2

我有一个可扩展列表，带有一个自定义适配器、两个光标（来自基本可扩展列表适配器）和一个内容提供程序。

现在，我的主要目标是在插入带有意图调用的活动的新数据之后刷新这个可扩展列表。我正在尝试 Content Observer，但没有成功，因为没有完成刷新。

我把相关的代码（我认为）。非常感谢你。

public class ActPlacesManagement extends Activity{
private static final int DELETE_ID = Menu.FIRST;

private static final String TAG = null; 

public Cursor mPlacesCursor;
public Cursor mBoxesCursor;
ExpandableListView lstCategorias;
AdpPlacesManagement adapter;
String message, message1, message2;
String novo_local, nova_caixa;
Button btnNewPlace, btnNewBox;
Handler handler;

private static final String[] PROJECTION_PLACES = new String[] {
    ProvPersonalArchive.KEY_ROWID_PLACES,
    ProvPersonalArchive.KEY_DESIG_PLACES,
};

private static final String[] PROJECTION_BOXES = new String[] {
    ProvPersonalArchive.KEY_ROWID_BOXES,
    ProvPersonalArchive.KEY_DESIG_BOXES,
    ProvPersonalArchive.KEY_PLACE_BOXES,
};



protected void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);
    setContentView(R.layout.act_places_management);       

    mPlacesCursor = getContentResolver().query(ProvPersonalArchive.CONTENT_URI_PLACES, 
            PROJECTION_PLACES, null, null, null);

    mBoxesCursor = getContentResolver().query(ProvPersonalArchive.CONTENT_URI_BOXES, 
            PROJECTION_BOXES, null, null, null);



    lstCategorias = (ExpandableListView)this.findViewById(R.id.expandableGestaoCategorias);

    adapter = new AdpPlacesManagement(this, mPlacesCursor, mBoxesCursor, this);     

    lstCategorias.setAdapter(adapter);

    lstCategorias.setOnGroupClickListener(new ExpandableListView.OnGroupClickListener() {

        @Override
        public boolean onGroupClick(ExpandableListView parent, View v,
                int groupPosition, long id) {
            return lstCategorias_onGroupClick(parent, v, groupPosition, id);
        }
    });

    lstCategorias.setOnChildClickListener(new ExpandableListView.OnChildClickListener() {

        @Override
        public boolean onChildClick(ExpandableListView parent, View v,
                int groupPosition, int childPosition, long id) {
            return lstCategorias_onChildClick(parent, v, groupPosition, childPosition, id);
        }
    });



    btnNewPlace = (Button)this.findViewById(R.act_gestao_categorias.novo_lugar);
    btnNewBox = (Button)this.findViewById(R.act_gestao_categorias.nova_caixa);

    btnNewPlace.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View v) {
            btnNewPlace_onClick(v);
        }
    });

    btnNewBox.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View v) {
            btnNewBox_onClick(v);
        }
    });

    registerForContextMenu(lstCategorias);


    mPlacesCursor.registerContentObserver(new ObsPersonalArchive(handler));
    mBoxesCursor.registerContentObserver(new ObsPersonalArchive(handler));

}


// Eventos da lista de locais e caixas

public boolean lstCategorias_onGroupClick(ExpandableListView parent, View v,
        int groupPosition, long id) {
    return false;
}

public boolean lstCategorias_onChildClick(ExpandableListView parent, View v,
        int groupPosition, int childPosition, long id) {        
    return false;
}

// Termina a actividade e volta à ActInicial, levando o local

public void finish() {
  // Prepare data intent 
  Intent data = new Intent();
  setResult(RESULT_OK, data);
  data.putExtra("local", message);
  // Activity finished ok, return the data
  super.finish();
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    MenuInflater inflater = getMenuInflater();
    inflater.inflate(R.menu.act_start, menu);
    return true;
}


// Eventos dos botões para criar novo local e caixa

public void btnNewPlace_onClick(View view) {
    Intent intent = new Intent(this, ActNewPlace.class);
    startActivityForResult(intent, 1);
}

public void btnNewBox_onClick(View view) {
    Intent intent = new Intent(this, ActNewBox.class);
    startActivityForResult(intent, 2);
}

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
      if (resultCode == RESULT_OK && requestCode == 1) {
        if (data.hasExtra("novo_local") && data.hasExtra("nova_caixa")) {

            // Chama o método para gravar o local na base de dados
            Toast.makeText(this, "New place created!", Toast.LENGTH_LONG).show();
        }
      }
      if (resultCode == RESULT_OK && requestCode == 2) {
        if (data.hasExtra("novo_local") && data.hasExtra("nova_caixa")) {
            String novo_local = data.getExtras().getString("novo_local");
            String nova_caixa = data.getExtras().getString("nova_caixa");
            Toast.makeText(this, novo_local + nova_caixa, Toast.LENGTH_LONG).show();
        }
      }
    }




public class ObsPersonalArchive extends ContentObserver {

    public ObsPersonalArchive(Handler handler) {
        super(handler);        
        }
       @Override
       public void onChange(boolean selfChange) {
            super.onChange(selfChange);
       }        
}

}

迈克尔，我写的新课：

import android.app.Activity;
import android.content.Intent;
import android.database.ContentObserver;
import android.database.Cursor;
import android.database.DataSetObserver;
import android.net.Uri;
import android.os.Bundle;
import android.os.Handler;
import android.util.Log;
import android.view.ContextMenu;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.ContextMenu.ContextMenuInfo;
import android.widget.Button;
import android.widget.ExpandableListAdapter;
import android.widget.ExpandableListView;
import android.widget.Toast;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.LoaderManager;
import android.support.v4.content.CursorLoader;
import android.support.v4.content.Loader;
import android.support.v4.widget.CursorAdapter;


public class ActPlacesManagement extends FragmentActivity
implements LoaderManager.LoaderCallbacks<Cursor>{


private static final int DELETE_ID = Menu.FIRST;

private static final String TAG = null;


public Cursor mPlacesCursor;
public Cursor mBoxesCursor;
ExpandableListView lstCategorias;
AdpPlacesManagement adapter;
String message, message1, message2;
String novo_local, nova_caixa;
Button btnNewPlace, btnNewBox;
Handler handler;
LoaderManager loaderManager = getSupportLoaderManager();

private static final String[] PROJECTION_PLACES = new String[] {
    ProvPersonalArchive.KEY_ROWID_PLACES, // 0
    ProvPersonalArchive.KEY_DESIG_PLACES, // 1
};

private static final String[] PROJECTION_BOXES = new String[] {
    ProvPersonalArchive.KEY_ROWID_BOXES, // 0
    ProvPersonalArchive.KEY_DESIG_BOXES, // 1
    ProvPersonalArchive.KEY_PLACE_BOXES, // 2
};

private static final int PLACES_LOADER = 1;
private static final int BOXES_LOADER = 2;


private LoaderManager.LoaderCallbacks<Cursor> mCallbacks;

@Override
protected void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);
    setContentView(R.layout.act_places_management);       

    mPlacesCursor = getContentResolver().query(ProvPersonalArchive.CONTENT_URI_PLACES, 
            PROJECTION_PLACES, null, null, null);

    mBoxesCursor = getContentResolver().query(ProvPersonalArchive.CONTENT_URI_BOXES, 
            PROJECTION_BOXES, null, null, null);


    // Lista de locais e caixas

    lstCategorias = (ExpandableListView)this.findViewById(R.id.expandableGestaoCategorias);

    adapter = new AdpPlacesManagement(this, mPlacesCursor, mBoxesCursor, this);     

    lstCategorias.setAdapter(adapter);

    lstCategorias.setOnGroupClickListener(new ExpandableListView.OnGroupClickListener() {

