Activity設置為對話框屬性時（Theme.Dialog）時，改變其在屏幕中的位置

原帖http://stackoverflow.com/questions/2163427/android-dialog-activity-position

如果有需要要將Activity變成一個窗口形式（在Manifest.xml中的activity標簽設置android:theme="@android:style/Theme.Dialog" 屬性），默認Activity窗口彈出是在屏幕的正中央。通過覆寫Activity中onAttachedToWindow()方法，在期中將DecorView的參數重設一下就可以指定其顯示的位置了。

@Override
public void onAttachedToWindow() {
    super.onAttachedToWindow();

    View view = getWindow().getDecorView();
    WindowManager.LayoutParams lp = (WindowManager.LayoutParams) view.getLayoutParams();
    lp.gravity = Gravity.LEFT | Gravity.TOP;
    lp.x = 10;
    lp.y = 10;
    lp.width = 300;
    lp.height = 300;
    getWindowManager().updateViewLayout(view, lp);
}

lp.x , lp.y , lp.width ,lp.height的具體值可以定義到res/values/dimens.xml中，方便以后修改。

@Override
    public void onAttachedToWindow() {
        // 設置本Activity在父窗口的位置
        super.onAttachedToWindow();
        View view = getWindow().getDecorView();
        WindowManager.LayoutParams lp = (WindowManager.LayoutParams) view
                .getLayoutParams();
        lp.gravity = Gravity.RIGHT | Gravity.BOTTOM;
        lp.x = getResources().getDimensionPixelSize(
                R.dimen.playqueue_dialog_marginright);
        lp.y = getResources().getDimensionPixelSize(
                R.dimen.playqueue_dialog_marginbottom);
        lp.width = getResources().getDimensionPixelSize(
                R.dimen.playqueue_dialog_width);
        lp.height = getResources().getDimensionPixelSize(
                R.dimen.playqueue_dialog_height);
        getWindowManager().updateViewLayout(view, lp);
    }

 <resources>
 <dimen name="playqueue_dialog_marginright">0dp</dimen>
    <dimen name="playqueue_dialog_marginbottom">60dp</dimen>
    <dimen name="playqueue_dialog_width">250dp</dimen>
    <dimen name="playqueue_dialog_height">380dp</dimen>
    <dimen name="playqueue_dialog_select_item_from_top">90dp</dimen>
</resources>