当我启动我的应用程序时，我总是收到此消息：“不幸的是，'sql' 已停止”。这是我的 logcat 显示的内容：
07-12 10:53:33.607: E/AndroidRuntime(940): FATAL EXCEPTION: main
07-12 10:53:33.607: E/AndroidRuntime(940): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.formation.sql/com.formation.sql.Main}: java.lang.IllegalArgumentException: column '_id' does not exist
07-12 10:53:33.607: E/AndroidRuntime(940): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1956)
07-12 10:53:33.607: E/AndroidRuntime(940): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1981)
07-12 10:53:33.607: E/AndroidRuntime(940): at android.app.ActivityThread.access$600(ActivityThread.java:123)
07-12 10:53:33.607: E/AndroidRuntime(940): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1147)
07-12 10:53:33.607: E/AndroidRuntime(940): at android.os.Handler.dispatchMessage(Handler.java:99)
07-12 10:53:33.607: E/AndroidRuntime(940): at android.os.Looper.loop(Looper.java:137)
07-12 10:53:33.607: E/AndroidRuntime(940): at android.app.ActivityThread.main(ActivityThread.java:4424)
07-12 10:53:33.607: E/AndroidRuntime(940): at java.lang.reflect.Method.invokeNative(Native Method)
07-12 10:53:33.607: E/AndroidRuntime(940): at java.lang.reflect.Method.invoke(Method.java:511)
07-12 10:53:33.607: E/AndroidRuntime(940): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
07-12 10:53:33.607: E/AndroidRuntime(940): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
07-12 10:53:33.607: E/AndroidRuntime(940): at dalvik.system.NativeStart.main(Native Method)
07-12 10:53:33.607: E/AndroidRuntime(940): Caused by: java.lang.IllegalArgumentException: column '_id' does not exist
07-12 10:53:33.607: E/AndroidRuntime(940): at android.database.AbstractCursor.getColumnIndexOrThrow(AbstractCursor.java:267)
07-12 10:53:33.607: E/AndroidRuntime(940): at android.widget.CursorAdapter.init(CursorAdapter.java:168)
07-12 10:53:33.607: E/AndroidRuntime(940): at android.widget.CursorAdapter.(CursorAdapter.java:116)
07-12 10:53:33.607: E/AndroidRuntime(940): at android.widget.ResourceCursorAdapter.(ResourceCursorAdapter.java:52)
07-12 10:53:33.607: E/AndroidRuntime(940): at android.widget.SimpleCursorAdapter.(SimpleCursorAdapter.java:78)
07-12 10:53:33.607: E/AndroidRuntime(940): at com.formation.sql.Main.DataBind(Main.java:94)
07-12 10:53:33.607: E/AndroidRuntime(940): at com.formation.sql.Main.onCreate(Main.java:33)
07-12 10:53:33.607: E/AndroidRuntime(940): at android.app.Activity.performCreate(Activity.java:4465)
07-12 10:53:33.607: E/AndroidRuntime(940): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1049)
07-12 10:53:33.607: E/AndroidRuntime(940): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1920)
07-12 10:53:33.607: E/AndroidRuntime(940): ... 11 more
这是主要的：
package com.formation.sql;
import android.app.ListActivity;
import android.database.Cursor;
import android.os.Bundle;
import android.os.SystemClock;
import android.view.ContextMenu;
import android.view.ContextMenu.ContextMenuInfo;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.AdapterView;
import android.widget.Button;
import android.widget.ListView;
import android.widget.SimpleCursorAdapter;
import android.widget.Toast;
public class Main extends ListActivity implements OnClickListener {
/** Called when the activity is first created. */
DBAdapter db;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
getListView().setOnCreateContextMenuListener(this);
((Button)findViewById(android.R.id.button1)).setOnClickListener(this);
db = new DBAdapter(this);
db.open();
DataBind();
}
// Création du menu principal
public boolean onCreateOptionsMenu(Menu menu) {
menu.add(0,100,0,"Tout effacer");
return true;
}
// Selection d'un item du menu
public boolean onOptionsItemSelected(MenuItem item) {
switch(item.getItemId()){
case 100:
db.Truncate();
DataBind();
break;
}
return true;
}
@Override // Selection d'un item de la liste
protected void onListItemClick(ListView l, View v, int position, long id) {
Cursor cursor = (Cursor)l.getAdapter().getItem(position);
String titre = cursor.getString(cursor.getColumnIndex("titre"));
Toast.makeText(this,"Item id "+id+" : "+titre, Toast.LENGTH_SHORT).show();
super.onListItemClick(l, v, position, id);
}
@Override // Creation du menu contextuel
public void onCreateContextMenu(ContextMenu menu, View v, ContextMenuInfo menuInfo) {
super.onCreateContextMenu(menu, v, menuInfo);
menu.setHeaderTitle("Action");
menu.add(0,100,0,"Supprimer");
menu.add(0,200,1,"Editer");
}
@Override // Selection d'un item du menu contextuel
public boolean onContextItemSelected(MenuItem item) {
AdapterView.AdapterContextMenuInfo info = (AdapterView.AdapterContextMenuInfo) item.getMenuInfo();
switch(item.getItemId()){
case 100:
db.supprimerprovince(info.id);
DataBind();
break;
case 200:
Toast.makeText(this, "TODO", Toast.LENGTH_SHORT).show();
break;
}
return true;
}
@Override
protected void onDestroy() {
db.close();
super.onDestroy();
}
public void DataBind(){
Cursor c = db.recupererprovinceliste();
startManagingCursor(c);
SimpleCursorAdapter adapter = new SimpleCursorAdapter(this, R.layout.list_item,c,new String[]{"titre","description","codebarre"}, new int[] {R.id.textTitre,R.id.TextDescription,R.id.TextCodeBarre}); setListAdapter(adapter);
}
public void onClick(View v) {
long num = SystemClock.currentThreadTimeMillis();
db.insererprovince(""+num);
DataBind();
}
}
这是创建数据库的 DBAdapter 代码：
package com.formation.sql;
import java.util.ArrayList;
import java.util.List;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.widget.Toast;
public class DBAdapter {
DatabaseHelper DBHelper;
Context context;
SQLiteDatabase db;
public DBAdapter(Context context){
this.context = context;
DBHelper = new DatabaseHelper(context);
}
public class DatabaseHelper extends SQLiteOpenHelper{
Context context;
public DatabaseHelper(Context context) {
super(context, "provinces", null, 1);
this.context = context;
}
public void onCreate(SQLiteDatabase db) {
db.execSQL("create table if not exists provinces (_idprovince INTEGER PRIMARY KEY AUTOINCREMENT,"
+"nomprovince text not null"
+");");
}
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
Toast.makeText(context, "Mise à jour de la Base de données version "+oldVersion+" vers "+newVersion, Toast.LENGTH_SHORT).show();
db.execSQL("DROP TABLE IF EXISTS provinces");
onCreate(db);
}
}
public DBAdapter open(){
db = DBHelper.getWritableDatabase();
return this;
}
public void close(){
db.close();
}
public void Truncate(){
db.execSQL("DELETE FROM provinces");
}
public long insererprovince(String nom){
ContentValues values = new ContentValues();
values.put("nom", nom);
return db.insert("provinces", null, values);
}
public boolean supprimerprovince(long id){
return db.delete("provinces", "_idprovince="+id, null)>0;
}
public Cursor recupererprovinceliste(){
return db.query("provinces",new String[]{"nomprovince"}, null, null, null, null, null);
}
/**
* Getting all labels
* returns list of labels
* */
public List getAllprovinces(){
List labels = new ArrayList();
// Select All Query
String selectQuery = "SELECT * FROM provinces" ;
SQLiteDatabase db = this.getReadableDatabase();
Cursor c = db.rawQuery(selectQuery, null);
// looping through all rows and adding to list
if (c.moveToFirst()) {
do {
labels.add(c.getString(1));
} while (c.moveToNext());
}
// closing connection
c.close();
db.close();
// returning lables
return labels;
}
private SQLiteDatabase getReadableDatabase() {
// TODO Auto-generated method stub
return null;
}
}