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.

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