尝试连接到数据库，上下文 = null

Question

正在尝试连接到数据库;我有一个问题context = null（很可能一定是）。我不明白是什么问题

import java.util.HashMap;
    import android.app.Activity;
    import android.content.Context;
    import android.os.Bundle;
    public class DatabaseTable extends Activity {
        private Context context;
        @Override
        public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.database_table);

            LBD conection = LBD.get(context);  // (context = null) ???
            Settings setting = new Settings(conection.getSQLiteDatabase());
            setting.create();

        }
    }

Answer 1

试试这个 -

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.database_table);
    context = DatabaseTable.this; // you can give this instead of DatabaseTable.this also.
    LBD conection = LBD.get(context);  // (context = null) ???
    Settings setting = new Settings(conection.getSQLiteDatabase());
    setting.create();
}

或者你可以给喜欢——

    LBD conection = LBD.get(DatabaseTable.this);  // from this you don't need to Create any context instance of Context class. Directly pass the context here.
    Settings setting = new Settings(conection.getSQLiteDatabase());
    setting.create();

Answer 2

context=this;//you forgot this...
LBD conection = LBD.get(context);  // (context = null) ???
Settings setting = new Settings(conection.getSQLiteDatabase());
setting.create();

Answer 3

尝试LBD conection = LBD.get(this);