Android design mode-prototype and android Design Mode

Android design mode-prototype and android Design Mode

1. Definition:

Use a prototype instance to specify the object type and copy the prototype to create a new object.

2. Purpose:

Create another custom object from an object without any details.

3. functions:

3.1. simplified object creation;

3.2. The performance of processing large objects is much higher than that of new objects.

4. Category:

4.1 shallow copy: the basic data type in the object to be copied. It is not copied for arrays, container objects, and reference objects.

4.2 deep copy: All types are copied.

5. Note:

5.1 when an Object implements the Cloneable interface, the Object clone () method must be changed to public;

5.2 for basic data types, the encapsulation type of String does not need to be processed. They all perform deep copies.

6. Simple demo:

Shallow copy:

Package com. example. demo. prototype;/*** shallow copy * @ author qubian * @ data June 4, 2015 * @ email naibbian@163.com **/public class Prototype implements Cloneable {private int num; private String name; public int getNum () {return num;} public void setNum (int num) {this. num = num;} public String getName () {return name;} public void setName (String name) {this. name = name ;}@ Overridepublic Object clone () {Prototype prototype = null; try {prototype = (Prototype) super. clone ();} catch (CloneNotSupportedException e) {e. printStackTrace ();} return prototype ;}}

Deep copy:

Package com. example. demo. prototype; import java. util. arrayList; import java. util. vector;/*** deep copy * @ author qubian * @ data June 4, 2015 * @ email naibbian@163.com **/public class DeepPrototype implements Cloneable {private String name; private ArrayList <String> arrayList; private DeepObject deepObject; public String getName () {return name;} public void setName (String name) {this. name = name;} public ArrayList <String> getArrayList () {return arrayList;} public void setArrayList (ArrayList <String> arrayList) {this. arrayList = arrayList;} public DeepObject getDeepObject () {return deepObject;} public void setDeepObject (DeepObject deepObject) {this. deepObject = deepObject;}/*** clone method */@ SuppressWarnings ("unchecked") @ Overridepublic Object clone () {DeepPrototype prototype = null; try {prototype = (DeepPrototype) super. clone (); prototype. arrayList = (ArrayList <String>) this. arrayList. clone (); prototype. deepObject = (DeepObject) this. deepObject. clone ();} catch (CloneNotSupportedException e) {e. printStackTrace ();} return prototype;} class DeepObject implements Cloneable {String name; protected Object clone () {DeepObject deep = null; try {deep = (DeepObject) super. clone ();} catch (CloneNotSupportedException e) {e. printStackTrace () ;}return deep ;};}}

7. Application of prototype in Android:

The most obvious example is Intent, but it seems that its usage is unknown.

However, it is still a new object.

public class Intent implements Parcelable, Cloneable {    /**     * Copy constructor.     */    public Intent(Intent o) {        this.mAction = o.mAction;        this.mData = o.mData;        this.mType = o.mType;        this.mPackage = o.mPackage;        this.mComponent = o.mComponent;        this.mFlags = o.mFlags;        if (o.mCategories != null) {            this.mCategories = new ArraySet<String>(o.mCategories);        }        if (o.mExtras != null) {            this.mExtras = new Bundle(o.mExtras);        }        if (o.mSourceBounds != null) {            this.mSourceBounds = new Rect(o.mSourceBounds);        }        if (o.mSelector != null) {            this.mSelector = new Intent(o.mSelector);        }        if (o.mClipData != null) {            this.mClipData = new ClipData(o.mClipData);        }    }    @Override    public Object clone() {        return new Intent(this);    }}