How to use xmlns in Android

http://blog.csdn.net/lihenair/article/details/41009711

Custom controls are often required at work, except for keystrokes and draw, which require some initialization of the control's properties, such as margins, font size, color, and so on.

This article will implement a custom TextView based on the requirements.

1 Requirements

The font required for TextView is 30SP and the color is #ff00ffad.

For these two requirements, make the following definitions

Colors.xml

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1. <? XML version= "1.0" encoding="Utf-8"?>
2. <resources>
3. <color name="TextColor"> #FF00FFAD</color>
4. </Resources>

Dimens.xml

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2. <resources>
6. <!--Default screen margins, per the Android Design guidelines.
8. <dimen name="Activity_horizontal_margin">16dp</dimen>
10. <dimen name="Activity_vertical_margin">16dp</dimen>
14. <dimen name="text_size">30sp</dimen>
18. </Resources>

2 Defining attribute declarations

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2. <? XML version= "1.0" encoding="Utf-8"?>
4. <resources>
6. <declare-styleable name="Largetext">
8. <attr name="textsize" format="Dimension" />
10. <attr name="TextColor" format="color" />
12. </declare-styleable>
14. </Resources>

It is important to note that the definition of the Format property, format= "Reference", is typically used for strings, which means that a reference to a string is defined

3 Importing controls

With the above definition, we can add the above defined properties to the layout file.

Main.xml

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2. <relativelayout xmlns:android="http://schemas.android.com/apk/res/android"
4. xmlns:tools="Http://schemas.android.com/tools"
6. xmlns:largetext="http://schemas.android.com/apk/res/com.example.nfctest"//style of introducing custom attributes
8. android:layout_width="match_parent"
10. android:layout_height="match_parent"
12. android:paddingbottom="@dimen/activity_vertical_margin"
14. android:paddingleft="@dimen/activity_horizontal_margin"
16. android:paddingright="@dimen/activity_horizontal_margin"
18. android:paddingtop="@dimen/activity_vertical_margin"
20. tools:context=". Nfcactivity " >
24. <com.example.nfctest.LargeText android:id="@+id/state"
26. android:layout_width="wrap_content"
28. android:layout_height="wrap_content"
30. android:text="@string/hello_world"
32. largetext:textsize="@dimen/text_size"//reference custom font size
34. largetext:textcolor="@color/textcolor" />//reference Custom colors
38. </relativelayout>

Introduce custom controls to include PackageName in layout, format <package-name>.<customize-class_name>

The custom attribute style needs to be loaded in the layout or view's property column, in the format xmlns:<style-name>= "Http://schemas. android.com/apk/res/<package-name> "

The format for using custom attributes is <style-name>:<attrs-name>

4 Everything is ready, now you need to define Largetext.java

Largetext.java

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2. Package com.example.nfctest;
6. Import Android.content.Context;
8. Import Android.content.res.TypedArray;
10. Import Android.util.AttributeSet;
12. Import Android.widget.TextView;
16. Public class Largetext extends TextView {
20. Public Largetext (context context) {
22. This (context, null, 0);
24. //TODO auto-generated constructor stub
26. }
30. Public Largetext (context context, AttributeSet attrs) {
32. This (context, Attrs, 0);
34. //TODO auto-generated constructor stub
36. }
40. Public Largetext (context context, AttributeSet attrs, int defstyle) {
42. Super (context, attrs, Defstyle);
44. //TODO auto-generated constructor stub
46. TypedArray a = Context.obtainstyledattributes (Attrs, R.styleable.largetext, Defstyle, 0);
48. int textcolor = A.getcolor (R.styleable.largetext_textcolor,
50. 0XFFFFFFFF);
52. float textSize = a.getdimension (r.styleable.largetext_textsize, 36);
54. A.recycle (); //Using an array of types, you need to recycle it
56. Settextsize (textSize);
58. SetTextColor (TextColor);
60. }
64. }

With the 4 steps above, the custom TextView will display the text according to the attributes we define.

How to use xmlns in Android