建造者模式在实际开发中的运用

通过上篇《十分钟学习建造者模式》相信大家对建造者有了一个基本的认识了，但有些人会有疑问，对于建造者模式，怎么灵活运用到项目中，有时候我也会有这样的体会，对于一个知识点或者技术，看了一遍后就觉得会了，但却不知道怎么灵活运用，才疏学浅，只是分享下自己一些微薄的见解，如有错误，还请多多留言指教。

不多说了，直奔主题，先说一个需求，在我目前手里的两个项目里面，都有大量的popupwindow，这些popupwindow都是大同小异，有的是一个按钮，有的是两个按钮，有的有标题，有的没有标题，本人比较懒，不太喜欢重复造轮子，当有同样代码多次调用的时候，我就不想拷贝了，我坚信会有更好更优雅的方式去解决，嗯，现在先看一串代码，如下：

/**
 * created by zero on 2016-08-19
 */
public class BuilderActivity extends Activity
{
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        setContentView(drawView());
    }

    // 不想写xml，就直接动态编码了
    private View drawView() {
        // TODO Auto-generated method stub
        LayoutParams layout_params = new LayoutParams(
                LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT);
        LinearLayout ll_layout = new LinearLayout(this);
        ll_layout.setOrientation(LinearLayout.VERTICAL);
        ll_layout.setLayoutParams(layout_params);

        LayoutParams btn_params = new LayoutParams(LayoutParams.WRAP_CONTENT,
                LayoutParams.WRAP_CONTENT);
        btn_params.gravity = Gravity.CENTER_HORIZONTAL;
        Button btn1 = new Button(this);
        btn1.setLayoutParams(btn_params);
        btn1.setText("click1");
        btn1.setOnClickListener(new OnClickListener()
        {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                new CommonPopup.Builder(BuilderActivity.this)
                        .setContent("真的要删除历史记录吗？").setRightText("确定")
                        .setListenRight(new IListenRightCallBack()
                        {

                            @Override
                            public void rightListen() {
                                // TODO Auto-generated method stub
                                Toast.makeText(BuilderActivity.this, "right1",
                                        Toast.LENGTH_LONG).show();
                            }
                        }).build().showPopup();
            }
        });

        Button btn2 = new Button(this);
        btn2.setLayoutParams(btn_params);
        btn2.setText("click2");
        btn2.setOnClickListener(new OnClickListener()
        {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                new CommonPopup.Builder(BuilderActivity.this)
                        .setTitle("提示")
                        .setContent("真的要删除历史记录吗？")
                        .setLeftText("取消")
                        .setListenLeft(new IListenLeftCallBack()
                        {

                            @Override
                            public void leftListen() {
                                // TODO Auto-generated method stub
                                Toast.makeText(BuilderActivity.this, "left2",
                                        Toast.LENGTH_LONG).show();
                            }
                        }).setRightText("确定")
                        .setListenRight(new IListenRightCallBack()
                        {

                            @Override
                            public void rightListen() {
                                // TODO Auto-generated method stub
                                Toast.makeText(BuilderActivity.this, "right2",
                                        Toast.LENGTH_LONG).show();
                            }
                        }).build().showPopup();
            }
        });

        ll_layout.addView(btn1);
        ll_layout.addView(btn2);
        return ll_layout;
    }
}

建造者

/**
 * 
 * created by zero on 2016-08-19
 * 
 * 通过建造者模式构建一个popupwindow
 *
 */
public class CommonPopup extends PopupWindow
{
    private final Context context;
    private final String title;
    private final String content;
    private final IListenLeftCallBack iListenLeft;
    private final IListenRightCallBack iListenRight;
    private final String leftText;
    private final String rightText;

    public static class Builder{

        private final Context context;
        private String title;
        private String content;
        private IListenLeftCallBack iListenLeft;
        private IListenRightCallBack iListenRight;
        private String leftText;
        private String rightText;

        public Builder(Context context)
        {
            this.context = context;
        }

        public Builder setTitle(String title){
            this.title = title;
            return this;
        }

