警報對話框未在列表活動中顯示Android

Question

我正面臨一個問題。 我有一個擴展listactivity的類，它的代碼是這樣的：

public class QuestionListActivity extends ListActivity
{
//Members

private ImageButton bntRefresh;
private ImageButton bntSettings;
private ImageButton bntGetSurveys;


 /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.surveylist);

    initialize();

    currentSurveys=new SurveyList();
 }

private void initialize()
{
    bntRefresh= (ImageButton) findViewById(R.id.ibtnRefresh);
    bntRefresh.setImageResource(R.drawable.refresh);
    bntRefresh.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View v) {
        Toast.makeText(SurveyListActivity.this, "This will refresh the survey list.", Toast.LENGTH_SHORT).show();   
        }
    });



    bntSettings= (ImageButton) findViewById(R.id.ibtnSettings);
    bntSettings.setImageResource(R.drawable.settings);
    bntSettings.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View v) {
            Toast.makeText(SurveyListActivity.this, "This will open the settings.", Toast.LENGTH_SHORT).show(); 
        }
    });

    bntGetSurveys= (ImageButton) findViewById(R.id.ibtnGetSurveys);
    bntGetSurveys.setImageResource(R.drawable.getsurvey);
    bntGetSurveys.setOnClickListener(new OnClickListener() {
        @Override
        public void onClick(View v) 
        {
            AlertDialog getSurveyAlert = new AlertDialog.Builder(QuestionListActivity .this).create();
            getSurveyAlert.setTitle("Enter QR Code");
            getSurveyAlert.setMessage("Choose a source");
            getSurveyAlert.setButton("Camera", new DialogInterface.OnClickListener() {

                @Override
                public void onClick(DialogInterface dialog, int which) {

                }
            });
            getSurveyAlert.setButton2("text", new DialogInterface.OnClickListener() {

                @Override
                public void onClick(DialogInterface dialog, int which) {

                }
            });
        }
    });
}

    class SurveyAdapter extends ArrayAdapter<Survey>
    {
      //-- code here for adapter
    }
}

在我的初始化函數中，你可以看到我有三個圖像按鈕，我已經為它們實現了onClicklisteners。 對於設置和刷新按鈕，我顯示了一個Toast，它工作正常。 對於Get Button我已經顯示了一個對話框，它進一步要求用戶做某事，但我面臨的問題是對話框沒有出現，我不知道為什么？

Answer 1

你忘了，寫行

getSurveyAlert.show();

嘗試這個，

bntGetSurveys.setOnClickListener(new OnClickListener() {
        @Override
        public void onClick(View v) 
        {
            AlertDialog getSurveyAlert = new AlertDialog.Builder(QuestionListActivity .this).create();
            getSurveyAlert.setTitle("Enter QR Code");
            getSurveyAlert.setMessage("Choose a source");
            getSurveyAlert.setButton("Camera", new DialogInterface.OnClickListener() {

                @Override
                public void onClick(DialogInterface dialog, int which) {

                }
            });
            getSurveyAlert.setButton2("text", new DialogInterface.OnClickListener() {

                @Override
                public void onClick(DialogInterface dialog, int which) {

                }
            });
        getSurveyAlert.create().show();
}

Answer 2

調用show（）方法

@Override
        public void onClick(View v) 
        {
            AlertDialog getSurveyAlert = new AlertDialog.Builder(QuestionListActivity .this).create();
            getSurveyAlert.setTitle("Enter QR Code");
            getSurveyAlert.setMessage("Choose a source");
            getSurveyAlert.setButton("Camera", new DialogInterface.OnClickListener() {

                @Override
                public void onClick(DialogInterface dialog, int which) {

                }
            });
            getSurveyAlert.setButton2("text", new DialogInterface.OnClickListener() {

                @Override
                public void onClick(DialogInterface dialog, int which) {

                }
            });
getSurveyAlert.create().show();
        }
    });

Answer 3

AlertDialog getSurveyAlert = new AlertDialog.Builder（QuestionListActivity.this）.create（）; //使用此行代替此行

AlertDialog getSurveyAlert = new AlertDialog.Builder（QuestionListActivity .this）.show（）;