Android custom view implementation random verification code

For Android development, customizing the view is still an important skill, so here is an introduction to customizing the view, It is also a relatively simple function of randomly generating verification code: customizing the view is mainly divided into several steps. 1. Customizing the view properties. 2. Obtaining the custom properties in our custom layout. 3. Rewriting the onmesure method. 4. Rewriting the OnDraw method. Now let's go step by step, First, create our view attribute, create an attrs.xml file in the valuse directory, and then:

We have defined three attributes in total, one is color, content and size

Then we go to create our custom class

The above code is a custom class. It inherits view. It has three constructor methods. We need to get its properties, so we must go to the third one, but the default is the second one, so we need to call the third one in each one to ensure initialization. Note that the constructor of this is used when calling, not super. When our class comes out, The back is very simple

Just apply it in the layout, xmlns: verification = " http://schemas.android.com/apk/res-auto ”Is required, or the custom attribute cannot be found.

Well, so far, we have achieved the simplest

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The next step is to draw some scatter points and curves, and modify the OnDraw () method of our custom class

The init () method should be added to the constructor. OK, that's all. We'll just transplant it later. How about it? It's very simple

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