2016-08-24 94 views
-1

我有一个EditText,并且我想将EditText中的文本保存为共享首选项中的字符串(如果该字符串不为空或为空)。但是我的应用程序崩溃与下面的代码:EditText中的文本未保存在共享首选项中

Activity.java:

Button buttonNext = (Button) findViewById(R.id.buttonNext); 
    assert buttonNext != null; 
    buttonNext.setOnClickListener(new OnClickListener() { 
     @Override 
     public void onClick(View view) { 
      if (checkForGuardianNames()) { 
       Log.i("Guardian names: ", "check passed"); 
       Log.i("ActivityEditText", inputGuardian1.getText().toString()); 
       Toast toast = Toast.makeText(UserInfoActivity.this, inputGuardian1.getText().toString(), Toast.LENGTH_LONG); 
       toast.show(); 
       saveGuardianNames(); 

       } else { 
        promptToFillField("Guardian"); 
        Log.i("Guardian names: ", "check failed"); 
//     Toast toast = Toast.makeText(UserInfoActivity.this, "Works well part 2 "+ inputGuardian1.getText().toString(), Toast.LENGTH_LONG); 
//     toast.show(); 
       } 
      } 

现在我知道checkForGuardianNames()通行证,但在调用saveGuardianNames()方法的应用程序崩溃。

saveGuardianNames()

private void saveGuardianNames(){ 
    String guardian1 = inputGuardian1.getText().toString(); 
    String guardian2 = inputGuardian2.getText().toString(); 
    String guardian3 = inputGuardian3.getText().toString(); 
    String guardian4 = inputGuardian4.getText().toString(); 
    Log.i("Value: ", "Dummy"); 
    Log.i("saveGuardianNames", "Called"); 


     if (!inputGuardian1.getText().toString().matches("")){ 
      Log.i("Putting text", "in sp"); 
      sharedPreferences.edit().putString("Guardian 1", guardian1).apply(); 
      Log.i("Putting text", "passed"); 
     } 
} 

现在我看到saveGuardianNames: check passed在logcat中这样的方法是否正确调用,但该行的正上方,是不是(Log.i("Value: ", "Dummy");)并没有它的任何提及在logcat的。另外,据我所知,在执行Log.i("Putting text", "in sp");之前,if语句不会被调用或崩溃。

我的错误的logcat:

08-24 01:40:43.712 1497-1497/com.bluefirelabs.apptiva I/Guardian names:: check passed 
08-24 01:40:43.732 1497-1497/com.bluefirelabs.apptiva I/saveGuardianNames: Called 
08-24 01:40:43.732 1497-1497/com.bluefirelabs.apptiva E/AndroidRuntime: FATAL EXCEPTION: main 
                     Process: com.bluefirelabs.apptiva, PID: 1497 
                     java.lang.NullPointerException: Attempt to invoke interface method 'android.content.SharedPreferences$Editor android.content.SharedPreferences.edit()' on a null object reference 
                      at com.bluefirelabs.apptiva.UserInfoActivity$override.saveGuardianNames(UserInfoActivity.java:374) 
                      at com.bluefirelabs.apptiva.UserInfoActivity$override.static$access$200(UserInfoActivity.java:27) 
                      at com.bluefirelabs.apptiva.UserInfoActivity$override.access$dispatch(UserInfoActivity.java) 
                      at com.bluefirelabs.apptiva.UserInfoActivity.access$200(UserInfoActivity.java:0) 
                      at com.bluefirelabs.apptiva.UserInfoActivity$1$override.onClick(UserInfoActivity.java:112) 
                      at com.bluefirelabs.apptiva.UserInfoActivity$1$override.access$dispatch(UserInfoActivity.java) 
                      at com.bluefirelabs.apptiva.UserInfoActivity$1.onClick(UserInfoActivity.java:0) 
                      at android.view.View.performClick(View.java:5702) 
                      at android.widget.TextView.performClick(TextView.java:10885) 
                      at android.view.View$PerformClick.run(View.java:22533) 
                      at android.os.Handler.handleCallback(Handler.java:739) 
                      at android.os.Handler.dispatchMessage(Handler.java:95) 
                      at android.os.Looper.loop(Looper.java:158) 
                      at android.app.ActivityThread.main(ActivityThread.java:7229) 
                      at java.lang.reflect.Method.invoke(Native Method) 
                      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1230) 
                      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1120) 

我有点困惑,为什么某些行,同时一个之前,它是不是,为什么应用程序被保存到任何共享偏好坠毁前正在执行。任何帮助表示赞赏。

+0

作为日志'sharedPreferences'为空 –

+0

你在哪里创建和初始化'sharedPreferences',你能否显示 –

+0

在使用之前初始化sharedPreferences – SANAT

回答

1
if (!inputGuardian1.getText().toString().matches("")){ 
      Log.i("Putting text", "in sp"); 
      if(sharedPreferences != null){ 
      sharedPreferences.edit().putString("Guardian 1", guardian1).apply(); 
      Log.i("Putting text", "passed"); 
      }else{ 
      sharedPreferences = mContext.getSharedPreferences(PREF_NAME, PRIVATE_MODE); 
      sharedPreferences.edit().putString("Guardian 1", guardian1).apply(); 
      } 
     } 
0

因为你必须做sharedPreferences这样的:

SharedPreferences sharedPref = getSharedPreferences(
       getString(R.string.preference_file_key), Context.MODE_PRIVATE); 
SharedPreferences.Editor editor = sharedPref.edit(); 

然后editor.putString( ...

然后editor.apply()

0

SharedPreferences对象没有初始化,所以请初始化它,如

如果您在活动做然后做这样的

SharedPreferences.Editor editor = getSharedPreferences("YouKeyName", MODE_PRIVATE).edit(); 

editor.putString("Guardian 1", "Hi"); 
editor.commit(); 

如果你正在做的片段然后做这样的

SharedPreferences.Editor editor = getActivity().getSharedPreferences("UserInfo", getActivity().MODE_PRIVATE).edit(); 

editor.putString("Guardian 1", "Hi"); 
editor.commit(); 
0
SharedPreferences sharedpreferences = getSharedPreferences(MyPREFERENCES, Context.MODE_PRIVATE);   
sharedpreferences.edit().putString("key", "value").commit();