反射

获取有参构造和无参构造

基础类

public class Rat {

    public Rat(){
        go();
    }

    public Rat(int count){
        go(count);
    }

    private void go(int count) {
        Log.i("Rat","hello,你走了有参构造，小白鼠一共"+count+"只");
    }

    private void go() {
        Log.i("Rat","hello,你走了无参构造");
    }
}

实现：

        var rat:Rat? = null
        try {
            val clazz: Class<Rat> = Class.forName("com.yirong.myapplication.Rat") as Class<Rat>
//            rat = clazz.getDeclaredConstructor().newInstance()//获取无参构造
            rat = clazz.getDeclaredConstructor(Int::class.java).newInstance(27)//获取有参构造

        }catch (e: ClassNotFoundException){
            if (Log.isLoggable(TAG, Log.WARN)) {
                Log.w(
                    TAG, "ClassNotFound"
                )
            }
        } catch (e: InstantiationException) {
            Log.w(
                TAG, "InstantiationException"
            )
        } catch (e: IllegalAccessException) {
            Log.w(
                TAG, "IllegalAccessException"
            )
        } catch (e: NoSuchMethodException) {
            Log.w(
                TAG, "NoSuchMethodException"
            )
        } catch (e: InvocationTargetException) {
            Log.w(
                TAG, "InvocationTargetException"
            )
        }

查看日志

10:39:28.206 2207-2207/? I/Rat: hello,你走了无参构造
10:39:28.206 2207-2207/? I/Rat: hello,你走了有参构造，小白鼠一共27只