Android 膨胀布局时的NPE（尝试在空对象引用上调用虚拟方法'；布尔java.lang.String.equals（java.lang.Object）'；）
当我尝试在活动中使用Android 膨胀布局时的NPE（尝试在空对象引用上调用虚拟方法'；布尔java.lang.String.equals（java.lang.Object）'；）,android,nullpointerexception,layout-inflater,android-inflate,inflate-exception,Android,Nullpointerexception,Layout Inflater,Android Inflate,Inflate Exception,当我尝试在活动中使用ScrollView时，我不断得到java.lang.NullPointerException 奇怪的是，我在其他活动中使用了完全相同的Scrollview设置。突然间，我犯了错误。我尝试过清理项目和重建 我已经试过重新启动程序。今天我学到了很多关于空指针异常的知识，但是我还不能弄清楚为什么我总是出现渲染问题 这是在XML上抛出的java.lang.NullPointerException： java.lang.NullPointerException at andr
ScrollViewjava.lang.NullPointerExceptionScrollviewjava.lang.NullPointerExceptionjava.lang.NullPointerException
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:738)
at android.view.BridgeInflater.createViewFromTag(BridgeInflater.java:149)
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:704)
at android.view.LayoutInflater.rInflate_Original(LayoutInflater.java:835)
at android.view.LayoutInflater_Delegate.rInflate(LayoutInflater_Delegate.java:70)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:811)
at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:798)
at android.view.LayoutInflater.rInflate_Original(LayoutInflater.java:838)
at android.view.LayoutInflater_Delegate.rInflate(LayoutInflater_Delegate.java:70)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:811)
at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:798)
at android.view.LayoutInflater.rInflate_Original(LayoutInflater.java:838)
at android.view.LayoutInflater_Delegate.rInflate(LayoutInflater_Delegate.java:70)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:811)
at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:798)
at android.view.LayoutInflater.inflate(LayoutInflater.java:515)
at android.view.LayoutInflater.inflate(LayoutInflater.java:394)
at com.android.layoutlib.bridge.impl.RenderSessionImpl.inflate(RenderSessionImpl.java:223)
at com.android.layoutlib.bridge.Bridge.createSession(Bridge.java:426)
at com.android.ide.common.rendering.LayoutLibrary.createSession(LayoutLibrary.java:350)
at com.android.tools.idea.rendering.RenderTask$2.compute(RenderTask.java:510)
at com.android.tools.idea.rendering.RenderTask$2.compute(RenderTask.java:498)
at com.intellij.openapi.application.impl.ApplicationImpl.runReadAction(ApplicationImpl.java:888)
at com.android.tools.idea.rendering.RenderTask.createRenderSession(RenderTask.java:498)
at com.android.tools.idea.rendering.RenderTask.access$600(RenderTask.java:72)
at com.android.tools.idea.rendering.RenderTask$3.call(RenderTask.java:610)
at com.android.tools.idea.rendering.RenderTask$3.call(RenderTask.java:607)
at com.android.tools.idea.rendering.RenderService.runRenderAction(RenderService.java:362)
at com.android.tools.idea.rendering.RenderTask.render(RenderTask.java:607)
at com.android.tools.idea.rendering.RenderTask.render(RenderTask.java:629)
at org.jetbrains.android.uipreview.AndroidLayoutPreviewToolWindowManager.doRender(AndroidLayoutPreviewToolWindowManager.java:652)
at org.jetbrains.android.uipreview.AndroidLayoutPreviewToolWindowManager.access$1700(AndroidLayoutPreviewToolWindowManager.java:80)
at org.jetbrains.android.uipreview.AndroidLayoutPreviewToolWindowManager$7$1.run(AndroidLayoutPreviewToolWindowManager.java:594)
at com.intellij.openapi.progress.impl.CoreProgressManager$2.run(CoreProgressManager.java:152)
at com.intellij.openapi.progress.impl.CoreProgressManager.registerIndicatorAndRun(CoreProgressManager.java:452)
at com.intellij.openapi.progress.impl.CoreProgressManager.executeProcessUnderProgress(CoreProgressManager.java:402)
at com.intellij.openapi.progress.impl.ProgressManagerImpl.executeProcessUnderProgress(ProgressManagerImpl.java:54)
at com.intellij.openapi.progress.impl.CoreProgressManager.runProcess(CoreProgressManager.java:137)
at org.jetbrains.android.uipreview.AndroidLayoutPreviewToolWindowManager$7.run(AndroidLayoutPreviewToolWindowManager.java:589)
at com.intellij.util.ui.update.MergingUpdateQueue.execute(MergingUpdateQueue.java:320)
at com.intellij.util.ui.update.MergingUpdateQueue.execute(MergingUpdateQueue.java:310)
at com.intellij.util.ui.update.MergingUpdateQueue$2.run(MergingUpdateQueue.java:254)
at com.intellij.util.ui.update.MergingUpdateQueue.flush(MergingUpdateQueue.java:269)
at com.intellij.util.ui.update.MergingUpdateQueue.flush(MergingUpdateQueue.java:227)
at com.intellij.util.ui.update.MergingUpdateQueue.run(MergingUpdateQueue.java:217)
at com.intellij.util.concurrency.QueueProcessor.runSafely(QueueProcessor.java:238)
at com.intellij.util.Alarm$Request$1.run(Alarm.java:351)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)
java.lang.NullPointerException: Attempt to invoke virtual method 'boolean java.lang.String.equals(java.lang.Object)' on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2325)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2387)
at android.app.ActivityThread.access$800(ActivityThread.java:151)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1303)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5254)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'boolean java.lang.String.equals(java.lang.Object)' on a null object reference
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:715)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:806)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:809)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:809)
at android.view.LayoutInflater.inflate(LayoutInflater.java:504)
at android.view.LayoutInflater.inflate(LayoutInflater.java:414)
