In the Java class library, use Android Support Library custom view steps in detail
Steps to customize views with Android Support Library:
1. Introduce dependency library
In the built.gradle file of the project, add the following dependencies to introduce Android Support Library:
gradle
implementation 'com.android.support:appcompat-v7:28.0.0'
2. Create a custom view class
Create a new Java class and inherit the AppCompatimageView or AppCompattextView class.These classes are supporting backward view components provided by Android Support Library.
For example, create a customized ImageView:
public class CustomImageView extends AppCompatImageView {
// Add custom attributes and methods
}
3. Implement the structural method
Implement the structure method in a custom view class.At least need to implement a constructor with a Context parameter.This parameter is used to pass the Context object to the parent class when the view instantiated.
For example, to implement a customized imageView constructor:
public CustomImageView(Context context) {
super(context);
// Further initialization
}
4. Implement other methods and functions required
In a custom view class, other methods and functions that other required methods and functions can be implemented according to the needs.For example, you can add custom attributes, handle clicks, and rewrite drawing methods.
For example, add a custom attribute:
private int customAttribute;
public void setCustomAttribute(int value) {
customAttribute = value;
}
public int getCustomAttribute() {
return customAttribute;
}
5. Use a custom view in the layout file
In the XML layout file, you can use a custom view like other views.Just specify the complete class name as a label.
For example, using custom ImageView:
<com.example.app.CustomImageView
android:id="@+id/custom_image_view"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="@drawable/image"
app:customAttribute="123" />
6. Use a custom view in the code
In the Java code, you can use a custom view like an ordinary view.You can obtain instances through the FindViewByid method and call the corresponding method and attributes.
For example, using custom ImageView:
CustomImageView customImageView = findViewById(R.id.custom_image_view);
customImageView.setCustomAttribute(456);
In this way, you can use Android Support Library to create a custom view component.
Note: The above steps are a basic process, and the actual demand may be different.
