在使用EditText的XML 文件中加入一个属性：
android:textCursorDrawable="@null"
android:textCursorDrawable 这个属性是用来控制光标颜色的，
"@null" 是作用是让光标颜色和text color一样
android:textCursorDrawable 的用法可以查看android sdk
public static final int TextView_textCursorDrawable
Reference to a drawable that will be drawn under the insertion cursor.
Must be a reference to another resource, in the form "@[+][package:]type:name" or to a theme attribute in the form "?[package:][type:]name".
This corresponds to the global attribute resource symbol textCursorDrawable.