Reputation: 1521
Can someone explain to me why this AlertDialog crashes?
package com.clicker;
import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.content.DialogInterface.OnClickListener;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
public class Clicker extends Activity
{
public int clickerNumber = 0;
private TextView clickerText;
private Button clickerButton;
private Button resetButton;
// Called when the activity is first created.
@SuppressWarnings("null")
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
// Declare each of the layout objects
clickerText = (TextView)findViewById(R.id.clickerText);
clickerButton = (Button)findViewById(R.id.clickerButton);
resetButton = (Button)findViewById(R.id.resetButton);
clickerText.setText("0");
final AlertDialog.Builder resetQuestion = null;
resetQuestion.setTitle("Reset?");
resetQuestion.setMessage("Are you sure you want to reset the counter?");
resetQuestion.setPositiveButton("Yes", new OnClickListener() {
public void onClick(DialogInterface dialog, int whichButton) {
clickerNumber = 0;
clickerText.setText("0");
}
});
resetQuestion.setNegativeButton("No", new OnClickListener() {
public void onClick(DialogInterface dialog, int whichButton) {
dialog.dismiss();
}
});
clickerButton.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
clickerNumber++;
clickerText.setText(Integer.toString(clickerNumber));
}
});
resetButton.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
resetQuestion.show();
}
});
};
};
Upvotes: 1
Views: 1598
Reputation: 200170
This is a great fail:
final AlertDialog.Builder resetQuestion = null;
resetQuestion.setTitle("Reset?");
You are trying to use a null object, and that (of course) will throw a NullPointerException
This is how I create dialogs (and I think it's the best way to do it):
LayoutInflater factory = LayoutInflater.from(this);
final View textEntryView = factory.inflate(R.layout.dialogo_layout, null);
final AlertDialog.Builder resetQuestion = new AlertDialog.Builder(YourActivity.this)
// do whatever you want with the resetQuestion AlertDialog
Here, R.layout.dialogo_layout
represent a file called dialogo_layout.xml
in the res/layout
dir that contains the dialog layout.
Upvotes: 4