问题描述

fragement中控件空指针

public class FoundNew extends Fragment{

    private EditText ed_found_id;
    private Button btn_ok,btn_cancel;
    @Override
    public void onActivityCreated(@Nullable Bundle savedInstanceState) {
            // TODO Auto-generated method stub
            super.onActivityCreated(savedInstanceState);

    }

    @Override
    public View onCreateView(LayoutInflater inflater,
                    @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
            // TODO Auto-generated method stub
            super.onCreateView(inflater, container, savedInstanceState);
            View founNewView = inflater.inflate(R.layout.found_new, container,false);

            ed_found_id = (EditText)founNewView.findViewById(R.id.ed_found_id);
            btn_cancel = (Button)founNewView.findViewById(R.id.btn_fundNewCancel);
            btn_ok = (Button)founNewView.findViewById(R.id.btn_fundNewOk);

           btn_cancel.setOnClickListener(new OnClickListener() {

                    @Override
                    public void onClick(View arg0) {
                            // TODO Auto-generated method stub
                            String sttt = ed_found_id.getText().toString();
                            ed_found_id.setText("");
                    }
            });

            return founNewView;
    }

}

ed_found_id.setText("");执行不过

04-13 06:31:47.860: D/AndroidRuntime(941): Shutting down VM
04-13 06:31:47.860: W/dalvikvm(941): threadid=1: thread exiting with uncaught exception (group=0x409c01f8)
04-13 06:31:47.880: E/AndroidRuntime(941): FATAL EXCEPTION: main
04-13 06:31:47.880: E/AndroidRuntime(941): java.lang.NullPointerException
04-13 06:31:47.880: E/AndroidRuntime(941): at com.example.foundmanager.FoundNew$1.onClick(FoundNew.java:77)
04-13 06:31:47.880: E/AndroidRuntime(941): at android.view.View.performClick(View.java:3511)
04-13 06:31:47.880: E/AndroidRuntime(941): at android.view.View$PerformClick.run(View.java:14105)
04-13 06:31:47.880: E/AndroidRuntime(941): at android.os.Handler.handleCallback(Handler.java:605)
04-13 06:31:47.880: E/AndroidRuntime(941): at android.os.Handler.dispatchMessage(Handler.java:92)
04-13 06:31:47.880: E/AndroidRuntime(941): at android.os.Looper.loop(Looper.java:137)
04-13 06:31:47.880: E/AndroidRuntime(941): at android.app.ActivityThread.main(ActivityThread.java:4424)
04-13 06:31:47.880: E/AndroidRuntime(941): at java.lang.reflect.Method.invokeNative(Native Method)
04-13 06:31:47.880: E/AndroidRuntime(941): at java.lang.reflect.Method.invoke(Method.java:511)
04-13 06:31:47.880: E/AndroidRuntime(941): atcom.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
04-13 06:31:47.880: E/AndroidRuntime(941): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
04-13 06:31:47.880: E/AndroidRuntime(941): at dalvik.system.NativeStart.main(Native Method)

好像ed_found_id是空指针 大神帮忙呀

解决方案

ed_found_id.getText() 都没有出错，说明 ed_found_id 不为空 。
ed_found_id.setText(""); 却不行，难道是参数的问题？在双引号中间增加一个空格试试吧。

解决方案二：

没见过get没问题，但set有问题的
如果没有跟踪过，跟踪一下看看，是不是findviewbyid的时候就是没有获取到或者获取后在fragment其他地方又重写置null了。