Question

我知道这个问题可能会被问到其他人，但我无法找到适合我的解决方案。基本上我有fragment一个按钮。当用户按下该按钮时，新的activity被打开（该活动只扫描qr代码），我想将扫描结果传回我的fragment。所以基本上

public class UiFragment extends Fragment implements ServiceCallBack {
    // tons of code
    scanButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(getActivity(), ScanActivity.class); // start scan activity
                startActivity(intent);
            }
        });
}

public class ScanActivity extends AppCompatActivity {
   // lots of code
     public void onActivityResult(int requestCode, int resultCode, Intent intent) {
        IntentResult scanResult = IntentIntegrator.parseActivityResult(requestCode, resultCode, intent);
        if (scanResult != null) {
            String result = scanResult.getContents();
            if(result != null && result.length() > 0){
                // now I want to go back to my previous fragment and pass result
            }
        }
        finish();
    }
}

请注意，我希望活动分段通信！我试图使用界面，但这对我没有用。有可能吗？

Answer 1

如果我正确理解了您的问题，那么您必须有1个活动才能启动片段。我们将该活动命名为MainActivity。现在将UiFragment更改为

public class UiFragment extends Fragment implements ServiceCallBack {
// tons of code

public static final SCAN_REQUEST_CODE = 1001; //Any number

    scanButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(getActivity(), ScanActivity.class); // start scan activity
                startActivityForResult(intent, SCAN_REQUEST_CODE);
            }
        });
}

您的MainActivity将onActivityResult()

public class MainActivity extends AppCompatActivity {
   // lots of code
     public void onActivityResult(int requestCode, int resultCode, Intent intent) {
if(requestCode == UiFragment.SCAN_REQUEST_CODE){
//Check for result code if you want to
if(resultCode == RESULT_OK){
        IntentResult scanResult = IntentIntegrator.parseActivityResult(requestCode, resultCode, intent);
        if (scanResult != null) {
            String result = scanResult.getContents();
            if(result != null && result.length() > 0){


//Now check if your fragment is visible
 UiFragment uiFragment = (UiFragment) getSupportFragmentManager().findFragmentByTag(your_fragment_tag_name);
                if (uiFragment != null && uiFragment.isAdded()) {
//Call your fragment's public method here. let's say you have a method update in your fragment then write
                    uiFragment.update(); // you can pass arguments in this method depending on your requirements.
                }
                }
            }

        }
    }
    }
    }

您的ScanActivity将没有onActivityResult()方法

    public class ScanActivity extends AppCompatActivity {
       // lots of code

//Some method which scans and setResult
         public void scan() {
         setResult(RESULT_OK);
            finish();
        }
    }

片段通信的Android活动

1 个答案: