singleton_with_context.java

public class MySingleton {
    private static MySingleton sInstance;
    private final Context mContext;

    private MySingleton(Context context) {
        mContext = context.getApplicationContext();
    }

    public getInstance(Context context) {
        synchronized (MySingleton.class) {
            if (sInstance == null) {
                sInstance = new MySingleton(context);
            }
            return sInstance
        }
    }

    public doSomethingNeedingContext() {
        mContext.getString();
    }
}