Question

 java.lang.NullPointerException
                      at android.support.v4.app.FragmentPagerAdapter.instantiateItem(FragmentPagerAdapter.java:89)
                      at android.support.v4.view.ViewPager.addNewItem(ViewPager.java:1006)
                      at android.support.v4.view.ViewPager.populate(ViewPager.java:1154)
                      at android.support.v4.view.ViewPager.populate(ViewPager.java:1088)
                      at android.support.v4.view.ViewPager.onMeasure(ViewPager.java:1614)
                      at android.view.View.measure(View.java:15848)
                      at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5012)
                      at android.support.design.widget.CoordinatorLayout.onMeasureChild(CoordinatorLayout.java:700)
                      at android.support.design.widget.HeaderScrollingViewBehavior.onMeasureChild(HeaderScrollingViewBehavior.java:90)
                      at android.support.design.widget.AppBarLayout$ScrollingViewBehavior.onMeasureChild(AppBarLayout.java:1364)
                      at android.support.design.widget.CoordinatorLayout.onMeasure(CoordinatorLayout.java:765)
                      at android.view.View.measure(View.java:15848)
                      at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5012)
                      at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
                      at android.view.View.measure(View.java:15848)
                      at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5012)
                      at android.support.design.widget.CoordinatorLayout.onMeasureChild(CoordinatorLayout.java:700)
                      at android.support.design.widget.CoordinatorLayout.onMeasure(CoordinatorLayout.java:767)
                      at android.view.View.measure(View.java:15848)
                      at android.support.v4.widget.DrawerLayout.onMeasure(DrawerLayout.java:1085)
                      at android.view.View.measure(View.java:15848)
                      at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5012)
                      at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
                      at android.support.v7.widget.ContentFrameLayout.onMeasure(ContentFrameLayout.java:135)
                      at android.view.View.measure(View.java:15848)
                      at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5012)
                      at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1404)
                      at android.widget.LinearLayout.measureVertical(LinearLayout.java:695)
                      at android.widget.LinearLayout.onMeasure(LinearLayout.java:588)
                      at android.view.View.measure(View.java:15848)
                      at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5012)
                      at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
                      at android.view.View.measure(View.java:15848)
                      at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5012)
                      at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1404)
                      at android.widget.LinearLayout.measureVertical(LinearLayout.java:695)
                      at android.widget.LinearLayout.onMeasure(LinearLayout.java:588)
                      at android.view.View.measure(View.java:15848)
                      at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5012)
                      at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
                      at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2189)
                      at android.view.View.measure(View.java:15848)
                      at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:1905)
                      at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1104)
                      at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1284)
                      at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1004)
                      at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5481)
                      at android.view.Choreographer$CallbackRecord.run(Choreographer.java:749)
                      at android.view.Choreographer.doCallbacks(Choreographer.java:562)
                      at android.view.Choreographer.doFrame(Choreographer.java:532)
                      at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:735)
                      at android.os.Handler.handleCallback(Handler.java:730)
                      at android.os.Handler.dispatchMessage(Handler.java:92)
                      at android.os.Looper.loop(Looper.java:137)
                      at android.app.ActivityThread.main(ActivityThread.java:5103)
                      at java.lang.reflect.Method.invokeNative(Native Method)
                      at java.lang.reflect.Method.invoke(Method.java:525)
                      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)

申请已终止。

Answer 1

空引用异常总是表示某些内容为空。

避免使用

if(yourObject != null)
{
 // put code you want to execute here
}

为了更好的答案，请与我们分享代码。

单击导航抽屉中的选项菜单时出现此错误？

1 个答案: