Framework Basics (annotations + reflections)

Create a layout annotation class Mycontentview.java, with the following code:

@Retention (Retentionpolicy.runtime)

@Target ({elementtype.type})

Public @interface Mycontentview {

int value ();

}

Create a control callout class Myviewinject. Java with the following code:

@Retention (Retentionpolicy.runtime)

@Target (Elementtype.field)

Public @interface Myviewinject {

int value ();

}

Create a reflection class that handles annotations Myviewutils. Java with the following code:

public class Myviewutils {

//Construction Method injection Event

public static void inject (activity activity) {

injectobject (activity, new viewfinder);//methods of actually injecting objects

}

//method of Event injection object

private static void Injectobject (Object obj, viewfinder viewfinder) {

//Inject the annotation information into the actual method, implement the layout initialization, get the entity class

Class clz = Obj.getclass ();

//Get CLZ annotation information (custom annotation information)

Mycontentview Mycontentview = (mycontentview) clz.getannotation (Mycontentview.class);

//Get the actual annotations that exist

if (mycontentview! = null) {

/** layout annotations Get the XML layout **/

//Get the value of the annotation

int value = Mycontentview.value ();

//get content injected into the established method

try {

//Set the Setcontentview parameter (Getdeclaremethod cannot get the public method?)

//Setcontentview method is the way to get the XML layout

method = Clz.getmethod ("Setcontentview", new class[] {integer.type});

method.setaccessible (TRUE);//This setting means ignoring permissions and getting directly

method.invoke (obj, value);//The Setcontentview method that gets the parameter is added to the specified class

} catch (Nosuchmethodexception e) {

e.printstacktrace ();

} catch (InvocationTargetException e) {

e.printstacktrace ();

} catch (Illegalaccessexception e) {

e.printstacktrace ();

}

/** control annotations Gets the XML layout control **/

//Get information about the control and inject the content, get all the members of the field[] on the Myviewinject,

To have declared, you can access the private properties

//visible, the creation of the control must be defined as a member variable before annotations can be used

field[] fields = Clz.getdeclaredfields ();

//has member variables, and the number is not 0

if (Fields! = NULL && fields.length! = 0) {

for (int i = 0; i < fields.length; i++) {

Field field = Fields[i];

//Get information about annotations (on member variables)

Myviewinject inject = field.getannotation (Myviewinject.class);

if (inject! = null) {

//Get the actual content

int fieldvalue = Inject.value ();

//custom method get viewfinder, call Findviewbyid method, help current obj find control

View view = Viewfinder.findviewbyid (Fieldvalue);

if (view! = null) {

try {

field.setaccessible (TRUE);//Ignore access rights

field.set (obj, view);//Assign him to the field member variable

} catch (Illegalaccessexception e) {

e.printstacktrace ();

}

}

}

}

}

}

}

//Custom, to find the control

public static class viewfinder {

private activity activity;

private View view;

Public viewfinder (activity activity) {

this.activity = activity;

}

Public viewfinder (view view) {

this.view = view;

}

//ID fill in and return the actual view

public View findviewbyid (int id) {

View view = Activity.findviewbyid (ID);

return view;

}

}

}

Finally, test, test the class Testviewutilsactivity.java, the code is as follows:

@MyContentView (R.layout.activity_test_view_utils)

public class Testviewutilsactivity extends Activity {

@MyViewInject (R.id.textview_text)

Private TextView TextView;

protected void OnCreate (Bundle savedinstancestate) {

Super.oncreate (savedinstancestate);

Myviewutils.inject (this);

Textview.settext ("test data, Annotations + reflection mode");

}

}

The layout file contains only one text box, which is no longer on the code.

Framework Basics (annotations + reflections)