I'm working on a project bus routes and I need help with the debugging part. My tables are not created in the databases and I'm having problems like when my icon is clicked it says "unfortunately the app is stopped".
myactivity.java
public class MainActivity extends Activity {
SQLiteDatabase db;
DbHelper dbHelper;
Button route;
protected String[] columns;
String[] strings = {
"TAMBARAM",
"PERUNGULATHUR",
"VANDALUR",
"URAPAKKAM",
"GUDUVANCHERI",
"POTHERI",
"KATTANKULATHUR",
"M.M.NAGAR",
"CHENGALPET",
};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
db = dbHelper.getReadableDatabase();
try {
} catch (SQLException e) {
e.getMessage();
}
route = (Button) findViewById(R.id.route);
try {
} catch (SQLException e) {
e.printStackTrace();
}
route.setOnClickListener(new OnClickListener() {
public void onClick(View v)
{
Cursor cursor = db.rawQuery("select busno from bus_detail);", null);
if (cursor != null && cursor.moveToFirst()) {
TextView places = (TextView) findViewById(R.id.show);
places.setText(cursor.getString(2));
}
}
});
db.close();
ArrayAdapter<String> adapter = new ArrayAdapter<String>(this, android.R.layout.simple_dropdown_item_1line,
strings);
AutoCompleteTextView source = (AutoCompleteTextView) findViewById(R.id.source);
AutoCompleteTextView destination = (AutoCompleteTextView) findViewById(R.id.dest);
source.setThreshold(1);
source.setAdapter(adapter);
destination.setThreshold(1);
destination.setAdapter(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.main, menu);
return true;
}
}
databasehelper.java
public class DbHelper extends SQLiteOpenHelper {
// Database Name
private static final String DATABASE_NAME = "bus_routes.db";
private static final int DATABASE_VERSION = 1;
// table names
private static final String BUS_MASTER = "bus_master";
private static final String BUS_DETAIL = "bus_detail";
// Columns names
private static final String BUS_NO = "bus_no";
private static final String SOURCE = "source";
private static final String DESTINATION = "destination";
private static final String PLACE = "place";
private static final String ARRIVAL_TIME = "arrival_time";
public DbHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
// TODO Auto-generated constructor stub
}
@Override
public void onCreate(SQLiteDatabase db) {
// TODO Auto-generated method stub
String CREATE_BUS_MASTER = "CREATE TABLE " + BUS_MASTER + "(" + BUS_NO + " INTEGER PRIMARY KEY," + SOURCE
+ " TEXT," + DESTINATION + " TEXT" + ")";
String CREATE_BUS_DETAIL = "CREATE TABLE " + BUS_DETAIL + "(" + BUS_NO
+ " INTEGER FOREIGN KEY REFERNCES BUS_MASTER(BUS_NO)," + PLACE + " TEXT," + ARRIVAL_TIME + " TEXT"
+ ")";
db.execSQL(CREATE_BUS_MASTER);
db.execSQL(CREATE_BUS_DETAIL);
}
public void onOpen(SQLiteDatabase DB) {
onOpen(DB);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// TODO Auto-generated method stub
db.execSQL("DROP TABLE IF EXISTS " + BUS_MASTER);
db.execSQL("DROP TABLE IF EXISTS " + BUS_DETAIL);
// Create tables again
onCreate(db);
}
public void addBus(int bus_no, String source, String destination) {
// TODO Auto-generated method stub
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put("busno", BUS_NO);
values.put("source", SOURCE); // source
values.put("destination", DESTINATION); // destination
// Inserting Row
db.insert(BUS_MASTER, null, values);
}
public void addBus_detail(int bus_no, String place, String arrival_time) {
// TODO Auto-generated method stub
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put("busno", BUS_NO);
values.put("place", PLACE);
values.put("arrival_time", ARRIVAL_TIME);
db.insert(BUS_DETAIL, null, values);
}
}
xml file
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:gravity="top"
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=".MainActivity" >
