基本概念：

1. 构建者模式的定义
   将构建的过程和表示过程进行分离
   构建的过程：隐藏
   表示过程 ： 开放
2. 构建者模式的场景
   创建一个复杂的对象，同时改复杂对象有很多默认值（初始化）的时候，可以使用构建者模式。（典型：给对象设置可选参数）
3. 构建者模式案例
   AlretDialog
4. 构建者模式-UML类图结构
   4.1 分析角色划分
   角色一：产品
   角色二：抽象构建者
   角色三：具体构建者
   角色四：组装

 public class ComListDialog extends Dialog {
            public static Context mContext;
            private TextView btnCancel;
            private LinearLayout lyContents;
             private static List<CommonListMenuItem> btnMenu;
          public ComListDialog(@NonNull Context context) {
        super(context, R.style.common_dialog);
    }
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        Window win = getWindow();
        win.getDecorView().setPadding(0, 0, 0, 0);
        WindowManager.LayoutParams lp = win.getAttributes();
        lp.width = WindowManager.LayoutParams.MATCH_PARENT;
        lp.height = WindowManager.LayoutParams.MATCH_PARENT;

        win.setWindowAnimations(R.style.listDialogWindowAnim);

        win.setAttributes(lp);

        setContentView(R.layout.common_list_dialog);
        setCanceledOnTouchOutside(true);
        setCancelable(true);

        findViewById(R.id.menu_base_content).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                dismiss();
            }
        });
        btnCancel = (TextView) findViewById(R.id.menu_cancel);
        btnCancel.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                dismiss();
            }
        });

        lyContents = (LinearLayout) findViewById(R.id.menu_content);
        if (btnMenu != null && btnMenu.size() > 0) {
            for (int i = 0; i < btnMenu.size(); i++) {
                View v = View.inflate(mContext, R.layout.common_list_dialog_item, null);
                if (i == 0) {
                    v.findViewById(R.id.menu_line).setVisibility(View.GONE);
                }
                TextView tv = (TextView) v.findViewById(R.id.menu_button);
                tv.setText(btnMenu.get(i).getName());
                tv.setTextColor(btnMenu.get(i).color);
                tv.setPadding(20, 0, 20, 0);
                tv.setGravity(Gravity.CENTER);
                if (btnMenu.get(i).textsize != 0) {
                    tv.setTextSize(TypedValue.COMPLEX_UNIT_SP, btnMenu.get(i).textsize);
                }
                tv.setOnClickListener(btnMenu.get(i).getClickListener());
                lyContents.addView(v);
            }
        }
    }

    //  类似于Javabean
    public static class CommonListMenuItem {
        private String name;
        private View.OnClickListener clickListener;
        private int color = Color.parseColor("#209E89");
        private int textsize = 0;

        public CommonListMenuItem(String name, View.OnClickListener clickListener, int color) {
            this.name = name;
            this.clickListener = clickListener;
            this.color = color;
        }

        public CommonListMenuItem(String name, View.OnClickListener clickListener, int color, int textsize) {
            this.name = name;
            this.clickListener = clickListener;
            this.color = color;
            this.textsize = textsize;
        }

        public CommonListMenuItem(String name, int color, int textsize) {
            this.name = name;
            this.color = color;
            this.textsize = textsize;
        }

        public CommonListMenuItem(String name, View.OnClickListener clickListener) {
            this.name = name;
            this.clickListener = clickListener;
        }

        public String getName() {
            return name;
        }

        public void setName(String name) {
            this.name = name;
        }

        public View.OnClickListener getClickListener() {
            return clickListener;
        }

        public void setClickListener(View.OnClickListener clickListener) {
            this.clickListener = clickListener;
        }
    }

    //构建
    public static class Builder {

        public Builder(Context context) {
            mContext = context;
            btnMenu = new ArrayList<CommonListMenuItem>();
        }

        public Builder addMenuItem(CommonListMenuItem item) {
            btnMenu.add(item);
            return this;
        }

        public ComListDialog show() {
            if (null != mContext && (!(mContext instanceof Activity) || !((Activity) mContext).isFinishing())) {
                ComListDialog dialog = new ComListDialog(mContext);
                dialog.show();
                return dialog;
            }
            return null;
        }
    }

    @Override
    public void dismiss() {
        super.dismiss();
        btnMenu = null;
        mContext = null;
    }
}

5F54B8A8-BB9A-4123-95F4-F6C3E9400AB7.png

demo下载地址