"Android own definition control" define the View property yourself

1. Define the properties of your view

2. Get our own defined properties in the view's construction method

3. Rewrite onmesure

4. Rewrite OnDraw

3 This step is not necessary, of course, most of the cases still need to be rewritten.

1, you define the properties of the view, first set up a attrs.xml under res/values/, in which we define our properties and declare our entire style.

<?xml version= "1.0" encoding= "Utf-8"?><resources>    <attr name= "txtname" format= "string"/>    <attr name= "txtcolor" format= "color"/> <attr name=    "txtsize" format= "Dimension"/>        < Declare-styleable name= "TitleStyle" >        <attr name= "txtname"/> <attr        name= "Txtcolor"/>        <attr name= "Txtsize"/>    </declare-styleable></resources>

Defines the font, font color, font size 3 properties, format is the value type of the property:

A common ownership: String,color,demension,integer,enum,reference,float,boolean,fraction,flag;

When you write the tool will remind you to use which, do not know also can Google search under

Next, define the view yourself.

public class Customtitleview extends view{    private  String txtname;    private int txtcolor,txtsize;    Private  Paint Mpaint;    Private Rect mbounds;    Public Customtitleview (Context context) {This        (context, NULL);    }    Public Customtitleview (context context, AttributeSet attrs) {This        (context, attrs, 0);    }    Public Customtitleview (context context, AttributeSet attrs, int defstyleattr) {           //detailed operation    }}

When you define your own view, it is time to call our own definition of view.

<?xml version= "1.0" encoding= "Utf-8"? ><relativelayout xmlns:android= "http://schemas.android.com/apk/res/ Android "    xmlns:title=" Http://schemas.android.com/apk/res/com.example.androidDemo "" "    Android:o rientation= "vertical" android:layout_width= "match_parent"    android:layout_height= "match_parent" >    < Com.example.androidDemo.View.CustomTitleView        android:layout_width= "wrap_content"        android:layout_height = "Wrap_content"        android:layout_centerhorizontal= "true"        android:layout_centervertical= "true"        android:padding= "5DP"        title:txtname= "Hello"        title:txtcolor= "#ffffff"        title:txtsize= "16SP"/>< /relativelayout>

Note This line in the code, define the namespace yourself, Com.example.androidDemo is the project package path

Xmlns:title= "Http://schemas.android.com/apk/res/com.example.androidDemo"

To define a namespace with yourself:

        Title:txtname= "Hello"        title:txtcolor= "#ffffff"        title:txtsize= "16SP"

In the construction method of the view, get our own defined style

public class Customtitleview extends view{private String txtname;    private int txtcolor,txtsize;    Private Paint Mpaint;    Private Rect mbounds;    Public Customtitleview (Context context) {This (context, NULL);    } public Customtitleview (context context, AttributeSet Attrs) {This (context, attrs, 0); } public Customtitleview (context context, AttributeSet attrs, int defstyleattr) {Super (context, Attrs, Defstyle        ATTR);        TypedArray TypedArray = Context.gettheme (). Obtainstyledattributes (attrs,r.styleable.titlestyle,defstyleattr,0);        int n = typedarray.getindexcount ();            for (int i = 0; i < n; i++) {int attr = Typedarray.getindex (i);                    Switch (attr) {Case 0:txtname = typedarray.getstring (attr);                Break                    Case 1:txtcolor = Typedarray.getcolor (attr, Color.Black);                Break                  Case 2:  Txtsize = Typedarray.getdimensionpixelsize (attr, (int) typedvalue.applydimension (typedvalue.                    COMPLEX_UNIT_SP, Getresources () getdisplaymetrics ());            Break        }} typedarray.recycle ();        /** * Get the width and height of the drawn text */mpaint = new paint ();        Mpaint.settextsize (txtsize);        Mpaint.setcolor (Mtitletextcolor);        Mbounds = new Rect ();    Mpaint.gettextbounds (txtname, 0, Txtname.length (), mbounds); } @Override protected void onmeasure (int widthmeasurespec, int heightmeasurespec) {int widthmode = Measu            Respec.getmode (WIDTHMEASURESPEC);            int widthsize = measurespec.getsize (Widthmeasurespec);            int heightmode = Measurespec.getmode (Heightmeasurespec);            int heightsize = measurespec.getsize (Heightmeasurespec);            int width;            int height; if (Widthmode = = measurespec.exactly) {width =Widthsize;                } else {mpaint.settextsize (txtsize);                Mpaint.gettextbounds (txtname, 0, Txtname.length (), mbounds);                float textWidth = Mbounds.width ();                int desired = (int) (Getpaddingleft () + TextWidth + getpaddingright ());            width = desired;            } if (Heightmode = = measurespec.exactly) {height = heightsize;                } else {mpaint.settextsize (txtsize);                Mpaint.gettextbounds (txtname, 0, Txtname.length (), mbounds);                float textHeight = Mbounds.height ();                int desired = (int) (Getpaddingtop () + TextHeight + getpaddingbottom ());            height = desired;    } setmeasureddimension (width, height);        } @Override protected void OnDraw (canvas canvas) {mpaint.setcolor (color.yellow); Canvas.drawrect (0, 0, getmeasuredwidth (), Getmeasuredheight (), MpaiNT);        Mpaint.setcolor (Txtcolor);    Canvas.drawtext (Txtname, getwidth ()/2-mbounds.width ()/2, GetHeight ()/2 + mbounds.height ()/2, mpaint); }}

Of

measurespec.exactly infer the width and height of your descendants is not an exact assignment.

Android:layout_width= "Wrap_content"
android:layout_height= "Wrap_content"

Assuming it's wrap_content,

Mpaint.settextsize (txtsize);                Mpaint.gettextbounds (txtname, 0, Txtname.length (), mbounds);                float textWidth = Mbounds.width ();                int desired = (int) (Getpaddingleft () + TextWidth + getpaddingright ());                width = desired;

The assumption is that the exact width and height values of 200DP

if (Widthmode = = measurespec.exactly)            {                width = widthsize;            

, is it very useful?

"Android own definition control" define the View property yourself