Use of custom attributes (ATTR. XML, typedarray) in Android!

From: http://blog.csdn.net/android_tutor/article/details/5508615

InXMLWe are used to defining the properties of controls in the file.Android: attrs = ""Can we define our own attributes, for example:Test: attrs = ""What about it? The answer is yes.

 

Well, I will not turn to the topic. I will go directly to the topic. Perform the following steps:

 

I,InRes/ValuesFile definesAttrs. xmlFile. The Code is as follows:

 

 

[Java]
View plaincopy

1. 1. Define an attrs. xml file under the Res/values file. The Code is as follows:
2. <? XML version = "1.0" encoding = "UTF-8"?>
3. <Resources>
4. <Declare-styleable name = "myview">
5. <ATTR name = "textcolor" format = "color"/>
6. <ATTR name = "textsize" format = "dimension"/>
7. </Declare-styleable>
8. </Resources>

 

 

II,InMyview. JavaThe code is modified as follows. The following constructor is the focus, and we get the defined attributes.R. sytleable. myview_textcolor,The default value (Float textsize = A. getdimension (R. styleable. myview_textsize,
36 );),Prevent us fromXMLFile is not defined. Use the default value!

Get,MyviewIs defined in<Declare-styleable name = "myview"> </declare-styleable>To obtain the attributes.Name_attributeConnect.TypedarrayUsually the last call. Recycle ()To maintain the consistency of future use of this attribute!

 

[Java]
View plaincopy

1. Public myview (context, attributeset attrs)
2. {
3. Super (context, attrs );
4. Mpaint = new paint ();
6. Typedarray A = context. obtainstyledattributes (attrs,
7. R. styleable. myview );
9. Int textcolor = A. getcolor (R. styleable. myview_textcolor,
10. 0 xffffffff );
11. Float textsize = A. getdimension (R. styleable. myview_textsize, 36 );
13. Mpaint. settextsize (textsize );
14. Mpaint. setcolor (textcolor );
16. A. Recycle ();
17. }

 

Myview. JavaThe Code is as follows:

 

[Java]
View plaincopy

1. Package com. Android. tutor;
2. Import Android. content. context;
3. Import Android. content. res. typedarray;
4. Import Android. Graphics. Canvas;
5. Import Android. Graphics. color;
6. Import Android. Graphics. paint;
7. Import Android. Graphics. rect;
8. Import Android. Graphics. Paint. style;
9. Import Android. util. attributeset;
10. Import Android. View. view;
11. Public class myview extends view {
12. Private paint mpaint;
13. Private context mcontext;
14. Private Static final string mstring = "welcome to Mr Wei's blog ";
16. Public myview (context ){
17. Super (context );
18. Mpaint = new paint ();
19. }
20. Public myview (context, attributeset attrs)
21. {
22. Super (context, attrs );
23. Mpaint = new paint ();
25. Typedarray A = context. obtainstyledattributes (attrs,
26. R. styleable. myview );
28. Int textcolor = A. getcolor (R. styleable. myview_textcolor,
29. 0 xffffffff );
30. Float textsize = A. getdimension (R. styleable. myview_textsize, 36 );
32. Mpaint. settextsize (textsize );
33. Mpaint. setcolor (textcolor );
35. A. Recycle ();
36. }
37. @ Override
38. Protected void ondraw (canvas ){
39. // Todo auto-generated method stub
40. Super. ondraw (canvas );
41. // Set Filling
42. Mpaint. setstyle (style. Fill );
44. // Draw a rectangle. The first two are the coordinates in the upper left corner of the rectangle, and the last two are the coordinates in the lower right corner.
45. Canvas. drawrect (New rect (10, 10,100,100), mpaint );
47. Mpaint. setcolor (color. Blue );
48. // Draw text
49. Canvas. drawtext (mstring, 10,110, mpaint );
50. }
51. }

 

3. DefineMyviewAdd LayoutMain. xmlFile, and use custom properties, the custom properties must be added:

Xmlns: test = "http://schemas.android.com/apk/res/com.android.tutor"BlueIs the prefix of custom attributes,RedIs our package name.

Main. xmlThe Code is as follows:

 

[Java]
View plaincopy

1. <? XML
2. Version = "1.0" encoding = "UTF-8"?>
3. <Linearlayout
4. Xmlns: Android = "http://schemas.android.com/apk/res/android"
6. Xmlns: test = "http://schemas.android.com/apk/res/com.android.tutor"
7. Android: Orientation = "vertical"
8. Android: layout_width = "fill_parent"
9. Android: layout_height = "fill_parent"
10. >
11. <Textview
12. Android: layout_width = "fill_parent"
13. Android: layout_height = "wrap_content"
14. Android: text = "@ string/hello"
15. />
16. <Com. Android. Tutor. myview
17. Android: layout_width = "fill_parent"
18. Android: layout_height = "fill_parent"
19. Test: textsize = "20px"
20. Test: textcolor = "# fff"
21. />
22. </Linearlayout>

 

4. The running effect is as follows: