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我是一個新的android developper和我得到一個空指針異常，當我嘗試插入數據到sqlite數據庫。Android的sqlite數據庫空指針異常插入
希望有人能幫助我。
這裏是我的代碼：
DatabaseHelper.java
public class DatabaseHelper extends SQLiteOpenHelper {
private static final String TABLE_ALBUM = "table_album";
private static final String COL_ID = "ID";
private static final String COL_ARTIST = "ARTIST";
private static final String COL_TITLE = "TITLE";
private static final String CREATE_BDD = "CREATE TABLE " + TABLE_ALBUM
+ " (" + COL_ID + " INTEGER PRIMARY KEY AUTOINCREMENT, "
+ COL_ARTIST + " TEXT NOT NULL, " + COL_TITLE + " TEXT NOT NULL);";
public DatabaseHelper(Context context, String name, CursorFactory factory,
int version) {
super(context, name, factory, version);
// TODO Auto-generated constructor stub
}
@Override
public void onCreate(SQLiteDatabase db) {
// TODO Auto-generated method stub
db.execSQL(CREATE_BDD);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// TODO Auto-generated method stub
db.execSQL("DROP TABLE " + TABLE_ALBUM + ";");
onCreate(db);
}
}
Album_db.java
public class Album_db {
private static String DATABASE_NAME = "playlist.db";
private static final int VERSION_BDD = 1;
private static final String TABLE_ALBUM = "table_album";
private static final String COL_ID = "ID";
private static final String COL_ARTIST = "ARTIST";
private static final String COL_TITLE = "TITLE";
private SQLiteDatabase db;
private DatabaseHelper oDB;
public Album_db(Context context) {
oDB = new DatabaseHelper(context, DATABASE_NAME, null, VERSION_BDD);
}
public void open() {
db = oDB.getWritableDatabase();
}
public void close() {
oDB.close();
}
public SQLiteDatabase getBd() {
return db;
}
public long insertAlbum(Album album) {
ContentValues values = new ContentValues(); // hashmap
values.put(COL_ARTIST, album.getArtist());
values.put(COL_TITLE, album.getTitle());
return db.insert(TABLE_ALBUM, null, values); // insert ds la base par le ContentValues
}
public int updateAlbum(int id, Album album) {
ContentValues values = new ContentValues();
values.put(COL_ARTIST, album.getArtist());
values.put(COL_TITLE, album.getTitle());
return db.update(TABLE_ALBUM, values, COL_ID + " = " + id,
null);
}
public int removeAlbum(int id) {
// Suppression BDD via id
return db.delete(TABLE_ALBUM, COL_ID + " = " + id, null);
}
public ArrayList<String> getAlbums() {
ArrayList<String> output = new ArrayList<String>();
String[] colonnesARecup = new String[] { "ARTIST", "TITLE" };
Cursor cursorResults = db.query(TABLE_ALBUM, colonnesARecup,
null, null, null, null, "ARTIST asc, TITLE asc", null);
if (null != cursorResults) {
if (cursorResults.moveToFirst()) {
do {
int columnIdxArtiste = cursorResults
.getColumnIndex("ARTIST");
int columnIdxTitre = cursorResults.getColumnIndex("TITLE");
String oItem = cursorResults.getString(columnIdxArtiste)
+ " - " + cursorResults.getString(columnIdxTitre);
output.add(oItem);
} while (cursorResults.moveToNext());
}
}
return output;
}
PlayListActivity.java
public class PlayListActivity extends Activity implements OnClickListener {
/** Called when the activity is first created. */
private static final int CODE_ACTIVITY = 1;
Button btAdd;
Button btList;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
btAdd = (Button) findViewById(R.id.btAdd);
btAdd.setOnClickListener(this);
btList = (Button) findViewById(R.id.btTab2);
btList.setOnClickListener(this);
}
public void onClick(View v) {
// TODO Auto-generated method stub
if (v == btAdd) {
Album_db db = new Album_db(this);
String artiste = ((EditText) this.findViewById(R.id.editArtist))
.getText().toString();
String titre = ((EditText) this.findViewById(R.id.editTitle))
.getText().toString();
Album album = new Album(artiste, titre);
db.insertAlbum(album);
updateList();
}
if (v == btList) {
Intent oIntent = new Intent(PlayListActivity.this,
ListActivity.class);
startActivityForResult(oIntent, CODE_ACTIVITY);
updateList();
}
}
public void updateList() {
Album_db db = new Album_db(this);
ListView listeAlbum = (ListView) this.findViewById(R.id.albListView);
ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,
android.R.layout.simple_list_item_1, db.getAlbums());
listeAlbum.setAdapter(adapter);
}
日誌：
02-09 13:06:22.170: E/AndroidRuntime(531): FATAL EXCEPTION: main
02-09 13:06:22.170: E/AndroidRuntime(531): java.lang.NullPointerException
02-09 13:06:22.170: E/AndroidRuntime(531): at test.themit.com.Album_db.insertAlbum(Album_db.java:42)
02-09 13:06:22.170: E/AndroidRuntime(531): at test.themit.com.PlayListActivity.onClick(PlayListActivity.java:43)
02-09 13:06:22.170: E/AndroidRuntime(531): at android.view.View.performClick(View.java:3511)
02-09 13:06:22.170: E/AndroidRuntime(531): at android.view.View$PerformClick.run(View.java:14105)
02-09 13:06:22.170: E/AndroidRuntime(531): at android.os.Handler.handleCallback(Handler.java:605)
02-09 13:06:22.170: E/AndroidRuntime(531): at android.os.Handler.dispatchMessage(Handler.java:92)
02-09 13:06:22.170: E/AndroidRuntime(531): at android.os.Looper.loop(Looper.java:137)
02-09 13:06:22.170: E/AndroidRuntime(531): at android.app.ActivityThread.main(ActivityThread.java:4424)
02-09 13:06:22.170: E/AndroidRuntime(531): at java.lang.reflect.Method.invokeNative(Native Method)
02-09 13:06:22.170: E/AndroidRuntime(531): at java.lang.reflect.Method.invoke(Method.java:511)
02-09 13:06:22.170: E/AndroidRuntime(531): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
02-09 13:06:22.170: E/AndroidRuntime(531): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
02-09 13:06:22.170: E/AndroidRuntime(531): at dalvik.system.NativeStart.main(Native Method)
Updatealbum正在工作？ – KarlKarlsom 2012-02-09 13:53:52
專輯參數可以爲空...檢查它 – Prasham 2012-02-09 13:55:10