activity 窗口样式 继承@android:style/Theme.Dialog ,

Window win = this.getWindow();
win.getDecorView().setPadding(0, 0, 0, 0);
WindowManager.LayoutParams lp = win.getAttributes();
lp.width = WindowManager.LayoutParams.MATCH_PARENT;
lp.height = WindowManager.LayoutParams.WRAP_CONTENT;
lp.gravity = Gravity.TOP;//设置对话框置顶显示
win.setAttributes(lp);

activity 窗口样式