Android App Dev lesson serial - Activity

1. Activity
Michael Pan

2. The project

3. Blank Activity

4. Layout - activity_record.xml

5. Project View

6. AndroidManifest.xml
DailyRecord > app > src > main > AndroidManifest.xml

7. Application attributes
<?xml version="1.0" encoding="utf-8"?>!
<manifest xmlns:android="http://schemas.android.com/apk/res/android"!
package="com.zencher.dailyrecord.app" >!
!
<application!
android:allowBackup="true" !
android:icon="@drawable/ic_launcher"!
android:label="@string/app_name"!
android:theme="@style/AppTheme" >!
<activity!
android:name="com.zencher.dailyrecord.app.RecordActivity"!
android:label="@string/app_name" >!
<intent-filter>!
<action android:name="android.intent.action.MAIN" />!
!
<category android:name="android.intent.category.LAUNCHER" />!
</intent-filter>!
</activity>!
</application>!
!
</manifest>
http://bit.ly/1msJ804
Backup App
image

8. Change icon
@drawable/ic_launcher
app > src > main > res > drawable-xxxx

9. Run - Change Icon

10. Application attributes - android:label
<?xml version="1.0" encoding="utf-8"?>!
<manifest xmlns:android="http://schemas.android.com/apk/res/android"!
package="com.zencher.dailyrecord.app" >!
!
<application!
android:allowBackup="true" !
android:icon="@drawable/ic_launcher"!
android:label="@string/app_name"!
android:theme="@style/AppTheme" >!
<activity!
android:name="com.zencher.dailyrecord.app.RecordActivity"!
android:label="@string/app_name" >!
<intent-filter>!
<action android:name="android.intent.action.MAIN" />!
!
<category android:name="android.intent.category.LAUNCHER" />!
</intent-filter>!
</activity>!
</application>!
!
</manifest>

11. Another resource
@string/app_name
app > src > main > res > values > strings.xml

12. Tag - activity
<?xml version="1.0" encoding="utf-8"?>!
<manifest xmlns:android="http://schemas.android.com/apk/res/android"!
package="com.zencher.dailyrecord.app" >!
!
<application!
android:allowBackup="true" !
android:icon="@drawable/ic_launcher"!
android:label="@string/app_name"!
android:theme="@style/AppTheme" >!
<activity!
android:name="com.zencher.dailyrecord.app.RecordActivity"!
android:label="@string/app_name" >!
<intent-filter>!
<action android:name="android.intent.action.MAIN" />!
!
<category android:name="android.intent.category.LAUNCHER" />!
</intent-filter>!
</activity>!
</application>!
!
</manifest>
Class name

13. activity - android:label
<?xml version="1.0" encoding="utf-8"?>!
<manifest xmlns:android="http://schemas.android.com/apk/res/android"!
package="com.zencher.dailyrecord.app" >!
!
<application!
android:allowBackup="true" !
android:icon="@drawable/ic_launcher"!
android:label="@string/app_name"!
android:theme="@style/AppTheme" >!
<activity!
android:name="com.zencher.dailyrecord.app.RecordActivity"!
android:label="@string/app_name" >!
<intent-filter>!
<action android:name="android.intent.action.MAIN" />!
!
<category android:name="android.intent.category.LAUNCHER" />!
</intent-filter>!
</activity>!
</application>!
!
</manifest>

14. Create a new string tag

15. Run
@string/main_activity_label

16. intent-filter
<?xml version="1.0" encoding="utf-8"?>!
<manifest xmlns:android="http://schemas.android.com/apk/res/android"!
package="com.zencher.dailyrecord.app" >!
!
<application!
android:allowBackup="true" !
android:icon="@drawable/ic_launcher"!
android:label="@string/app_name"!
android:theme="@style/AppTheme" >!
<activity!
android:name="com.zencher.dailyrecord.app.RecordActivity"!
android:label="@string/app_name" >!
<intent-filter>!
<action android:name="android.intent.action.MAIN" />!
!
<category android:name="android.intent.category.LAUNCHER" />!
</intent-filter>!
</activity>!
</application>!
!
</manifest>

17. intent
Message among activities
intent-filter
filter intent event
must have a action
android.intent.action.MAIN - the initial activity
category
android.intent.category.LAUNCHER - Should be displayed in the
top-level launcher

18. Add some Control
EditText
Button

19. activity_record.xml in layout
app > src > main > res > layout > activity_record.xml
<RelativeLayout >!
!
<TextView />!
!
<EditText />!
!
<Button />!
!
</RelativeLayout>

20. Design & Text - layout xml
Design Text

21. RecordActivity.java
app > src > main > java > (domain) > RecordActivity.java
public class RecordActivity extends Activity {!
!
@Override!
protected void onCreate(Bundle savedInstanceState) {!
super.onCreate(savedInstanceState);!
setContentView(R.layout.activity_record);!
} !
! ! // ignored… !
}

22. R
Auto generated Class
files in res/ will be the field in R
app > build > source > r > debug > (domain) > R

23. layout xml in R

24. Compiling process
res/ AndroidManifest.xml R.java
Asset
Packaging Tool
(aapt)
src/
RecordActivity.java
Compile Java
Java bytecode
.classCross Compile
to Dalvik
Dalvik bytecode
.dex
Compiled
Resource
Build & Sign
apk
Android Package
.apk
Install &
Run

25. setContentView(R.layout.activity_record);
<RelativeLayout >!
!
<TextView />!
!
<EditText />!
!
<Button />!
!
</RelativeLayout>
ClassLoader.loadClass(“RelativeLayout”) RelativeLayout
ClassLoader.loadClass(“TextView”) TextView
EditText
Button
ClassLoader.loadClass(“EditText”)
ClassLoader.loadClass(“Button”)

26. Run

27. Get instance into variable

28. import class
option + Enter

29. EditText & Button

30. Get instance in Activity
findViewById()
protected void onCreate(Bundle savedInstanceState) {!
super.onCreate(savedInstanceState);!
setContentView(R.layout.activity_record);!
mTopTextView = (TextView) findViewById(R.id.textView);!
}
activity_record.xml

31. Apply into three variables

32. OnClickListener

33. View.OnClickListener
new View.OnClickListener() {!
! @Override!
! public void onClick(View v) {!
! ! mTopTextView.setText(mInputView.getText());!
! }!
}

34. Question