Question

我已为我的问题准备了a simple test project at GitHub。

它基于the well-known Navigation Drawer Example by Google - 由右侧抽屉扩展，在ListView中与音乐相关的操作：

screenshot

这些操作都在 res / values / strings.xml ：

中定义

<string-array name="music_actions">
    <item>Play</item>
    <item>Pause</item>
    <item>Stop</item>
    <item>Shuffle</item>
</string-array>

<integer-array name="music_icons">
    <item>@drawable/ic_play_arrow_black_24dp</item>
    <item>@drawable/ic_pause_black_24dp</item>
    <item>@drawable/ic_stop_black_24dp</item>
    <item>@drawable/ic_shuffle_black_24dp</item>
</integer-array>

以下是从资源中读取它们的代码（这很有效）：

public class MainActivity extends AppCompatActivity {
    private String[] mActions;
    private int[] mIcons;

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

        mActions = getResources().getStringArray(R.array.music_actions);

        TypedArray ta = getResources().obtainTypedArray(R.array.music_icons);
        mIcons = new int[ta.length()];
        for (int i = 0; i < mIcons.length; i++)
                mIcons[i] = ta.getResourceId(i, R.drawable.ic_menu_black_24dp);
        ta.recycle();

我的问题是：

从ListView的监听器中的onItemClick方法 - 如何在Fragment中调用相应的方法？

我只看到丑陋的方式，就像这里使用硬编码switch声明一样：

    mRightDrawer.setAdapter(new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, mActions) {
        @Override
        public View getView(int position, View convertView, ViewGroup parent) {
            TextView view = (TextView) super.getView(position, convertView, parent);
            view.setCompoundDrawablesWithIntrinsicBounds(mIcons[position], 0, 0, 0);
            return view;
        }
    });
    mRightDrawer.setOnItemClickListener(new OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
            if (mActiveFragment instanceof GameFragment) {
                GameFragment fragment = (GameFragment) mActiveFragment;
                switch (position) {
                case 0:
                    fragment.playMusic(); // and then this calls myView.playMusic();
                    break;
                case 1:
                    fragment.pauseMusic(); // calls myView.pauseMusic();
                    break;
                }
            }

            mDrawerLayout.closeDrawer(mRightDrawer);
        }
    });

这很难看，因为我必须跟踪当前活动的Fragment，然后使用包装器方法最终在我的自定义View上调用方法。

如何改善这种情况，我是否可以在自定义视图中使用BroadcastReceiver？

我希望，我可以在我的资源中定义 icon + title + action ，然后只使用它们。

更新：

目前我正在使用BroadcastReceiver，但想知道它是否是一个合适的解决方案（或者可能太重了？）。

在我的片段中，我打电话：

@Override
public void onResume() {
    super.onResume();

    myView.register();
}

@Override
public void onPause() {
    super.onPause();

    myView.unregister();
}

在我的自定义视图中，我有：

public class MyView extends View {

    public final static String ACTION_PLAY    = "de.afarber.myapp.play";
    public final static String ACTION_PAUSE   = "de.afarber.myapp.pause";
    public final static String ACTION_STOP    = "de.afarber.myapp.stop";
    public final static String ACTION_SHUFFLE = "de.afarber.myapp.shuffle";

   private BroadcastReceiver mMessageReceiver = new BroadcastReceiver() {
          @Override
          public void onReceive(Context context, Intent intent) {
              String action = intent.getAction();
              if (ACTION_PLAY.equals(action))
                  playMusic();
              else if (ACTION_PAUSE.equals(action))
                  pauseMusic();
              else if (ACTION_STOP.equals(action))
                  stopMusic();
              else if (ACTION_SHUFFLE.equals(action))
                  shuffleMusic();
          }
    };

    public void register() {
        IntentFilter filter = new IntentFilter();
        filter.addAction(ACTION_PLAY);
        filter.addAction(ACTION_PAUSE);
        filter.addAction(ACTION_STOP);
        filter.addAction(ACTION_SHUFFLE);
        getContext().registerReceiver(mMessageReceiver, filter);
    }

我希望有一些＆＃34;上下文菜单＆＃34;片段 - 定义标题+图标+动作 - 然后可以被右侧Drawer中的actions-ListView使用...

    public void unregister() {
        getContext().unregisterReceiver(mMessageReceiver);
    }

Answer 1

广播适用于我的基于DrawerLayout的应用，但为了更好的安全性和效率，我已切换到LocalBroadcastManager -

MainActivity.java（右侧动作抽屉菜单发送广播）：

    mRightDrawer.setOnItemClickListener(new OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
            String action = mActions[position];
            Intent intent = new Intent(action);
            //intent.putExtra("message", "data");
            LocalBroadcastManager.getInstance(getApplicationContext()).sendBroadcast(intent);
            mDrawerLayout.closeDrawer(mRightDrawer);
        }
    });

PlanetFragment.java（活动片段接收应用内部广播）：

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
        Bundle savedInstanceState) {
    ...
    mManager = LocalBroadcastManager.getInstance(getActivity());

    mFilter = new IntentFilter();
    mFilter.addAction(ACTION_PLAY);
    mFilter.addAction(ACTION_PAUSE);
    mFilter.addAction(ACTION_STOP);
    mFilter.addAction(ACTION_SHUFFLE);
    ...
}

@Override
public void onResume() {
    super.onResume();
    mManager.registerReceiver(mMessageReceiver, mFilter);
}

@Override
public void onPause() {
    super.onPause();
    mManager.unregisterReceiver(mMessageReceiver);
}

DrawerLayout与ListView表示动作 - 如何在视图上调用动作方法？

1 个答案: