El cambio amplía la clase de actividad

Hola estoy intentando crear mi primera aplicación en android. Lo siento mucho por la pregunta estúpida, pero estoy desesperado.

He creado nueva aplicación con actividad en blanco en el estudio de Android.

XML:

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" android:paddingLeft="@dimen/activity_horizontal_margin" android:paddingRight="@dimen/activity_horizontal_margin" android:paddingTop="@dimen/activity_vertical_margin" android:paddingBottom="@dimen/activity_vertical_margin" tools:context=".MainActivity"> <TextView android:text="@string/hello_world" android:layout_width="wrap_content" android:layout_height="wrap_content" /> </RelativeLayout> 

Java:

 public class MainActivity extends AppCompatActivity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); } . . . } 

Entonces quiero cambiar la clase extendida de la actividad a ListActivity:

 public class MainActivity extends ListActivity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); } . . . } 

Cuando lo ejecuto (sin otros cambios) en aplicaciones móviles se bloquea con algo como "Aplicación xy se ha detenido".

Sé que esto es un fracaso estúpido, pero no sé cómo puedo solucionarlo.

Manifiesto:

 <?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.example.kubitas.listviewapp" > <application android:allowBackup="true" android:icon="@mipmap/ic_launcher" android:label="@string/app_name" android:theme="@style/AppTheme" > <activity android:name=".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> </application> </manifest> 

Por favor, ayúdame.

Una ListActivity debe tener una lista declarada en la actividad denominada: "@android: id / list". Este es un requisito de usar ListActivity. Si no está usando realmente una ListActivity entonces necesita extender Actividad o AppCompatActivity en su lugar. Si quieres jugar con una ListActivity a continuación, agrega un ListView en su archivo de diseño y el nombre que tengo a continuación.

Por favor, consulte: http://developer.android.com/reference/android/app/ListActivity.html

 <?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" android:paddingLeft="@dimen/activity_horizontal_margin" android:paddingRight="@dimen/activity_horizontal_margin" android:paddingTop="@dimen/activity_vertical_margin" android:paddingBottom="@dimen/activity_vertical_margin" tools:context=".MainActivity"> <ListView android:layout_width="wrap_content" android:layout_height="wrap_content" android:id="@android:id/list" android:layout_centerVertical="true" android:layout_centerHorizontal="true" /> </RelativeLayout> 

La clase que extiende ListActivity

 public class MainActivity extends ListActivity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); } } 

Decidió responder en vez de comentar 🙂

El problema podría estar relacionado con el hecho de que ListActivity no extiende AppCompatActivity y es probable que utilice un tema de la biblioteca de soporte. Volvería a AppCompatActivity y usaría un fragmento android.support.v4.app.ListFragment .

El otro problema podría ser que ListActivity espera que su diseño tenga un ListView con un id de "@android: id / list"

En una de mis aplicaciones no quería cambiar a un ListFragment así que hackeado juntos un AppCompactListActivity que extiende AppCompatActivity :

 import android.os.Handler; import android.view.View; import android.view.animation.AnimationUtils; import android.widget.AdapterView; import android.widget.ListAdapter; import android.widget.ListView; import android.widget.TextView; public abstract class AppCompatListActivity extends android.support.v7.app.AppCompatActivity { static final int INTERNAL_EMPTY_ID = 0x00ff0001; static final int INTERNAL_PROGRESS_CONTAINER_ID = 0x00ff0002; static final int INTERNAL_LIST_CONTAINER_ID = 0x00ff0003; final private Handler mHandler = new Handler(); final private Runnable mRequestFocus = new Runnable() { public void run() { mList.focusableViewAvailable(mList); } }; final private AdapterView.OnItemClickListener mOnClickListener = new AdapterView.OnItemClickListener() { public void onItemClick(AdapterView<?> parent, View v, int position, long id) { onListItemClick((ListView)parent, v, position, id); } }; ListAdapter mAdapter; ListView mList; View mEmptyView; TextView mStandardEmptyView; View mProgressContainer; View mListContainer; CharSequence mEmptyText; boolean mListShown; public AppCompatListActivity() { } /** * Provide default implementation to return a simple list view. Subclasses * can override to replace with their own layout. If doing so, the * returned view hierarchy <em>must</em> have a ListView whose id * is {@link android.R.id#list android.R.id.list} and can optionally * have a sibling view id {@link android.R.id#empty android.R.id.empty} * that is to be shown when the list is empty. * * <p>If you are overriding this method with your own custom content, * consider including the standard layout {@link android.R.layout#list_content} * in your layout file, so that you continue to retain all of the standard * behavior of ListFragment. In particular, this is currently the only * way to have the built-in indeterminant progress state be shown. */ /* @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { FrameLayout root = new FrameLayout(context); // ------------------------------------------------------------------ LinearLayout pframe = new LinearLayout(context); pframe.setId(INTERNAL_PROGRESS_CONTAINER_ID); pframe.setOrientation(LinearLayout.VERTICAL); pframe.setVisibility(View.GONE); pframe.setGravity(Gravity.CENTER); ProgressBar progress = new ProgressBar(context, null, android.R.attr.progressBarStyleLarge); pframe.addView(progress, new FrameLayout.LayoutParams( ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT)); root.addView(pframe, new FrameLayout.LayoutParams( ViewGroup.LayoutParams.FILL_PARENT, ViewGroup.LayoutParams.FILL_PARENT)); // ------------------------------------------------------------------ FrameLayout lframe = new FrameLayout(context); lframe.setId(INTERNAL_LIST_CONTAINER_ID); TextView tv = new TextView(getActivity()); tv.setId(INTERNAL_EMPTY_ID); tv.setGravity(Gravity.CENTER); lframe.addView(tv, new FrameLayout.LayoutParams( ViewGroup.LayoutParams.FILL_PARENT, ViewGroup.LayoutParams.FILL_PARENT)); ListView lv = new ListView(getActivity()); lv.setId(android.R.id.list); lv.setDrawSelectorOnTop(false); lframe.addView(lv, new FrameLayout.LayoutParams( ViewGroup.LayoutParams.FILL_PARENT, ViewGroup.LayoutParams.FILL_PARENT)); root.addView(lframe, new FrameLayout.LayoutParams( ViewGroup.LayoutParams.FILL_PARENT, ViewGroup.LayoutParams.FILL_PARENT)); // ------------------------------------------------------------------ root.setLayoutParams(new FrameLayout.LayoutParams( ViewGroup.LayoutParams.FILL_PARENT, ViewGroup.LayoutParams.FILL_PARENT)); return root; } @Override public void onViewCreated(View view, Bundle savedInstanceState) { super.onViewCreated(view, savedInstanceState); ensureList(); } */ /** * Detach from list view. */ @Override public void onDestroy() { mHandler.removeCallbacks(mRequestFocus); mList = null; mListShown = false; mEmptyView = mProgressContainer = mListContainer = null; mStandardEmptyView = null; super.onDestroy(); } /** * This method will be called when an item in the list is selected. * Subclasses should override. Subclasses can call * getListView().getItemAtPosition(position) if they need to access the * data associated with the selected item. * * @param l The ListView where the click happened * @param v The view that was clicked within the ListView * @param position The position of the view in the list * @param id The row id of the item that was clicked */ public void onListItemClick(ListView l, View v, int position, long id) { } /** * Provide the cursor for the list view. */ public void setListAdapter(ListAdapter adapter) { boolean hadAdapter = mAdapter != null; mAdapter = adapter; if (mList != null) { mList.setAdapter(adapter); if (!mListShown && !hadAdapter) { // The list was hidden, and previously didn't have an // adapter. It is now time to show it. //setListShown(true, getView().getWindowToken() != null); setListShown(true, false); } } } /** * Set the currently selected list item to the specified * position with the adapter's data * * @param position - */ public void setSelection(int position) { ensureList(); mList.setSelection(position); } /** * Get the position of the currently selected list item. */ public int getSelectedItemPosition() { ensureList(); return mList.getSelectedItemPosition(); } /** * Get the cursor row ID of the currently selected list item. */ public long getSelectedItemId() { ensureList(); return mList.getSelectedItemId(); } /** * Get the activity's list view widget. */ public ListView getListView() { ensureList(); return mList; } /** * The default