我們自定義Dialog的時候，都會繼承系統dialog的樣式Theme.Dialog ,如圖所示，系統的樣式中給dialog添加了padding,即使你設定成全屏顯示還是會有padding

<item name="listPreferredItemPaddingLeft">10dip</item>
<item name="listPreferredItemPaddingRight">10dip</item>
<item name="listPreferredItemPaddingStart">10dip</item>
<item 
 
name="listPreferredItemPaddingEnd">10dip</item>

Window win = dialog.getWindow();
win.getDecorView().setPadding(0, 0, 0, 0);
WindowManager.LayoutParams lp = win.getAttributes();
lp.width = 700;
lp.height = WindowManager.LayoutParams.MATCH_PARENT;
win.setGravity(Gravity.RIGHT);
win.setAttributes(lp);
dialog.show();