在Tab Activity的onCreate中，在Android中的ActionBar选项卡框架中初始化值

Question

我的应用程序使用ActionBar选项卡片段来创建/修改设备详细信息。 Device属性分为不同的片段。我想在Tab Activity的OnCreate中初始化每个片段。在每个选项卡片段中都有 SetValues 方法，该方法初始化要在片段中查看的值。我注意到当我点击特定标签时会创建片段。

标签活动

public class CameraDetails extends Activity {
 private CameraData camera = new CameraData();

 Fragment network = new NetworkFragment();
 Fragment remoteUser = new RemoteUserFragment();

 private G.Interface mNetworkInterface = null;
 private G.Interface mRemoteUserInterface = null;    

/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.cameradetails);

    ActionBar actionBar = getActionBar();
    actionBar.setDisplayShowHomeEnabled(false);
    actionBar.setDisplayShowTitleEnabled(false);
    actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);

    // network tab
    ActionBar.Tab tab = actionBar.newTab();
    tab.setText("Network");
    tab.setIcon(R.drawable.ic_launcher);
    tab.setTabListener(new TabListener(network));
    actionBar.addTab(tab);

    // remote user tab
    tab = actionBar.newTab();
    tab.setText("Remote User");
    tab.setIcon(R.drawable.ic_launcher);
    tab.setTabListener(new TabListener(remoteUser));
    actionBar.addTab(tab);

    final Handler handler = new Handler();
    handler.postDelayed(new Runnable() {
      @Override
      public void run() {
          init();
      }
    }, 1000);
}

public void init(){
    try{
        byte[] by = new byte[512];
        String extStorageDirectory = Environment.getExternalStorageDirectory().toString();
        File file = new File(extStorageDirectory, "dump.hex");
        BufferedInputStream in = new BufferedInputStream( new FileInputStream(file));
        in.read(by);
        in.close();
        camera.set( by );

        mNetworkInterface.SetValues();
        mRemoteUserInterface.SetValues();           

    } catch(Exception e){
        e.printStackTrace();
    }

}

public CameraData getCameraData(){
    return camera;
}

public void setNetworkListener( G.Interface Interface ){
    this.mNetworkInterface = Interface;
}

public void setRemoteUserListener( G.Interface Interface ){
    this.mRemoteUserInterface = Interface;
}
}

其中一个片段标签

public class NetworkFragment extends Fragment implements G.Interface {
View rootView;
Activity mActivity;
CameraData camera;

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    rootView = inflater.inflate(R.layout.network_layout, container, false);
    Log.i("NetworkFragment", "CreateView");
    return rootView;
}

@Override
public void onAttach(Activity activity) {
    mActivity = activity;
    ((CameraDetails)mActivity).setNetworkListener(this);
    camera = ((CameraDetails)mActivity).getCameraData();
    Log.i("NetworkFragment", "Activity Attached");
    super.onAttach(activity);
}

@Override
public void SetValues() {
    try {
        // ip address
        EditText et = (EditText)rootView.findViewById(R.id.cd_ip_address);
        et.setText(camera.mNetwork.IPAddress);

        // subnet mask
        et = (EditText)rootView.findViewById(R.id.cd_subnetmask);
        et.setText(camera.mNetwork.SubnetMask);

        // gateway
        et = (EditText)rootView.findViewById(R.id.cd_gateway);
        et.setText(camera.mNetwork.Gateway);

        // com port
        et = (EditText)rootView.findViewById(R.id.cd_comm_port);
        et.setText(""+camera.mNetwork.CommPort);

        // mimg port
        et = (EditText)rootView.findViewById(R.id.cd_mimg_port);
        et.setText(""+camera.mNetwork.MImgPort);

        // webserver port
        et = (EditText)rootView.findViewById(R.id.cd_web_server_port);
        et.setText(""+camera.mNetwork.WebServerPort);

        // wifi id
        et = (EditText)rootView.findViewById(R.id.cd_wifi_id);
        et.setText(camera.mNetwork.WiFiId);

        // wifi password
        et = (EditText)rootView.findViewById(R.id.cd_wifi_pwd);
        et.setText(camera.mNetwork.WiFiPassword);

        // wifi mode
        Spinner sp = (Spinner)rootView.findViewById(R.id.cd_wifi_mode);
        sp.setSelection(camera.mNetwork.WiFiMode, true);            

        Log.i("NetworkFragment", "SetValues OK");

