我有一个代码从数据库中检索并在listView中显示结果..当我试图复制代码并将其粘贴到另一个项目，这是平板电脑应用程序，它没有工作！为什么？有人可以告诉我吗？
这是我的java类
public class EditExs extends ListActivity {
// Progress Dialog
private ProgressDialog pDialog;
// Creating JSON Parser object
JSONParser jParser = new JSONParser();
ArrayList<HashMap<String, String>> productsList;
// url to get all products list
private static String url_all_products = "http://www.lamia.byethost18.com/get_all_ex.php";
// JSON Node names
private static final String TAG_SUCCESS = "success";
private static final String TAG_PRODUCTS = "products";
private static final String TAG_PID = "ID_exercise";
private static final String TAG_NAME = "ID_exercise";
// products JSONArray
JSONArray products = null;
public String cha,lev;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_edit_exs);
Intent i = getIntent();
cha = i.getStringExtra("chapter");
lev = i.getStringExtra("level");
Log.d(null, cha);
Log.d(null, lev);
// Hashmap for ListView
productsList = new ArrayList<HashMap<String, String>>();
// Loading products in Background Thread
new LoadAllProducts().execute();
// Get listview
ListView lv = getListView();
// on seleting single product
// launching Edit Product Screen
lv.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
// getting values from selected ListItem
TextView t=(TextView) view.findViewById(R.id.pid);
String pid =t.getText().toString();
Intent in = new Intent(getApplicationContext(), EditEx.class);
in.putExtra("ID", pid);
startActivity(in);
/* // Starting new intent
Intent in = new Intent(getApplicationContext(),
EditProductActivity.class);
// sending pid to next activity
// starting new activity and expecting some response back
startActivityForResult(in, 100);*/
}
});
}
// Response from Edit Product Activity
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
// if result code 100
if (resultCode == 100) {
// if result code 100 is received
// means user edited/deleted product
// reload this screen again
Intent intent = getIntent();
finish();
startActivity(intent);
}
}
/**
* Background Async Task to Load all product by making HTTP Request
* */
class LoadAllProducts extends AsyncTask<String, String, String> {
/**
* Before starting background thread Show Progress Dialog
* */
@Override
protected void onPreExecute() {
super.onPreExecute();
pDialog = new ProgressDialog(EditExs.this);
pDialog.setMessage("Loading products. Please wait...");
pDialog.setIndeterminate(false);
pDialog.setCancelable(false);
pDialog.show();
}
/**
* getting All products from url
* */
protected String doInBackground(String... args) {
String l=lev;
String ch=cha;
// Building Parameters
List<NameValuePair> params = new ArrayList<NameValuePair>();
//params.add(new BasicNameValuePair("ID_chapter", ch));
//params.add(new BasicNameValuePair("level", l));
// getting JSON string from URL
JSONObject json = jParser.makeHttpRequest(url_all_products, "GET", params);
// Check your log cat for JSON reponse
Log.d("All Products: ", json.toString());
try {
// Checking for SUCCESS TAG
int success = json.getInt(TAG_SUCCESS);
if (success == 1) {
// products found
// Getting Array of Products
products = json.getJSONArray(TAG_PRODUCTS);
// looping through All Products
for (int i = 0; i < products.length(); i++) {
JSONObject c = products.getJSONObject(i);
// Storing each json item in variable
String id = c.getString(TAG_PID);
String name = c.getString(TAG_NAME);
// creating new HashMap
HashMap<String, String> map = new HashMap<String, String>();
// adding each child node to HashMap key => value
map.put(TAG_PID, id);
map.put(TAG_NAME, name);
// adding HashList to ArrayList
productsList.add(map);
}
} else {
// no products found
// Launch Add New product Activity
Intent i = new Intent(getApplicationContext(),
NewProductActivity.class);
// Closing all previous activities
i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(i);
}
} catch (JSONException e) {
e.printStackTrace();
}
return null;
}
/**
* After completing background task Dismiss the progress dialog
* **/
protected void onPostExecute(String file_url) {
// dismiss the dialog after getting all products
pDialog.dismiss();
// updating UI from Background Thread
runOnUiThread(new Runnable() {
public void run() {
/**
* Updating parsed JSON data into ListView
* */
ListAdapter adapter = new SimpleAdapter(
EditExs.this, productsList,
R.layout.item_list_3, new String[] {TAG_NAME},
new int[] { R.id.pid});
// updating listview
setListAdapter(adapter);
}
});
}
}
}
activity_edit_exs.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:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".ViewExs" >
<ListView
android:id="@android:id/list"
android:layout_width="fill_parent"
android:layout_height="wrap_content"/>
</RelativeLayout>
item_list_3.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="vertical" >
<TextView
android:id="@+id/pid"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:visibility="visible" />
</RelativeLayout>
我得到的错误是：
10-01 02:02:28.333: E/AndroidRuntime(923): FATAL EXCEPTION: main
10-01 02:02:28.333: E/AndroidRuntime(923): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.anistat/com.example.anistat.AdminEditExs}: java.lang.RuntimeException: Your content must have a ListView whose id attribute is 'android.R.id.list'
10-01 02:02:28.333: E/AndroidRuntime(923): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2211)
10-01 02:02:28.333: E/AndroidRuntime(923): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2261)
10-01 02:02:28.333: E/AndroidRuntime(923): at android.app.ActivityThread.access$600(ActivityThread.java:141)
10-01 02:02:28.333: E/AndroidRuntime(923): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256)
10-01 02:02:28.333: E/AndroidRuntime(923): at android.os.Handler.dispatchMessage(Handler.java:99)
10-01 02:02:28.333: E/AndroidRuntime(923): at android.os.Looper.loop(Looper.java:137)
10-01 02:02:28.333: E/AndroidRuntime(923): at android.app.ActivityThread.main(ActivityThread.java:5103)
10-01 02:02:28.333: E/AndroidRuntime(923): at java.lang.reflect.Method.invokeNative(Native Method)
10-01 02:02:28.333: E/AndroidRuntime(923): at java.lang.reflect.Method.invoke(Method.java:525)
10-01 02:02:28.333: E/AndroidRuntime(923): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
10-01 02:02:28.333: E/AndroidRuntime(923): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
10-01 02:02:28.333: E/AndroidRuntime(923): at dalvik.system.NativeStart.main(Native Method)
10-01 02:02:28.333: E/AndroidRuntime(923): Caused by: java.lang.RuntimeException: Your content must have a ListView whose id attribute is 'android.R.id.list'
10-01 02:02:28.333: E/AndroidRuntime(923): at android.app.ListActivity.onContentChanged(ListActivity.java:243)
10-01 02:02:28.333: E/AndroidRuntime(923): at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:270)
10-01 02:02:28.333: E/AndroidRuntime(923): at android.app.Activity.setContentView(Activity.java:1895)
10-01 02:02:28.333: E/AndroidRuntime(923): at com.example.anistat.AdminEditExs.onCreate(AdminEditExs.java:56)
10-01 02:02:28.333: E/AndroidRuntime(923): at android.app.Activity.performCreate(Activity.java:5133)
10-01 02:02:28.333: E/AndroidRuntime(923): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
10-01 02:02:28.333: E/AndroidRuntime(923): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2175)
10-01 02:02:28.333: E/AndroidRuntime(923): ... 11 more
也试图改变这一行
ListView lv = getListView();
到这个
lv = (ListView) findViewById(android.R.id.list);
但它没有用
我也尝试了一个简单的listview，当我运行它时，项目之间有一个巨大的空间如何解决它？
我想知道手机和平板电脑的实施是否存在差异？
有人能帮帮我吗？谢谢。答案 0 :(得分：1)
好吧我认为问题是在xml文件中声明的上下文中。
只需将tools:context=".ViewExs"更改为tools:context=".EditExs"
检查一下。 多数民众赞成......