        @Override
        public boolean onGroupClick(ExpandableListView parent, View v,
                int groupPosition, long id) {
            return lstCategorias_onGroupClick(parent, v, groupPosition, id);
        }
    });

    lstCategorias.setOnChildClickListener(new ExpandableListView.OnChildClickListener() {

        @Override
        public boolean onChildClick(ExpandableListView parent, View v,
                int groupPosition, int childPosition, long id) {
            return lstCategorias_onChildClick(parent, v, groupPosition, childPosition, id);
        }
    });


    // Botões para novo lugar e caixa

    btnNewPlace = (Button)this.findViewById(R.act_gestao_categorias.novo_lugar);
    btnNewBox = (Button)this.findViewById(R.act_gestao_categorias.nova_caixa);

    btnNewPlace.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View v) {
            btnNewPlace_onClick(v);
        }
    });

    btnNewBox.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View v) {
            btnNewBox_onClick(v);
        }
    });

    registerForContextMenu(lstCategorias);

    getSupportLoaderManager().initLoader(BOXES_LOADER, null, mCallbacks);
    getSupportLoaderManager().initLoader(PLACES_LOADER, null, mCallbacks);

}


// Eventos da lista de locais e caixas

public boolean lstCategorias_onGroupClick(ExpandableListView parent, View v,
        int groupPosition, long id) {
    return false;
}

public boolean lstCategorias_onChildClick(ExpandableListView parent, View v,
        int groupPosition, int childPosition, long id) {
    return false;
}


public void finish() { 
  Intent data = new Intent();
  setResult(RESULT_OK, data);
  data.putExtra("local", message);
  super.finish();
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    MenuInflater inflater = getMenuInflater();
    inflater.inflate(R.menu.act_start, menu);
    return true;
}


// Eventos dos botões para criar novo local e caixa

public void btnNewPlace_onClick(View view) {
    Intent intent = new Intent(this, ActNewPlace.class);
    startActivityForResult(intent, 1);
}

public void btnNewBox_onClick(View view) {
    Intent intent = new Intent(this, ActNewBox.class);
    startActivityForResult(intent, 2);
}

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
      if (resultCode == RESULT_OK && requestCode == 1) {
        if (data.hasExtra("novo_local") && data.hasExtra("nova_caixa")) {
            Toast.makeText(this, "New place created!", Toast.LENGTH_LONG).show();
        }
      }
      if (resultCode == RESULT_OK && requestCode == 2) {
        if (data.hasExtra("novo_local") && data.hasExtra("nova_caixa")) {
            String novo_local = data.getExtras().getString("novo_local");
            String nova_caixa = data.getExtras().getString("nova_caixa");
            Toast.makeText(this, novo_local + nova_caixa, Toast.LENGTH_LONG).show();
        }
      }
    }



// Menu de contexto

public void onCreateContextMenu(ContextMenu menu, View v, ContextMenuInfo menuInfo) {
super.onCreateContextMenu(menu, v, menuInfo);
ExpandableListView.ExpandableListContextMenuInfo info;

try {
    // Casts the incoming data object into the type for AdapterView objects.
    info = (ExpandableListView.ExpandableListContextMenuInfo) menuInfo;
} catch (ClassCastException e) {
    // If the menu object can't be cast, logs an error.
    Log.e(TAG, "bad menuInfo", e);
    return;
}


int place = ExpandableListView.getPackedPositionGroup(info.packedPosition);
int box = ExpandableListView.getPackedPositionChild(info.packedPosition);
int tipo_clic = ExpandableListView.getPackedPositionType(info.packedPosition);
String titulo = null;

if (tipo_clic == ExpandableListView.PACKED_POSITION_TYPE_CHILD){
    titulo = (String) adapter.getChild(place, box);
    menu.add(0, DELETE_ID, 0, R.string.delete_box);
}

if (tipo_clic == ExpandableListView.PACKED_POSITION_TYPE_GROUP){
    titulo = (String) adapter.getGroup(place);
    menu.add(0, DELETE_ID, 0, R.string.delete_place);
}

if (titulo == null) {
    // For some reason the requested item isn't available, do nothing
    return;
}
menu.setHeaderTitle(titulo);