content for a ListFragment has a TextView that can * be shown when the list is empty. If you would like to have it * shown, call this method to supply the text it should use. */ public void setEmptyText(CharSequence text) { ensureList(); if (mStandardEmptyView == null) { throw new IllegalStateException("Can't be used with a custom content view"); } mStandardEmptyView.setText(text); if (mEmptyText == null) { mList.setEmptyView(mStandardEmptyView); } mEmptyText = text; } /** * Control whether the list is being displayed. You can make it not * displayed if you are waiting for the initial data to show in it. During * this time an indeterminant progress indicator will be shown instead. * * <p>Applications do not normally need to use this themselves. The default * behavior of ListFragment is to start with the list not being shown, only * showing it once an adapter is given with {@link #setListAdapter(ListAdapter)}. * If the list at that point had not been shown, when it does get shown * it will be do without the user ever seeing the hidden state. * * @param shown If true, the list view is shown; if false, the progress * indicator. The initial value is true. */ public void setListShown(boolean shown) { setListShown(shown, true); } /** * Like {@link #setListShown(boolean)}, but no animation is used when * transitioning from the previous state. */ public void setListShownNoAnimation(boolean shown) { setListShown(shown, false); } /** * Control whether the list is being displayed. You can make it not * displayed if you are waiting for the initial data to show in it. During * this time an indeterminant progress indicator will be shown instead. * * @param shown If true, the list view is shown; if false, the progress * indicator. The initial value is true. * @param animate If true, an animation will be used to transition to the * new state. */ private void setListShown(boolean shown, boolean animate) { ensureList(); if (mProgressContainer == null) { throw new IllegalStateException("Can't be used with a custom content view"); } if (mListShown == shown) { return; } mListShown = shown; if (shown) { if (animate) { mProgressContainer.startAnimation(AnimationUtils.loadAnimation(this, android.R.anim.fade_out)); mListContainer.startAnimation(AnimationUtils.loadAnimation(this, android.R.anim.fade_in)); } else { mProgressContainer.clearAnimation(); mListContainer.clearAnimation(); } mProgressContainer.setVisibility(View.GONE); mListContainer.setVisibility(View.VISIBLE); } else { if (animate) { mProgressContainer.startAnimation(AnimationUtils.loadAnimation(this, android.R.anim.fade_in)); mListContainer.startAnimation(AnimationUtils.loadAnimation(this, android.R.anim.fade_out)); } else { mProgressContainer.clearAnimation(); mListContainer.clearAnimation(); } mProgressContainer.setVisibility(View.VISIBLE); mListContainer.setVisibility(View.GONE); } } /** * Get the ListAdapter associated with this activity's ListView. */ public ListAdapter getListAdapter() { return mAdapter; } private void ensureList() { if (mList != null) { return; } View root = findViewById(android.R.id.content).getRootView(); if (root == null) { throw new IllegalStateException("Content view not yet created"); } if (root instanceof ListView) { mList = (ListView)root; } else { mStandardEmptyView = (TextView)root.findViewById(INTERNAL_EMPTY_ID); if (mStandardEmptyView == null) { mEmptyView = root.findViewById(android.R.id.empty); } else { mStandardEmptyView.setVisibility(View.GONE); } mProgressContainer = root.findViewById(INTERNAL_PROGRESS_CONTAINER_ID); mListContainer = root.findViewById(INTERNAL_LIST_CONTAINER_ID); View rawListView = root.findViewById(android.R.id.list); if (!(rawListView instanceof ListView)) { if (rawListView == null) { throw new RuntimeException( "Your content must have a ListView whose id attribute is " + "'android.R.id.list'"); } throw new RuntimeException( "Content has view with id attribute 'android.R.id.list' " + "that is not a ListView class"); } mList = (ListView)rawListView; if (mEmptyView != null) { mList.setEmptyView(mEmptyView); } else if (mEmptyText != null) { mStandardEmptyView.setText(mEmptyText); mList.setEmptyView(mStandardEmptyView); } } mListShown = true; mList.setOnItemClickListener(mOnClickListener); if (mAdapter != null) { ListAdapter adapter = mAdapter; mAdapter = null; setListAdapter(adapter); } else { // We are starting without an adapter, so assume we won't // have our data right away and start with the progress indicator. if (mProgressContainer != null) { setListShown(false, false); } } mHandler.post(mRequestFocus); } } 

La mayor parte del código se tomó prestado de la implementación de ListFragment por lo que verá los métodos onCreateView y onViewCreated .

  • No se puede resolver el método getMap ()
  • Android: pase el objeto a través de bluetooth
  • (Retrofit) No se pudo localizar el convertidor para la aplicación de bloqueo de clase
  • Reflexión para un campo que va mal
  • Impresión arabe de Android usando la impresora cebra imz320 muestra como carácter invertido
  • JSONParser no se puede resolver a un tipo
  • ¿Cómo puedo hacer que este zip rxjava funcione en paralelo?
  • Cuándo utilizar Enum / Int Constantes
  • Android Cambia el texto de TextView de otra clase
  • Error en la conversión de fechas en java
  • Cómo realizar una búsqueda binaria de un archivo de texto
  • FlipAndroid es un fan de Google para Android, Todo sobre Android Phones, Android Wear, Android Dev y Aplicaciones para Android Aplicaciones.