    } catch( Exception e ){

    }
}
}

标签活动的初始化方法会将值初始化为片段 NetworkFragment 和 RemoteUserFragment 。为NetworkFragment初始化值。但RemoteUserFragment的NullPointerException。

logcat的

    06-11 12:06:38.161: W/System.err(677): java.lang.NullPointerException
    06-11 12:06:38.201: W/System.err(677):  at com.mtxlabs.cameraviewer.CameraDetails.init(CameraDetails.java:114)
    06-11 12:06:38.201: W/System.err(677):  at com.mtxlabs.cameraviewer.CameraDetails$1.run(CameraDetails.java:98)
    06-11 12:06:38.201: W/System.err(677):  at android.os.Handler.handleCallback(Handler.java:615)
    06-11 12:06:38.211: W/System.err(677):  at android.os.Handler.dispatchMessage(Handler.java:92)
    06-11 12:06:38.211: W/System.err(677):  at android.os.Looper.loop(Looper.java:137)
    06-11 12:06:38.211: W/System.err(677):  at android.app.ActivityThread.main(ActivityThread.java:4745)
    06-11 12:06:38.211: W/System.err(677):  at java.lang.reflect.Method.invokeNative(Native Method)
    06-11 12:06:38.211: W/System.err(677):  at java.lang.reflect.Method.invoke(Method.java:511)
    06-11 12:06:38.211: W/System.err(677):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
    06-11 12:06:38.211: W/System.err(677):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
    06-11 12:06:38.211: W/System.err(677):  at dalvik.system.NativeStart.main(Native Method)

我如何解决这个问题或是否使用其他技术来做到这一点。

提前谢谢

Answer 1

我在片段的onCreateView中调用了 SetValues 方法。最后我解决了问题

主要活动

public class CameraDetails extends Activity {
    private CameraData camera = new CameraData();

    Fragment network = new NetworkFragment();
    Fragment remoteUser = new RemoteUserFragment();
    Fragment rtsp = new RTSPFragmentTab();
    Fragment video = new VideoFragmentTab();
    Fragment record = new RecordFragmentTab();
    Fragment alarm = new AlarmFragmentTab();
    Fragment productinfo = new ProductInfoFragmentTab();

    private G.Interface mNetworkInterface = null;
    private G.Interface mRemoteUserInterface = null;    

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.cameradetails);

        initCameraData();

        ActionBar actionBar = getActionBar();
        actionBar.setDisplayShowHomeEnabled(false);
        actionBar.setDisplayShowTitleEnabled(false);
        actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);

        // network tab
        ActionBar.Tab tab = actionBar.newTab();
        tab.setText("Network");
        tab.setIcon(R.drawable.ic_launcher);
        tab.setTabListener(new TabListener(network));
        actionBar.addTab(tab);

        // remote user tab
        tab = actionBar.newTab();
        tab.setText("Remote User");
        tab.setIcon(R.drawable.ic_launcher);
        tab.setTabListener(new TabListener(remoteUser));
        actionBar.addTab(tab);        
    }

    public void initCameraData(){
        try{
            byte[] by = new byte[512];
            String extStorageDirectory = Environment.getExternalStorageDirectory().toString();
            File file = new File(extStorageDirectory, "dump.hex");
            BufferedInputStream in = new BufferedInputStream( new FileInputStream(file));
            in.read(by);
            in.close();
            camera.set( by );           
        } catch(Exception e){
            e.printStackTrace();
        }

    }

    public void onClick(View v){
        getActionBar().setSelectedNavigationItem(0);
        if(!mNetworkInterface.Validate())
            return;

        getActionBar().setSelectedNavigationItem(1);
        if(!mRemoteUserInterface.Validate())
            return;

        try{
            byte[] bytes = camera.get();
            String extStorageDirectory = Environment.getExternalStorageDirectory().toString();
            File file = new File(extStorageDirectory, "dump.hex");
            BufferedOutputStream out = new BufferedOutputStream( new FileOutputStream(file, false));
            out.write(bytes);
            out.close();
            Log.v("Data", "Setup data updated");
        } catch (Exception e) {
            e.printStackTrace();
            return ;
        }
    }

    public CameraData getCameraData(){
        return camera;
    }

    public void setNetworkListener( G.Interface Interface ){
        this.mNetworkInterface = Interface;
    }

    public void setRemoteUserListener( G.Interface Interface ){
        this.mRemoteUserInterface = Interface;
    }

}

网络片段

public class NetworkFragment extends Fragment implements G.Interface {
    View rootView;
    Activity mActivity;
    CameraData camera;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        rootView = inflater.inflate(R.layout.network_layout, container, false);
        Log.i("NetworkFragment", "CreateView");
        SetValues();
        return rootView;
    }

    @Override
    public void onAttach(Activity activity) {
        mActivity = activity;
        ((CameraDetails)mActivity).setNetworkListener(this);
        camera = ((CameraDetails)mActivity).getCameraData();
        Log.i("NetworkFragment", "Activity Attached");
        super.onAttach(activity);
    }

    @Override
    public boolean Validate() {
        try {
            String s;
            int i;

