Android：PopupWindow

1、概述

一、構造方法

部分經常使用：

PopupWindow(View contentView, int width, int height)
Create a new non focusable popup window which can display the contentView.
PopupWindow(View contentView, int width, int height, boolean focusable)
Create a new popup window which can display the contentView.

contentView爲要顯示的view，width和height爲寬和高，值爲像素值，也能夠是MATCHT_PARENT和WRAP_CONTENT。

focusable爲是否能夠得到焦點，也能夠經過set方法設置：

// Changes the focusability of the popup window
setFocusable(boolean focusable)

根據網上的資料，focusable參數的主要做用是：

若是focusable爲false，在一個Activity彈出一個PopupWindow，按返回鍵，因爲PopupWindow沒有焦點，會直接退出Activity。若是focusable爲true，PopupWindow彈出後，全部的觸屏和物理按鍵都由PopupWindow處理。

若是PopupWindow中有Editor的話，focusable要爲true。

 

2、初始化PopupWindow

/**
 * 初始化rightPopupWindow
 */
private PopupWindow initPopupWindow() {

	LayoutInflater inflater = LayoutInflater.from(this);
	View popView = inflater.inflate(R.layout.popupwindow_content, null);
	TextView item = (TextView) popView.findViewById(R.id.text_item);
		
	// 建立PopupWindow
	final PopupWindow popupWindow = createPopupWindow(popView);

	popView.setOnTouchListener(new View.OnTouchListener() {
		@Override
		public boolean onTouch(View v, MotionEvent event) {
			if (rightPop != null && rightPop.isShowing()) {
				popupWindow.dismiss();
			}
			return true;
		}
	});

	item.setOnClickListener(new View.OnClickListener() {
		@Override
		public void onClick(View v) {
			popupWindow.dismiss();
			// ...
		}
	});
		
	return popupWindow;
} 

3、建立一個PopupWindow

/**
 * 建立PopupWindow
 * 
 * @param popView
 *            指定PopupWindow的內容
 */
private PopupWindow createPopupWindow(View popView) {

	PopupWindow popupInstance = new PopupWindow(popView, LayoutParams.MATCH_PARENT,
			LayoutParams.MATCH_PARENT);
	popupInstance.setFocusable(true);
	popupInstance.setBackgroundDrawable(new ColorDrawable(0));
	popupInstance.setOutsideTouchable(true);
	// 監聽器
	popupInstance.setOnDismissListener(new PopupWindow.OnDismissListener() {
		@Override
		public void onDismiss() {
			// ...
		}
	});

	return popupInstance;
}

4、顯示

 例如一個button，點擊該按鈕，顯示popupWindow，而且要求popupWindow顯示在該按鈕下面，則

btn.setOnClickListener(new View.OnClickListener() {
	@Override
	public void onClick(View v) {
		PopupWindow popupWindow = ...;
		popupWindow.showAsDropDown(v);
	}
});

另外，還支持指定位+置偏移量顯示：

public void showAsDropDown(View anchor, int xoff, int yoff);

 

public void showAtLocation (View parent, int gravity, int x, int y)

Display the content view in a popup window at the specified location. If the popup window cannot fit on screen, it will be clipped. See WindowManager.LayoutParams for more information on how gravity and the x and y parameters are related. Specifying a gravity of NO_GRAVITY is similar to specifying Gravity.LEFT | Gravity.TOP.

Parameters
parent	a parent view to get the getWindowToken() token from
gravity	the gravity which controls the placement of the popup window
x	the popup's x location offset
y	the popup's y location offset

5、popupWindow顯示優化

    一、動畫效果

     例如顯示的時候，從底部出現或者從頂部出現等，能夠添加自定義動畫效果。

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android" >

    <translate
        android:duration="250"
        android:fromYDelta="100.0%"
        android:toYDelta="0.0" />

</set>

 

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android" >

    <translate
        android:duration="250"
        android:fromYDelta="0.0"
        android:toYDelta="100%" />

</set>

    二、其餘效果

     默認的popupWindow顯示的時候，是沒有像Dialog那樣的背景變成灰色半透明效果的。能夠本身添加相似Dialog或ios那樣的效果。

    例如，設置popupWindow的顯示內容的佈局文件的background屬性爲灰色半透明顏色，而後popupWindow在建立的時候指定寬、高屬性爲MATCH_PARENT便可實現除了popupWindow之外區域變成灰色半透明效果。

    固然，這個灰色區域，其實也屬於popupWindow，只是沒有真正的內容。這時候若是須要設置點擊popupWindow之外區域讓它自動消失的話，就須要額外處理。由於點擊灰色部分，你仍然點擊的是popupWindow自己。

    一種方法是給popupWindow的整個佈局區域添加onTouch事件監聽器，手動讓popupWindow去dismiss()掉。