at android.view.LayoutInflater.inflate(LayoutInflater.java:365)
at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:378)
at android.app.Activity.setContentView(Activity.java:2145)
at com.mitchellpalermo.tutroubleshooting.ContactPage.onCreate(ContactPage.java:11)
at android.app.Activity.performCreate(Activity.java:5990)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1106)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2278)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2387)
at android.app.ActivityThread.access$800(ActivityThread.java:151)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1303)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5254)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)
NullPointerExceptionsScrollView<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="fill_parent"
android:orientation="vertical"
tools:context="com.mitchellpalermo.tutroubleshooting.ComputerOrProjector">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:orientation="vertical">
<TextView
style="@style/HeaderStyle"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:text="@string/solutions"
android:textStyle="bold" />
<!-- A CardView that contains a TextView -->
<android.support.v7.widget.CardView xmlns:card_view="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:layout_margin="15dp"
card_view:cardBackgroundColor="#FFFFFF"
card_view:cardCornerRadius="4dp"
card_view:cardElevation="5dp">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<TextView
style="@style/Solution"
android:text="@string/pc_v_fifth" />
<View
android:layout_width="match_parent"
android:layout_height="2dp"
android:background="@android:color/darker_gray" />
<TextView
style="@style/Solution"
android:text="@string/pc_v_first" />
<View
android:layout_width="match_parent"
android:layout_height="2dp"
android:background="@android:color/darker_gray" />
<TextView
style="@style/Solution"
android:text="@string/pc_v_second" />
<View
android:layout_width="match_parent"
android:layout_height="2dp"
android:background="@android:color/darker_gray" />
<TextView
style="@style/Solution"
android:text="@string/pc_v_third" />
<View
android:layout_width="match_parent"
android:layout_height="2dp"
android:background="@android:color/darker_gray" />
<TextView
style="@style/Solution"
android:text="@string/pc_v_fourth" />
<View
android:layout_width="match_parent"
android:layout_height="2dp"
android:background="@android:color/darker_gray" />
</LinearLayout>
</android.support.v7.widget.CardView>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
<Button
style="@style/NextButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:onClick="sendEmail"
android:text="@string/fixed"
android:textStyle="bold" />
<Button
style="@style/NextButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:onClick="notFixedButton"
android:text="@string/not_fixed"
android:textStyle="bold" />
</LinearLayout>
</LinearLayout>
</ScrollView>
<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:fillViewport="false">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<TextView
style="@style/HeaderStyle"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:text="@string/still_not_fixed" />
<!-- A CardView that contains a TextView -->
<android.support.v7.widget.CardView xmlns:card_view="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:layout_margin="15dp"
card_view:cardBackgroundColor="#FFFFFF"
card_view:cardCornerRadius="4dp"
card_view:cardElevation="5dp">
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="@string/hector" />
<view
android:layout_width="match_parent"
android:layout_height="2dp"
android:backgroundTint="@android:color/darker_gray" />
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="@string/robert" />
<view
android:layout_width="match_parent"
android:layout_height="2dp"
android:backgroundTint="@android:color/darker_gray" />
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="@string/mitch" />
</android.support.v7.widget.CardView>
</LinearLayout>
</ScrollView>
有什么建议吗？提前非常感谢你 更改
两天后，我解决了这个问题，使用查看而不是查看
<View
android:layout_width="match_parent"
android:layout_height="1dp"
android:background="#faf4f4"></View>
代码中的某个地方正在调用字符串。等于带有空字符串的
。这不是标准的NPE，因为它在系统充气操作中。因此，我已重新提出这项质询，因为这项质询并非与原质询重复。这是一个有效且有用的问题，有一个有用的答案。检查解决方案：还有更多，非常感谢你，伊戈尔！我不知道我怎么会错过，因为我没有用如此详细的解释和奖金大写这个令人敬畏的答案。谢谢，这真是任何开发人员都会犯的打字错误。上帝和很好的详细解释。这也解决了我的问题！多么愚蠢的错误！谢谢对于如此容易犯的错误，lint真的应该警告用户。我现在浪费了这么多时间来寻找这个：/
<view
android:layout_width="wrap_content"
android:layout_height="wrap_content"
class="com.your.package.YourCustomView" />
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'boolean java.lang.String.equals(java.lang.Object)' on a null object reference
//...
View createViewFromTag(View parent, String name, Context context, AttributeSet attrs,
boolean ignoreThemeAttr) {
if (name.equals("view")) { // line 724
name = attrs.getAttributeValue(null, "class"); // line 725
}
// Apply a theme wrapper, if allowed and one is specified.
if (!ignoreThemeAttr) {
final TypedArray ta = context.obtainStyledAttributes(attrs, ATTRS_THEME);
final int themeResId = ta.getResourceId(0, 0);
if (themeResId != 0) {
context = new ContextThemeWrapper(context, themeResId);
}
ta.recycle();
}
if (name.equals(TAG_1995)) { // line 738
// Let's party like it's 1995!
return new BlinkLayout(context, attrs);
}
//...
<view
android:layout_width="wrap_content"
android:layout_height="wrap_content"
class="blink">
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="center"
android:text="Some text" />
</view>
<View
android:layout_width="match_parent"
android:layout_height="1dp"
android:background="#faf4f4"></View>