SQLite Tabelle in anderer Activity auslesen

Hi,

ich habe mir eine SQLite Datenbank nach dem Schema des Tutorials http://www.programmierenlernenhq.de/daten-in-sqlite-datenbank-schreiben-und-lesen-in-android/#comment-17756 aufgebaut. Ich möchte aber meine Daten in einer ersten Activity eingeben und in einer zweiten ausgeben. Ich habe das bereits probiert, indem ich die dataSource der Einlese-Activity public definiert habe um sie dann in der Ausgabe-Activity zu benutzen.

Leider stürzt an dieser Stelle meine App ab.

Hat jemand eine Idee? Ich bin für jede Antwort dankbar.

Viele Grüße Basti

Oh tschuldigung..

Eingabe-Acitvity (Signal-Activity):

public class SignalActivity extends AppCompatActivity implements View.OnClickListener {

    public static MeasurementMemoDataSource dataSource;

@Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_signal);
}

//Button-Definition......onclick
//.........
                    dataSource = new MeasurementMemoDataSource(this);
                    Log.d(LOG_TAG, "Die Datenquelle wird geöffnet.");
                    dataSource.open();


                   MeasurementMemo shoppingMemo = 
                   dataSource.createMeasurementMemo(spinnerAuswahl, zeitpunkt);


                   Log.d(LOG_TAG, "Es wurde der folgende Eintrag in die Datenbank 
                   geschrieben:");
                   Log.d(LOG_TAG, "ID: " + measurement.getId() + ", Inhalt: " + 
                   measurementMemo.toString());


                    Log.d(LOG_TAG, "Die Datenquelle wird geschlossen.");
                    dataSource.close();

Ausgabe-Activity (DatenbankActivity):

public class DatenbankActivity extends AppCompatActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_datenbank);

SignalActivity.dataSource.open();

    Log.d(LOG_TAG, "Folgende Einträge sind in der Datenbank vorhanden:");
    showAllListEntries();

    SignalActivity.dataSource.close();
}

private void showAllListEntries () {
            List<MeasurementMemo> measurementMemoList =
            SignalActivity.dataSource.getAllMeasurementMemos();

            ArrayAdapter<MeasurementMemo> measurementMemoArrayAdapter = new ArrayAdapter<>(
            this,
            android.R.layout.simple_list_item_multiple_choice,
            measurementMemoList);

            ListView measurementMemosListView = (ListView) findViewById(R.id.list_item);
            measurementMemosListView.setAdapter(measurementMemoArrayAdapter);
}

ListView-XML:

<?xml version="1.0" encoding="utf-8"?>

android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:padding="10dp"
android:paddingLeft="10dp"
android:paddingRight="10dp" >


<TextView
    android:id="@+id/id"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:paddingBottom="2dip"
    android:paddingTop="6dip"
    android:textStyle="bold" />

<TextView
    android:id="@+id/typ"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:paddingBottom="2dip"
    android:textStyle="bold"/>

<TextView
    android:id="@+id/zeitstempel"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:paddingBottom="2dip"
    android:textStyle="bold"/>

Error-Log beim Öffnen der Datenbank-Activity:

04-20 14:39:03.913 15290-15290/com.example.standard.measuringapp V/ActivityThread: updateVisibility : ActivityRecord{a53b2c5 token=android.os.BinderProxy@c9f61f8 {com.example.standard.measuringapp/com.example.standard.measuringapp.MainActivity}} show : false

04-20 14:39:08.063 16342-16342/com.example.standard.measuringapp W/ResourcesManager: getTopLevelResources: /data/app/com.example.standard.measuringapp-1/base.apk / 1.0 running in com.example.standard.measuringapp rsrc of package null
04-20 14:39:08.113 16342-16342/com.example.standard.measuringapp W/System: ClassLoader referenced unknown path: /data/app/com.example.standard.measuringapp-1/lib/arm
04-20 14:39:08.483 16342-16342/com.example.standard.measuringapp W/System: ClassLoader referenced unknown path: /data/app/com.example.standard.measuringapp-1/lib/arm
04-20 14:39:08.753 16342-16342/com.example.standard.measuringapp W/ResourcesManager: getTopLevelResources: /data/app/com.example.standard.measuringapp-1/base.apk / 1.0 running in com.example.standard.measuringapp rsrc of package null
04-20 14:39:08.873 16342-16342/com.example.standard.measuringapp W/art: Before Android 4.1, method android.graphics.PorterDuffColorFilter android.support.graphics.drawable.VectorDrawableCompat.updateTintFilter(android.graphics.PorterDuffColorFilter, android.content.res.ColorStateList, android.graphics.PorterDuff$Mode) would have incorrectly overridden the package-private method in android.graphics.drawable.Drawable
04-20 14:39:09.323 16342-16342/com.example.standard.measuringapp D/SecWifiDisplayUtil: Metadata value : none
04-20 14:39:09.363 16342-16342/com.example.standard.measuringapp D/ViewRootImpl: #1 mView = com.android.internal.policy.PhoneWindow$DecorView{d8676d1 I.E...... R.....ID 0,0-0,0}
04-20 14:39:09.363 16342-16428/com.example.standard.measuringapp D/OpenGLRenderer: Use EGL_SWAP_BEHAVIOR_PRESERVED: true
04-20 14:39:09.433 16342-16428/com.example.standard.measuringapp I/Adreno-EGL: : EGL 1.4 QUALCOMM build: (Ia10634f51b)
OpenGL ES Shader Compiler Version: E031.29.00.00
Build Date: 01/28/16 Thu
Local Branch: ss
Remote Branch:
Local Patches:
Reconstruct Branch:
04-20 14:39:09.433 16342-16428/com.example.standard.measuringapp D/libEGL: eglInitialize EGLDisplay = 0x9d7327c4
04-20 14:39:09.433 16342-16428/com.example.standard.measuringapp I/OpenGLRenderer: Initialized EGL, version 1.4
04-20 14:39:09.573 16342-16342/com.example.standard.measuringapp W/DisplayListCanvas: DisplayListCanvas is started on unbinded RenderNode (without mOwningView)
04-20 14:39:09.763 16342-16342/com.example.standard.measuringapp D/ViewRootImpl: MSG_RESIZED_REPORT: ci=Rect(0, 0 - 0, 0) vi=Rect(0, 0 - 0, 0) or=1
04-20 14:39:09.793 16342-16342/com.example.standard.measuringapp I/Timeline: Timeline: Activity_idle id: android.os.BinderProxy@c9f61f8 time:157726961
04-20 14:39:11.983 16342-16342/com.example.standard.measuringapp D/ViewRootImpl: ViewPostImeInputStage processPointer 0
04-20 14:39:12.023 16342-16342/com.example.standard.measuringapp D/ViewRootImpl: ViewPostImeInputStage processPointer 1
04-20 14:39:12.113 16342-16342/com.example.standard.measuringapp I/ListPopupWindow: Could not find method setEpicenterBounds(Rect) on PopupWindow. Oh well.
04-20 14:39:12.163 16342-16342/com.example.standard.measuringapp W/art: Before Android 4.1, method int android.support.v7.widget.ListViewCompat.lookForSelectablePosition(int, boolean) would have incorrectly overridden the package-private method in android.widget.ListView
04-20 14:39:12.213 16342-16342/com.example.standard.measuringapp D/AbsListView: Get MotionRecognitionManager
04-20 14:39:12.223 16342-16342/com.example.standard.measuringapp E/MotionRecognitionManager: mSContextService = android.hardware.scontext.ISContextService$Stub$Proxy@52b3d3b
04-20 14:39:12.223 16342-16342/com.example.standard.measuringapp E/MotionRecognitionManager: motionService = com.samsung.android.motion.IMotionRecognitionService$Stub$Proxy@6b33c58
