Android 我可以用生成器模式创建抽象片段类吗?
我制作了一些扩展topFragment类的片段。但是它有可变的参数——自定义侦听器、一些模型等等Android 我可以用生成器模式创建抽象片段类吗?,android,android-fragments,builder-pattern,Android,Android Fragments,Builder Pattern,我制作了一些扩展topFragment类的片段。但是它有可变的参数——自定义侦听器、一些模型等等 public abstract class TopFragment extend Fragment { public interface OnCustomListener { void onCustomListener(); } protected OnCustomListener onCustomListener; protected int imp
public abstract class TopFragment extend Fragment {
public interface OnCustomListener {
void onCustomListener();
}
protected OnCustomListener onCustomListener;
protected int importantValue;
protected String importantString;
protected abstract void doSomething();
public static class Builder() {
protected OnCustomListener onCustomListener;
protected int importantValue;
protected String importantString;
public Builder(OnCustomListener onCustomListener) {
this.onCustomListener = onCustomListener;
}
public Builder setValue(int value) {
this.importantValue = value;
return this;
}
public Builder setString(String value) {
this.importantString = value;
return this;
}
}
}
这是第二个片段类
public class SecondFragment extend TopFragment {
@Override
protected void doSomething() {
// do something.
}
}
public class ThirdFragment extend TopFragment {
@Override
protected void doSomething() {
// do something.
}
}
TopFragment fragment=newsecondfragment()代码>
它起作用了。那么如何使用生成器创建继承片段类的实例呢?类的外部环境的实现绑定到生成器
,它有一个私有的构造函数
,该构造函数以生成器
对象作为参数,例如
public class ThirdFragment extend TopFragment {
@Override
protected void doSomething() {
// do something.
}
private ThirdFragment(Builder builder) {
// use the members of builder to build your object
}
}
而Builder
本身有一个调用该构造函数的build()
方法。例如
public ThirdFragment build() {
return new ThirdFragment(this);
}
现在Fragment
既不能有私有构造函数,也不能有接受参数的构造函数,因此不能真正使用Builder
模式