Android中RelativeLayout的字符水平（垂直居中）對齊

【背景】

此處Android中顯示出來的TextView中的內容，水平中間不對其。

想要實現水平居中對齊。

【折騰過程】

1.搜：

android RelativeLayout horizontal center

參考：

android – TextView horizontal center in RelativeLayout – Stack Overflow

試過了：

android:layout_centerHorizontal="true"

但沒用。

2.后來看到：

relativelayout – Android Relative Layout Align Center – Stack Overflow

去試了試：

android:layout_centerVertical="true"

才明白：

我上面是錯誤的搜了horizontal ，實際上該去搜Vertical才對。

現在效果是所需要的了：

【總結】

想要水平居中對齊，則只需要去設置：

android:layout_centerVertical="true"

即可。

【引申】

更多的其他參數，可以去官網：

RelativeLayout.LayoutParams | Android Developers

中找到：

Attribute Name	Related Method	Description
android:layout_above	Positions the bottom edge of this view above the given anchor view ID.
android:layout_alignBaseline	Positions the baseline of this view on the baseline of the given anchor view ID.
android:layout_alignBottom	Makes the bottom edge of this view match the bottom edge of the given anchor view ID.
android:layout_alignEnd	Makes the end edge of this view match the end edge of the given anchor view ID.
android:layout_alignLeft	Makes the left edge of this view match the left edge of the given anchor view ID.
android:layout_alignParentBottom	If true, makes the bottom edge of this view match the bottom edge of the parent.
android:layout_alignParentEnd	If true, makes the end edge of this view match the end edge of the parent.
android:layout_alignParentLeft	If true, makes the left edge of this view match the left edge of the parent.
android:layout_alignParentRight	If true, makes the right edge of this view match the right edge of the parent.
android:layout_alignParentStart	If true, makes the start edge of this view match the start edge of the parent.
android:layout_alignParentTop	If true, makes the top edge of this view match the top edge of the parent.
android:layout_alignRight	Makes the right edge of this view match the right edge of the given anchor view ID.
android:layout_alignStart	Makes the start edge of this view match the start edge of the given anchor view ID.
android:layout_alignTop	Makes the top edge of this view match the top edge of the given anchor view ID.
android:layout_alignWithParentIfMissing	If set to true, the parent will be used as the anchor when the anchor cannot be be found for layout_toLeftOf, layout_toRightOf, etc.
android:layout_below	Positions the top edge of this view below the given anchor view ID.
android:layout_centerHorizontal	If true, centers this child horizontally within its parent.
android:layout_centerInParent	If true, centers this child horizontally and vertically within its parent.
android:layout_centerVertical	If true, centers this child vertically within its parent.
android:layout_toEndOf	Positions the start edge of this view to the end of the given anchor view ID.
android:layout_toLeftOf	Positions the right edge of this view to the left of the given anchor view ID.
android:layout_toRightOf	Positions the left edge of this view to the right of the given anchor view ID.
android:layout_toStartOf	Positions the end edge of this view to the start of the given anchor view ID.

至於每個都是什么效果，就可以自己去多試試就知道了。