意向不从片段开始活动

Question

I am having a problem with intens from fragments in Android. I have an Activity that holds a Fragment which in turn holds a ListView. I have registered an onItemClickListener to the ListView and this worked well when I had the listView right in the Activity. I needed to wrap it in the fragment however.

So instead of calling getContext() I call now getActivity() as was recomended everywhere. This does in fact return the correct Activity. The click is registered as well, as my LogCat is being printed. But the intent is never started. Nothing happens. Can anyone tell me what I am missing please?

Here is my code:

_dealList.setOnItemClickListener(new AdapterView.OnItemClickListener()
        {
            @Override
            public void onItemClick(AdapterView<?> parent, View v, int position, long id)
            {
                Intent in = new Intent(getActivity(), DealView.class);
                in.putExtra("deal", position);
                in.putExtra("city", _citySearchBar.getText());
                startActivity(in);
                Log.d("BASE_FRAGMENT", "Activity should have been started here");
            }
        });
    }

This code lives inside an abstract class but moving it to the subclasses does not make a difference.

This is the DealView class the intent is aimed at:

public class DealView extends AppCompatActivity {
    private TextView _priceView;
    private TextView _descriptionView;
    private TextView _titleView;
    private TextView _storeView;
    private ImageView _imageView;
    private String _cityName;

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

            Intent fromDealSelection = getIntent();
            _cityName = fromDealSelection.getStringExtra("city");

            //Initializing the different components of the view
            _priceView = (TextView) findViewById(R.id.priceInputDealView);

            _descriptionView = (TextView) findViewById(R.id.dealDescriptionDealView);

            _titleView = (TextView) findViewById(R.id.dealTitleDealView);

            _storeView = (TextView) findViewById(R.id.storeDealView);

            _imageView = (ImageView) findViewById(R.id.imageViewDealView);

            _cityName = fromDealSelection.getStringExtra("city");

        }

Here is the LogCat output:

03/01 09:42:23: Launching app
W/System: ClassLoader referenced unknown path: /data/data/de.coding.mb.konstisapp/lib
Hot swapped changes, activity restarted
D/BASE_FRAGMENT: Activity should have been started here
D/BASE_FRAGMENT: Activity should have been started here

Here is my AndroidManifest.xml file:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
          package="de.coding.mb.konstisapp">

    <uses-feature
        android:name="android.hardware.camera"
        android:required="false"/>

    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/>
    <uses-permission
        android:name="android.permission.WRITE_EXTERNAL_STORAGE"
        android:maxSdkVersion="18"/>
    <uses-permission android:name="android.permission.INTERNET"/>

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".activities.GreatingsActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN"/>

                <category android:name="android.intent.category.LAUNCHER"/>
            </intent-filter>
        </activity>
        <activity
            android:name=".activities.DealSelectionActivity"
            android:label="@string/title_activity_deal_selection"
            android:parentActivityName=".activities.GreatingsActivity"
            android:theme="@style/AppTheme.NoActionBar">
            <meta-data
                android:name="android.support.PARENT_ACTIVITY"
                android:value="de.coding.mb.konstisapp.activities.GreatingsActivity"/>
        </activity>
        <activity
            android:name=".activities.DealCreationActivity"
            android:label="@string/title_activity_activity_deal_creation"
            android:parentActivityName=".activities.DealSelectionActivity"
            android:theme="@style/AppTheme.NoActionBar">
            <meta-data
                android:name="android.support.PARENT_ACTIVITY"
                android:value="de.coding.mb.konstisapp.activities.DealSelectionActivity"/>
        </activity>
        <activity android:name=".activities.DealView"
                  android:label="@string/title_activity_deal_view"
                  android:parentActivityName=".activities.DealSelectionActivity"
                  android:theme="@style/AppTheme.NoActionBar">
            <meta-data
                android:name="android.support.PARENT_ACTIVITY"
                android:value="de.coding.mb.konstisapp.activities.DealSelectionActivity">

            </meta-data>
        </activity>
</manifest>

Answer 1

As the starting of a new Activity from within the Fragment doesn't work, you could try migrating the code to the hosting Activity. A clean and reusable way is to create an Interface in a new file.

public interface myInterface {
    public void startMyIntent(Intent i);
}

Then, implement this Interface in the Activity class, hosting your Fragment

public class hostingActivity extends AppCompatActivity implements myInterface {
    @Override
    public void startMyIntent(Intent i) {
        startActivity(i);
    }
}

In your Fragment's onItemClickListener , you can call it like this

_dealList.setOnItemClickListener(new AdapterView.OnItemClickListener()
    {
        @Override
        public void onItemClick(AdapterView<?> parent, View v, int position, long id)
        {
            Activity parentActivity = getActivity();
            Intent in = new Intent(parentActivity, DealView.class);
            in.putExtra("deal", position);
            in.putExtra("city", _citySearchBar.getText());
            ((myInterface)parentActivity).startMyIntent(in);
            Log.d("BASE_FRAGMENT", "Activity should have been started here");
        }
    });
}

Answer 2

From inside a Fragment, you can't just use startActivity()
You have to use getActivity().startActivity(in)

_dealList.setOnItemClickListener(new AdapterView.OnItemClickListener()
    {
        @Override
        public void onItemClick(AdapterView<?> parent, View v, int position, long id)
        {
            Intent in = new Intent(getActivity(), DealView.class);
            in.putExtra("deal", position);
            in.putExtra("city", _citySearchBar.getText());
            getActivity().startActivity(in);
            Log.d("BASE_FRAGMENT", "Activity should have been started here");
        }
    });
}

See also How do I start an activity from within a Fragment?

Answer 3

Changed Code

_dealList.setOnItemClickListener(new AdapterView.OnItemClickListener()
        {
           @Override
            public void onItemClick(AdapterView<?> parent, View v, int position, long id)
            {
                Intent in = new Intent(v.getContext(), DealView.class);
                in.putExtra("deal", position);
                in.putExtra("city", _citySearchBar.getText());
                startActivity(in);
                Log.d("BASE_FRAGMENT", "Activity should have been started here");
            }
        });
    }

Answer 4

use FLAG_ACTIVITY_NEW_TASK in intent.setFlags(...) method.

_dealList.setOnItemClickListener(new AdapterView.OnItemClickListener()
    {
       @Override
        public void onItemClick(AdapterView<?> parent, View v, int position, long id)
        {
            Intent in = new Intent(v.getContext(), DealView.class);
            in.putExtra("deal", position);
            in.putExtra("city", _citySearchBar.getText());
            in.setFlag(Acitvity.FLAG_ACTIVITY_NEW_TASK);
            getActivity().startActivity(in);
            Log.d("BASE_FRAGMENT", "Activity should have been started here");
        }
    });
}