Android警报对话框不会在模拟器中打开

Question

当选择了旋转器中的某些选项时，我一直试图调试一个警告对话框的问题，当选择了某个旋转器中的某些选项时，它不会在单击图像按钮时打开。

下面是我的MainActivity.java文件，其中包括警报对话框的相关代码(遗漏了按预期工作的自旋器代码)，任何帮助都将不胜感激！

    public class MainActivity extends AppCompatActivity {
    public static final String EXTRA_MESSAGE = "com.example.myfirstapp.MESSAGE";


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        // Initialise Inputs & Fields
        this.UnitSelector();
        Spinner spinner = (Spinner) findViewById(R.id.options_spinner);

        // UI Relationships
        ImageButton tapeButton = (ImageButton)findViewById(R.id.imageButton_tape);

        Log.d("SpinnerValue", spinner.getSelectedItem().toString());

        EditText editText = (EditText) findViewById(R.id.value);
        String message = editText.getText().toString();

        // Listeners & Actions
        tapeButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                String spinnerValue = spinner.getSelectedItem().toString();
//                float messageFloat = Float.parseFloat(message);
                Log.d("Button Clicked", spinnerValue);
                if (spinnerValue == "Kilogram" || spinnerValue == "Celsius"){
                    createDialog("Nah mate", "Okay", MainActivity.this);
                }
            }
        });
    }

void createDialog( String title, String msg, Context context){
        AlertDialog.Builder builder
                = new AlertDialog
                .Builder(context);

        // Set the message show for the Alert time
        builder.setMessage(msg);

        // Set Alert Title
        builder.setTitle(title);

        // Set Cancelable false
        // for when the user clicks on the outside
        // the Dialog Box then it will remain show
        builder.setCancelable(true);


        builder.setNeutralButton("Yes", new DialogInterface.OnClickListener() {
            @Override public void onClick(DialogInterface dialog, int which){
                dialog.cancel();
            }
        });


        // Create the Alert dialog
        AlertDialog alertDialog = builder.create();
        alertDialog.show();
    }
}

Answer 1

我想你忘了设置适配器

  Spinner spinner = (Spinner) findViewById(R.id.options_spinner);

        String[] values = {"Kilogram","Celsius","other"};

        ArrayAdapter<String> adapter = new ArrayAdapter<>(this, android.R.layout.simple_list_item_1,values);
        adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);

        spinner.setAdapter(adapter);

        ImageButton tapeButton = (ImageButton)findViewById(R.id.imageButton_tape);

        tapeButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                String spinnerValue = spinner.getSelectedItem().toString();
                if (spinnerValue.equals("Kilogram") || spinnerValue.equals("Celsius")){
                    createDialog("Nah mate", "Okay", MainActivity.this);
                }
            }
        });