1.edittext增加长度限制

app/src/main/res/layout/activity_main.xml

                 android:layout_width="100dp"
                 android:layout_height="100dp"
                 android:text="管理页面"
-                android:visibility="visible" />
+                android:visibility="gone" />
 
 
             <LinearLayout
                     android:paddingLeft="28dp"
                     android:paddingRight="28dp"
                     android:singleLine="true"
+                    android:maxLength="20"
                     android:textColor="@color/codetipscolor"
                     android:textColorHint="@color/codehintcolor"
                     android:textSize="16sp" />