android - 从 fragment 调用 startActivityForResult 时出错

Question

我正在尝试从 fragment 调用 ZXingScannerActivity

NewInventoryFragement.java

package info.androidhive.wolf;

import android.app.Fragment;
import android.content.Intent; 
import android.content.pm.PackageManager;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;

import info.androidhive.wolf.qrcode.ZXingScannerActivity;
import info.androidhive.wolf.qrcode.ZXingConstants;
import com.google.zxing.BarcodeFormat;

/**
 * Created by Admin on 4/22/2015.
 */
public class NewInventoryFragment extends Fragment{

    private static final int ZXING_SCANNER_REQUEST = 0;
    private static final int ZXING_QR_SCANNER_REQUEST = 1;
    Button button;
   public NewInventoryFragment(){};
   @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View rootView = inflater.inflate(R.layout.new_inventory_fragment, container, false);

        button=(Button) rootView.findViewById(R.id.button2);
       button.setOnClickListener(new View.OnClickListener() {
           @Override
           public void onClick(View view) {
               launchQRScanner(view);
           }
       });
        return rootView;
    }

    public void launchQRScanner(View v) {
        if (isCameraAvailable()) {
            Intent intent = new Intent(getActivity().getApplicationContext(), ZXingScannerActivity.class);
            intent.putExtra(ZXingConstants.SCAN_FORMATS, BarcodeFormat.QR_CODE.toString());
            getActivity().startActivityForResult(intent, ZXING_SCANNER_REQUEST);
        } else {
            Toast.makeText(getActivity().getApplicationContext(), "Rear Facing Camera Unavailable", Toast.LENGTH_SHORT).show();
        }
    }

    public boolean isCameraAvailable() {
        PackageManager pm = getActivity().getPackageManager();
        return pm.hasSystemFeature(PackageManager.FEATURE_CAMERA);
    }



    @Override
    public void onActivityResult(int requestCode, int resultCode, Intent data) {
        switch (requestCode) {
            case ZXING_SCANNER_REQUEST:
            case ZXING_QR_SCANNER_REQUEST:
                if (resultCode == 1) {
                    Toast.makeText(getActivity().getApplicationContext(), "Scan Result = " + data.getStringExtra(ZXingConstants.SCAN_RESULT) +
                            ", Scan Format = " + data.getStringExtra(ZXingConstants.SCAN_RESULT_FORMAT), Toast.LENGTH_SHORT).show();

                     }
                break;
        }
    }

}

Logcat 说

26260-26260/info.androidhive.slidingmenu E/AndroidRuntime﹕ FATAL EXCEPTION: main
    android.content.ActivityNotFoundException: Unable to find explicit activity class {info.androidhive.slidingmenu/info.androidhive.wolf.qrcode.ZXingScannerActivity}; have you declared this activity in your AndroidManifest.xml?
            at android.app.Instrumentation.checkStartActivityResult(Instrumentation.java:1556)
            at android.app.Instrumentation.execStartActivity(Instrumentation.java:1530)
            at android.app.Activity.startActivityFromFragment(Activity.java:3922)
            at android.app.Fragment.startActivityForResult(Fragment.java:1025)
            at android.app.Fragment.startActivityForResult(Fragment.java:1009)
            at info.androidhive.wolf.NewInventoryFragment.launchQRScanner(NewInventoryFragment.java:46)
            at info.androidhive.wolf.NewInventoryFragment$1.onClick(NewInventoryFragment.java:36)
            at android.view.View.performClick(View.java:4222)
            at android.view.View$PerformClick.run(View.java:17343)
            at android.os.Handler.handleCallback(Handler.java:615)
            at android.os.Handler.dispatchMessage(Handler.java:92)
            at android.os.Looper.loop(Looper.java:137)
            at android.app.ActivityThread.main(ActivityThread.java:4895)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:511)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:994)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:761)
            at dalvik.system.NativeStart.main(Native Method)

@line #46 getActivity().startActivityForResult(intent, ZXING_SCANNER_REQUEST);我从 Stack 中引用了这个

我在Manifest.xml 中添加了 Activity

   <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="info.androidhive.wolf.MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

        <activity
            android:name="info.androidhive.wolf.qrcode.ZXingScannerActivity"
            android:screenOrientation="landscape"
            android:label="@string/app_name"
             />


    </application>

实际上，我在这里所做的是 MainActivity.java 是扩展 Activity 并具有抽屉导航以使用多个 fragment 进行导航。

Inventory 是带有添加新库存按钮的 fragment 之一，意味着导航到 NewInventoryFragment。

NewInventoryFragment 具有此@line #46 getActivity().startActivityForResult(intent, ZXING_SCANNER_REQUEST);

这是正确的做法吗？？

Answer 1

你不能在 Fragment 上处理这个事件，因为它是从它自己的 Activity 中处理的。

我的意思是， fragment 没有上下文，因为它们是 Activity 的一部分。有些事件只能在上下文中处理，因此，您必须在包含 fragment 的 Activity 中编写此类方法。