04-20 14:39:12.223 16342-16342/com.example.standard.measuringapp E/MotionRecognitionManager: motionService = com.samsung.android.motion.IMotionRecognitionService$Stub$Proxy@6b33c58
04-20 14:39:12.253 16342-16342/com.example.standard.measuringapp D/ViewRootImpl: #1 mView = android.widget.PopupWindow$PopupDecorView{55cc696 V.E...... ......I. 0,0-0,0}
04-20 14:39:12.413 16342-16342/com.example.standard.measuringapp W/DisplayListCanvas: DisplayListCanvas is started on unbinded RenderNode (without mOwningView)
04-20 14:39:12.443 16342-16342/com.example.standard.measuringapp D/ViewRootImpl: MSG_RESIZED_REPORT: ci=Rect(0, 0 - 0, 0) vi=Rect(0, 0 - 0, 0) or=1
04-20 14:39:13.233 16342-16342/com.example.standard.measuringapp D/ViewRootImpl: ViewPostImeInputStage processPointer 0
04-20 14:39:13.293 16342-16342/com.example.standard.measuringapp D/ViewRootImpl: ViewPostImeInputStage processPointer 1
04-20 14:39:13.363 16342-16342/com.example.standard.measuringapp I/Timeline: Timeline: Activity_launch_request id:com.example.standard.measuringapp time:157730529
04-20 14:39:13.413 16342-16342/com.example.standard.measuringapp W/ResourcesManager: getTopLevelResources: /data/app/com.example.standard.measuringapp-1/base.apk / 1.0 running in com.example.standard.measuringapp rsrc of package null
04-20 14:39:13.433 16342-16342/com.example.standard.measuringapp D/AbsListView: Get MotionRecognitionManager
04-20 14:39:13.433 16342-16342/com.example.standard.measuringapp E/MotionRecognitionManager: mSContextService = android.hardware.scontext.ISContextService$Stub$Proxy@38a9664
04-20 14:39:13.433 16342-16342/com.example.standard.measuringapp E/MotionRecognitionManager: motionService = com.samsung.android.motion.IMotionRecognitionService$Stub$Proxy@12cb0cd
04-20 14:39:13.433 16342-16342/com.example.standard.measuringapp E/MotionRecognitionManager: motionService = com.samsung.android.motion.IMotionRecognitionService$Stub$Proxy@12cb0cd
04-20 14:39:13.463 16342-16342/com.example.standard.measuringapp D/AndroidRuntime: Shutting down VM
04-20 14:39:13.463 16342-16342/com.example.standard.measuringapp E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.standard.measuringapp, PID: 16342
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.standard.measuringapp/com.example.standard.measuringapp.DatenbankActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'void com.example.standard.measuringapp.MeasurementMemoDataSource.open()' on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3253)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3349)
at android.app.ActivityThread.access$1100(ActivityThread.java:221)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1794)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:158)
at android.app.ActivityThread.main(ActivityThread.java:7224)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1230)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1120)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void com.example.standard.measuringapp.MeasurementMemoDataSource.open()' on a null object reference
at com.example.standard.measuringapp.DatenbankActivity.onCreate(DatenbankActivity.java:78)
at android.app.Activity.performCreate(Activity.java:6876)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1135)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3206)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3349)
at android.app.ActivityThread.access$1100(ActivityThread.java:221)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1794)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:158)
at android.app.ActivityThread.main(ActivityThread.java:7224)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1230)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1120)

