Add custom controls for Android Widgets

First, let's look at a reference:

Aremoteviews object (and, consequently, an app widget) can support thefollowing layout classes:

* Framelayout

* Linearlayout

* Relativelayout

 

Andthe following widget classes:

 

* Analogclock

* Button

* Chronometer

* Imagebutton

* Imageview

* Progressbar

* Textview

Descendantsof these classes are not supported.

 

We can see Widget Only the following controls can be used: Analogclock ,Button ,Chronometer ,Imagebutton ,Mageview ,Progressbar ,Textview This 7 Type, Listview , Editview , Scrollview These commonly used controls cannot be found in our Widget . In fact, the source code of all the controls is Framework/base/CORE/Java/Android/widget In this directory 7 Controls are available because @ Remoteview Here, we can look at the source code:

 
Analogclock. Java: 39: @ remoteview

Analogclock. java-40-publicclass analogclockExtendsView {


Imagebutton. Java: 66: @ remoteview

Imagebutton. java-67-publicclass imagebuttonExtendsImageview {
 

.....

 

So we want Widget Such Listview For such controls , You need to write Listview Identical class , Add @ Remoteview Tag , And copy Framework/base/CORE/Java/Android/widget Under this directory.

Then we canWidgetUse the control we wrote in, because it has the same@ RemoteviewTag,Then he can beRemoteviewThe object is recognized.

 

Now that we know the principle, you can follow the steps below to implementAnalogclockFor example ):

 

 

 

1.First, I copiedAnalogclock. JavaName itMyclock. JavaToFramework/base/CORE/Java/Android/widgetUnder this directory, and then modified as neededCode.

 

 

2.ThisMyclock. JavaResource files used must be stored inFrameworks/base/CORE/RES/ResDirectory. It must be referenced in this way:Com. Android. Internal. R. drawable .*

However, changing resources is not convenient. We know that each system control hasStyleFile, so my approach is:

 

 

First look at the system'sAnalogclock. JavaOfStyleSource file:

Frameworks/base/CORE/RES/values/attrs. xml:

<Declare-styleableName= "Analogclock">

<!-Save some code->

<Attrname= "Hand_minute"Format= "Reference"/>

</Declare-styleable>
 

 

 Private Drawable mminutehand;

Public Myclock (context, attributeset attrs, intdefstyle ){

 Super (Context, attrs, defstyle );

Resources r = context. getresources ();


Typedarray A = context. obtainstyledattributes (attrs, Com. Android. Internal. R. styleable. analogclock, defstyle, 0 );

Mminutehand = A. getdrawable (COM. Android. Internal. R. styleable. analogclock_hand_minute ); //  The parameters in attrs. XML are called.  
 

 If (Mminutehand =Null ){

Mminutehand = R. getdrawable (COM. Android. Internal. R. drawable. clock_hand_minute ); //  In this example, resources under the frameworks/base/CORE/RES directory are called.  
 
}


}

On my ownWidgetIs defined in the layout configuration file:

<Myclock

Xmlns: Android= "Http://schemas.android.com/apk/res/android"

Android: ID= "@ + ID/rl_widget_clockview"

<! -Save some code->

Android: hand_minute = "@ drawable/minute_white" // reference resources under local drawable

Android: layout_width = "80dp"

Android: layout_height = "80dp"

/>
 

.. I also tested the source code repeatedly.

 

 

3. at this time, most of the work has been completed, we need to compile the entire SDK . However, note that I have encountered various compilation errors during compilation, and the prompts are unknown , this is very confusing. I finally come up with a very high success rate compilation method.

first in the root directory make-j4 compile the entire pure source code (do not add any classes and resources defined by ourselves), about 1-2 after compilation, copy the custom classes and resources to framework bottom, again in the root directory make-j4 compile.

To test the added code, runEmulatorCommand to start a new simulator, and then install ourAPK.

Basically, I have already reached the conclusion. I may have missed some trivial issues. I can discuss them with you.