/androidintro

Completed project from my Intro to Android Session

Primary LanguageJava

Introduction to Android

Create and Run a Simple App

  1. Open Android Studio
  2. Start A New Android Studio Project
  3. Name it "Hello"
  4. Change the domain to ladev.com
  5. Change the location as you wish
  6. Next
  7. Choose the defaults for Target Android Devices (Phone and Tablet Only)
  8. Next
  9. Choose an Empty Activity
  10. Next
  11. Leave the defaults
  12. Next
  13. Finish (Wait)
  14. Expand the Res Folder in the Project View, then expand the Layouts folder
  15. Open activity_main.xml
  16. Click the Hello World TextView
  17. In the Properties Pane, change the text to something different.
  18. In the main Toolbar, click the Run button

Create the Catch Phrase App

  1. Open Android Studio

  2. Start A New Android Studio Project

  3. Name it "CatchPhrase" (no spaces)

  4. Change the domain to ladev.com

  5. Change the location as you wish

  6. Next

  7. Choose the defaults for Target Android Devices (Phone and Tablet Only)

  8. Next

  9. Choose an Empty Activity

  10. Next

  11. Leave the defaults

  12. Next

  13. Finish (Wait)

  14. Expand the Res Folder in the Project View, then expand the values folder

  15. Open strings.xml

  16. Add the following XML snippet:

    <string name="quote_bang">Bazinga!</string>
<string name="quote_seinfeld">Hello Neuman</string>
<string name="quote_friends">How you Doin?</string>
<string name="quote_mother">Suit Up!</string>

  17. Expand the Res Folder in the Project View, then expand the layouts folder

  18. Open activity_main.xml

  19. Change "android.support.constraint.ConstraintLayout" to "RelativeLayout"

  20. Delete the entire TextView element

  21. Add the following XML Snippet inside the RelativeLayout

    <Button
    android:id="@+id/bang"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginLeft="60dp"
    android:layout_marginTop="100dp"
    android:text="@string/quote_bang"/>
<Button
    android:id="@+id/friend"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignTop="@id/bang"
    android:layout_toRightOf="@id/bang"
    android:layout_marginLeft="50dp"
    android:text="@string/quote_friends"/>
<Button
    android:id="@+id/mother"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignLeft="@id/bang"
    android:layout_below="@id/bang"
    android:layout_marginTop="50dp"
    android:text="@string/quote_mother"/>
<Button
    android:id="@+id/seinfeld"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginLeft="50dp"
    android:layout_toRightOf="@id/bang"
    android:layout_below="@id/bang"
    android:layout_marginTop="50dp"
    android:text="@string/quote_seinfeld"/>

  22. Right-Click the com.ladev.catchphrase package in the Project pane

  23. Add a new Empty Activity

  24. Name it Display

  25. Finish

  26. Open activity_display.xml

  27. Change "android.support.constraint.ConstraintLayout" to "RelativeLayout"

  28. Add a TextView

    <TextView
    android:id="@+id/phrase"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_centerHorizontal="true"
    android:layout_centerVertical="true"
    android:textSize="36sp"/>

  29. Open MainActivity.java

  30. Create a private inner class for handling button taps

    private class ButtonListener implements View.OnClickListener {
    @Override
    public void onClick(View v) {

        Button button = (Button) v;

        String phrase = button.getText().toString();

        Intent displayIntent = new Intent(MainActivity.this, Display.class);
        displayIntent.putExtra("phrase", phrase);
        startActivity(displayIntent);
    }
}

  31. Wire up each button to an instance of the ButtonListener class in the onCreate method below the layout inflation:

    Button bangButton = (Button) findViewById(R.id.bang);
bangButton.setOnClickListener(new ButtonListener());

Button friendButton = (Button) findViewById(R.id.friend);
friendButton.setOnClickListener(new ButtonListener());

Button seinfeldButton = (Button) findViewById(R.id.seinfeld);
seinfeldButton.setOnClickListener(new ButtonListener());

Button motherButton = (Button) findViewById(R.id.mother);
motherButton.setOnClickListener(new ButtonListener());

  32. Open Display.java

  33. Retrieve the data from the intent and load it into the TextView

    Intent intent = getIntent();

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

TextView display = (TextView) findViewById(R.id.phrase);
display.setText(phrase);

  34. Try the app in the emulator or device