Download Android Tutorial: Part 1

Android Tutorial:
Part 1
Creating a Simple Edit Text Box and
Button
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• Follow the tutorial:
• http://developer.android.com/training/index.html
• Start the tutorial from:
– Creating an Android Project
• End the tutorial after you have completed:
– Building a Simple User Interface
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• After running your
application on the emulator,
You should end up with the
following:
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Instruction 3:
Building a Simple User Interface
•
Under Section “Create a Linear Layout”, replace the text “activity_my.xml” with “content_my.xml”. Note that
the “activity_my.xml” file includes the “content_my.xml” file.
•
•
Find line: “Here’s how your complete activity_my.xmllayout file should now look:
Change the code that follwos the above line to as follows:
<?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="match_parent"
android:orientation="horizontal">
<EditText android:id="@+id/edit_message"
android:layout_weight="1"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:hint="@string/edit_message" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/button_send" />
</LinearLayout>
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Instruction 4:
Running a Simple User Interface
• After running your
application on the
emulator, You should end
up with the following:
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Instructions 5:
Refactoring
• Manually change the names of the following widgets:
– EditText id from edit_message to: my_message
– EditText hint from edit_message to: my_message
– Button text string from button_send to: my_button
• Ensure you change the entries in strings.xml
• Run the app to verify it still compiles successfully and displays as before.
• Using the Refactor feature of the IDE, change the names of the following
widgets:
– EditText id from my_message to: IP_Address_Text
– EditText hint from my_message to: my_message
– Button text string from my_button to: IP_Address_Button
•
Run the app to verify it still compiles sucessfuly and displays as before.
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Instructions 6:
Adding a Method for a Button
• In file content_my.xml file:
– Append the following to the Button widget:
android:onClick=“IPButtonPressed”
– Add the following method to the MyActivity.java file:
public void IPButtonPressed(View view) {
EditText myIPAddressTextBox = (EditText)findViewById(R.id.IP_Address_Text);
String theIPAddress = myIPAddressTextBox.getText().toString();
}
– Place a breakpoint at the ending brace of the
IPButtonPressed method.
– Debug the app, enter an IP address in the box, and then
verify the string theIPAddress has your item.
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