CODEWITHSUNDEEP
javaandroidsharedpreferences
Zahid H
Zahid H

Reputation: 245

See if a SharedPreference variable is null or not

Global Variable:

SharedPreferences prefs;
SharedPreferences.Editor editor;

Saved during onDestory():

editor.putInt("InfType", rgTypeOfInf.getCheckedRadioButtonId()); //saving value

Being called during onCreate():

rgTypeOfInf = (RadioGroup) mFrame2.findViewById(R.id.rgType);
rgTypeOfInf.check(prefs.getInt("InfType", 2131230725)); //retrieving the value

How can I check when my app loads to see if the saved variable exist or if it's null. If it exist, check the radio button of the radiogroup otherwise if it's null, check the radiogroup[0] position by default?

My XML file:

    <RadioGroup
        android:id="@+id/rgType"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_weight="1" >
        <RadioButton
            android:id="@+id/rbBridge"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:checked="true"
            android:text="Bridge" />
        <RadioButton
            android:id="@+id/rbTunnel"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Tunnel" />
        <RadioButton
            android:id="@+id/rbHighway"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Highway" />
    </RadioGroup>

Upvotes: 1

Views: 734

Answers (2)

Boris Mocialov
Boris Mocialov

Reputation: 3489

Put:

int checked = -1;
RadioGroup rg = (RadioGroup) findViewById(R.id.rgType);
for(int i = 0; i < rg.getChildCount(); i++){
  if(((RadioButton)rg.getChildAt(i)).isChecked()){
     checked = i;
  }
}
editor.putInt("InfType", checked);

Retrieve:

int InfType = prefs.getInt("InfType", -1);
RadioGroup rg = (RadioGroup) findViewById(R.id.rgType);
if(InfType > -1) {
  ((RadioButton)rg.getChildAt(InfType)).toggle();
} else{
  ((RadioButton)rg.getChildAt(0)).toggle();
}

Havent tested

Used:

http://developer.android.com/guide/topics/ui/controls/radiobutton.html http://developer.android.com/reference/android/content/SharedPreferences.html#getInt(java.lang.String,%20int)

Upvotes: 1

Vic Vuci
Vic Vuci

Reputation: 7051

So you have a 'default' setting already if its null

See, your rgTypeOfInf.check(prefs.getInt("InfType", 2131230725)); has 2131230725 as the default value of the pref if it does not exist.

So, you can set it to something like -1, then say

int type = prefs.getInt("InfType", -1);

if (type == -1){
   //was never set
} else{
  //...
}

Upvotes: 2

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