Question

I’m new to Android. A part of my Activity contains

TextView message = (TextView) findViewById(R.id.show_message);
Intent intent = getIntent();
String name = intent.getStringExtra(MainActivity.EXTRA_MESSAGE);
message.setText(name);

MainActivity was the previous activity from which the current one was called. Also, the layout file for the above activity is

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent" >

<TextView  
    android:id="@+id/show_message" 
    android:layout_height="wrap_content" 
    android:textAppearance="?android:attr/textAppearanceLarge" 
    android:layout_width="wrap_content">

</TextView>

<Button
    android:id="@+id/button_back"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_below="@+id/show_message"
    android:layout_centerHorizontal="true"
    android:layout_marginTop="17dp"
    android:onClick="goBack"
    android:text="Go Back to Activity Lifecycle" />

I know that message.setText(name) sets the String value of name to message but how come it also changes show_message? When the Activity starts in the app, it shows the String value of name where it is supposed to display show_message.

Actually, I want the code to perform in the way it is doing right now but I can’t understand why.

Thanks in advance!

Answer 1

The value of String name isn’t being set by message.setText rather it’s being set by the StringExtra in the received intent (that starts the activity)

TextView message is pointing to the TextView R.id.show_message

So message.setText("anything") would set the text value of show_message to “anything”

message.setText(name) sets the text of show_message to whatever String name represents… here the value passed in the intent.