ZXing 扫描二维码时不调用 onActivityResult

ZXing not calling onActivityResult, When scanning QR Code

我正在使用ZXing Android嵌入式库读取二维码,但扫描成功后onActivityResult没有被调用,求助。

public class ScanActivity extends AppCompatActivity {

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

        Button scanButton = (Button) findViewById(R.id.scan_button);
        scanButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                IntentIntegrator integrator = new IntentIntegrator(ScanActivity.this);
                integrator.initiateScan();
            }
        });
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        System.out.println("*************** Why is this method not called?");
        IntentResult result = IntentIntegrator.parseActivityResult(requestCode, resultCode, data);
        if (result != null) {
            if (result.getContents() == null) {
                Toast.makeText(this, "Result Not Found", Toast.LENGTH_LONG).show();
            } else {
                Toast.makeText(this, "Result is: ", Toast.LENGTH_LONG).show();
            }
        } else {
            super.onActivityResult(requestCode, resultCode, data);
        }
    }
}
IntentIntegrator integrator = new IntentIntegrator(ScanActivity.this);
            integrator.initiateScan();

integrator.initiateScan();不调用或不反映 startActivityForResult 操作。

必须按顺序调用startActivityForResult才能在onActivityResult中有回调

这段代码的问题是我在清单文件

中的ScanActivity上使用了android:noHistory="true"
<activity
    android:name=".ScanActivity" android:noHistory="true" />

删除 android:noHistory="true" 解决了问题

<activity
    android:name=".ScanActivity" />