This is MainActivity. Java code
Package com. Example. Myapplication;

import androidx.appcompat.app.AppCompatActivity;

The import android. OS. Bundle;
The import android. View. The view;
import android.widget.Button;
The import android. Widget. TextView;
Import the Java. Lang. String;

Public class MainActivity extends AppCompatActivity {
Private TextView JAVAtext1;
Private TextView JAVAtext2;
Private TextView JAVAtext3;
Private Button JAVAbut;
Private Float num1.
Private Float num2;
Private String str1;
Private String str2;
@ Override
Protected void onCreate (Bundle savedInstanceState) {

super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
JAVAtext1=(TextView) enclosing the findViewById (R.i which the ext);
JAVAtext2=(TextView) enclosing the findViewById (R.i which however);
JAVAtext3=(TextView) enclosing the findViewById (R.i which ext3);
JAVAbut=(Button) enclosing the findViewById (R.i db ut);
Str1=(String) JAVAtext1. GetText ();
JAVAtext2 str2=(String). The getText ();
Num1=Float. ParseFloat (str1);
Num2=Float. ParseFloat (str2);
JAVAbut. SetOnClickListener (new View. An OnClickListener () {
//@ Overrides
//Float num3=MainActivity. This. Num1.
//Float num4=MainActivity. This. Num2;
Public void onClick (View v) {
//Float. ToString ((num1 + num2))
JAVAtext3. SetText (" Float. ToString (num3 + num4) ");
}
});
}
}

CodePudding user response:

Look at the logcat log

CodePudding user response:

App startup flash back, at the same time the logcat these what does it mean

CodePudding user response:

These is not all right, you carefully check, find the error log

CodePudding user response:

OnCreate cannot do some operations, add a button, instead to do these functions in the button, the interface first run out;

Mean
Delete the
Str1=(String) JAVAtext1. GetText ();
JAVAtext2 str2=(String). The getText ();
Num1=Float. ParseFloat (str1);
Num2=Float. ParseFloat (str2);
This a few words

CodePudding user response:

String. The valueOf (num1 + num2);