<TextView
android:id="@+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:layout_marginTop="57dp"
android:text="@string/source"
android:textAppearance="?android:attr/textAppearanceMedium" />
<AutoCompleteTextView
android:id="@+id/source"
android:layout_width="150dp"
android:layout_height="wrap_content"
android:layout_alignBottom="@+id/textView1"
android:layout_alignRight="@+id/dest"
android:layout_toRightOf="@+id/textView2"
android:ems="10"
android:labelFor="2"
android:text="@string/s" />
<requestFocus />
<AutoCompleteTextView
android:id="@+id/dest"
android:layout_width="150dp"
android:layout_height="wrap_content"
android:layout_alignBottom="@+id/textView2"
android:layout_alignLeft="@+id/route"
android:layout_alignParentRight="true"
android:layout_marginRight="16dp"
android:ems="10"
android:text="@string/d" />
<Button
android:id="@+id/route"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@+id/textView2"
android:layout_marginTop="26dp"
android:layout_toRightOf="@+id/textView2"
android:text="@string/routes" />
<TextView
android:id="@+id/show"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/textView2"
android:layout_alignParentBottom="true"
android:layout_alignRight="@+id/dest"
android:layout_below="@+id/route"
android:layout_marginTop="81dp"
android:text="@string/disp"
android:textAppearance="?android:attr/textAppearanceMedium" />
<TextView
android:id="@+id/textView2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_below="@+id/textView1"
android:layout_marginTop="44dp"
android:text="@string/dest"
android:textAppearance="?android:attr/textAppearanceMedium" />
</RelativeLayout>
logcat:
04-04 14:14:43.700: D/AndroidRuntime(868): Shutting down VM
04-04 14:14:43.700: W/dalvikvm(868): threadid=1: thread exiting with uncaught exception (group=0x40a71930)
04-04 14:14:43.720: E/AndroidRuntime(868): FATAL EXCEPTION: main
04-04 14:14:43.720: E/AndroidRuntime(868): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.bus/com.example.bus.MainActivity}: java.lang.NullPointerException
04-04 14:14:43.720: E/AndroidRuntime(868): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180)
04-04 14:14:43.720: E/AndroidRuntime(868): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
04-04 14:14:43.720: E/AndroidRuntime(868): at android.app.ActivityThread.access$600(ActivityThread.java:141)
04-04 14:14:43.720: E/AndroidRuntime(868): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
04-04 14:14:43.720: E/AndroidRuntime(868): at android.os.Handler.dispatchMessage(Handler.java:99)
04-04 14:14:43.720: E/AndroidRuntime(868): at android.os.Looper.loop(Looper.java:137)
04-04 14:14:43.720: E/AndroidRuntime(868): at android.app.ActivityThread.main(ActivityThread.java:5041)
04-04 14:14:43.720: E/AndroidRuntime(868): at java.lang.reflect.Method.invokeNative(Native Method)
04-04 14:14:43.720: E/AndroidRuntime(868): at java.lang.reflect.Method.invoke(Method.java:511)
04-04 14:14:43.720: E/AndroidRuntime(868): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
04-04 14:14:43.720: E/AndroidRuntime(868): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
04-04 14:14:43.720: E/AndroidRuntime(868): at dalvik.system.NativeStart.main(Native Method)
04-04 14:14:43.720: E/AndroidRuntime(868): Caused by: java.lang.NullPointerException
04-04 14:14:43.720: E/AndroidRuntime(868): at com.example.bus.MainActivity.onCreate(MainActivity.java:44)
04-04 14:14:43.720: E/AndroidRuntime(868): at android.app.Activity.performCreate(Activity.java:5104)
04-04 14:14:43.720: E/AndroidRuntime(868): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)
04-04 14:14:43.720: E/AndroidRuntime(868): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144)
04-04 14:14:43.720: E/AndroidRuntime(868): ... 11 more