条件在sharedpreferences android中不起作用 [英] Condition is not working in sharedpreferences android

问题描述

我有一个登录页面，因此我使用了 SharedPreferences.我正在尝试保存值.没有值，它不应该转到另一个 Activity 因为我在登录页面中给出了这个:

I have a Login page, so for that I am using SharedPreferences. I am trying to save values. Without values, it shouldn't go to the another Activity for that I have given this in Login page:

 if((spf != null) && (spv !=null) && (et1v != null) && (et2v != null) && (et3v != null) &&

             (sp != null) && (et1 != null) && (et2 != null) && (et3 != null)){

            finish();
            Intent i = new Intent(Login.this,Welcome.class);
            startActivity(i);
     }
       else{
           btn1.setOnClickListener(
                   new View.OnClickListener() {
                       @Override
                       public void onClick(View view) {

                           if (sp.getSelectedItem().toString().length() > 0 &&
                                   et1.getText().toString().length() > 0 &&
                                   et2.getText().toString().length() > 0 &&
                                   et3.getText().toString().length() > 0 )

                           {
                               SharedPreferences spf = getSharedPreferences("newprfs", Context.MODE_PRIVATE);
                               SharedPreferences.Editor spe = spf.edit();
                               spe.putString("uname",sp.getSelectedItem().toString());
                               spe.putString("password",et1.getText().toString());
                               spe.putString("mobile",et2.getText().toString());
                               spe.putString("dept",et3.getText().toString());

                               spe.commit();

                               finish();
                               Intent i = new Intent(Login.this,Welcome.class);
                               startActivity(i);
                           }
                       }
                   }
           );
        }

这是我的欢迎页面

SharedPreferences spf = getSharedPreferences("newprfs", Context.MODE_PRIVATE);
        SharedPreferences.Editor spe = spf.edit();
        String spv = spf.getString("uname","");
        String et1v = spf.getString("password","");
        String et2v = spf.getString("mobile","");
        String et3v = spf.getString("dept","");

        if((spe != null) && (spv !=null) && (et1v != null) && (et2v != null) && (et3v != null) &&
                (sp != null) && (et1 != null) && (et2 != null) && (et3 != null)){
        new Handler().postDelayed(new Runnable(){
            @Override
            public void run() {
                    Intent i = new Intent(Welcome.this,MainActivity.class);
                    startActivity(i);
                    Welcome.this.finish();
            }
        }, SPLASH_DISPLAY_LENGTH);
    }
        else{
            Intent i = new Intent(Welcome.this,Login.class);
            startActivity(i);
            Welcome.this.finish();
        }
    }       

问题是它总是显示一个空白屏幕.我试图检查 Log.d("@@@@@@@@@@@@@@Loginpage@@@@@@@@@@@@@@@@");所以我认识到它总是在登录页面加载并且 if condition 不起作用..有人可以告诉我 if Condition.. 有什么问题吗?

The problem is that it always showing a blank screen. I tried to check with Log.d("@@@@@@@@@@@@@@Loginpage@@@@@@@@@@@@@@@@"); so i recognised to its loading always in Login page and if condition is not working.. can any one suggest me whats wrong in if Condition..?

更新这里不是共享首选项的问题......但这里是条件的问题......

Update Here Its not Problem with Shared Prefs.. But here Its the Problem with Condition...

我没有输入值的 If Condition 它不应该移动到下一个......而且如果之前已经定义了值，它应该移动到下一页......

I the If Condition without Entering Values it should not move to Next... and Also if values already Defined previously it should Move to next page...

所以它移动到下一页和在下一页也发生同样的事情，因为我给出了相同的条件，再次它再次移动到登录页面.所以它停留在单页上，我得到了空白屏幕.

So Its moving to next page and In next page Also Same happening Because I have given same condition and Again Its moving to Login page again. So it stays on the Single page and I am getting blank Screen.

推荐答案

你需要试试 contains(String Key)

试试这个 spv.contains("uname") 而不是 (spv !=null) 或 spv.equals("")我也遇到过这个问题最好使用 Hashmap ......但这适用于你的案例..

Try this spv.contains("uname") instead of (spv !=null) or spv.equals("") I also Faced this issue Better To use Hashmap... but this works for your Case..

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