Android 应用程序崩溃与 NullPointerException 在 ChoreoGrapher

android java

2022-09-04 05:56:11

我有以下代码，试图在ListView中创建一个简单的ListAdapter（我以前有这个代码工作，这是我唯一改变过的东西的地方）：

public BuddyListAdapter(Context context, HashMap<String, Buddy> hashMap) {
    buddyList = new ArrayList<Buddy>(hashMap.values());
    mInflater = LayoutInflater.from(context);
    ctx = context;
}

当单步执行时，什么也没发生，但是当运行时，我得到一个 in ，当我创建一个空的，它不会崩溃：NullPointerExceptionChoreoGrapher.doCallbacksArrayList

public BuddyListAdapter(Context context, HashMap<String, Buddy> hashMap) {
    buddyList = new ArrayList<Buddy>();
    mInflater = LayoutInflater.from(context);
    ctx = context;
}

是什么，为什么它会使我的应用程序崩溃？ChoreoGrapher

我完全被困在可能是什么问题，或者如何找出问题所在。Eclipse 调试器或崩溃信息并没有真正的帮助。

整个堆栈跟踪如下所示：

Thread [<1> main] (Suspended (exception NullPointerException))  
    Choreographer.doCallbacks(int, long) line: 558  
    Choreographer.doFrame(long, int) line: 525  
    Choreographer$FrameDisplayEventReceiver.run() line: 711 
    Handler.handleCallback(Message) line: 615   
    Choreographer$FrameHandler(Handler).dispatchMessage(Message) line: 92   
    Looper.loop() line: 137 
    ActivityThread.main(String[]) line: 4745    
    Method.invokeNative(Object, Object[], Class, Class[], Class, int, boolean) line: not available [native method]  
    Method.invoke(Object, Object...) line: 511  
    ZygoteInit$MethodAndArgsCaller.run() line: 786  
    ZygoteInit.main(String[]) line: 553 
    NativeStart.main(String[]) line: not available [native method]

