我已经创建了一个ListFragment，并且试图将List的值打开到其他onItemClick中的每个Item的on Fragment。
我已经成功创建了两个，并通过Google文档中所述的活动通过fragments通过interface进行了交流。
但是，当我尝试在列表的每个项目单击上创建一个新的Fragment并通过界面进行通信时，我在该视图上得到一个Null Pointer Exception
public class Details extends Fragment {
ViewGroup view_details;
static int count;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
view_details = (ViewGroup) inflater.inflate( R.layout.details, container , false);
return view_details;
}
public void setTextView(String details_string){
Log.d("TAG", ""+details_string.toString());
TextView txt_view_details = (TextView) view_details.findViewById(R.id.txt_details);
//Getting Null POinter Here
txt_view_details.setText(details_string.toString());
}
}
我将新的Fragment插入FrameLayout的接口方法是：
@Override
public void connectIt(String time) {
Details details = new Details();
FragmentTransaction fragmentTransaction = getFragmentManager().beginTransaction();
fragmentTransaction.replace( R.id.frameLayout , details );
fragmentTransaction.addToBackStack(null);
if (details != null ) {
details.setTextView(time);
}
fragmentTransaction.commit();
}
12-17 18:18:06.740: E/AndroidRuntime(15917): FATAL EXCEPTION: main
12-17 18:18:06.740: E/AndroidRuntime(15917): java.lang.NullPointerException
12-17 18:18:06.740: E/AndroidRuntime(15917): at com.raweng.fragmentdemo.Details.setTextView(Details.java:31)
12-17 18:18:06.740: E/AndroidRuntime(15917): at com.raweng.fragmentdemo.FragmentDemo.connectIt(FragmentDemo.java:46)
12-17 18:18:06.740: E/AndroidRuntime(15917): at com.raweng.fragmentdemo.ListData.updateIt(ListData.java:41)
12-17 18:18:06.740: E/AndroidRuntime(15917): at com.raweng.fragmentdemo.ListData.onListItemClick(ListData.java:34)
12-17 18:18:06.740: E/AndroidRuntime(15917): at android.app.ListFragment$2.onItemClick(ListFragment.java:160)
12-17 18:18:06.740: E/AndroidRuntime(15917): at android.widget.AdapterView.performItemClick(AdapterView.java:298)
12-17 18:18:06.740: E/AndroidRuntime(15917): at android.widget.AbsListView.performItemClick(AbsListView.java:1128)
12-17 18:18:06.740: E/AndroidRuntime(15917): at android.widget.AbsListView$PerformClick.run(AbsListView.java:2812)
12-17 18:18:06.740: E/AndroidRuntime(15917): at android.widget.AbsListView$1.run(AbsListView.java:3571)
12-17 18:18:06.740: E/AndroidRuntime(15917): at android.os.Handler.handleCallback(Handler.java:725)
12-17 18:18:06.740: E/AndroidRuntime(15917): at android.os.Handler.dispatchMessage(Handler.java:92)
12-17 18:18:06.740: E/AndroidRuntime(15917): at android.os.Looper.loop(Looper.java:153)
12-17 18:18:06.740: E/AndroidRuntime(15917): at android.app.ActivityThread.main(ActivityThread.java:5297)
12-17 18:18:06.740: E/AndroidRuntime(15917): at java.lang.reflect.Method.invokeNative(Native Method)
12-17 18:18:06.740: E/AndroidRuntime(15917): at java.lang.reflect.Method.invoke(Method.java:511)
12-17 18:18:06.740: E/AndroidRuntime(15917): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:833)
12-17 18:18:06.740: E/AndroidRuntime(15917): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:600)
12-17 18:18:06.740: E/AndroidRuntime(15917): at dalvik.system.NativeStart.main(Native Method)
真正感谢任何帮助...
最佳答案
这是因为在您调用details.setTextView（time）;的时间。片段的视图尚未创建。
您应该将时间作为参数传递给片段。在细节片段类中创建此方法
public static Detail newInstance(String time) {
Detail fragment = new Detail();
Bundle args = new Bundle();
args.putString("time", time);
fragment.setArguments(args);
return fragment;
}
然后您可以获取时间并在onCreateView中进行设置：
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
view_details = (ViewGroup) inflater.inflate( R.layout.details, container , false);
TextView txt_view_details = (TextView) view_details.findViewById(R.id.txt_details);
txt_view_details.setText(getArguments().getString("title"));
return view_details;
}
然后在您的活动中创建如下片段：
@Override
public void connectIt(String time) {
Details details = Details.newInstance(time);
FragmentTransaction fragmentTransaction = getFragmentManager().beginTransaction();
fragmentTransaction.replace( R.id.frameLayout , details );
fragmentTransaction.addToBackStack(null);
fragmentTransaction.commit();
}