Android studio button 按钮 四种绑定事件的方法

package com.geli_2.sujie.sujiegeili2testbutton;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;
public class MainActivity extends AppCompatActivity implements View.OnClickListener
{
  private Button mBtClick;
  private Button mBtClick2;
  private Button mBtClick3;
  private Button mBtClick4;
  @Override
  protected void onCreate(Bundle savedInstanceState)
  {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    mBtClick = (Button) findViewById(R.id.btnTest1);      //1、fdv 找到button id
                                  // 2、 Alt Ctrl F 形成类全局Field
    mBtClick.setOnClickListener(new View.OnClickListener()   //3、键入此行代码自动嵌入内部类方法
    {
      @Override
      public void onClick(View v)
      {                            //4、 Toast tab tab 调出toast 方法 以上为方法一
        Toast.makeText(MainActivity.this, "hello world", Toast.LENGTH_SHORT).show();
      }
    });
    mBtClick2 = (Button) findViewById(R.id.btnSample2);     //5、找出button 2 的 button id  fdv
    mBtClick2.setOnClickListener(new Button_2_OnClickListener()); //9、实例化方法给button 绑定 以上是方法二
    mBtClick3 = (Button) findViewById(R.id.btnTry3);      //10、找出button 3 的 button id  fdv
    mBtClick3.setOnClickListener(this);             //11、 this 表示 main acitivity
                                  //12 但是这里是方法参数是onclicklistener接口，此处 this Alt Enter 会在此方法上加上实现的接口
    mBtClick4 = (Button) findViewById(R.id.btnExample4);    //5、找出button 4 的 button id  fdv
  }
  /**
   * Called when a view has been clicked.
   *
   * @param v The view that was clicked.
   */
  @Override
  public void onClick(View v)
  {
    //方法三
  }
  class Button_2_OnClickListener implements View.OnClickListener //6、设置一个 click 方法 命名后继承自 view
                                  // onclicklistener
                                  //7、 后在 继承 implements 上 alt + enter 来实现方法
  {
    /**
     * Called when a view has been clicked.
     *
     * @param v The view that was clicked.
     */
    @Override
    public void onClick(View v)
    {
      //方法二
    }
  }
  public void click(View view)
  {
    //方法四
  }
}