的介绍,你怎么能动态插入使用适配器的看法,阅读与适配器建筑平面布置
使用装载机
使用CursorLoader是查询光标作为一个异步任务,以避免与查询阻止你的应用程序的主线程的标准方式。当CursorLoader收到光标结果,LoaderCallbacks收到回调onLoadFinished(),这是你更新了新光标和列表视图然后显示结果的适配器。
虽然CursorLoader API是在Android 3.0的(API级别11)首先介绍,他们也是在支持库可用,以便同时支持运行Android 1.6或更高版本的设备您的应用程序可以使用它们。
有关使用装载机异步加载数据的详细信息,请参阅装载机指南。
例
下面的示例使用ListActivity,它是包括一个ListView作为默认其唯一布局元件的活性。它执行一个查询到联系人提供程序的名字和电话号码的列表。
活动实现了LoaderCallbacks接口,以便使用该动态加载数据的列表视图CursorLoader
public class ListViewLoader extends ListActivity implements LoaderManager.LoaderCallbacks<Cursor> { // This is the Adapter being used to display the list's data SimpleCursorAdapter mAdapter; // These are the Contacts rows that we will retrieve static final String[] PROJECTION = new String[] {ContactsContract.Data._ID, ContactsContract.Data.DISPLAY_NAME}; // This is the select criteria static final String SELECTION = "((" + ContactsContract.Data.DISPLAY_NAME + " NOTNULL) AND (" + ContactsContract.Data.DISPLAY_NAME + " != '' ))"; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); // Create a progress bar to display while the list loads ProgressBar progressBar = new ProgressBar(this); progressBar.setLayoutParams(new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT, Gravity.CENTER)); progressBar.setIndeterminate(true); getListView().setEmptyView(progressBar); // Must add the progress bar to the root of the layout ViewGroup root = (ViewGroup) findViewById(android.R.id.content); root.addView(progressBar); // For the cursor adapter, specify which columns go into which views String[] fromColumns = {ContactsContract.Data.DISPLAY_NAME}; int[] toViews = {android.R.id.text1}; // The TextView in simple_list_item_1 // Create an empty adapter we will use to display the loaded data. // We pass null for the cursor, then update it in onLoadFinished() mAdapter = new SimpleCursorAdapter(this, android.R.layout.simple_list_item_1, null, fromColumns, toViews, 0); setListAdapter(mAdapter); // Prepare the loader. Either re-connect with an existing one, // or start a new one. getLoaderManager().initLoader(0, null, this); } // Called when a new Loader needs to be created public Loader<Cursor> onCreateLoader(int id, Bundle args) { // Now create and return a CursorLoader that will take care of // creating a Cursor for the data being displayed. return new CursorLoader(this, ContactsContract.Data.CONTENT_URI, PROJECTION, SELECTION, null, null); } // Called when a previously created loader has finished loading public void onLoadFinished(Loader<Cursor> loader, Cursor data) { // Swap the new cursor in. (The framework will take care of closing the // old cursor once we return.) mAdapter.swapCursor(data); } // Called when a previously created loader is reset, making the data unavailable public void onLoaderReset(Loader<Cursor> loader) { // This is called when the last Cursor provided to onLoadFinished() // above is about to be closed. We need to make sure we are no // longer using it. mAdapter.swapCursor(null); } @Override public void onListItemClick(ListView l, View v, int position, long id) { // Do something when a list item is clicked } }注:由于此示例执行的联系人提供的查询,如果你想尝试这个代码,你的应用程序必须要求在manifest文件中READ_CONTACTS权限:
<uses-permission android:name="android.permission.READ_CONTACTS" />