Losing Data When Rotate Screen

Losing data when rotate screen

By default, when the screen is rotated your Activity is killed and restarted. To make sure no data is lost, you need to properly save and restore your data using the lifecycle methods. See Saving Persistent State.

Handle screen rotation without losing data - Android

can use override method onSaveInstanceState() and onRestoreInstanceState().
or to stop calling onCreate() on screen rotation just add this line in your manifest xml android:configChanges="keyboardHidden|orientation"

note: your custom class must implements Parcelable example below.

@Override
    public void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        outState.putParcelable("obj", myClass);
    }

@Override
protected void onRestoreInstanceState(Bundle savedInstanceState) {
 // TODO Auto-generated method stub
 super.onRestoreInstanceState(savedInstanceState);
 myClass=savedInstanceState.getParcelable("obj"));
}

public class MyParcelable implements Parcelable {
     private int mData;

 public int describeContents() {
     return 0;
 }

 /** save object in parcel */
 public void writeToParcel(Parcel out, int flags) {
     out.writeInt(mData);
 }

 public static final Parcelable.Creator<MyParcelable> CREATOR
         = new Parcelable.Creator<MyParcelable>() {
     public MyParcelable createFromParcel(Parcel in) {
         return new MyParcelable(in);
     }

     public MyParcelable[] newArray(int size) {
         return new MyParcelable[size];
     }
 };

 /** recreate object from parcel */
 private MyParcelable(Parcel in) {
     mData = in.readInt();
 }

}

Viewmodel data lost on rotation

Solution was to let the underlying activity save the viewmodels data in it's onPause function.

Handle screen rotation progress without losing data by using Seekbar - Android Kotlin

You are passing string to the progress function of seekbar.
We need to pass integer.
So, simply use
seekbar_weight.progress = value.toInt()

UPDATE AFTER GOING THROUGH YOUR CODE:

In your code, in the setVariable() function, you are setting some UI's according to the Units user picked.

While doing that, you are setting your progress of the seekbar to 0. And this function is being called after the progress value is restored from onRestoreInstateState. After it gets restored, you are again setting it back to zero from setVariable() function.

So, you just need to remove 8 lines (which are used to set seekbar progress and text to show seekbar progress) from your setVariable() function.

So, your setVariable() function should look like:

    private fun setVariable() {
    //Set the text of units and the max progress
    spinner_units.onItemSelectedListener = object : AdapterView.OnItemSelectedListener {
        override fun onItemSelected(
            parent: AdapterView<*>?,
            view: View?,
            position: Int,
            id: Long
        ) {
            if (position == 0) {
                text_weight.text = "Weight (kg)"
                text_height.text = "Height (cm)"
                seekbar_weight.max = 450
                seekbar_height.max = 250
                number_picker_age.value = 2
                bmi_meter.speedTo(0F)
            } else if (position == 1) {
                text_weight.text = "Weight (ibs)"
                text_height.text = "Height (in)"
                seekbar_weight.max = 770
                seekbar_height.max = 80
                number_picker_age.value = 2
                bmi_meter.speedTo(0F)
            }

        }
        override fun onNothingSelected(parent: AdapterView<*>?) {
        }
    }
}

UPDATE 2: AFTER UPDATED REQUIREMENT

For your updated requirement here you can go:
Bring back those 8 lines those were deleted from setVariable() method.

In your strings.xml file, add one item 'Select' in the string array for the spinner.

<string-array name="units">
        <item>Select</item>
        <item>Metric</item>
        <item>Imperial</item>
</string-array>

In MainActivity, override onPause() method and set the spinner to position 0.

override fun onPause() {
    super.onPause()
    spinner_units.setSelection(0)
}

That should solve your problem. If not please comment back.

Data from textView deleting after i rotate screen after i implemented onSaveInstance and onRestoreInstance

Yes, you need to use onSaveInstanceState. This methods will save your variables which you have in your textViews or something else. In your case you need to declare your views like findViewById in onSaveInstanceState and onRestoreInstanceState. You can try something like this, this code is working:

public class MainActivity extends AppCompatActivity {

Button Btn;
TextView textView;
String cnt = "";

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    Btn = (Button) findViewById(R.id.button);
}

public void onBtnClick(View view) {
    textView = (TextView) findViewById(R.id.textView);
    textView.setText("Hehe");
}

protected void onSaveInstanceState(Bundle outState) {
    super.onSaveInstanceState(outState);
    textView = (TextView) findViewById(R.id.textView);
    cnt = (String) textView.getText();
    outState.putString("count", cnt);
}

protected void onRestoreInstanceState(Bundle savedInstanceState) {
    super.onRestoreInstanceState(savedInstanceState);
    cnt = savedInstanceState.getString("count");
    textView = (TextView) findViewById(R.id.textView);
    textView.setText(cnt);
}
}

Save data in Fragments on screen rotation in Android

for each class extending fragment inside your application store the value you want to retain it when you change the screen orientation inside onSaveInstanceState method and then retain inside onCreateView method.

for example for the video problem you are having , you can do something like this:

@Override
public void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
outState.putInt("cp", videoview.getCurrentPosition());  
 }

then retain it like this

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
        Bundle savedInstanceState) {
    if(savedInstanceState!=null)
    {
        int a=savedInstanceState.getInt("cp");
        videoview.seekTo(a);
    }

//the rest of your code then....
}

hope i got you.

---

Related Topics