Builder模式的简化
1.省略Director角色，Builder定义在Product内，ConcreteBuilder定义在Product子类中。
2.省略抽象Builder角色，只剩下ConcreteBuilder和Product两个角色。
具体做法是在Procuct中定义内部类Builder并提供具体的实现。
Android中的应用
1.Android中的AlertDialog.Builder
AlertDialog.Builder builder=newAlertDialog.Builder(context);
builder.setIcon(R.drawable.icon).setTitle("标题") .setMessage("消息").setPositiveButton("取消",newDialogInterface.OnClickListener() {@Override public void onClick(DialogInterface dialog,int which){//todo} }).setNegativeButton("确定",newDialogInterface.OnClickListener() {@Override public void onClick(DialogInterface dialog,int which){//todo} });
builder.create().show();
2.OkHttp中OkHttpClient的创建
Request request = new Request.Builder().url("http://publicobject.com/helloworld.txt").build();
3.Retrofit中Retrofit对象的创建
Retrofit retrofit =newRetrofit.Builder() .client(createOkHttp()) .addConverterFactory(GsonConverterFactory.create()) .addCallAdapterFactory(RxJavaCallAdapterFactory.create()) .baseUrl(BASE_URL) .build();
示例代码
public class Product {
private String name;
private int size;
private Product(Builder builder){
this.name=builder.name;
this.size=builder.size;
}
public String getName() {return name; }
public void setName(String name) {this.name = name; }
public int getSize() {return size; }
public void setSize(int size) {this.size= size; }
static class Builder{
private String name;
private int size;
public Builder setName(String name) {
this.name=name;
return this;
}
public Builder setSize(int size) {
this.size=size;
return this;
}
public Product build(){
return new Product(this);
}
}
}
创建Product的示例：
Product productA= new Product.Builder()
.setName("产品A")
.setSize(100)
.build();
Product productB= new Product.Builder()
.setSize(200)
.setName("产品B")
.build();
