设计模式-创建型-构建者模式设计模式-创建型-构建者模式

基本概念：

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
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）
构建者模式案例
AlretDialog
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 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(); }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; } }