}


public boolean onContextItemSelected(MenuItem item) {
ExpandableListView.ExpandableListContextMenuInfo info =     
(ExpandableListView.ExpandableListContextMenuInfo) item.getMenuInfo();
int tipo_clic = ExpandableListView.getPackedPositionType(info.packedPosition);
switch(item.getItemId()) {
case DELETE_ID:
    if (tipo_clic == ExpandableListView.PACKED_POSITION_TYPE_CHILD){
        Toast.makeText(this, "The box was deleted", Toast.LENGTH_LONG).show();
    }

    if (tipo_clic == ExpandableListView.PACKED_POSITION_TYPE_GROUP){
        Toast.makeText(this, "The place was deleted", Toast.LENGTH_LONG).show();
    }
    return true;
}
return super.onContextItemSelected(item);
}


public Loader<Cursor> onCreateLoader(int id, Bundle arg1) {

CursorLoader cursorLoader = new CursorLoader(getBaseContext());

if (id == BOXES_LOADER){
    cursorLoader = new CursorLoader(ActPlacesManagement.this,
 ProvPersonalArchive.CONTENT_URI_BOXES, PROJECTION_BOXES, null, null, null);
 };

 if (id == PLACES_LOADER){
     cursorLoader = new CursorLoader(ActPlacesManagement.this,
  ProvPersonalArchive.CONTENT_URI_PLACES, PROJECTION_PLACES, null, null, null);
  };

return cursorLoader;
}



public void onLoadFinished(Loader<Cursor> loader, Cursor cursor) {

switch (loader.getId()) {
case BOXES_LOADER:
    mPlacesCursor = cursor;
  break;
case PLACES_LOADER:
    mBoxesCursor = cursor;
    break;
} 

adapter = new AdpPlacesManagement(this, mPlacesCursor, mBoxesCursor, this);     

lstCategorias.setAdapter(adapter);
}



public void onLoaderReset(Loader<Cursor> loader) {
switch (loader.getId()) {
case BOXES_LOADER:
    mPlacesCursor = null;
  break;
case PLACES_LOADER:
    mBoxesCursor = null;
    break;
} 

adapter = new AdpPlacesManagement(this, mPlacesCursor, mBoxesCursor, this);

}

public class ObsPersonalArchive extends ContentObserver {

    public ObsPersonalArchive(Handler handler) {
        super(handler);        
        }
       @Override
       public void onChange(boolean selfChange) {
            super.onChange(selfChange);
       }        
}   
}

