使用startActivityForResult使Activity2的输入返回Activity1时不显示返回值

Activity1
public class MainActivity extends AppCompatActivity {

private TextView mTvMain;
private Button mBtnMain;
private int REQUEST_CODE=0;

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


private void initView() {
    mTvMain = (TextView) findViewById(R.id.tv_main);
    mBtnMain = (Button) findViewById(R.id.btn_main);
    mBtnMain.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            Intent intent = new Intent(MainActivity.this, SecondActivity.class);
            startActivityForResult(intent, REQUEST_CODE);
        }
    });
}

    @Override
    protected void onActivityResult(int requestCode,int resultCode,Intent data){
    super.onActivityResult(requestCode,resultCode,data);
    if (requestCode == REQUEST_CODE){
        switch (resultCode){
            case 1:
                  String content = data.getStringExtra("ccontent");
                  mTvMain.setText(content);
                break;
            default;
        }
    }
}

}

Activity2
public class SecondActivity extends AppCompatActivity {

private EditText mEtSec;
private Button mBtnSec;
private final int RESULT_CODE = 1;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_second);
    initView();
}
private void initView(){
    mEtSec = (EditText)findViewById(R.id.et_second);
    mBtnSec =(Button) findViewById(R.id.btn_second);
    mBtnSec.setOnClickListener(new View.OnClickListener(){
        @Override
                public void onClick(View view){
            String content = mEtSec.getText().toString();
            Intent intent = new Intent();
            intent.putExtra("content",content);
            setResult(RESULT_CODE,intent);
            finish();
        }
    });
}

}

Activity2返回时需要

setResult(Activity.RESULT_OK, intent);