方法一：指定按钮功能

  1）Activity_main.xml增加两个按钮：

  <Button

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:id="@+id/button1"

        android:onClick="onClick"

        android:text="Button1"/>

  <Button

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:id="@+id/button2"

        android:onClick="onClick"

        android:text="Button2"

        android:layout_marginStart="55dp"

        android:layout_alignParentTop="true"

        android:layout_toEndOf="@+id/button1"/>

  2）修改string.xml

  <string name="button1">button1</string>

  <string name="button2">button2</string>

  3）修改MainActivity.java，增加如下内容

  Toast tst;

  public void onClick(View view){

    switch (view.getId()){

        case R.id.button1:

            tst=Toast.makeText(this,"button1",Toast.LENGTH_SHORT);

            tst.show();

            break;

        case R.id.button2:

            tst=Toast.makeText(this,"button2",Toast.LENGTH_SHORT);

            tst.show();

            break;

        default:break;

    }

  }

  总结：这种方法是在xml文件中指定按钮的onclick属性，这样点击按钮就会利用反射的方式调用对应Activity中的onClick方法

方法二：自定义事件

  1）增加onClick()方法

  public void onClick(View view) {

            switch (view.getId()){

                case R.id.button1:

                   tst=Toast.makeText(MainActivity.this,"button1",Toast.LENGTH_SHORT);

                    tst.show();

                    break;

                case R.id.button2:

                   tst=Toast.makeText(MainActivity.this,"button2",Toast.LENGTH_SHORT);

                    tst.show();

                    break;

                default:break;

        }

  2）在onCreate方法中调用onClick方法

  btn1=(Button)findViewById(R.id.button1);

  btn2=(Button)findViewById(R.id.button2);

  btn1.setOnClickListener(new clickListener());

  btn2.setOnClickListener(new clickListener());

方法三：

  1）重写onClick方法

  public void onClick(View view){

    switch (view.getId()){

        case R.id.button1:

            tst=Toast.makeText(MainActivity.this,"button1",Toast.LENGTH_SHORT);

            tst.show();

            break;

        case R.id.button2:

            tst=Toast.makeText(MainActivity.this,"button2",Toast.LENGTH_SHORT);

            tst.show();

            break;

        default:break;

    }

  }

  2）修改onCreate方法

  btn1=(Button)findViewById(R.id.button1);

  btn2=(Button)findViewById(R.id.button2);

  btn1.setOnClickListener(this);

  btn2.setOnClickListener(this);

  总结：Activity继承View.OnClickListener，由Activity实现OnClick(View view)方法，在OnClick(View view)方法中用switch-case对不同id代表的button进行相应的处理