Question

您好我正在尝试为持久性/共享首选项编写代码。我成功地将数据保存在持久性存储中。但每次我启动我的应用程序时，它都会将我带到存储活动。我有两个活动主要活动和第二个活动。在主要活动中，我保存数据，第二个活动，我显示存储的数据。我想要的是第一次存储数据时它应该直接移动到第二个活动。我想实现像watsapp注册过程之类的东西，你第一次输入你的号码和别针，直到你卸载应用程序或手动清除数据它才会要求它。我该怎么办以下是我尝试过的代码。

public class MainActivity extends Activity {

    public static final String PREFS_NAME = "MSISDN and PIN";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        final SharedPreferences settings = getSharedPreferences(PREFS_NAME, 0);
        int id = settings.getInt("PREFS_NAME", 0);
        if (id > 0) {
            Intent second = new Intent(getApplicationContext(), seond.class);
            startActivity(second);
        }
        final EditText name = (EditText) findViewById(R.id.editText1);
        final EditText email = (EditText) findViewById(R.id.editText2);
        Button btn = (Button) findViewById(R.id.btnsaveprefs);
        btn.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                SharedPreferences.Editor editor = settings.edit();
                editor.putString("MSISDN", name.getText().toString());
                editor.putString("PIN", email.getText().toString());
                editor.commit();
                Intent second = new Intent(getApplicationContext(), seond.class);
                startActivity(second);
            }
        });
    }
}

和我的第二项活动

public class seond extends Activity {

    public static final String PREFS_NAME = "MSISDN and PIN";

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.second);
        TextView tvname = (TextView) findViewById(R.id.uname);
        TextView tvemail = (TextView) findViewById(R.id.uemail);
        SharedPreferences settings = getSharedPreferences(PREFS_NAME, 0);
        tvname.setText(settings.getString("MSISDN", "Unknown"));
        tvemail.setText(settings.getString("PIN", "Email default"));
    }
}

Answer 1

我认为你的问题在这里：

int id = settings.getInt("PREFS_NAME", 0);

您获取“PREFS_NAME”的值，然后检查它是否为> 0，但您从未存储密钥PREFS_NAME的值。我想你想在这里使用PIN或MSISDN？

Answer 2

这是正确的方法：

public class MainActivity extends Activity {

    public static final String PREFS_NAME = "MSISDN and PIN";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        final SharedPreferences settings = getSharedPreferences(PREFS_NAME, 0);
        int id = settings.getInt("PREFS_NAME", 0);
        if (id > 0) {
            Intent second = new Intent(getApplicationContext(), Second.class);
            startActivity(second);
        }
        final EditText name = (EditText) findViewById(R.id.editText1);
        final EditText email = (EditText) findViewById(R.id.editText2);
        Button btn = (Button) findViewById(R.id.btnsaveprefs);
        btn.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                SharedPreferences.Editor editor = settings.edit();
                editor.putString("MSISDN", name.getText().toString());
                editor.putString("PIN", email.getText().toString());
                editors.putInt("PREFS_NAME", 1); // id = 1
                editor.commit();
                Intent second=new Intent(getApplicationContext(), Second.class);
                startActivity(second);
            }
        });
    }
}

public class Second extends Activity { // classes begin with CAPITAL

    public static final String PREFS_NAME = "MSISDN and PIN";

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.second);
        TextView tvname = (TextView) findViewById(R.id.uname);
        TextView tvemail = (TextView) findViewById(R.id.uemail);
        SharedPreferences settings = getSharedPreferences(PREFS_NAME, 0);
        tvname.setText(settings.getString("MSISDN", "Unknown"));
        tvemail.setText(settings.getString("PIN", "Email default"));
    }
}

请注意，您未在其他答案中设置ID。顺便提一下，你的编码风格很糟糕：永远不要用小写字母开始一个类名，为什么id是一个int？你用它作为布尔值。为什么要在名为PIN的首选项中保存一封电子邮件，并在名为MSISDN的首选项中保存一个名称???

android中的持久/共享存储

2 个答案: