More Related Content Similar to android design pattern (20) 2. In a nutshell
MVC
MVVM
Observer
Adapter
Façade
Bridge
Factory
Template
Composition
Decorator
2
4. MVC - View
res/layout/main.xml
http://developer.android.com/resources/tutorials/views/hello-gridview.html
<?xml version="1.0" encoding="utf-8"?>
<GridView
xmlns:android="http://schemas.android.com/apk/
res/android"
android:id="@+id/gridview"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:columnWidth="90dp"
android:numColumns="auto_fit"
android:verticalSpacing="10dp"
android:horizontalSpacing="10dp"
android:stretchMode="columnWidth"
android:gravity="center"
/>
4
5. MVC - Controller
http://developer.android.com/resources/tutorials/views/hello-listview.html
HelloGridView.java
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
GridView gridview = (GridView) findViewById(R.id.gridview);
gridview.setAdapter(new ImageAdapter(this));
gridview.setOnItemClickListener(new OnItemClickListener() {
public void onItemClick(AdapterView<?> parent, View v, int
position, long id) {
Toast.makeText(HelloGridView.this, "" + position,
Toast.LENGTH_SHORT).show();
}
});
}
5
6. MVC - Model
public class ImageAdapter extends BaseAdapter {
private Context mContext;
public ImageAdapter(Context c) {
mContext = c;
}
public int getCount() {
return mThumbIds.length;
}
public Object getItem(int position) {
return null;
}
public long getItemId(int position) {
return 0;
}
// create a new ImageView for each item referenced by the
Adapter
public View getView(int position, View convertView,
ViewGroup parent) {
ImageView imageView;
if (convertView == null) { // if it's not recycled,
initialize some attributes
imageView = new ImageView(mContext);
6
7. MVC: all in one
ListActiviy
Ref:
http://www.ideasandroid.com/archives/295
http://developer.android.com/reference/android/app/ListActivity.html
7
Exercise
Write your custom GridActivity
8. Variant – MVVM
Model View ViewModel
8
Ref:
http://en.wikipedia.org/wiki/Model_View_ViewModel
http://www.codeproject.com/KB/android/androidbinding.aspx
Android Binding
9. MVVM (cont’d)
public static interfaceSimpleCursorAdapter
bindView(View view, Context context, Cursor
cursor)
ViewBinder
setViewValue(View view, Object data, String
textRepresentation)
9
Ref:
http://developer.android.com/reference/android/widget/SimpleCursorAdapter.ViewBinder.html
10. Observer
BroadCastReciever
Sensor Listener
OnClickListener
onClick
OnCreateMenuListener
onCreateContextMenu
AsyncTask
onProgressUpdate, onPostExecute
Activity lifecycle callbacks (onStart, onResume, etc.) although with
only one dedicated subscriber.
?Many observerables support only one observer, how to extend?
View.setOnClickListener(new OnClickListener())…
10
11. Observer (cont’d)
Handler
handleMessage()
sendMessage()
Single thread model v.s. Multiple thread
model
Update UI in UI thread
Looper, Handler , MessageQueue
Kill Thread
11
12. Observer (cont’d)
UI Sync:
ES 文件浏览器
ListView, GridView, etc,
Delete, add, rename file .
App alliance
App downloading
Downloading cancelled/ failed
App installed
12
13. Adapter
View
AdapterView
ExpandableListView
Gallery
GridView
ListView
Spinner
13
Data
Adapter
View
ListView
GridView
CustomView
Data Source
Content Provider
SharedPreference
Resources
SQLite
File System
14. public interfaceAdapter
abstract int getCount()
abstract Object getItem(int position)
abstract long getItemId(int position)
abstract int getItemViewType(int position)
abstract View getView(int
position, View convertView, ViewGroup parent)
abstract int getViewTypeCount()
abstract boolean hasStableIds()
abstract boolean isEmpty()
abstract void registerDataSetObserver(DataSetObserver observer)
abstract void unregisterDataSetObserver(DataSetObserver observer)
14
Adapter (cont’)
ArrayAdapter<T>
BaseAdapter
CursorAdapter
HeaderViewListAdapter
ListAdapter
ResourceCursorAdapter
SimpleAdapter
SimpleCursorAdapter
SpinnerAdapter
WrapperListAdapter
15. Façade
A facade is an object that provides a
simplified interface to a larger body of
code, such as a class library.
wrap a poorly-designed collection of APIs
with a single well-designed API (as per task
needs).
Hide Complexity
App network
ExchangeViewManager
15
17. Bridge
"decouple an abstraction from
its implementation so that the two can
vary independently“
17
Adapter
CursorAdapter
SimpleCursorAdapter
ArrayAdapter
AdapterView
AdapterViewFlipper
ExpandableListView
Gallery
18. Factory Method
Defer instantiation to subclasses
18
View
Activity
ListView
OnCreate()
ListActivity
OnCreate()
...
View= FactoryMethod()
...
return new ListView
19. Factory Method (cont’d)
View.
protected Dialog onCreateDialog(int id)
Builder
AlertDialog.Builder builder = new
AlertDialog.Builder(this);
19
22. Composition (cont’d)
View
ViewGroup
? Why does ViewGroup subclass View,
what pattern is used?
?交换的小把手有很多样式，用哪种设计模式？
22
public abstract class ViewGroup extends View implements ViewParent{
private View[] mChildren;
…
}
Reference:
GOF: Design Pattern, chap 2
