在ZXing 2.0 QR码扫描后启动片段

Question

如果我通过ZXing 2.0库执行QR码扫描,我在启动片段时遇到了一些问题.

我有这个例外:

java.lang.RuntimeException: Failure delivering result ResultInfo{who=null, request=0, result=-1, data=Intent { act=com.google.zxing.client.android.SCAN flg=0x80000 (has extras) }} to activity {fraiss.yucrowd/fraiss.yucrowd.activities.ScanQrCode}: java.lang.IllegalStateException: Can not perform this action after onSaveInstanceState*

当我执行此代码时:

@Override
    public void onCreate(Bundle bundle) {
        // TODO Auto-generated method stub
        super.onCreate(bundle);
        setContentView(R.layout.scan_qr_code);

        Intent intent = new Intent("com.google.zxing.client.android.SCAN");
        intent.putExtra("SCAN_MODE", "QR_CODE_MODE");
        startActivityForResult(intent, 0);
    }

public void onActivityResult(int requestCode, int resultCode, Intent intent) {
        if (requestCode == 0)
        {
            if (resultCode == RESULT_OK)
            {
                String contents = intent.getStringExtra("SCAN_RESULT");
                String format = intent.getStringExtra("SCAN_RESULT_FORMAT");
                // Handle successful scan
                Log.d("MENU", "Scan result: " + contents + " as " + format);

                // Load details for qr code
                    FragmentTransaction fragmentTransaction = getSupportFragmentManager()
                            .beginTransaction();

                    Fragment fragmentDetails = new FragmentDetails(
                            contents);

                    fragmentTransaction
                            .setTransition(FragmentTransaction.TRANSIT_FRAGMENT_FADE);
                    fragmentTransaction.replace(R.id.fragment_main,
                            fragmentDetails);
                    fragmentTransaction.addToBackStack(null);
                    fragmentTransaction.commit();  
            }
            else if (resultCode == RESULT_CANCELED)
            {
                // Handle cancel
                Log.d("MENU", "Scan canceled");
            }
        }
    }

我想知道为什么会这样.是否无法在ActivityResult结束时启动Fragment-Transaction？

Thx提前为您提供帮助.

Answer 1

这是可能的onActivityResult之前叫onResume,你不能添加新的片段活动已经ATLEAST调用之前onResume.

因此,您需要存储所有数据onActivityResult,检查onResume并在那里执行片段更改.

Answer 2

这基本上是因为您的活动已暂停，并onActivityResult在之后调用onSaveInstanceState，因此出现消息：“无法在 onSaveInstanceState 之后执行此操作”。保存 requestCode、resultCode 和 Intent，并检查onResume是否有任何需要处理的内容。