Android java : SQLiteDatabase db = this.getWritableDatabase() 错误；

Question

我是 android java 的初学者。

中的 SQLiteDatabase db = this.getWritableDatabase(); 行出错

public boolean deleteItem(Todomodel todomodel){

    SQLiteDatabase db = this.getWritableDatabase(); //HERE
    ContentValues cv = new ContentValues();
    int numb = todomodel.getId();
    String whereClause = "id=?";
    String whereArgs[] = {String.valueOf(numb)};
    db.delete("CUSTOMER_TABLE", whereClause, whereArgs);
    db.close();

    return false;
}

错误：

E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.example.monday, PID: 9794
    java.lang.NullPointerException: Attempt to invoke virtual method 'java.io.File android.content.Context.getDatabasePath(java.lang.String)' on a null object reference
        at android.content.ContextWrapper.getDatabasePath(ContextWrapper.java:330)
        at android.database.sqlite.SQLiteOpenHelper.getDatabaseLocked(SQLiteOpenHelper.java:292)
        at android.database.sqlite.SQLiteOpenHelper.getWritableDatabase(SQLiteOpenHelper.java:238)
        at com.example.monday.database.deleteItem(database.java:72)

我已经在插入函数中调用了getWritabledatabase。但是当我再次尝试写的时候。没用。

Answer 1

您需要将有效的 Context 传递给您的 SQLiteOpenHelper 构造函数。

Android java : SQLiteDatabase db = this.getWritableDatabase() 错误；

Android java : Error on SQLiteDatabase db = this.getWritableDatabase();

java

android

android-sqlite