);

                attributeStepsId = b.getResourceId(0, 0);
                a.recycle();
                fragment = WizardHelpPageFragment.getInstance(attributeResourceId, R.string.wizard_help_step4_title, R.string.activity_wizard_help_step4_line2, attributeStepsId);
            }

            else {
                if (Util.getSharedPref(WizardHelpActivity.this).getInt("Theme", ConstantData.AppTheme.Dark.getValue()) == ConstantData.AppTheme.Dark.getValue()) {
                    a = getTheme().obtainStyledAttributes(R.style.Dark, new int[] { R.attr.wizard1 });
                    b = getTheme().obtainStyledAttributes(R.style.Dark, new int[] { R.attr.step1 });
                } else {
                    a = getTheme().obtainStyledAttributes(R.style.Light, new int[] { R.attr.wizard1 });
                    b = getTheme().obtainStyledAttributes(R.style.Light, new int[] { R.attr.step1 });
                }
                attributeResourceId = a.getResourceId(0, 0);
                attributeStepsId = b.getResourceId(0, 0);
                a.recycle();
                fragment = WizardHelpPageFragment.getInstance(attributeResourceId, R.string.wizard_help_step1_title, R.string.activity_wizard_help_step1_line2, attributeStepsId);
            }
            break;
        default:
            break;
        }
    } catch (Exception e) {
        e.printStackTrace();
        new SendEmailAsyncTask(getApplicationContext(), getClass().getName(),"getItem(int position)", e).execute();
    }

    return fragment;
}

/* (non-Javadoc)
 * @see android.support.v4.view.PagerAdapter#getCount()
 */
@Override
public int getCount() {
    return 4;
}

}

Answer 1

使用

try {
    // you full code here
} catch (NullPointerException n){
    Toast.makeText(getApplicationContext(),n.toString(),Toast.LENGTH.LONG).show();
}

这将向您展示异常的全部细节。 希望这将帮助您解决错误。