How to use onSavedInstanceState example please

Question

I am confused when it comes to maintaining state. Therefore, I know that onSaveInstanceState(Bundle) is called when the action needs to be destroyed. But how do you store your information in it and return it to its original state in onCreate(Bundle savedInstanceState) ? I do not understand how this package will recover information. It would be helpful if someone could give an example. The Dev manual does not explain this very well.

 public class Conversation extends Activity { private ProgressDialog progDialog; int typeBar; TextView text1; EditText edit; Button respond; private String name; private String textAtView; private String savedName; public void onCreate(Bundle savedInstanceState){ super.onCreate(savedInstanceState); setContentView(R.layout.dorothydialog); text1 = (TextView)findViewById(R.id.dialog); edit = (EditText)findViewById(R.id.repsond); respond = (Button)findViewById(R.id.button01); if(savedInstanceState != null){ savedInstanceState.get(savedName); text1.setText(savedName); } else{ text1.setText("Hello! What is your name?"); respond.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { name = edit.getText().toString(); text1.setText("Nice to meet you "+ name); } }); } } @Override public void onSaveInstanceState(Bundle outState){ super.onSaveInstanceState(outState); outState.putString(savedName, name); } } 

Answer 1

Bundle is a container for all the information you want to keep. You use put * functions to insert data into it. Here's a short list (there are more) of put functions that you can use to store data in the Bundle .

 putString putBoolean putByte putChar putFloat putLong putShort putParcelable (used for objects but they must implement Parcelable) 

In your onCreate function onCreate this Bundle returned to the program. The best way to check if the application is restarting or starting for the first time:

 if (savedInstanceState != null) { // Then the application is being reloaded } 

To return data, use the get * functions in the same way as the put * functions. Data is stored as a name-value pair. It looks like a hash map. You provide the key and value, and then when you want to return the value, you give the key, and the function gets the value. Here is a brief example.

 @Override public void onSaveInstanceState(Bundle outState) { outState.putString("message", "This is my message to be reloaded"); super.onSaveInstanceState(outState); } @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); if (savedInstanceState != null) { String message = savedInstanceState.getString("message"); Toast.makeText(this, message, Toast.LENGTH_LONG).show(); } } 

Your saved message will be fried on the screen. Hope this helps.

Answer 2

One of the main points that all new Android developers should be aware of is that any information in widgets (TextView, Buttons, etc.) will be saved automatically by Android until you assign them an ID. Therefore, this means that most of the state of the user interface is taken care of without problems. Only when you need to store other data does it become a problem.

From Android docs :

The only work you require is to provide a unique identifier (with android: id) for each widget you want to keep its state. If the widget does not have an identifier, then it cannot save its state

Answer 3

Good info: you don't need to check if the Bundle object is null in the onCreate () method. Use the onRestoreInstanceState () method, which the system calls after the onStart () method. The system calls onRestoreInstanceState () only if the saved state is required for recovery, so you do not need to check if the Bundle is null

Answer 4

Store Information:

 static final String PLAYER_SCORE = "playerScore"; static final String PLAYER_LEVEL = "playerLevel"; @Override public void onSaveInstanceState(Bundle savedInstanceState) { // Save the user current game state savedInstanceState.putInt(PLAYER_SCORE, mCurrentScore); savedInstanceState.putInt(PLAYER_LEVEL, mCurrentLevel); // Always call the superclass so it can save the view hierarchy state super.onSaveInstanceState(savedInstanceState); } 

If you do not want to recover information in your onCreate method:

Here are some examples: Restore activity

Instead of restoring state during onCreate (), you can choose the onRestoreInstanceState () implementation that the system calls after the onStart () method. The system calls onRestoreInstanceState () only if the saved state is required for recovery, so you do not need to check if the Bundle is null

 public void onRestoreInstanceState(Bundle savedInstanceState) { // Always call the superclass so it can restore the view hierarchy super.onRestoreInstanceState(savedInstanceState); // Restore state members from saved instance mCurrentScore = savedInstanceState.getInt(PLAYER_SCORE); mCurrentLevel = savedInstanceState.getInt(PLAYER_LEVEL); } 

Answer 5

Basically onSaveInstanceState (Bundle outBundle) will give you a kit. When you look at the Bundle class, you will see that you can put many different things inside it. The next time you call onCreate (), you simply get this Bundle back as an argument. Then you can read your values ​​again and restore your activity.

Suppose you have an action using EditText. The user wrote the text inside it. After that, the system calls your onSaveInstanceState (). You read text from EditText and write it to the Bundle via Bundle.putString ("edit_text_value", theValue).

Now onCreate is called. You check to see if the supplied kit is included. If so, you can restore your value through Bundle.getString ("edit_text_value") and put it back into your EditText.

Answer 6

This is additional information.

Imagine this scenario

• ActivityA launches ActivityB.

• ActivityB Launches New ActivityAPrime

   Intent intent = new Intent(getApplicationContext(), ActivityA.class); startActivity(intent); 

• ActivityAPrime is not related to ActivityA.
  In this case, the Bundle in ActivityAPrime.onCreate () will be null.

If ActivityA and ActivityAPrime should be the same and not different actions, ActivityB should call finish (), than use startActivity ().

Answer 7

If the data is not loaded from savedInstanceState , use the following code.
The problem is that the url call is not fully completed, check if the data is loaded to show the value of instanceState.

 //suppose data is not Loaded to savedInstanceState at 1st swipe if (savedInstanceState == null && !mAlreadyLoaded){ mAlreadyLoaded = true; GetStoryData();//Url Call } else { if (listArray != null) { //Data Array From JsonArray(ListArray) System.out.println("LocalData " + listArray); view.findViewById(R.id.progressBar).setVisibility(View.GONE); }else{ GetStoryData();//Url Call } }