ID值资源：Android Studio

Question

https://developer.android.com/training/basics/firstapp/starting-activity#BuildIntent

I am following along the demo on this website to gain a general idea of how Android Studio works. For the following portion of the code, it says to "press Alt+Enter" to clear errors. The problem is that the editText in line 3 ( R.id.editText ) is making me create a new id value resource or renaming the reference (which I do not want to do).

public void sendMessage(View view) {
    Intent intent = new Intent(this, DisplayMessageActivity.class);
    EditText editText = (EditText) findViewById(R.id.editText);
    String message = editText.getText().toString();
    intent.putExtra(EXTRA_MESSAGE, message);
    startActivity(intent);
}

Can someone explain what the id value resource is? Also, suggestions on how to fix this issue? I am new to Android Studio, so I do not understand what exactly this means.

Thank you. it says "error: cannot find symbol"

Answer 1

To solve your issue, i suppose in your activity main layout you have added an editText as view, this is how to add Editext into your layout

<EditText 
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:id="@+id/editTextTextPersonName" //this is the id value
    />

In your activity code set the id this way

public void sendMessage(View view) {
    Intent intent = new Intent(this, DisplayMessageActivity.class);
    EditText editText = (EditText) findViewById(R.id.editTextTextPersonName);
    String message = editText.getText().toString();
    intent.putExtra(EXTRA_MESSAGE, message);
    startActivity(intent);
}

Answer 2

Id of a resource is uniq identifier, such as name of a variable. It should be uniq or you will have problems with names.

Xml file where it write:

 <?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:layout_gravity="center_vertical"
tools:context=".MainActivity">

<!--LOOOOOOOOOOOOOK HERE-->
<TextView
    android:id="@+id/placeHereIdWhichYouWant"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Some text"
/>

</LinearLayout>

Your string editText.getText().toString(); just take text from your EditText View. Just give the id for EditText and all will work, if it doesn't import R. to your class

package com.example.test //here name of your package

import android.os.Bundle
import android.widget.TextView
import androidx.appcompat.app.AppCompatActivity