<style name="Dialog_Fullscreen">
<item name="android:windowFullscreen">true</item>
<item name="android:windowNoTitle">true</item>
</style>
AlertDialog shareDialog = new AlertDialog.Builder(MyGalleryActivity.this,R.style.Dialog_Fullscreen).setView(R.layout.activity_share).create();
Window shareWindow = shareDialog.getWindow();
shareWindow.setGravity(Gravity.BOTTOM);
WindowManager.LayoutParams lp = shareWindow.getAttributes();
WindowManager m = MyGalleryActivity.this.getWindowManager();
Display d = m.getDefaultDisplay(); // 获取屏幕宽、高用
lp.height = (int) (d.getHeight() * 0.6); // 高度设置为屏幕的0.6
shareWindow.setAttributes(lp);
shareDialog.show();