我有以下代码,试图在ListView中创建一个简单的ListAdapter(我之前有这个代码工作,这是我改变了一些东西的唯一地方):
public BuddyListAdapter(Context context, HashMap<String, Buddy> hashMap) {
buddyList = new ArrayList<Buddy>(hashMap.values());
mInflater = LayoutInflater.from(context);
ctx = context;
}
单步执行时,没有任何反应,但在运行时,我会NullPointerException进入ChoreoGrapher.doCallbacks,当我创建一个空的时ArrayList,它不会崩溃:
public BuddyListAdapter(Context context, HashMap<String, Buddy> hashMap) {
buddyList = new ArrayList<Buddy>();
mInflater = LayoutInflater.from(context);
ctx = context;
}
什么是ChoreoGrapher,为什么它崩溃我的应用程序？
我完全坚持可能是什么问题,或者如何找出问题所在.Eclipse调试器或崩溃信息并没有真正帮助.
整个堆栈跟踪如下:
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Handler在主要活动中也有一个.当它没有做任何事情时,listview不会崩溃.但是,在打开listview之前,我会从中删除所有回调.
Pet*_*rdk 30
我的应用程序只在Android 4.4上有这个错误.
在调试器中,它显示与问题提供者相同的消息.但是,当没有调试DDMS中的完整堆栈跟踪时:
完整的堆栈跟踪:
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)
通过在6124行查看TextView的4.4源代码,结果发现这是由椭圆形时缺少布局参数引起的.这很奇怪,因为代码在a内部失败ListAdapter,你不提供布局参数getView.
我曾经android.R.layout.simple_spinner_item为标准的微调项目充气.看起来这个项目使用ellipsing.所以getView我现在打电话给我:
view.setEllipsize(null);
这解决了我在Android 4.4上遇到的问题.
编辑
事实证明,问题不是椭圆形,而是对视图的不正确膨胀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false的不会立即将视图附加到父级,因为这是在需要时附加子级的适配器中.否则你会收到错误.
当你正确地充气,你并不需要设置ellipseSize到null.这是因为当您使用父对象充气时,它会LayoutParams正确处理,导致椭圆代码不会升高NullPointerException.
所以,正确膨胀,然后你不必再担心了.
我在另一个应用程序中再次使用相同的东西.它似乎是由getView列表适配器中的未处理异常引起的.