这是我的Arrival.java
package one.two;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import android.app.ListActivity;
import android.database.Cursor;
import android.os.Bundle;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.SimpleCursorAdapter;
public class Arrival extends ListActivity
{
private ListView listView;
/** Called when the activity is first created. */
public void onCreate(Bundle savedInstanceState)
{
ArrayList<String> retList = new ArrayList<String>();
System.out.println("Start onCreate Function\n");
super.onCreate(savedInstanceState);
setContentView(R.layout.listview);
System.out.println("In onCreate Function\n");
System.out.println("In of GetData\n");
DBAdapter db = new DBAdapter(this);
System.out.println("DB Open\n");
db.open();
System.out.println("DB Opened\n");
retList = getData();
System.out.println("Out of GetData\n");
// force count no. of records in table
// dump to check index
int cnt = 2;
int i=0;
for (i = 0; i<cnt; i++)
System.out.println(retList.toString());
System.out.println("Array 2 String\n");
Cursor c = db.getCursor();
String[] from = new String[] {DBAdapter.status};
int[] to = new int[] {R.id.txt1};
SimpleCursorAdapter mAdapter = new SimpleCursorAdapter(this, R.layout.listtext, c, from, to);
this.setListAdapter(mAdapter);
System.out.println("Show List\n");
db.close();
}
public static ArrayList<String> getData()
{
ArrayList<String> items = DBAdapter.getAllTitles();
System.out.println("Return a LIST titles\n");
return items;
}
}
DBAdapter.java
package one.two;
import java.util.List;
import android.app.ListActivity;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.database.sqlite.SQLiteDatabase.CursorFactory;
import java.util.ArrayList;
public class DBAdapter
{
public static String status = "status";
public String id = "id";
public String arrival = "arrival";
public String destination = "destination";
public String ferry = "ferry";
private static String DB_PATH = "/data/data/one.two/databases/";
private static final String DATABASE_NAME = "ferry.db";
private static final String DATABASE_TABLE = "port";
public static Context context;
public Cursor c;
public static SQLiteDatabase DbLib;
//overloaded non-null constructor
public DBAdapter(Context context)
{
DbLib = context.openOrCreateDatabase(DATABASE_NAME, SQLiteDatabase.CREATE_IF_NECESSARY,null);
System.out.println("OpenOrCreateDB Done");
}
public class DatabaseHelper extends SQLiteOpenHelper
{
Context context;
DatabaseHelper(Context context)
{
super(context, DATABASE_NAME, null, DATABASE_VERSION);
this.context = context;
}//end constructor DatabaseHelper
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion,
int newVersion)
{
}//end onUpgrade()
@Override
public void onCreate(SQLiteDatabase db)
{
}//end onCreate()
}// end class DatabaseHelper
private static DatabaseHelper DBHelper;
//private static SQLiteDatabase DbLib;
private static final int DATABASE_VERSION = 1;
//// context brought up /////////////
//private final Context context;
/*public void DBAdapter() throws SQLException
{
String myPath = DB_PATH + DATABASE_NAME;
db = SQLiteDatabase.openDatabase(myPath, null,
SQLiteDatabase.OPEN_READONLY);
}//end DBAdapter()*/
public static ArrayList<String> getAllTitles()
{
ArrayList<String> port = new ArrayList<String>();
Cursor c=null;
c = DbLib.query("port",
new String[] { "status", "id", "arrival",
"destination", "ferry" }, null, null,
null, null, null);
try {
if (c!=null) { // start - when there is at least 1 record
System.out.println("Cursor is NOT NULL");
int i =0;
for (c.moveToFirst(); !c.isAfterLast(); c.moveToNext())
{
// Debug Stm
System.out.println("Record No. "+i);
System.out.println(c.getString(0));
System.out.println(c.getString(1));
System.out.println(c.getString(2));
System.out.println(c.getString(3));
System.out.println(c.getString(4));
// Assign database cursor.records to arraylist
port.add(i,c.getString(0));
port.add(i,c.getString(1));
port.add(i,c.getString(2));
port.add(i,c.getString(3));
port.add(i,c.getString(4));
i = i + 1;
}
} // end - where there is at least 1 record
} finally {
if (c!=null) {
c.close();
}
}
return port;
}//end getAllTitles()
public void open() {
//Open the database
String myPath = DB_PATH + DATABASE_NAME;
DbLib = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);
}
public Cursor getCursor(){
return c;
}
public void close()
{
DbLib.close();
}
}//end class DBAdapter
main.xml中
<?xml version="1.0" encoding="utf-8"?>
<AbsoluteLayout
android:id="@+id/widget0"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
xmlns:android="http://schemas.android.com/apk/res/android"
>
<TextView
android:id="@+id/widget32"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Ferry Hub"
android:textSize="25sp"
android:textStyle="bold"
android:textColor="#ff009999"
android:layout_x="97px"
android:layout_y="15px"
>
</TextView>
<TextView
android:id="@+id/widget35"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Arrival Time"
android:layout_x="116px"
android:layout_y="48px"
>
</TextView>
<TextView
android:id="@+id/Text1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text=""
android:layout_x="200px"
android:layout_y="90px"
>
</TextView>
<Button
android:id="@+id/widget36"
android:layout_width="96px"
android:layout_height="40px"
android:text="Back"
android:layout_x="101px"
android:layout_y="299px"
>
</Button>
<ListView
android:layout_width="wrap_content"
android:layout_y="132dip"
android:layout_x="150dip"
android:id="@android:id/list"
android:layout_height="wrap_content">
</ListView>
</AbsoluteLayout>
logcat错误：
07-23 07:00:45.625: ERROR/AndroidRuntime(725): Uncaught handler: thread main exiting due to uncaught exception
07-23 07:00:45.654: ERROR/AndroidRuntime(725): java.lang.RuntimeException: Unable to start activity ComponentInfo{one.two/one.two.Departure}: java.lang.ClassCastException: java.util.ArrayList
07-23 07:00:45.654: ERROR/AndroidRuntime(725): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2268)
07-23 07:00:45.654: ERROR/AndroidRuntime(725): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2284)
07-23 07:00:45.654: ERROR/AndroidRuntime(725): at android.app.ActivityThread.access$1800(ActivityThread.java:112)
07-23 07:00:45.654: ERROR/AndroidRuntime(725): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1692)
07-23 07:00:45.654: ERROR/AndroidRuntime(725): at android.os.Handler.dispatchMessage(Handler.java:99)
07-23 07:00:45.654: ERROR/AndroidRuntime(725): at android.os.Looper.loop(Looper.java:123)
07-23 07:00:45.654: ERROR/AndroidRuntime(725): at android.app.ActivityThread.main(ActivityThread.java:3948)
07-23 07:00:45.654: ERROR/AndroidRuntime(725): at java.lang.reflect.Method.invokeNative(Native Method)
07-23 07:00:45.654: ERROR/AndroidRuntime(725): at java.lang.reflect.Method.invoke(Method.java:521)
07-23 07:00:45.654: ERROR/AndroidRuntime(725): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:782)
07-23 07:00:45.654: ERROR/AndroidRuntime(725): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:540)
07-23 07:00:45.654: ERROR/AndroidRuntime(725): at dalvik.system.NativeStart.main(Native Method)
07-23 07:00:45.654: ERROR/AndroidRuntime(725): Caused by: java.lang.ClassCastException: java.util.ArrayList
07-23 07:00:45.654: ERROR/AndroidRuntime(725): at one.two.Departure.onCreate(Departure.java:27)
07-23 07:00:45.654: ERROR/AndroidRuntime(725): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1123)
07-23 07:00:45.654: ERROR/AndroidRuntime(725): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2231)
07-23 07:00:45.654: ERROR/AndroidRuntime(725): ... 11 more
我知道为什么我的ListView上没有显示任何数据？
答案 0 :(得分：1)
我的代码中有两个错误，我现在可以发现。第一个应该不是问题。您正在创建两个ListAdapter并将它们设置为两者。
setListAdapter(new SimpleCursorAdapter(this, android.R.id.list, c, from, to));
SimpleCursorAdapter mAdapter = new SimpleCursorAdapter(this, android.R.id.list, c, from, to);
this.setListAdapter(mAdapter);
接下来是您定义SimpleCursorAdapter的方式：
new SimpleCursorAdapter(this, android.R.id.list, c, from, to)
如在Documentatio中所见，SimpleCursorAdapter需要一个布局的id，该布局将用作List中的单元格。您正在提供列表本身的ID。适配器现在将在项目中查找与android列表具有相同ID的布局文件，然后尝试对此布局进行膨胀，并找到to数组中提到的视图，并将光标的值设置为此值。那不行。至少应该在Logcat中看到错误。
此外，您提供的to id不应位于主布局中，而应位于行布局本身中。如果没有显示错误，你确定光标中有数据吗？
答案 1 :(得分：0)
在使用数据填充容器后，尝试在适配器上手动调用notifyDataSetChanged。