【Android】IllegalArgumentException: parameter must be a descendant of this view Error

• 引言

java.lang.IllegalArgumentException: parameter must be a descendant of this view
at android.view.ViewGroup.offsetRectBetweenParentAndChild(ViewGroup.java:4153)
at android.view.ViewGroup.offsetDescendantRectToMyCoords(ViewGroup.java:4090)
at android.view.ViewRootImpl.scrollToRectOrFocus(ViewRootImpl.java:2129)
at android.view.ViewRootImpl.draw(ViewRootImpl.java:1849)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1641)
at android.view.ViewRootImpl.handleMessage(ViewRootImpl.java:2449)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:4424)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
at dalvik.system.NativeStart.main(Native Method)

当我尝试使用 Intent 或 finish（） 返回此视图时，会发生此错误;方法。当我使用 Back Button 时，偶尔也会出现问题。

这是我的解决方案：
代码实现:

mViewFlow.setDescendantFocusability(ViewGroup.FOCUS_BLOCK_DESCENDANTS);

或者:

android:descendantFocusability = afterDescendants

知识点:

他定义在查找 a 以获得焦点时 与其后代之间的关系。ViewGroup View

必须是以下常量值之一。

±-----------------------------------------------------------------------------------------+
| Constant Value Description |
±-----------------------------------------------------------------------------------------+
| afterDescendants 1 The ViewGroup will get focus only if |
| none of its descendants want it. |
±-----------------------------------------------------------------------------------------+
| beforeDescendants 0 The ViewGroup will get focus before |
| any of its descendants. |
±-----------------------------------------------------------------------------------------+
| blocksDescendants 2 The ViewGroup will block its descendants from |
| receiving focus. |
±-----------------------------------------------------------------------------------------+
您可以在此处查看完整示例。

代码段为：

public void onItemSelected(AdapterView<?> parent, View view,
        int position, long id) {
    ListView listView = getListView();
    Log.d(TAG, "onItemSelected gave us " + view.toString());
    Button b = (Button) view.findViewById(R.id.button);
    EditText et = (EditText) view.findViewById(R.id.editor);
    if (b != null || et != null) {
        // Use afterDescendants to keep ListView from getting focus
        listView.setDescendantFocusability(ViewGroup.FOCUS_AFTER_DESCENDANTS);
        if(et!=null) et.requestFocus();
        else if(b!=null) b.requestFocus();
    } else {
        if (!listView.isFocused()) {
            // Use beforeDescendants so that previous selections don't re-take focus
            listView.setDescendantFocusability(ViewGroup.FOCUS_BEFORE_DESCENDANTS);
            listView.requestFocus();
        }
    }
}

根据上面的代码片段， 用于防止获得焦点，以便 or 可以请求焦点。afterDescendants listview EditText Button