Android中点击按钮启动另一个Activity及Activity之间传值问题

Button secondActivityButton = (Button)findViewById(R.id.secondActivity);
  secondActivityButton.setOnClickListener(new View.OnClickListener() {
   @Override
   public void onClick(View v) {
    //第一个参数是当前Activity 第二个参数是要启动的Activity
    Intent intent = new Intent(MainActivity.this,SecondActivity.class);
    startActivity(intent);
   }
  });

 Button closeButton = (Button) findViewById(R.id.closeButton);
   closeButton.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {
     finish();
    }
   });

 Button paramActivityButton = (Button)findViewById(R.id.paramActivity);
  paramActivityButton.setOnClickListener(new View.OnClickListener() {
   @Override
   public void onClick(View v) {
    Intent intent = new Intent(MainActivity.this, SecondActivity.class);
    //可传递多个键值对形式的数据
    intent.putExtra("key","霸道流氓气质");
    intent.putExtra("key1","霸道的程序猿");
    startActivity(intent);
   }
  });

 Button valueButton = (Button) findViewById(R.id.valueButton);
  valueButton.setOnClickListener(new View.OnClickListener() {
   @Override
   public void onClick(View v) {
    String valueString = (String)getIntent().getExtras().get("key");
    String valueString1 = (String)getIntent().getExtras().get("key1");
    Toast.makeText(SecondActivity.this,"获取到的第一个参数为:"+valueString+"第二个参数为:"+valueString1,Toast.LENGTH_LONG).show();
   }
  });