如何在多个方法之间共享变量？

Question

after saved instance I need share "int audio" to check() method to do several operations. I've an "info" option: when I click I see info dialog and I'd like listen audio (stop it when I click on "cancel"). But when I rotate emulator, I've another audio stars.

int audio;
static int Info;

@Override
public void onCreate(Bundle savedInstanceState){ 
super.onCreate(savedInstanceState);
if (savedInstanceState != null) {
int Info = savedInstanceState.getInt("dialoginfo");
int audio = savedInstanceState.getInt("audio");
}

if(Info != 0)
  {
      Info();
}

private void Info(){
    Info = 1;
    sobCheck();
    LayoutInflater li = LayoutInflater.from(this);
    View view = li.inflate(R.layout.info, null);
    AlertDialog.Builder builder = new AlertDialog.Builder(this);
    builder.setView(view).create();
    TextView text=(TextView) findViewById(R.id.infoView1);
    builder.setCancelable(false); 
    builder.setPositiveButton("Chiudi", new DialogInterface.OnClickListener() {  
           public void onClick(DialogInterface dialog, int id) {  
               Info = 0;
               mp.stop();
               mp.reset();
               mp.release();
                mp = null;
                audio = 0;                  
               dialog.cancel();
        }  
        });  
    builder.show();
        }


private void sobCheck(){
if (audio == 0){
mp = MediaPlayer.create(this, R.raw.sob);
mp.start();
audio = 1;
}



protected void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
outState.putInt("audio", a);

after rotate screen, "audio" is always "0"

Answer 1

The problem is that you've created locally scoped variables that shadow your application level variables here:

    @Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    if (savedInstanceState != null) {
        int Info = savedInstanceState.getInt("dialoginfo");
        int audio = savedInstanceState.getInt("audio");
    }

    if (Info != 0) {
        Info();
    }
}

This declares and initializes two new variables Info and audio that are scoped to your if check and discarded immediately after. They do not actually change the application level variables you declared outside the onCreate method. Try changing it to this:

    @Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    if (savedInstanceState != null) {
        Info = savedInstanceState.getInt("dialoginfo");
        audio = savedInstanceState.getInt("audio");
    }

    if (Info != 0) {
        Info();
    }
}

This prevents Info and audio from being redeclared in your local scope and should instead result in your already declared variables being initialized.

Answer 2

You have to declare it outside onCreate() scope:

int audio;

@Override
public void onCreate(Bundle savedInstanceState){ 
    super.onCreate(savedInstanceState);
    if (savedInstanceState != null) {
        audio = savedInstanceState.getInt("audio");
}

Answer 3

you re-initialize "audio" inside the method. just take out the "int" before you assign the value of audio.