Android:获取错误“无法解析GetSharedReferences（java.lang.String，int）”

Question

我试图访问非活动类中的SharedReferences，但我总是遇到这个错误cannot resolve getSharedPreferences(java.lang.String, int)。但是当我在正常活动类中使用GetSharedReferences时，我没有得到这个错误

有人知道怎么解决这个问题吗

这是我的密码：

public class ConnectionClass {

SharedPreferences pref = getSharedPreferences("MyPrefs", Context.MODE_PRIVATE);
String ip = pref.getString("serverIP", "");

// String ip = "";
// String ip = server_IP;
String classDriver = "net.sourceforge.jtds.jdbc.Driver";
String db = "passoDB";
String un = "sa";
String password = "dhen1234";

@SuppressLint("NewApi")
public Connection CONN(Context context) {

    StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder()
            .permitAll().build();
    StrictMode.setThreadPolicy(policy);
    Connection conn = null;
    String ConnURL = null;
    try {
        Class.forName(classDriver);
        ConnURL = "jdbc:jtds:sqlserver://" + ip + ";"
                + "databaseName=" + db + ";user=" + un + ";password="
                + password + ";";
        conn = DriverManager.getConnection(ConnURL);
    } catch (SQLException se) {
        Log.e("ERRO", se.getMessage());
    } catch (ClassNotFoundException e) {
        Log.e("ERRO", e.getMessage());
    } catch (Exception e) {
        Log.e("ERRO", e.getMessage());
    }
    return conn;
}
}

Answer 1

你必须把它写进你的方法中

@SuppressLint("NewApi")
public Connection CONN(Context context) {
SharedPreferences pref = context.getSharedPreferences("MyPrefs",Context.MODE_PRIVATE);

}

或者你也可以把它写进Constructor

Answer 2

你需要在一个Context中，或者有一个包含Context的变量来调用这个方法

public class ConnectionClass {
    Context context;
    SharedPreferences pref;
    public ConnectionClass(Context context) {
        this.context = context;
        pref = context.getSharedPreferences("MyPrefs", Context.MODE_PRIVATE);
    }

Answer 3

是的，正如simon所说，访问共享首选项需要上下文，所以为了使代码正常工作，我将添加这一行

    public class ConnectionClass {


String classDriver = "net.sourceforge.jtds.jdbc.Driver";
String db = "passoDB";
String un = "sa";
String password = "dhen1234";


 String ip = "";


 public ConnectionClass(Context context){
        SharedPreferences prefs = context.getSharedPreferences("MyPrefs", context.MODE_PRIVATE);
        ip = prefs.getString("serverIP", "");

 }


@SuppressLint("NewApi")
public Connection CONN(Context context) {

    StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder()
            .permitAll().build();
    StrictMode.setThreadPolicy(policy);
    Connection conn = null;
    String ConnURL = null;
    try {
        Class.forName(classDriver);
        ConnURL = "jdbc:jtds:sqlserver://" + ip + ";"
                + "databaseName=" + db + ";user=" + un + ";password="
                + password + ";";
        conn = DriverManager.getConnection(ConnURL);
    } catch (SQLException se) {
        Log.e("ERRO", se.getMessage());
    } catch (ClassNotFoundException e) {
        Log.e("ERRO", e.getMessage());
    } catch (Exception e) {
        Log.e("ERRO", e.getMessage());
    }
    return conn;
}
}

我没有正确地缩进，希望能有所帮助

在调用类时，您应该这样调用：

ConnectionClass connectionClass = new ConnectionClass(YourActivity.this);//if in activity

ConnectionClass connectionClass = new ConnectionClass(getActivity());//if in fragment