java.lang.NullPointerException: Attempt to invoke virtual method 'void com.moreunion.zhenghao.ui.pr

09-18 11:41:23.223 2992-2992/com.moreunion.zhenghao E/AndroidRuntime: FATAL EXCEPTION: main
                                                                      Process: com.moreunion.zhenghao, PID: 2992
                                                                      java.lang.NullPointerException: Attempt to invoke virtual method 'void com.moreunion.zhenghao.ui.product.adapter.MsgAdapter.notifyDataSetChanged()' on a null object reference
                                                                          at com.moreunion.zhenghao.ui.product.session.P2PMessageActivity.onTextMessageSendButtonPressed(P2PMessageActivity.java:625)
                                                                          at com.moreunion.zhenghao.ui.product.session.P2PMessageActivity.lambda$initEditText$4(P2PMessageActivity.java:451)
                                                                          at com.moreunion.zhenghao.ui.product.session.P2PMessageActivity$$Lambda$7.onEditorAction(Unknown Source)
                                                                          at android.widget.TextView.onEditorAction(TextView.java:5003)
                                                                          at com.android.internal.widget.EditableInputConnection.performEditorAction(EditableInputConnection.java:138)
                                                                          at com.android.internal.view.IInputConnectionWrapper.executeMessage(IInputConnectionWrapper.java:367)
                                                                          at com.android.internal.view.IInputConnectionWrapper$MyHandler.handleMessage(IInputConnectionWrapper.java:91)
                                                                          at android.os.Handler.dispatchMessage(Handler.java:102)
                                                                          at android.os.Looper.loop(Looper.java:156)
                                                                          at android.app.ActivityThread.main(ActivityThread.java:6524)
                                                                          at java.lang.reflect.Method.invoke(Native Method)
                                                                          at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:941)
                                                                          at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:831)