erstmal danke für die schnelle Rückmeldung.

Also mache ich jetzt aus meiner MeasurementMemoDataSource-Klasse eine Singleton-Klasse?

hab nun meiner MeasurementMemoDataSource-Class folgendes hinzugefügt:

public class MeasurementMemoDataSource{
private static MeasurementMemoDataSource _instance;

private MeasurementMemoDataSource() {

}

public synchronized static MeasurementMemoDataSource getInstance() {
    if (_instance == null) {
        _instance = new MeasurementMemoDataSource();
    }
    return _instance;
}

//restlicher Code
}

ist das so richtig? Sorry ich mach das zum ersten Mal..

Ja gut dann lösche ich das synchronized wieder..

Und wie bekomme ich jetzt meine dataSource von der Signal-Activity in meine Datenbank-Activity?

— geändert am 20.04.2017, 16:39:16

habe meinen letzten Beitrag nochmal bearbeitet.. meinte natürlich die dataSource aus der Signal-Activity.

Leider stürzt die App immer noch ab..

public class DatenbankActivity extends AppCompatActivity {

MeasurementMemoDataSource dataSource;


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    setContentView(R.layout.activity_datenbank);





    dataSource = MeasurementMemoDataSource.getInstance();
    Log.d(LOG_TAG, "Die Datenquelle wird geöffnet.");
    dataSource.open();

    Log.d(LOG_TAG, "Folgende Einträge sind in der Datenbank vorhanden:");
    showAllListEntries();

    dataSource.close();

}

private void showAllListEntries () {
    List<MeasurementMemo> measurementMemoList = dataSource.getAllMeasurementMemos();

    ArrayAdapter<MeasurementMemo> measurementMemoArrayAdapter = new ArrayAdapter<>(
            this,
            android.R.layout.simple_list_item_multiple_choice,
            measurementMemoList);

    ListView measurementMemosListView = (ListView) findViewById(R.id.list_item);
    measurementMemosListView.setAdapter(measurementMemoArrayAdapter);
}

Die ID der ListView war schon mal falsch, da hast du recht. Leider haut irgendwas immer noch nicht hin..

Hier mein ErrorLog:

04-21 09:13:02.874 5901-5901/com.example.standard.measuringapp E/MotionRecognitionManager: mSContextService = android.hardware.scontext.ISContextService$Stub$Proxy@38a9664
04-21 09:13:02.874 5901-5901/com.example.standard.measuringapp E/MotionRecognitionManager: motionService = com.samsung.android.motion.IMotionRecognitionService$Stub$Proxy@12cb0cd
04-21 09:13:02.874 5901-5901/com.example.standard.measuringapp E/MotionRecognitionManager: motionService = com.samsung.android.motion.IMotionRecognitionService$Stub$Proxy@12cb0cd
04-21 09:13:02.874 5901-5901/com.example.standard.measuringapp D/MainActivity: Die Datenquelle wird geöffnet.
04-21 09:13:02.874 5901-5901/com.example.standard.measuringapp D/MeasurementMemoDataSource: Eine Referenz auf die Datenbank wird jetzt angefragt.
04-21 09:13:02.874 5901-5901/com.example.standard.measuringapp D/AndroidRuntime: Shutting down VM
04-21 09:13:02.874 5901-5901/com.example.standard.measuringapp E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.standard.measuringapp, PID: 5901
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.standard.measuringapp/com.example.standard.measuringapp.DatenbankActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'android.database.sqlite.SQLiteDatabase com.example.standard.measuringapp.MeasurementMemoDbHelper.getWritableDatabase()' on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3253)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3349)
at android.app.ActivityThread.access$1100(ActivityThread.java:221)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1794)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:158)
at android.app.ActivityThread.main(ActivityThread.java:7224)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1230)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1120)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'android.database.sqlite.SQLiteDatabase com.example.standard.measuringapp.MeasurementMemoDbHelper.getWritableDatabase()' on a null object reference
at com.example.standard.measuringapp.MeasurementMemoDataSource.open(MeasurementMemoDataSource.java:51)
at com.example.standard.measuringapp.DatenbankActivity.onCreate(DatenbankActivity.java:79)
at android.app.Activity.performCreate(Activity.java:6876)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1135)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3206)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3349) 
at android.app.ActivityThread.access$1100(ActivityThread.java:221) 
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1794) 
at android.os.Handler.dispatchMessage(Handler.java:102) 
at android.os.Looper.loop(Looper.java:158) 
at android.app.ActivityThread.main(ActivityThread.java:7224) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1230) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1120) 

nein, denk bitte nicht, dass ich deine beiträge ignorier. Ich glaube eher, dass ich das nicht ganz verstanden habe.
Ich versuche das mal und melde mich dann wieder.

Außerdem habe ich deine variante auch schon probiert gehabt, so wie dus oben beschrieben hast. das hat leider auch nicht auf anhieb geklappt deswegen bin ich wieder auf die andere möglichkeit umgesprungen.

— geändert am 21.04.2017, 14:42:14

Also habe es bis jetzt leider noch icht hinbekommen. Ich hab nun mal versucht meine Datenbank (also den ListView) in die gleiche Klasse/Activity einzubauen. Leider bekomme ich auch hier den gleichen Fehler ("Unable to start the activity"). Bedeutet ja im Endeffekt, dass es an was anderem liegt.. oder verstehe ich das falsch?