Question

尝试检查是否存在共享首选项。我需要的是允许用户到达页面，如果他们之前在这里（即共享偏好存在并且不等于“”）或者如果他们第一次在应用程序上将它们放到欢迎页面（即共享首选项为空白，因为用户尚未输入任何数据）。

public class PersonalDetails extends Activity {
        private SharedPreferences sharedPreferences;  


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_personal_details);


if (sharedPreferences.contains("")) {
          Intent intent = new Intent(PersonalDetails.this, Welcome.class);
            startActivity(intent);
        }

Answer 1

<强>尝试

public class PersonalDetails extends Activity {
    private SharedPreferences sharedPreferences;  


@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_personal_details);


      if (isFirstTime()){
        Intent intent = new Intent(PersonalDetails.this,Welcome.class);
        startActivity(intent);
        }
      }



private boolean isFirstTime() {
    SharedPreferences preferences = getPreferences(MODE_PRIVATE);
    boolean ranBefore = preferences.getBoolean("RanBefore", false);
    if (!ranBefore) {
        // first time
        SharedPreferences.Editor editor = preferences.edit();
        editor.putBoolean("RanBefore", true);
        editor.commit();
    }
    return !ranBefore;
}

Answer 2

我认为getPreferences需要两个输入，如下所示。

public abstract SharedPreferences getSharedPreferences(String name,
        int mode);
// Example 
getSharedPreferences("your_app_name", MODE_PRIVATE);

检查共享首选项是否存在

2 个答案: