I have been trying to populate my list view in a different manner. My database class already has a function defined which returns a cursor.
I would like to know whether my way is possible or not? As of now when I try to get to the ListView, my app crashes.
Here is the code:
public class ProjectExplorer extends ListActivity {
private projectdatabase database;
protected Cursor cursor;
protected ListAdapter adapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//setContentView(R.layout.activity_project_explorer);
openDatabase();
}
private void openDatabase() {
database.open();
cursor = database.getDataforDisplay();
adapter = new SimpleCursorAdapter(this, android.R.layout.simple_list_item_1, cursor, null, null, 0);
setListAdapter(adapter);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.activity_project_explorer, menu);
return true;
} }
Code for the method which returns the cursor:
public Cursor getDataforDisplay () {
String[] columns = new String[] {KEY_ROWID, PROJECT_NAME, PROJECT_FINISH_DATE, PROJECT_DIFFICULTY, PROJECT_STATUS};
Cursor c = projectDatabase.query(DATABASE_TABLE, columns, null, null, null, null, null);
return c;
}
As requested, complete database class code:
public class projectdatabase {
public static final String KEY_ROWID = "_id";
public static final String PROJECT_NAME = "project_name";
public static final String PROJECT_ID = "project_id";
public static final String PROJECT_DIFFICULTY = "project_difficulty";
public static final String PROJECT_STATUS = "project_status";
public static final String PROJECT_START_DATE = "project_start_date";
public static final String PROJECT_FINISH_DATE = "project_finsish_date";
private static final String DATABASE_NAME = "project_db";
static final String DATABASE_TABLE = "project_details";
private static final int DATABASE_VERSION = 1;
private DbHelper ourHelper;
private final Context projectdbContext;
private SQLiteDatabase projectDatabase;
private static class DbHelper extends SQLiteOpenHelper {
public DbHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
@Override
public void onCreate(SQLiteDatabase db) {
// TODO Auto-generated method stub
db.execSQL("CREATE TABLE "+ DATABASE_TABLE + " (" +
KEY_ROWID + " INTEGER PRIMARY KEY AUTOINCREMENT, " +
PROJECT_NAME + " TEXT NOT NULL, " +
PROJECT_ID + " INTEGER, " +
PROJECT_START_DATE + " TEXT, " +
PROJECT_FINISH_DATE + " TEXT, " +
PROJECT_DIFFICULTY + " TEXT, " +
PROJECT_STATUS + " TEXT);"
);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// TODO Auto-generated method stub
db.execSQL("DROP TABLE IF EXIST " + DATABASE_NAME);
onCreate(db);
}
}
public projectdatabase (Context c) {
projectdbContext = c;
}
public projectdatabase open() { //Open database
ourHelper = new DbHelper(projectdbContext);
projectDatabase = ourHelper.getWritableDatabase();
return this;
}
public void close() { //Close database
ourHelper.close();
}
public long createEntry(String name, String pid, String startdate, String finishdate, String difficulty) { //Enter project data into database
ContentValues cv = new ContentValues();
cv.put(PROJECT_NAME, name);
cv.put(PROJECT_ID, pid);
cv.put(PROJECT_START_DATE, startdate);
cv.put(PROJECT_FINISH_DATE, finishdate);
cv.put(PROJECT_DIFFICULTY, difficulty);
return projectDatabase.insert(DATABASE_TABLE, null, cv);
}
public String getData() { //Retrieve all project data
String[] columns = new String[] {KEY_ROWID, PROJECT_NAME, PROJECT_ID, PROJECT_START_DATE, PROJECT_FINISH_DATE, PROJECT_DIFFICULTY, PROJECT_STATUS};
Cursor c = projectDatabase.query(DATABASE_TABLE, columns, null, null, null, null, null);
String result = "";
int iRow = c.getColumnIndex(KEY_ROWID);
int iName = c.getColumnIndex(PROJECT_NAME);
int iID = c.getColumnIndex(PROJECT_ID);
int iStartDate = c.getColumnIndex(PROJECT_START_DATE);
int iFinishDate = c.getColumnIndex(PROJECT_FINISH_DATE);
int iDifficulty = c.getColumnIndex(PROJECT_DIFFICULTY);
int iStatus = c.getColumnIndex(PROJECT_STATUS);
for(c.moveToFirst(); !c.isAfterLast(); c.moveToNext()) {
result = result + c.getString(iRow) + "|" + c.getString(iName) + "|" + c.getString(iID) + "|" + c.getString(iStartDate) + "|" + c.getString(iFinishDate) + "|" + c.getString(iDifficulty) + "|" + c.getString(iStatus) + "\n";
}
return result;
}
public Cursor getDataforDisplay () { //Display selected data for 'User profile' *Incomplete*
String[] columns = new String[] {KEY_ROWID, PROJECT_NAME, PROJECT_FINISH_DATE, PROJECT_DIFFICULTY, PROJECT_STATUS};
Cursor c = projectDatabase.query(DATABASE_TABLE, columns, null, null, null, null, null);
c.moveToFirst();
return c;
}
}
Logcat:
This error comes up when I run the project in the AVD:
12-29 00:35:14.333: E/dalvikvm(4804): Unable to open stack trace file '/data/anr/traces.txt': Permission denied
Then when I open the activity which is supposed to show the ListView but the app crashes:
12-29 00:38:04.245: E/AndroidRuntime(4804): FATAL EXCEPTION: main
12-29 00:38:04.245: E/AndroidRuntime(4804): java.lang.RuntimeException: Unable to start
activity ComponentInfo{com.kk.project/com.kk.project.ProjectExplorer}:
java.lang.IllegalArgumentException: column 'name' does not exist
12-29 00:38:04.245: E/AndroidRuntime(4804): at
android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1956)
12-29 00:38:04.245: E/AndroidRuntime(4804): at
android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1981)
12-29 00:38:04.245: E/AndroidRuntime(4804): at
android.app.ActivityThread.access$600(ActivityThread.java:123)
12-29 00:38:04.245: E/AndroidRuntime(4804): at
android.app.ActivityThread$H.handleMessage(ActivityThread.java:1147)
12-29 00:38:04.245: E/AndroidRuntime(4804): at
android.os.Handler.dispatchMessage(Handler.java:99)
12-29 00:38:04.245: E/AndroidRuntime(4804): at
android.os.Looper.loop(Looper.java:137)
12-29 00:38:04.245: E/AndroidRuntime(4804): at
android.app.ActivityThread.main(ActivityThread.java:4424)
12-29 00:38:04.245: E/AndroidRuntime(4804): at
java.lang.reflect.Method.invokeNative(Native Method)
12-29 00:38:04.245: E/AndroidRuntime(4804): at
java.lang.reflect.Method.invoke(Method.java:511)
12-29 00:38:04.245: E/AndroidRuntime(4804): at
com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
12-29 00:38:04.245: E/AndroidRuntime(4804): at
com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
12-29 00:38:04.245: E/AndroidRuntime(4804): at
dalvik.system.NativeStart.main(Native Method)
12-29 00:38:04.245: E/AndroidRuntime(4804): Caused by:
java.lang.IllegalArgumentException: column 'name' does not exist
12-29 00:38:04.245: E/AndroidRuntime(4804): at
android.database.AbstractCursor.getColumnIndexOrThrow(AbstractCursor.java:267)
12-29 00:38:04.245: E/AndroidRuntime(4804): at
android.support.v4.widget.SimpleCursorAdapter.findColumns(SimpleCursorAdapter.java:317)
12-29 00:38:04.245: E/AndroidRuntime(4804): at
android.support.v4.widget.SimpleCursorAdapter.<init>(SimpleCursorAdapter.java:92)
12-29 00:38:04.245: E/AndroidRuntime(4804): at
com.kk.project.ProjectExplorer.openDatabase(ProjectExplorer.java:29)
12-29 00:38:04.245: E/AndroidRuntime(4804): at
com.kk.project.ProjectExplorer.onCreate(ProjectExplorer.java:21)
12-29 00:38:04.245: E/AndroidRuntime(4804): at
android.app.Activity.performCreate(Activity.java:4465)
12-29 00:38:04.245: E/AndroidRuntime(4804): at
android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1049)
12-29 00:38:04.245: E/AndroidRuntime(4804): at
android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1920)
12-29 00:38:04.245: E/AndroidRuntime(4804): ... 11 more
You need to initialize the database before trying to use it.
EDIT :