Android rewrite view and custom attribute instance analysis _android

The example in this article analyzes the way that Android overrides view and customizes attributes. Share to everyone for your reference, specific as follows:

This is achieved by customizing the properties shown in the following illustration:

First step: Create a new file in the Res\values directory Attrs.xml

Declaring some custom properties

<?xml version= "1.0" encoding= "Utf-8"?>
<resources>
  <declare-styleable name= " Customviewstyle ">
    <attr name=" CustomText format= "string"/>
    <attr "Name=" format= "Color"/>
    <attr name= "customtextsize" format= "Dimension"/>
  </declare-styleable>
</resources>

Step Two: Create a new layout file in the layout directory Activity_main.xml

Pay special attention to adding this declaration to the outer control:

Format: xmlns: (your custom name) = "http://schemas.android.com/apk/(name of package you apply)"

Xmlns:xr= "Http://schemas.android.com/apk/res/com.rong.test"

Or

Xmlns:xr= "Http://schemas.android.com/apk/res-auto"

Recommended use of the second

Add these custom properties to the layout file:

<?xml version= "1.0" encoding= "Utf-8"?> <relativelayout xmlns:android=
"http://schemas.android.com/apk" /res/android "
  xmlns:xr=" http://schemas.android.com/apk/res/com.rong.test "
  android:layout_width=" Match_ Parent "
  android:layout_height=" match_parent "
  android:background=" @android: Color/black "
  android:o rientation= "vertical" >
  <com.rong.activity.customview
    android:layout_width= "300DP"
    android: layout_height= "300DP"
    android:layout_centerinparent= "true"
    android:background= "#ff0000"
    XR: customtext= "Custom Control"
    xr:customtextcolor= "#000000"
    xr:customtextsize= "40sp"/>
</ Relativelayout>

Part III inheritance View rewrite

Package com.rong.activity;
Import COM.RONG.TEST.R;
Import Android.content.Context;
Import Android.content.res.TypedArray;
Import Android.graphics.Canvas;
Import Android.graphics.Color;
Import Android.graphics.Paint;
Import Android.graphics.Rect;
Import Android.util.AttributeSet;
Import Android.view.View; /** * Custom Control * * @author Xu Rong * */public class CustomView extends View {/** * custom brushes/Private Paint Mpaint
  ;
  /** * Text range * * Private Rect mbounds;
  /** * Custom text/private String customtext;
  /** * Custom Size * * Private int customtextsize;
  /** * Custom color/private int customtextcolor;
    Public CustomView (context, AttributeSet attrs) {Super (context, attrs);
    TypedArray TypedArray = context.obtainstyledattributes (Attrs, R.styleable.customviewstyle);
    Gets the custom text CustomText = typedarray.getstring (R.styleable.customviewstyle_customtext); Get custom Text Size customtextsize = typedarray.getdimensionpixelsize (r.styleable.custoMviewstyle_customtextsize, 28);
    or custom text color Customtextcolor = Typedarray.getcolor (R.styleable.customviewstyle_customtextcolor, Color.WHITE);
    To recycle this TypedArray object Typedarray.recycle ();
  Initview ();
    public void Initview () {//init brush mpaint = new Paint ();
    Mpaint.setantialias (TRUE);
    Mpaint.setstyle (Paint.Style.FILL);
    Mpaint.setcolor (Customtextcolor);
    Mpaint.settextsize (customtextsize);
  Generate text Area mbounds = new Rect ();
    } @Override protected void OnDraw (Canvas Canvas) {Super.ondraw (Canvas);
    Get text display area Mbounds mpaint.gettextbounds (customtext, 0, Customtext.length (), mbounds);
    Center text wide = width of the control/2-width of text/2 float helfwidth = getwidth ()/2-mbounds.width ()/2;
    Make text High center = width of Control/2 + text width/2 float helfheight = getheight ()/2+mbounds.height ()/2;
  Draw Text Canvas.drawtext (CustomText, Helfwidth, Helfheight, Mpaint);

 }
}

Run!

More interested readers of Android-related content can view the site's topics: Introduction to Android Development and advanced tutorials, the summary of Android basic components usage, the overview of Android View View techniques, the Android Layout layout skills Summary, and A summary of the usage of Android controls

I hope this article will help you with the Android program.