我也有一个主要活动。当它不执行任何操作时，列表视图不会崩溃。但是，在打开列表视图之前，我从中删除了所有回调。Handler

答案 1

我的应用程序中只有这个错误，仅在Android 4.4上。

在调试器中，它显示与问题提问者相同的消息。但是，在不调试 DDMS 中的完整堆栈跟踪时，是：

全栈跟踪：

11-13 16:34:53.088: E/AndroidRuntime(1964): FATAL EXCEPTION: main
11-13 16:34:53.088: E/AndroidRuntime(1964): Process: appname, PID: 1964
11-13 16:34:53.088: E/AndroidRuntime(1964): java.lang.NullPointerException
11-13 16:34:53.088: E/AndroidRuntime(1964):     at android.widget.TextView.makeNewLayout(TextView.java:6124)
11-13 16:34:53.088: E/AndroidRuntime(1964):     at android.widget.TextView.onMeasure(TextView.java:6419)
11-13 16:34:53.088: E/AndroidRuntime(1964):     at android.view.View.measure(View.java:16458)
11-13 16:34:53.088: E/AndroidRuntime(1964):     at android.widget.Spinner.setUpChild(Spinner.java:632)
11-13 16:34:53.088: E/AndroidRuntime(1964):     at android.widget.Spinner.makeView(Spinner.java:585)
11-13 16:34:53.088: E/AndroidRuntime(1964):     at android.widget.Spinner.getBaseline(Spinner.java:431)
11-13 16:34:53.088: E/AndroidRuntime(1964):     at android.widget.LinearLayout.measureHorizontal(LinearLayout.java:1262)
11-13 16:34:53.088: E/AndroidRuntime(1964):     at android.widget.LinearLayout.onMeasure(LinearLayout.java:590)
11-13 16:34:53.088: E/AndroidRuntime(1964):     at android.view.View.measure(View.java:16458)
11-13 16:34:53.088: E/AndroidRuntime(1964):     at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5125)
11-13 16:34:53.088: E/AndroidRuntime(1964):     at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1404)
11-13 16:34:53.088: E/AndroidRuntime(1964):     at android.widget.LinearLayout.measureVertical(LinearLayout.java:695)
11-13 16:34:53.088: E/AndroidRuntime(1964):     at android.widget.LinearLayout.onMeasure(LinearLayout.java:588)
11-13 16:34:53.088: E/AndroidRuntime(1964):     at android.view.View.measure(View.java:16458)
11-13 16:34:53.088: E/AndroidRuntime(1964):     at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5125)
11-13 16:34:53.088: E/AndroidRuntime(1964):     at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
11-13 16:34:53.088: E/AndroidRuntime(1964):     at android.view.View.measure(View.java:16458)
11-13 16:34:53.088: E/AndroidRuntime(1964):     at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5125)
11-13 16:34:53.088: E/AndroidRuntime(1964):     at com.android.internal.widget.ActionBarOverlayLayout.onMeasure(ActionBarOverlayLayout.java:327)
11-13 16:34:53.088: E/AndroidRuntime(1964):     at android.view.View.measure(View.java:16458)
11-13 16:34:53.088: E/AndroidRuntime(1964):     at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5125)
11-13 16:34:53.088: E/AndroidRuntime(1964):     at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
11-13 16:34:53.088: E/AndroidRuntime(1964):     at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2289)
11-13 16:34:53.088: E/AndroidRuntime(1964):     at android.view.View.measure(View.java:16458)
11-13 16:34:53.088: E/AndroidRuntime(1964):     at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:1914)
11-13 16:34:53.088: E/AndroidRuntime(1964):     at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1111)
11-13 16:34:53.088: E/AndroidRuntime(1964):     at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1293)
11-13 16:34:53.088: E/AndroidRuntime(1964):     at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:998)
11-13 16:34:53.088: E/AndroidRuntime(1964):     at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5582)
11-13 16:34:53.088: E/AndroidRuntime(1964):     at android.view.Choreographer$CallbackRecord.run(Choreographer.java:749)
11-13 16:34:53.088: E/AndroidRuntime(1964):     at android.view.Choreographer.doCallbacks(Choreographer.java:562)
11-13 16:34:53.088: E/AndroidRuntime(1964):     at android.view.Choreographer.doFrame(Choreographer.java:532)
11-13 16:34:53.088: E/AndroidRuntime(1964):     at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:735)
11-13 16:34:53.088: E/AndroidRuntime(1964):     at android.os.Handler.handleCallback(Handler.java:733)
11-13 16:34:53.088: E/AndroidRuntime(1964):     at android.os.Handler.dispatchMessage(Handler.java:95)
11-13 16:34:53.088: E/AndroidRuntime(1964):     at android.os.Looper.loop(Looper.java:137)
11-13 16:34:53.088: E/AndroidRuntime(1964):     at android.app.ActivityThread.main(ActivityThread.java:4998)
11-13 16:34:53.088: E/AndroidRuntime(1964):     at java.lang.reflect.Method.invokeNative(Native Method)
11-13 16:34:53.088: E/AndroidRuntime(1964):     at java.lang.reflect.Method.invoke(Method.java:515)
11-13 16:34:53.088: E/AndroidRuntime(1964):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:777)
11-13 16:34:53.088: E/AndroidRuntime(1964):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:593)
11-13 16:34:53.088: E/AndroidRuntime(1964):     at dalvik.system.NativeStart.main(Native Method)

查看 TextView 第 6124 行的 4.4 源代码，发现这是由于省略时缺少布局参数引起的。这很奇怪，因为代码在中失败，您没有在中提供布局参数。ListAdaptergetView

我曾经为标准微调器项目充气。看起来这个项目使用.所以在我的现在打电话给：android.R.layout.simple_spinner_itemellipsinggetView

view.setEllipsize(null);

这解决了我在Android 4.4上的问题。

编辑

事实证明，问题不在于省略号，而在于视图中视图的不当膨胀。getView

inflater.inflate(android.R.layout.simple_spinner_item, null);//WRONG
inflater.inflate(android.R.layout.simple_spinner_item, parent, false);//GOOD

请注意，您提供的不是立即将视图附加到父级，因为这是在适配器中，该适配器在需要时附加子级。否则，您将收到错误。false

正确充气后，无需设置为。这是因为当您使用父级以良好的方式膨胀时，它会正确处理，从而导致椭圆代码不会引发。ellipseSizenullLayoutParamsNullPointerException

因此，正确充气，然后您就不必担心了。

答案 2

我在另一个应用程序中再次遇到同样的事情。它似乎是由列表适配器中未处理的异常引起的。getView