View setEnabled(false) 影响力

最新推荐文章于 2025-08-14 10:00:05 发布

原创最新推荐文章于 2025-08-14 10:00:05 发布 · 5.8k 阅读

1 ·

CC 4.0 BY-SA版权

文章标签：

#android

Android 同时被 2 个专栏收录

522 篇文章

订阅专栏

交互

54 篇文章

订阅专栏

探讨了在特定场景下，视图设置为不可用时如何影响按键事件和触摸事件的处理过程，揭示了在视图被禁用时，如何通过判断视图标志位来屏蔽这些事件，并解释了其背后的原理。

@RemotableViewMethod
	public void setEnabled(boolean enabled) {
		if (enabled == isEnabled()) return;

		setFlags(enabled ? ENABLED : DISABLED, ENABLED_MASK);

		/*
		 * The View most likely has to change its appearance, so refresh
		 * the drawable state.
		 */
		refreshDrawableState();

		// Invalidate too, since the default behavior for views is to be
		// be drawn at 50% alpha rather than to change the drawable.
		invalidate(true);

		if (!enabled) {
			cancelPendingInputEvents();
		}
	}

可以看到setEnable(false) 将View的flag打上了DISABLED.

public boolean onKeyDown(int keyCode, KeyEvent event) {
..............................................................

		if (KeyEvent.isConfirmKey(keyCode)) {
			if ((mViewFlags & ENABLED_MASK) == DISABLED) {
				return true;
			}
...................................................................
	}

	public boolean onKeyUp(int keyCode, KeyEvent event) {
		if (KeyEvent.isConfirmKey(keyCode)) {
			if ((mViewFlags & ENABLED_MASK) == DISABLED) {
				return true;
			}
...................................................................
	}

	private boolean isHoverable() {
.................................................................
		if ((viewFlags & ENABLED_MASK) == DISABLED) {
			return false;
		}
....................................................................
	}

public boolean onTouchEvent(MotionEvent event) {
		final int viewFlags = mViewFlags;

		if ((viewFlags & ENABLED_MASK) == DISABLED) {
			if (event.getAction() == MotionEvent.ACTION_UP && (mPrivateFlags & PFLAG_PRESSED) != 0) {
				setPressed(false);
			}
............................................................
}

可以看到，Enable false 把key event和 touch event都屏蔽掉了。