安卓跳转页面，并在页面之间传值

   //点击按钮进行页面的跳转
        btnToA01.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                //获取电话号码
                String strtel = "";
                strtel = etTel.getText().toString();

                //获取短信内容
                String strSMS = "";
                strSMS = editMes.getText().toString();

                //初始化Intent对象，并把需要传递的数据放到intent中
                Intent intent = new Intent(MainActivity.this,A02Activity.class);
                intent.putExtra("Tel",strtel);
                intent.putExtra("Sms",strSMS);
                startActivity(intent);
            }
        });

 protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_a01);
        btnBack = (Button)findViewById(R.id.btnBack) ;
        tvMsg = (TextView)findViewById(R.id.tv_message);

        //获取intent
        Intent intent = null;
        intent = getIntent();

        //获取数据
        String strTel = "";
        String strSms = "";

        strTel = intent.getStringExtra("Tel");
        strSms = intent.getStringExtra("Sms");

        tvMsg.setText("电话号：" + strTel + "短信内容：" + strSms);

     btnBack.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                finish();
            }
        });
    }