Android Selector detailed (background selector)

Definition: A drawable object defined in XML that can change different pictures for the same shape depending on the state. For example, there can be several different states (pressed,focused or other) for a button control, and you can use the state list to set the button's background image for each of these states.

the location of the XML: Android Selector is configured in the res/drawable/



tags and properties:android:constantsizeThis is a Boolean, false indicates the sizes (size) of each state are different, true all the states in the table have the same size (whichever is the largest). default is False
android:dither Boolean type. True indicates that if a bitmap in a screen has this different pixel configuration,enable jitter for bitmaps. False indicates that the bitmap is not enabled for jitter. According to degree Niang: dither, jitter, is a deliberate cause of noise used to randomize the quantization error, to prevent the large lifting of the image caused by the like banding (ribbon) such problems.  
android:variablepadding   The inner margin of the drawable will vary depending on the state of the default = False  
android:enterfadeduration/android:exitfadeduration drawable has multiple states, you can define the fade before it is displayed.
in the Item tab, we can configure several properties:
Green font: Focus

Android:drawable	Specify resource
Android:state_pressed	Boolean value. True refers to the state of the control when the user taps or touches it. Default is False
android:state_focused	Boolean value. Ture refers to the state of the current control when it receives focus. The default is False
android:state_hovered	Boolean value. True indicates that the cursor is moved to the state on the current control. The default is False
android:state_selected	Boolean value. True indicates the selected state, such as selecting one of the options under the arrow keys in a drop-down list.
android:state_checkable	Boolean value. Ture indicates the status that can be checked. This only works if the control has transitions between the checked and unchecked states.
android:state_checked	Boolean value. True indicates that the current control is checked (check's status)
android:state_enabled	Boolean value. True indicates that the current control is out of available state. For example, you can be clicked
android:state_activated	Boolean value. True indicates the state of the current control being activated.
android:state_window_focused	Boolean value. True indicates that the application window obtains the state of focus when the current control is out of the front.

Android Selector detailed (background selector)