Android advanced tutorial (3) ---- Android custom View application

Hello everyone, our tutorial is to customize the View in the Android tutorial. For Beginners, they are used to the traditional page layout method of Android, as shown in the following code:

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<? Xml version = "1.0" encoding = "UTF-8"?>
<LinearLayout xmlns: android = "http://schemas.android.com/apk/res/android"
Android: orientation = "vertical"
Android: layout_width = "fill_parent"
Android: layout_height = "fill_parent"
>
<TextView
Android: layout_width = "fill_parent"
Android: layout_height = "wrap_content"
Android: text = "@ string/hello"
/>
</LinearLayout>

Of course, the layout method above can help us develop simple applications, but if you want to write a complex application, it will be a little far-fetched. If you don't believe it, you can study the source code, the layout of high handwriting is usually written as follows:

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<? Xml version = "1.0" encoding = "UTF-8"?>
<A>
<B> </B>
</A>

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A extends LinerLayout and B extends TextView.

To help you better understand it, I wrote a simple Demo. The specific steps are as follows:

First, create an Android project named ViewDemo.

Then customize a View class named MyView (extends View). The Code is as follows:

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Package com. android. tutor;
Import android. content. Context;
Import android. graphics. Canvas;
Import android. graphics. Color;
Import android. graphics. Paint;
Import android. graphics. Rect;
Import android. graphics. Paint. Style;
Import android. util. AttributeSet;
Import android. view. View;
Public class MyView extends View {
Private Paint mPaint;
Private Context mContext;
Private static final String mString = "Welcome to Mr Weis blog ";

Public MyView (Context context ){
Super (context );

}
Public MyView (Context context, AttributeSet attr)
{
Super (context, attr );

}
@ Override
Protected void onDraw (Canvas canvas ){
// TODO Auto-generated method stub
Super. onDraw (canvas );

MPaint = new Paint ();

// Set the paint brush color
MPaint. setColor (Color. RED );
// Set Filling
MPaint. setStyle (Style. FILL );

// 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.
Canvas. drawRect (new Rect (10, 10,100,100), mPaint );

MPaint. setColor (Color. BLUE );
// Draw text
Canvas. drawText (mString, 10,110, mPaint );
}
}

Add the custom View to the main. xml layout file. The Code is as follows:

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<? Xml version = "1.0" encoding = "UTF-8"?>
<LinearLayout xmlns: android = "http://schemas.android.com/apk/res/android"
Android: orientation = "vertical"
Android: layout_width = "fill_parent"
Android: layout_height = "fill_parent"
>
<TextView
Android: layout_width = "fill_parent"
Android: layout_height = "wrap_content"
Android: text = "@ string/hello"
/>
<Com. android. tutor. MyView
Android: layout_width = "fill_parent"
Android: layout_height = "fill_parent"
/>
</LinearLayout>

The final execution result is as follows:

 

OK, it's all done. I wrote it here today and started cooking. My wife and children waited for me to cook, lol ~