Android Button点击事件的四种实现方法

<button
    android:id="@+id/bt1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:onclick="doclick"
    android:text="xml添加doclick"
    android:layout_above="@+id/bt2"
    android:layout_marginbottom="47dp"
    />

public void doclick(view view) {
    switch (view.getid()) {
      case r.id.bt1:
        toast.maketext(mainactivity.this, "第一种点击事件：xml添加doclick", toast.length_short).show();
        break;

    }

  }

button bt2 = (button) findviewbyid(r.id.bt2);
    bt2.setonclicklistener(new view.onclicklistener() {
       @override
       public void onclick(view v) {
         toast.maketext(mainactivity.this, "第二种点击事件：匿名内部类", toast.length_short).show();
       }
     });

button bt3 = (button) findviewbyid(r.id.bt3);
     bt3.setonclicklistener(new mylistener());
class mylistener implements view.onclicklistener {
  @override
  public void onclick(view v) {
    toast.maketext(mainactivity.this, "第三种方法：自定义点击事件", toast.length_short).show();
  }
}

public class mainactivity extends appcompatactivity implements view.onclicklistener {
  @override
  protected void oncreate(bundle savedinstancestate) {
    super.oncreate(savedinstancestate);
    setcontentview(r.layout.activity_main);
 button bt4=(button)findviewbyid(r.id.bt4);
  bt4.setonclicklistener(this);
}

@override
  public void onclick(view v) {
    switch (v.getid()) {
      case r.id.bt4:
        toast.maketext(mainactivity.this,
            "第四种点击事件：activity继承view.onclicklistener，由activity实现onclick(view view)方法",
            toast.length_short).show();
    }
  }
}