Java Source Code (Cont.)

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import android.widget.TextView;

Displays text to the user and optionally allows them to edit it. A TextView is a complete text editor, however the basic class is configured to not allow editing; see EditText for a subclass that configures the text view for editing.

final TextView tvView = (TextView) findViewById( R.id.tvView );

The method findViewById of the class View looks for a child view with the given id such as R.id.tvView.

Intent intent = getIntent( );

Create an intent, which is an abstract description of an operation to be performed. The intent is from the MainActivity using startActivity to launch the current activity.

String name = intent.getStringExtra( "name" );

Retrieve extended data from the intent, where the "name" is the name of the desired item.

tvView.setText( "Welcome, " + name );

Set the text that this TextView is to display and also sets whether it is stored in a styleable/spannable buffer and whether it is editable.

HelloWorld/app/src/main/java/com/example/wenchen/helloworld/NextActivity.java

view source print? 01 package com.example.wenchen.helloworld; 02   03 import android.app.Activity; 04 import android.content.Intent; 05 import android.os.Bundle; 06 import android.view.Menu; 07 import android.view.MenuItem; 08 import android.view.View; 09 import android.widget.Button; 10 import android.widget.TextView; 11   12 public class NextActivity extends Activity { 13   /** Called when the activity is first created. */ 14   @Override 15   public void onCreate( Bundle savedInstanceState ) { 16     super.onCreate( savedInstanceState ); 17     setContentView( R.layout.activity_next ); 18   19     final TextView tvView = (TextView) findViewById( R.id.tvView ); 20     Intent intent = getIntent( ); 21     String name = intent.getStringExtra( "name" ); 22     tvView.setText( "Welcome, " + name ); 23     final Button button = (Button) findViewById( R.id.home ); 24     button.setOnClickListener( 25       new View.OnClickListener( ) { 26         public void onClick( View v ) { 27           Intent i = new Intent( NextActivity.this, MainActivity.class ); 28           startActivity( i ); 29         } 30       } 31     ); 32   } 33   34   @Override 35   public boolean onCreateOptionsMenu( Menu menu ) { 36     // Inflate the menu; this adds items to the action bar if it is present. 37     getMenuInflater( ).inflate( R.menu.menu_next, menu ); 38     return true; 39   } 40   41   @Override 42   public boolean onOptionsItemSelected( MenuItem item ) { 43     // Handle action bar item clicks here. The action bar will 44     // automatically handle clicks on the Home/Up button, so long 45     // as you specify a parent activity in AndroidManifest.xml. 46     int id = item.getItemId( ); 47   48     // noinspection SimplifiableIfStatement 49     if ( id == R.id.action_settings ) { 50       return true; 51     } 52     else if ( id == R.id.home ) { 53       Intent i = new Intent( NextActivity.this, MainActivity.class ); 54       startActivity( i ); 55     } 56     return super.onOptionsItemSelected( item ); 57   } 58 }