            // ip address
            camera.mNetwork.IPAddress = G.GetIPText(rootView, R.id.cd_ip_address);
            if( camera.mNetwork.IPAddress.isEmpty()){
                Toast.makeText(mActivity, "Please enter a valid ip address", Toast.LENGTH_SHORT).show();
                return false;
            }

            // subnet mask
            camera.mNetwork.SubnetMask = G.GetIPText(rootView, R.id.cd_subnetmask);
            if( camera.mNetwork.SubnetMask.isEmpty() ){
                Toast.makeText(mActivity, "Please enter a valid subnetmask", Toast.LENGTH_SHORT).show();
                return false;
            }


            // gateway
            camera.mNetwork.Gateway = G.GetIPText(rootView, R.id.cd_gateway);
            if( camera.mNetwork.Gateway.isEmpty()){
                Toast.makeText(mActivity, "Please enter a valid gateway", Toast.LENGTH_SHORT).show();
                return false;
            }

            // com port
            camera.mNetwork.CommPort = G.GetInteger(rootView, R.id.cd_comm_port);
            if( camera.mNetwork.CommPort < 0 ){
                Toast.makeText(mActivity, "Please enter a valid Communication Port", Toast.LENGTH_SHORT).show();
                return false;
            }

            // mimg port
            camera.mNetwork.MImgPort = G.GetInteger(rootView, R.id.cd_mimg_port);
            if( camera.mNetwork.MImgPort < 0 ){
                Toast.makeText(mActivity, "Please enter a valid MIMG Port", Toast.LENGTH_SHORT).show();
                return false;
            }

            // webserver port
            camera.mNetwork.WebServerPort = G.GetInteger(rootView, R.id.cd_web_server_port);
            if( camera.mNetwork.WebServerPort < 0 ){
                Toast.makeText(mActivity, "Please enter a valid webserver Port", Toast.LENGTH_SHORT).show();
                return false;
            }

            // wifi id
            camera.mNetwork.WiFiId = G.GetText(rootView, R.id.cd_wifi_id);
            if( camera.mNetwork.WiFiId.isEmpty() ){
                Toast.makeText(mActivity, "Please enter a valid WiFi Id", Toast.LENGTH_SHORT).show();
                return false;
            }

            // wifi password
            camera.mNetwork.WiFiPassword = G.GetText(rootView, R.id.cd_wifi_pwd);
            if( camera.mNetwork.WiFiPassword.isEmpty() ){
                Toast.makeText(mActivity, "Please enter a valid WiFi Password", Toast.LENGTH_SHORT).show();
                return false;
            }

            // wifi mode
            camera.mNetwork.WiFiMode = (byte)G.GetSpinnerOptions(rootView, R.id.cd_wifi_mode);
            if( camera.mNetwork.WiFiMode == -1 ){
                Toast.makeText(mActivity, "Please select a valid wifi mode from list", Toast.LENGTH_SHORT).show();
                return false;
            }

            Log.i("NetworkFragment", "Validation OK");
        } catch( Exception e ){
            e.printStackTrace();
        }
        return true;
    }

    public void SetValues() {
        try {
            // ip address
            EditText et = (EditText)rootView.findViewById(R.id.cd_ip_address);
            et.setText(camera.mNetwork.IPAddress);

            // subnet mask
            et = (EditText)rootView.findViewById(R.id.cd_subnetmask);
            et.setText(camera.mNetwork.SubnetMask);

            // gateway
            et = (EditText)rootView.findViewById(R.id.cd_gateway);
            et.setText(camera.mNetwork.Gateway);

            // com port
            et = (EditText)rootView.findViewById(R.id.cd_comm_port);
            et.setText(""+camera.mNetwork.CommPort);

            // mimg port
            et = (EditText)rootView.findViewById(R.id.cd_mimg_port);
            et.setText(""+camera.mNetwork.MImgPort);

            // webserver port
            et = (EditText)rootView.findViewById(R.id.cd_web_server_port);
            et.setText(""+camera.mNetwork.WebServerPort);

            // wifi id
            et = (EditText)rootView.findViewById(R.id.cd_wifi_id);
            et.setText(camera.mNetwork.WiFiId);

            // wifi password
            et = (EditText)rootView.findViewById(R.id.cd_wifi_pwd);
            et.setText(camera.mNetwork.WiFiPassword);

            // wifi mode
            Spinner sp = (Spinner)rootView.findViewById(R.id.cd_wifi_mode);
            sp.setSelection(camera.mNetwork.WiFiMode, true);


            Log.i("NetworkFragment", "SetValues OK");

        } catch( Exception e ){
            e.printStackTrace();
        }
    }

}

无论如何，感谢 @ cricket_007 帮助我理解片段标签操作