android - Bundel.getString ("") 在 onActivityResult() 给出空值

Question

我正在开发 android 应用程序，在该应用程序中，我将数据从 Activity 2 传回 Activity 1。我正在通过 Intent 传递它。问题是在 Activity 1 中，它显示的是 bundle 中的值，但是当我使用 bundle.getString(""); 时，它显示的是 null 值。在调试中，我正在使用 bundle Bundle[{list_size=3}]。我的代码如下，请帮帮我。

Activity 1:

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

        if(resultCode==105){
            TextView txtCounter = (TextView) findViewById(R.id.txtCounter);
// It showing value at MBuddle, but at MBuddle it is showing null.
            Bundle MBuddle = data.getExtras();
            String MMessage = MBuddle .getString("list_size");
            txtCounter.setText(MMessage);
        }
}

Activity 2:

@Override
    public void onBackPressed() {
        int REQUEST_CONTACTS = 105;
        Intent intent = new Intent();
        intent.putExtra("list_size", fListContacts.size());
        setResult(REQUEST_CONTACTS, intent);
        finish();
    }

Answer 1

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

 if (requestCode == REQUEST_CODE) {
                if (resultCode == Activity.RESULT_OK) {
                    String contents = intent.getStringExtra(Intents.Scan.RESULT);
                }}
}

===============

            Intent intent = new Intent(getIntent().getAction());
            intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_WHEN_TASK_RESET);
            intent.putExtra(KEY, data);
            setResult(RESULT_OK, intent);
            finish();

RESULT_OK 可以是一个 int 值