今天學校電力電子學作業超難
差點沒心力繼續學了zzz

昨天學向下一個Activity傳遞數據
今天學傳過去的數據接收之後再傳數據回來

一樣兩個Activity

public class ActRequestActivity extends AppCompatActivity implements View.OnClickListener {

    private static final String mRequest = "開開心心";
    private ActivityResultLauncher<Intent> register;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        EdgeToEdge.enable(this);
        setContentView(R.layout.activity_act_request);
        ViewCompat.setOnApplyWindowInsetsListener(findViewById(R.id.main), (v, insets) -> {
            Insets systemBars = insets.getInsets(WindowInsetsCompat.Type.systemBars());
            v.setPadding(systemBars.left, systemBars.top, systemBars.right, systemBars.bottom);
            return insets;
        });
        TextView textView = findViewById(R.id.tv_request);
        textView.setText("要發送的訊息："  + mRequest);
        TextView tv_response = findViewById(R.id.tv_response);

        findViewById(R.id.btn_request).setOnClickListener(this);

        register = registerForActivityResult(new ActivityResultContracts.StartActivityForResult(), result -> {
            if(result != null){
                Intent intent = result.getData();
                if(intent != null && result.getResultCode() == Activity.RESULT_OK){
                    Bundle bundle = intent.getExtras();
                    String time = bundle.getString("response_time");
                    String msg = bundle.getString("response_msg");
                    String desc = String.format("現在時間:%s\n收到的訊息為%s",time,msg);

                    tv_response.setText(desc);
                }
            }
        });
    }

    @Override
    public void onClick(View view) {
        Intent intent = new Intent(this, ActResponseActivity.class);
        Bundle bundle = new Bundle();
        bundle.putString("time", DateUtil.getNowTime());
        bundle.putString("msg",mRequest);
        intent.putExtras(bundle);
        register.launch(intent);
    }
}

public class ActResponseActivity extends AppCompatActivity implements View.OnClickListener {

    private static final String mResponse = "328又在搞";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        EdgeToEdge.enable(this);
        setContentView(R.layout.activity_act_response);
        ViewCompat.setOnApplyWindowInsetsListener(findViewById(R.id.main), (v, insets) -> {
            Insets systemBars = insets.getInsets(WindowInsetsCompat.Type.systemBars());
            v.setPadding(systemBars.left, systemBars.top, systemBars.right, systemBars.bottom);
            return insets;
        });

        TextView textView = findViewById(R.id.tv_request);
        Bundle bundle = getIntent().getExtras();
        String time = bundle.getString("time");
        String msg = bundle.getString("msg");
        String desc = String.format("現在時間:%s\n收到的訊息為%s",time,msg);
        textView.setText(desc);

        findViewById(R.id.btn_response).setOnClickListener(this);
        TextView tv_response = findViewById(R.id.tv_response);
        tv_response.setText("待返回的消息"+mResponse);
    }

    @Override
    public void onClick(View view) {
        Intent intent = new Intent();
        Bundle bundle = new Bundle();
        bundle.putString("response_time", DateUtil.getNowTime());
        bundle.putString("response_msg",mResponse);
        intent.putExtras(bundle);
        setResult(Activity.RESULT_OK,intent);
        finish();
    }
}

差不多先這樣 趕快去睡了
明天要去交作業呢 :(