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 world1", 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以上是方法三
         mBtClick4 = (Button) findViewById(R.id.btnExample4);        //5、找出button 4 的 button id   fdv  方法四这行没用

     }

     /**
      * Called when a view has been clicked.
      *
      * @param v The view that was clicked.
      */
     @Override
     public void onClick(View v)
     {
         Toast.makeText(MainActivity.this, "hello world 3", Toast.LENGTH_SHORT).show();//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)
         {
             Toast.makeText(MainActivity.this, "hello world 2", Toast.LENGTH_SHORT).show();//方法二
         }
     }
     public void click(View view)
     {
         Toast.makeText(MainActivity.this, "hello world 4", Toast.LENGTH_SHORT).show();//方法四
     }

 }