子控件无法获取焦点

在开发中，时常会碰到作为列表 Item 的复杂组合控件，这个时候，如果碰到 Item 无法获取 Focus，不能响应事件的情况（比如：ListView 的 Item 不能响应 onItenClick）时，有如下两种方法解决：

1、可以在 Item 的根布局上添加代码：
android:descendantFocusability="blocksDescendant"
2、如果不嫌麻烦的话，也可以通过单独给每个子控件设置 focusable 属性为 false 的方式解决。

总之，列表里面出现复杂的Item，导致列表事件或者Item事件不正常时，都可以尝试 方法1。

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ViewGroup 的源码片段：

/*** This view will get focus before any of its descendants.*/
public static final int FOCUS_BEFORE_DESCENDANTS = 0×20000;
/*** This view will get focus only if none of its descendants want it.*/
public static final int FOCUS_AFTER_DESCENDANTS = 0×40000;
/*** This view will block any of its descendants from getting focus, even if they are focusable.*/
public static final int FOCUS_BLOCK_DESCENDANTS = 0×60000;
/*** This view will get focus before any of its descendants.*/
public static final int FOCUS_BEFORE_DESCENDANTS = 0×20000;
/*** This view will get focus only if none of its descendants want it.*/
public static final int FOCUS_AFTER_DESCENDANTS = 0×40000;
/*** This view will block any of its descendants from getting focus, even if they are focusable.*/
public static final int FOCUS_BLOCK_DESCENDANTS = 0×60000;