how to achieve something like “finish” in a non-activity class in android?

问题

This dialog asks whether you want to install some other app...so when onclicked no button it must go back to the previous screen

    downloadDialog.setNegativeButton(stringButtonNo,
            new DialogInterface.OnClickListener() {
                public void onClick(DialogInterface dialogInterface, int i) {
                         finish();
                }
            });

this gives the error:

The method finish() is undefined for the type new DialogInterface.OnClickListener(){}

how can i achieve what i wanted???

package com.Android.barcode;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.widget.TextView;

public class BarcodeActivity extends Activity {
    public static String upc;

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        IntentIntegrator.initiateScan(this);
    }

    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        switch (requestCode) {
        case IntentIntegrator.REQUEST_CODE: {
            if (resultCode != RESULT_CANCELED) {
                IntentResult scanResult = IntentIntegrator.parseActivityResult(
                        requestCode, resultCode, data);
                if (scanResult != null) {
                    upc = scanResult.getContents();

                    Intent intent = new Intent(BarcodeActivity.this, BarcodeResult.class);
                    startActivity(intent);
                    // put whatever you want to do with the code here
/*                  TextView tv = new TextView(this);
                    tv.setText(upc);
                    setContentView(tv);*/
                }
            }
            break;
        }
        }
    }
}

回答1:

Since you don't want to create that dialog from that activity : You have two options

1) Call an Intent back to the activity you want the user to go to.

Intent intent = new Intent(getBaseContext(), theActivity.class); 
getApplication().startActivity(intent) ;

or Else

2) Create a constructor for that class consisting of the dialog.

public class ABC {
    Context iContext=null;
   public ABC(Context con){
    iContext=con;
   }
 ....

}

Call the class with the Context of the activity. Like ABC(Cont) .And then use ((Activity)iContext).finish() within that class to finish that activity as you wish.

回答2:

if Your class having constructor which having Context assign in it than u can Use this way

   AlertDialog.Builder adb=new AlertDialog.Builder(context);
                adb.setTitle("Are You Sure Want To Delete?");
                adb.setPositiveButton("OK", new AlertDialog.OnClickListener() {
                    public void onClick(DialogInterface dialog, int which) {

                    }});
                adb.setNegativeButton("CANCEL", new AlertDialog.OnClickListener() {
                    public void onClick(DialogInterface dialog, int which) {
                        ((Activity) context).finish();
                    }});
                adb.show();

回答3:

The method finish() is undefined for the type new DialogInterface.OnClickListener(){}

It is likely to give this error because DialogInterface.OnClickListener doesn't have any such method. If you want to finish your Activity you have to use

ActivityName.this.finish();

回答4:

Best solution is use dialog fragment for any type of dialog it will just open a dialog on your activity. And on listeners remove this dialog. Please have a look on the following link:

http://developer.android.com/reference/android/app/DialogFragment.html

It is recommended from Android guys as well.

来源：https://stackoverflow.com/questions/10662372/how-to-achieve-something-like-finish-in-a-non-activity-class-in-android

标签

android

android-alertdialog

activity-finish