Android：Activity信息传递(一)

public class WelcomeActivity extends Activity {
    public static final String TITLE = "title";
    public static final String USER_INFO = "userInfo";
    public static final int REQUEST_CODE = 0000;
    Handler mHandler=new Handler();
    private TextView textView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_welcome);

        textView = findViewById(R.id.tv_welcome);
        final String title= textView.getText().toString();
        mHandler.postDelayed(new Runnable() {
            @Override
            public void run() {
                //跳转到MainActivity
                UserInfo userInfo=new UserInfo("小米",22);
                Intent intent=new Intent(WelcomeActivity.this,MainActivity.class);
                intent.putExtra(TITLE,title);
                intent.putExtra(USER_INFO,userInfo);
                startActivityForResult(intent, REQUEST_CODE);

            }
        },1000);
    }
    @Override
    protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
        super.onActivityResult(requestCode, resultCode, data);

        if (requestCode==REQUEST_CODE&&resultCode==MainActivity.RESULT_CODE){
            if(data !=null){
                String title=data.getStringExtra(TITLE);
                textView.setText(title);
            }
        }
    }
}

public class MainActivity extends AppCompatActivity {


    public static final int RESULT_CODE = 1234;



    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        findViewById(R.id.finish).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent=new Intent();
                intent.putExtra(WelcomeActivity.TITLE,"我是");
                setResult(RESULT_CODE,intent);

                finish();


            }
        });
         Intent intent=getIntent();
         if(intent != null){

             String title=intent.getStringExtra(WelcomeActivity.TITLE);
             UserInfo userInfo= (UserInfo) intent.getSerializableExtra(WelcomeActivity.USER_INFO);
             setTitle("名字是："+userInfo.getmUserName());

         }

    }


}