Android中带有switch语句的AlertDialog

Question

I'm on the way of making an android app for my client for the first time. He needs to implement multiple languages in the app. So, I put some relative layouts and while clicking it will be changed to the particular language. But now, want to put an 'alert dialog' for selection confirmation. For that, I made an alert box and implement a switch statement in the positive button. But, it's not working and I'm not having any errors.:( This is my piece of code:

rl_german.setOnClickListener(new OnClickListener() {
    @Override
    public void onClick(View v) {
        AlertDialog();; 

    }
});
rl_english.setOnClickListener(new OnClickListener() {

    @Override
    public void onClick(View v) {

    AlertDialog();

    }
});
  }

 private void AlertDialog()
   {
        new AlertDialog.Builder(this)
        .setTitle("")
        .setMessage("Are you sure you want to change the language?")
        .setPositiveButton("Yes", new DialogInterface.OnClickListener() {

 public void onClick(DialogInterface dialog, int which) { 
        switch(which){
        case R.id.rl_english:
            startActivity(new Intent(Language.this,HomeActivity2.class));   
        break;
        case R.id.rl_german:

        break;
        case R.id.rl_french:

        break;
    }
    }
 })
.setNegativeButton("No", new DialogInterface.OnClickListener() {
    public void onClick(DialogInterface dialog, int which) { 
        // do nothing
    }
 })
 .show();
} 

But, if I'm calling the 'startActivity' directly in my 'OnClick' method. Its working fine. Can anybody help me please. Thanks in advance :)

Answer 1

The problem here is that which refers to the id of the Button clicked in the AllertDialog.Builder (eg BUTTON_POSITIVE , BUTTON_NEGATIVE );

What you could do is make an Intent variable as a member variable (declared outside of a method) then call startActivity() with that variable as the parameter. Short example:

public class MyActivity extends Activity
{
     Intent i;

     public void onCreate(...)
     {
         ...
         rl_english.setOnClickListener(new OnClickListener() {
         @Override
         public void onClick(View v) {
         i = new Intent(Language.this,HomeActivity2.class);
         AlertDialog();
      }

 private void AlertDialog()
{
    new AlertDialog.Builder(this)
    .setTitle("")
    .setMessage("Are you sure you want to change the language?")
    .setPositiveButton("Yes", new DialogInterface.OnClickListener() {
      public void onClick(DialogInterface dialog, int which) { 
        startActivity(i));
}

This is quick untested code so you may need to adjust for your needs, add extra code and brackets, etc... The point is, that you are trying to compare which to the Button clicked in your Activity but this actually refers to the Button clicked in your AlertDialog . You need to instantiate the Intent depending on which Acitvity Button is clicked then start the Activity if the positive Button in your AlertDialog is clicked or cancel if the negative Button is clicked.

Answer 2

I think, the problem is, your switch is working on the base of "which" parameter coming from onClick(DialogInterface dialog, int which), but you are checking it with "R.id.rl_english". Your none of the cases are matching the condition because "which" gives the button clicked not the id of any view.