The implementation principles and optimization strategies of Android SUPPORT CARDVIEW V7 framework in the Java library

The implementation principles and optimization strategies of Android SUPPORT CARDVIEW V7 framework in the Java library Introduction: Android Support Library is a compatible and extended development library set for Google for different versions of Android.Among them, the CardView V7 framework provides developers with a simple and flexible card view control that can quickly implement the card -type layout in the APP.This article will focus on the implementation principles and optimization strategies of the CardView V7 framework in the Java class library, and provide the corresponding Java code example. 1. Implementation principle: 1. CardView V7 framework is based on the expansion of the View control. It mainly achieves the effect of card -type layout through custom attributes and drawing strategies. 2. The implementation principle in the Java library is as follows: a. Inheritance from the ViewGroup class: CardView as a card view control, inherited from the ViewGroup class, can contain sub -views, and layout and draw sub -view. b. Custom attributes: CardView uses custom attributes, such as the corner radius and shadow effect of the card to display different card styles. c. Background drawing: CardView can achieve the card effect by drawing the background, which can draw a rectangle with a rounded corner and add shadow.The drawing background can be implemented in the ONDRAW () method. d. Sub -view diagram: CardView is rewritten DispatchDraw () method to draw its own background, and then draw a sub -view.This can ensure that the sub -view is drawn on the background. e. Click Event processing: CardView can be handled by clicking the event by rewriting the ontouchevent () method, such as the click effect, the transmission of the event. 2. Optimization strategy: 1. Use hardware acceleration: In order to improve the drawing performance of CardView, the hardware acceleration can be enabled in the code, and the hardware acceleration type of the View is specified through the setlayertype () method. if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) { setLayerType(View.LAYER_TYPE_HARDWARE, null); } 2. Avoid frequent background drawing: In CardView, background drawing is a time -consuming operation. You can set up the background cache to avoid repeated drawing background. setWillNotDraw(false); setDrawingCacheEnabled(true); 3. Use the mask layer to replace the shadow effect: CardView's shadow drawing may have a great impact on performance. You can consider using the mask layer to replace shadow drawing to improve performance. 4. Optimize click Event processing: In CardView, the handling of the incident may lead to a stuttering phenomenon. You can optimize the logic of the clicks of the clicks by reasonable handling and consumption of the click event. @Override public boolean onTouchEvent(MotionEvent event) { // Treat the click event // ... return super.onTouchEvent(event); } Summarize: This article introduces the implementation principles and optimization strategies of Android Support Cardview V7 framework in the Java library.The CardView V7 framework inherits the ViewGroup class, custom attributes and drawing strategies, and achieve the effect of card -type layout.In terms of optimization, strategies such as hardware acceleration, background cache, mask layer replace shadow effects, and optimize click event processing and other strategies to improve CardView's performance and user experience. (Note: The example of the Java code provided in this article is only the example code, and the specific implementation is written according to the actual situation.)