和错误

12-17 17:28:59.775: I/ActivityThread(16376): 进入进程活动消息 = 101 12-17 17:28:59.795: I/ActivityThread(16376): 退出进程活动消息 = 101 12-17 17:28 :59.805: I/ActivityThread(16376): 进入进程活动 msg = 100 12-17 17:28:59.905: W/dalvikvm(16376): threadid=1: 线程退出未捕获异常 (group=0x2aacc8a0) 12-17 17 ：28：59.915：E / AndroidRuntime（16376）：致命异常：主要12-17 17：28：59.915：E / AndroidRuntime（16376）：java.lang.RuntimeException：无法启动活动ComponentInfo {com.smartmobilelife.personal。存档/com.smartmobilelife.personal.archive.ActPlacesManagement}：java.lang.NullPointerException 12-17 17:28:59.915：E/AndroidRuntime(16376)：在 android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2705) 12 -17 17:28:59.915：E/AndroidRuntime（16376）：在 android.app。ActivityThread.handleLaunchActivity(ActivityThread.java:2721) 12-17 17:28:59.915: E/AndroidRuntime(16376): 在 android.app.ActivityThread.access$2300(ActivityThread.java:132) 12-17 17:28:59.915 : E/AndroidRuntime(16376): 在 android.app.ActivityThread$H.handleMessage(ActivityThread.java:2071) 12-17 17:28:59.915: E/AndroidRuntime(16376): 在 android.os.Handler.dispatchMessage( Handler.java:99) 12-17 17:28:59.915: E/AndroidRuntime(16376): 在 android.os.Looper.loop(Looper.java:123) 12-17 17:28:59.915: E/AndroidRuntime( 16376): 在 android.app.ActivityThread.main(ActivityThread.java:4669) 12-17 17:28:59.915: E/AndroidRuntime(16376): 在 java.lang.reflect.Method.invokeNative(Native Method) 12- 17 17:28:59.915: E/AndroidRuntime(16376): 在 java.lang.reflect.Method.invoke(Method.java:521) 12-17 17:28:59.915:E/AndroidRuntime(16376): 在 com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:876) 12-17 17:28:59.915: E/AndroidRuntime(16376): 在 com.android.internal .os.ZygoteInit.main(ZygoteInit.java:634) 12-17 17:28:59.915: E/AndroidRuntime(16376): at dalvik.system.NativeStart.main(Native Method) 12-17 17:28:59.915: E/AndroidRuntime(16376): 引起: java.lang.NullPointerException 12-17 17:28:59.915: E/AndroidRuntime(16376): at android.support.v4.app.LoaderManagerImpl.createLoader(LoaderManager.java:487) 12-17 17:28:59.915: E/AndroidRuntime(16376): 在 android.support.v4.app.LoaderManagerImpl.createAndInstallLoader(LoaderManager.java:496) 12-17 17:28:59.915: E/AndroidRuntime(16376) ：在 android.support.v4.app.LoaderManagerImpl.initLoader(LoaderManager.java:550) 12-17 17:28:59.915:E/AndroidRuntime(16376): 在 com.smartmobilelife.personal.archive.ActPlacesManagement.onCreate(ActPlacesManagement.java:131) 12-17 17:28:59.915: E/AndroidRuntime(16376): 在 android.app.Instrumentation.callActivityOnCreate (Instrumentation.java:1047) 12-17 17:28:59.915: E/AndroidRuntime(16376): 在 android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2669) 12-17 17:28:59.915: E/AndroidRuntime (16376): ... 11 更多还有 11 个还有 11 个

4

1 回答 1

0

我建议使用 CursorLoader 并在收到更新时更新列表适配器上的光标。

CursorLoaders 默认是 ContentObservers，你只需要确保你的 ContentProvider 在返回查询游标时设置正确的 uri 并且通知更新/插入/删除的变化。

CursorLoader 文档：http: //developer.android.com/reference/android/content/CursorLoader.html

LoaderManager.LoaderCallbacks<Cursor> mLoaderCallback = new LoaderManager.LoaderCallbacks<Cursor>() {

@Override

public Loader<Cursor> onCreateLoader(int id, Bundle args) {

    CursorLoader loader = new CursorLoader(context);

    loader.setProjection(args.getStringArray("projection"));

    loader.setSelection(args.getString("selection"));

    loader.setSelectionArgs(args.getStringArray("selectionArgs"));

    loader.setUri(Uri.parse(args.getString("uri")));



    return loader;

}



@Override

public void onLoadFinished(Loader<Cursor> cursorLoader, Cursor cursor) {

    if (cursor == null) {

       return;

    }



    YourListAdapter adapter = (YourListAdapter) getListAdapter();

    adapter.swapCursor(cursor);

}



@Override

public void onLoaderReset(Loader<Cursor> cursorLoader) {

    YourListAdapter adapter = (YourListAdapter) getListAdapter();

    adapter.swapCursor(null);

}

};



/* Calling a loader sample. */



Bundle loaderArgs = new Bundle();

loaderArgs.putString("uri", URI);

loaderArgs.putStringArray("projection", PROJECTION);



LoaderManager loaderManager = getLoaderManager();

loaderManager.initLoader(YOUR_LOADER_ID, loaderArgs, mYourLoaderCallback);
于 2012-12-17T13:29:29.307 回答