優點:靈活,減少xml的編寫。
用途:動態設置Button、ImageView等組件在不同狀態下的背景/前景顯示效果。
參考:
[AndroidOpenSource]\frameworks\base\core\java\android\view\view.xml
[AndroidOpenSource]\frameworks\base\core\res\res\values\public.xml
代碼如下:
- /** 設置Selector。 */
- public static StateListDrawable newSelector(Context context, int idNormal, int idPressed, int idFocused,
- int idUnable) {
- StateListDrawable bg = new StateListDrawable();
- Drawable normal = idNormal == -1 ? null : context.getResources().getDrawable(idNormal);
- Drawable pressed = idPressed == -1 ? null : context.getResources().getDrawable(idPressed);
- Drawable focused = idFocused == -1 ? null : context.getResources().getDrawable(idFocused);
- Drawable unable = idUnable == -1 ? null : context.getResources().getDrawable(idUnable);
- // View.PRESSED_ENABLED_STATE_SET
- bg.addState(new int[] { android.R.attr.state_pressed, android.R.attr.state_enabled }, pressed);
- // View.ENABLED_FOCUSED_STATE_SET
- bg.addState(new int[] { android.R.attr.state_enabled, android.R.attr.state_focused }, focused);
- // View.ENABLED_STATE_SET
- bg.addState(new int[] { android.R.attr.state_enabled }, normal);
- // View.FOCUSED_STATE_SET
- bg.addState(new int[] { android.R.attr.state_focused }, focused);
- // View.WINDOW_FOCUSED_STATE_SET
- bg.addState(new int[] { android.R.attr.state_window_focused }, unable);
- // View.EMPTY_STATE_SET
- bg.addState(new int[] {}, normal);
- return bg;
- }