安卓中intent切换界面与传递数值

Intent intent = new Intent();  // Activity1
intent.putExtra("one", num1);
intent.putExtra("two", num2);
intent.setClass(FirstActivity.this, SecondActivity.class);
startActivity(intent);

Intent intent = getIntent();  //Activity2
String num1 = intent.getStringExtra("one");
String num2 = intent.getStringExtra("two");

Intent intent =new  Intent(AActivity.this,BActivity.class);
intent.putExtra("num1", num1) ;
intent.putExtra("num2", num2) ;
startActivity(intent)

String num1 =this.getIntent().getStringExtra("num1") ;
String num2 =this.getIntent().getStringExtra("num2")