This is the sixth day of my participation in the August More text Challenge. For details, see:August is more challenging

Recently, while preparing for the interview, the blogger began to review the knowledge related to the custom view. It happened that a junior in primary school encountered a problem that he could not get the custom value in the process of writing the custom view, so he wrote an article.

Project Scenario:

The Android custom View sets the color in the layout

Problem description:

Attrs. XML file

        <attr name="leftcolor" format="color"/>
        <attr name="rightcolor" format="color"/>
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Java file code to get the color

       int  leftcolor=attrs.getAttributeIntValue("http://schemas.android.com/apk/res-auto","leftcolor",Color.BLACK);
       int  rightcolor=attrs.getAttributeIntValue("http://schemas.android.com/apk/res-auto","rightcolor",Color.WHITE);
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In the layout file

       app:leftcolor="@color/colorPrimary"
       app:rightcolor="#ff0000"
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Rightcolor can get the color, and left can’t get the color. (Write #ff0000 to get it)

Problem analysis:

After writing a Demo, found that there is indeed a similar problem, the blogger tried several ways to solve, so later choose to see the Android source control, the solution is as follows

Solution:

/ / attrs. XML file
        <attr name="leftcolor" format="reference|color"/>
        <attr name="rightcolor" format="reference|color"/>
// Java file --TaiJiView for custom view name
        // Get custom attributes.
        TypedArray ta = context.obtainStyledAttributes(attrs, R.styleable.TaiJiView);
        // Get the color
        int  leftcolor = ta.getColor(R.styleable.TaiJiView_leftcolor, Color.BLACK);
        int  rightcolor=ta.getColor(R.styleable.TaiJiView_rightcolor, Color.WHITE);
        / / recycling
        ta.recycle();
/ / in the layout
        app:leftcolor="@color/colorPrimary"
        app:rightcolor="#ff0000"
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Extensions: Common types of attribute values

Format supports 11 types:
  • 1. Reference: Indicates the ID of a resource.
  • 2. Color: Color value.
  • 3. Boolean: Boolean value.
  • 4. Dimension: size value.
  • 5. Float: float value.
  • 6. Integer: Indicates an integer value.
  • 7. String: a string.
  • The number of children is a fraction.
  • 9. Enum: indicates the enum value.
  • 10. Flag: bit or operation.
  • 11. Mixed types: Multiple types of values can be specified when a property is defined.
format = "reference|color"
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