android點滴21：No Activity found to handle Intent

        在實現startActiivity(intent)方法時，提示No Activity found to handle Intent。這時只要在Androidmainfest.xml中實現startActiivity(intent)的Activity屬性裏添加語句

<category android:name="android.intent.category.DEFAULT"/>

便可！官網給出的具體的解釋是(待翻譯)：

For an intent to pass the category test, every category in the Intent object must match a category in the filter. The filter can list additional categories, but it cannot omit any that are in the intent.
In principle, therefore, an Intent object with no categories should always pass this test, regardless of what's in the filter. That's mostly true. However, with one exception, Android treats all implicit intents passed to startActivity() as if they contained at least one category: "android.intent.category.DEFAULT" (the CATEGORY_DEFAULT constant). Therefore, activities that are willing to receive implicit intents must include "android.intent.category.DEFAULT" in their intent filters. (Filters with "android.intent.action.MAIN" and "android.intent.category.LAUNCHER" settings are the exception. They mark activities that begin new tasks and that are represented on the launcher screen. They can include "android.intent.category.DEFAULT" in the list of categories, but don't need to.) See Using intent matching, later, for more on these filters.)