View關(guān)于坐標(biāo)方法系列

相對(duì)坐標(biāo)系列

MotionEvent 系列方法

• e.getX()/e.getY()

  /**
   * Returns the X coordinate of this event for the given pointer
   * <em>index</em> (use {@link #getPointerId(int)} to find the pointer
   * identifier for this index).
   * Whole numbers are pixels; the 
   * value may have a fraction for input devices that are sub-pixel precise. 
   * @param pointerIndex Raw index of pointer to retrieve.  Value may be from 0
   * (the first pointer that is down) to {@link #getPointerCount()}-1.
   *
   * @see #AXIS_X
   */
  

  觸摸點(diǎn)相對(duì)于View自身的X,Y坐標(biāo)偏移量。

View 系列方法

• view.getTop()/getLeft()/getRight()/getBottom()

  /**
   * Left position of this view relative to its parent.
   *
   * @return The left edge of this view, in pixels.
   */
  

  得到的坐標(biāo)是view相對(duì)于其父容器的坐標(biāo),也即是view在父容器中的繪制區(qū)域。實(shí)際上right-left 與bottom-top正好是view的width與height

  以父容器的左上角為坐標(biāo)原點(diǎn)

  具體測(cè)試代碼結(jié)果下文有貼入勒虾，這里簡(jiǎn)單描述一下結(jié)果脖卖。

  revenueLayout的top為100罐脊，恰好是其相對(duì)父容器的一個(gè)margin值炕婶；tvProfit的top為15兜蠕，恰好是其父容器revenueLayout的padding大小蝎毡。

• view.getTranslationX()/getTranslationY()

  /**
   * The vertical location of this view relative to its {@link #getTop() top} position.
   * This position is post-layout, in addition to wherever the object's
   * layout placed it.
   *
   * @return The vertical position of this view relative to its top position,
   * in pixels.
   */
  

  得到的值是其相對(duì)于初始的left or top 的平移距離厚柳，，這個(gè)與屬性動(dòng)畫(huà)中的translation設(shè)置有關(guān)系

絕對(duì)坐標(biāo)系列

以屏幕的左上角為坐標(biāo)原點(diǎn)

View系列方法

• view.getLocationInWindow(@Size(2) int[] outLocation)

  /**
   * <p>Computes the coordinates of this view in its window. The argument
   * must be an array of two integers. After the method returns, the array
   * contains the x and y location in that order.</p>
   *
   * @param outLocation an array of two integers in which to hold the coordinates
   */
  

  獲取當(dāng)前view在Window中的坐標(biāo)沐兵，也即是window的絕對(duì)坐標(biāo)

• view.getLocationOnScreen(@Size(2) int[] outLocation)

  /**
   * <p>Computes the coordinates of this view on the screen. The argument
   * must be an array of two integers. After the method returns, the array
   * contains the x and y location in that order.</p>
   *
   * @param outLocation an array of two integers in which to hold the coordinates
   */
  

  與getLocationInWindow()的返回相同别垮，下面的測(cè)試結(jié)果中也驗(yàn)證了是相同。具體是不是存在特殊的差異扎谎，還未發(fā)現(xiàn)

• view.getGlobalVisibleRect(Rect r)/getGlobalVisibleRect(Rect r, Point globalOffset)

  /**
   * If some part of this view is not clipped by any of its parents, then
   * return that area in r in global (root) coordinates. To convert r to local
   * coordinates (without taking possible View rotations into account), offset
   * it by -globalOffset (e.g. r.offset(-globalOffset.x, -globalOffset.y)).
   * If the view is completely clipped or translated out, return false.
   *
   * @param r If true is returned, r holds the global coordinates of the
   *        visible portion of this view.
   * @param globalOffset If true is returned, globalOffset holds the dx,dy
   *        between this view and its root. globalOffet may be null.
   * @return true if r is non-empty (i.e. part of the view is visible at the
   *         root level.
   */
  

  獲取當(dāng)前view在絕對(duì)坐標(biāo)系中的rect對(duì)象碳想，也即是繪制區(qū)域的絕對(duì)坐標(biāo)邊界。

MotionEvent 系列方法

• e.getRawX()/e.getRawY()

  /**
   * Returns the original raw X coordinate of this event.  For touch
   * events on the screen, this is the original location of the event
   * on the screen, before it had been adjusted for the containing window
   * and views.
   *
   * @see #getX(int)
   * @see #AXIS_X
   */
  

  觸摸點(diǎn)相對(duì)于屏幕原點(diǎn)的x,y坐標(biāo)毁靶。

測(cè)試案例

機(jī)型信息如下：

device_info.png

布局文件View位置

<RelativeLayout
    android:layout_marginTop="100px"
    android:id="@+id/revenue_layout"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:padding="15px">

    <TextView
        android:id="@+id/tv_balance"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="余額：0 元"
        android:textSize="12dp" />

    <TextView
        android:id="@+id/tv_profit"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentRight="true"
        android:text="據(jù)歷史收益可得：0.00 元"
        android:textSize="12dp" />

</RelativeLayout>

預(yù)覽截圖如下：

xml_preview.png

onResume()中執(zhí)行結(jié)果：

location_onresume.png

onResume中并沒(méi)有獲取到View坐標(biāo)信息

onWindowFocusChanged()中執(zhí)行結(jié)果：

activity 應(yīng)用全屏主題（NoTitle）

location_notitle.png

activity 為應(yīng)用全屏主題（有actionbar）

location_actionbar.png

從上述兩個(gè)運(yùn)行結(jié)果來(lái)看胧奔，getLocationInWindow()與getLocationOnScreen()并未存在差異。

其中tvBalance的position [15,169]老充，Y坐標(biāo)169是100（revenueLayout的margin）+15（revenueLayout的padding）+54（狀態(tài)欄status bar的高度葡盗，此值是反推出來(lái)的）。由此就可以看出獲取的確實(shí)是View的絕對(duì)坐標(biāo)啡浊。

而對(duì)于應(yīng)用非全屏（NoTitle）主題的結(jié)果觅够，position [15,337],恰好就是多出了一個(gè)actionbar的高度，即337-169 = 168巷嚣。而168恰好滿(mǎn)足56*3（density）,這里就看到了喘先，在系統(tǒng)默認(rèn)的配置下當(dāng)前的屏幕寬度下，actionbar的高度為56dp,當(dāng)前的density恰好是3.0廷粒，而換算成px就是168窘拯。到了這里红且，整個(gè)測(cè)試結(jié)果就完全驗(yàn)證了，上述方法的解釋涤姊。

備注：

• View的坐標(biāo)體系在OnCreate()中還未進(jìn)行初始化暇番，所以onCreate中無(wú)法獲取View的相關(guān)坐標(biāo)，都是return 0思喊；
• View的坐標(biāo)在onWindowFocusChanged(true)時(shí)壁酬，才會(huì)初始化完畢，故在此方法的回調(diào)是獲取View坐標(biāo)的最佳之處恨课。
• 由于onResume與onWindowFocusChanged的調(diào)用時(shí)機(jī)的不同舆乔，在第一次執(zhí)行onResume時(shí)也無(wú)法直接獲取到View的坐標(biāo)。

參考

• Android視圖坐標(biāo)體系總結(jié)
• Android MotionEvent詳解