我在GetView中有一个错误，我认为问题在于位置变量，但我尝试过的所有内容都无法改变任何内容.ListView设置为显示WebView的UrlHistory。我相信这是我打开活动时我的ListVies不可见的原因。如果不是那么我将不得不在以后弄明白。关于log.e我想知道我是否可以看到它是否在LogCat中获取数据但我找不到它在LogCat中的特定行。
UrlHistoryAdapter.Java
public View getView(int position, View convertView, ViewGroup parent) {
View view = convertView;
if (view == null) {
view =
LayoutInflater.from(context).inflate(R.layout.list_item,parent,false);
}
TextView textView = view.findViewById(android.R.id.title);
textView.setText(getItem(position));
Log.e(Tag, "received data");
return view;
}
logcat的
02-02 16:33:04.424 26544-26544/com.example.mickeyt.onyxbrowser E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.mickeyt.onyxbrowser, PID: 26544
java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.TextView.setText(java.lang.CharSequence)' on a null object reference
at com.example.mickeyt.onyxbrowser.UrlHistoryAdapter.getView(UrlHistoryAdapter.java:60)
at android.widget.AbsListView.obtainView(AbsListView.java:2406)
at android.widget.ListView.makeAndAddView(ListView.java:1975)
at android.widget.ListView.fillDown(ListView.java:709)
at android.widget.ListView.fillFromTop(ListView.java:770)
at android.widget.ListView.layoutChildren(ListView.java:1721)
at android.widget.AbsListView.onLayout(AbsListView.java:2205)
at android.view.View.layout(View.java:17564)
at android.view.ViewGroup.layout(ViewGroup.java:5654)
at android.support.constraint.ConstraintLayout.onLayout(ConstraintLayout.java:1197)
at android.view.View.layout(View.java:17564)
at android.view.ViewGroup.layout(ViewGroup.java:5654)
at android.support.constraint.ConstraintLayout.onLayout(ConstraintLayout.java:1197)
at android.view.View.layout(View.java:17564)
at android.view.ViewGroup.layout(ViewGroup.java:5654)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:323)
at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
at android.view.View.layout(View.java:17564)
at android.view.ViewGroup.layout(ViewGroup.java:5654)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1741)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1585)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1494)
at android.view.View.layout(View.java:17564)
at android.view.ViewGroup.layout(ViewGroup.java:5654)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:323)
at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
at android.view.View.layout(View.java:17564)
at android.view.ViewGroup.layout(ViewGroup.java:5654)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1741)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1585)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1494)
at android.view.View.layout(View.java:17564)
at android.view.ViewGroup.layout(ViewGroup.java:5654)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:323)
at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
at com.android.internal.policy.DecorView.onLayout(DecorView.java:725)
at android.view.View.layout(View.java:17564)
at android.view.ViewGroup.layout(ViewGroup.java:5654)
at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:2406)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:2126)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1286)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:6536)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:871)
at android.view.Choreographer.doCallbacks(Choreographer.java:683)
at android.view.Choreographer.doFrame(Choreographer.java:619)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:857)
at android.os.Handler.handleCallback(Handler.java:751)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6247)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:872)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:762)
答案 0 :(得分：1)
你的问题在这一行：
TextView textView = view.findViewById(android.R.id.title);
view布局不包含ID为android.R.id.title的视图
我认为问题是您使用android.R.id.title而不是R.id.title（开头没有安卓）。
因此，为了解决此问题，您应该将android.R.id.title更改为R.id.title
答案 1 :(得分：0)
它说你的TextView为空。检查它为何为空。
OBS：我建议您使用RecyclerView。
答案 2 :(得分：0)
您的textview为空，
尝试.. textView.setText（getItem（position）.toString） 或.. textView.setText（getItem（position）+＆＃34;＆＃34;）