// 確保 app 的 build.gradle中已經(jīng)引入了androidx.appcompat:appcompat
dependencies {
    implementation 'androidx.appcompat:appcompat:1.4.1' // 確定
}

package com.example.test1;
import androidx.activity.result.ActivityResult;
import androidx.activity.result.ActivityResultCallback;
import androidx.activity.result.ActivityResultLauncher;
import androidx.activity.result.contract.ActivityResultContracts;
import androidx.appcompat.app.AppCompatActivity;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.content.Intent;
import android.graphics.Color;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import android.widget.Toast;
import com.example.test1.ui.login.LoginActivity; // B頁面例子
import com.google.android.material.snackbar.Snackbar;
public class MainActivity extends AppCompatActivity implements View.OnClickListener {
    private static String TAG = "MainActivity";
    private ActivityResultLauncher<Intent> register;
    @SuppressLint("ResourceAsColor")
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        findViewById(R.id.my_button).setOnClickListener(this);
        register = registerForActivityResult(new ActivityResultContracts.StartActivityForResult(), new ActivityResultCallback<ActivityResult>() {
            @Override
            public void onActivityResult(ActivityResult result) {
                Log.i(TAG, "onActivityResult: _____" + result);
                if (result != null) {
                    Intent intent = result.getData();
                    if (intent != null && result.getResultCode() == Activity.RESULT_OK) {
                        Bundle myBundle = intent.getExtras();
                        String my_name = myBundle.getString("my_name");
                        String my_sex = myBundle.getString("my_sex");
                        // 下一個Activity回退后 在此獲取返回的值
                        Log.i(TAG, "onCreate: 獲取返回傳值my_name__________" + my_name); // ___獲取返回傳值my_namezhangsan000
                        Log.i(TAG, "onCreate: 獲取返回傳值my_sex__________" + my_sex); // ___獲取返回傳值my_sex男
                    }
                }
            }
        });
    }
    @Override
    public void onClick(View view) {
        if (view.getId() == R.id.my_button) {
            Intent intent = new Intent(this, LoginActivity.class);
            // 用register.launch跳轉(zhuǎn)至B
            register.launch(intent);
        }
    }
}

// B頁面的后退邏輯
public void myBack(View view) {
    Intent intent = new Intent();
    Bundle bundle = new Bundle();
    bundle.putString("my_name", "zhangsan000");
    bundle.putString("my_sex", "男");
    intent.putExtras(bundle);
    // 攜帶意圖返回上一個頁面 RESULT_OK代表處理成功了
    setResult(Activity.RESULT_OK, intent);
    // 結(jié)束當前頁面
    finish();
};