小编Shy*_*yam的帖子

我正在努力集成一个数据库来保存和存储以后要检索的基本联系信息.但是,我的应用程序现在在启动时崩溃,所以我甚至无法验证是否正在创建表等.

05-05 16:39:50.671  11631-11631/treehouse.greenlight E/AndroidRuntime?   FATAL EXCEPTION: main
Process: treehouse.greenlight, PID: 11631
java.lang.RuntimeException: Unable to start activity ComponentInfo{treehouse.greenlight/treehouse.greenlight.Home_screen}: java.lang.NullPointerException: Attempt to invoke virtual method 'android.database.sqlite.SQLiteDatabase android.content.Context.openOrCreateDatabase(java.lang.String, int, android.database.sqlite.SQLiteDatabase$CursorFactory, android.database.DatabaseErrorHandler)' on a null object reference
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2205)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2255)
        at android.app.ActivityThread.access$800(ActivityThread.java:142)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1203)
        at android.os.Handler.dispatchMessage(Handler.java:102)
        at android.os.Looper.loop(Looper.java:136)
        at android.app.ActivityThread.main(ActivityThread.java:5118)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:794)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:610)
 Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'android.database.sqlite.SQLiteDatabase android.content.Context.openOrCreateDatabase(java.lang.String, int, android.database.sqlite.SQLiteDatabase$CursorFactory, android.database.DatabaseErrorHandler)' on a null object reference
        at android.database.sqlite.SQLiteOpenHelper.getDatabaseLocked(SQLiteOpenHelper.java:224)
        at android.database.sqlite.SQLiteOpenHelper.getWritableDatabase(SQLiteOpenHelper.java:164)
        at treehouse.greenlight.MyDBHandler.addContact(MyDBHandler.java:54)
        at …