        public Builder setContent(String content){
            this.content = content;
            return this;
        }

        public Builder setListenLeft(IListenLeftCallBack iListenLeft){
            this.iListenLeft = iListenLeft;
            return this;
        }

        public Builder setLeftText(String leftText){
            this.leftText = leftText;
            return this;
        }

        public Builder setListenRight(IListenRightCallBack iListenRight){
            this.iListenRight = iListenRight;
            return this;
        }

        public Builder setRightText(String rightText){
            this.rightText = rightText;
            return this;
        }

        public CommonPopup build(){
            return new CommonPopup(this);
        }

    }

    public CommonPopup(Builder builder)
    {
        this.context = builder.context;
        this.title = builder.title;
        this.content = builder.content;
        this.iListenLeft = builder.iListenLeft;
        this.iListenRight = builder.iListenRight;
        this.leftText = builder.leftText;
        this.rightText = builder.rightText;
        initPopup();
    }

    private PopupWindow popupWindow;
    private View popView;
    private TextView txt_title;
    private TextView txt_info;

    private void initPopup(){
        popView = LayoutInflater.from(context).inflate(R.layout.popup_common_view, null);
        DisplayMetrics dm = new DisplayMetrics();
        WindowManager windowManager = (WindowManager) context
                .getSystemService(Context.WINDOW_SERVICE);
        windowManager.getDefaultDisplay().getMetrics(dm);
        popupWindow = new PopupWindow(popView, dm.widthPixels, dm.heightPixels);
        popupWindow.setFocusable(true);
        popupWindow.setOutsideTouchable(true);
        popupWindow.setBackgroundDrawable(new BitmapDrawable());
        txt_title = (TextView) popView.findViewById(R.id.txt_title);
        if(TextUtils.isEmpty(title)){
            txt_title.setVisibility(View.GONE);
        }else{
            txt_title.setText(title);
        }
        txt_info = (TextView) popView.findViewById(R.id.txt_info);
        if(TextUtils.isEmpty(content)){
            txt_info.setVisibility(View.GONE);
        }else{
            txt_info.setText(content);
        }
        Button btn_right = (Button) popView.findViewById(R.id.btn_right);
        if(!TextUtils.isEmpty(rightText)){
            btn_right.setText(rightText);
            btn_right.setOnClickListener(new OnClickListener()
            {

                @Override
                public void onClick(View v) {
                    // TODO Auto-generated method stub
                    popupWindow.dismiss();
                    if(iListenRight!=null){
                        iListenRight.rightListen();
                    }
                }
            });
        }else{
            btn_right.setVisibility(View.GONE);
        }
        Button btn_left = (Button) popView.findViewById(R.id.btn_left);
        if(!TextUtils.isEmpty(leftText)){
            btn_left.setText(leftText);
            btn_left.setOnClickListener(new OnClickListener()
            {

                @Override
                public void onClick(View v) {
                    // TODO Auto-generated method stub
                    popupWindow.dismiss();
                    if(iListenLeft!=null){
                        iListenLeft.leftListen();
                    }
                }
            });
        }else{
            btn_left.setVisibility(View.GONE);
        }
    }

    public void showPopup(){
        if(popupWindow==null){
            initPopup();
        }
        popupWindow.showAtLocation(popView, 0, 0, 0);
    }
}

接口类

public interface IListenLeftCallBack
{
    void leftListen();
}

public interface IListenRightCallBack
{
    void rightListen();
}

方便点击按钮后接收回调，可以在左右键做自己想要的操作。

看了这些代码，是不是瞬间想到了AlertDialog，对于很多教程讲到builder的时候，都是用AlertDialog，这也确实是builder模式的典型案例，但是有时候一些比较复杂的页面，AlertDialog还是实现不了，我们还是需要popupwindow去实现，就比如以下的popupwindow

在我们的那个产品里面，这个类似效果的popupwindow还有很多，有的也是两个按钮，有的也有标题。。。

上述是对建造者模式的简单使用，下一篇会再进一步讲解建造者模式，敬请期待，O(∩_∩)O哈哈~