按钮setOnClickListener方法不被调用

Question

下面是我试图从微调setOnClickListener方法为按钮validateUser得到选定的值的示例代码。

public class MainActivity extends Activity implements AdapterView.OnItemSelectedListener { 
     private Button validateUser; 
     private Spinner userTypeSpinner; 


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

     userTypeSpinner=(Spinner)findViewById(R.id.userTypeSpinner); 
     validateUser= (Button) findViewById(R.id.userValidate); 

     validateUser.setOnClickListener(new View.OnClickListener() { 
      @Override 
      public void onClick(View view) { 
       Toast.makeText(getApplicationContext(), "Button is Selected", Toast.LENGTH_SHORT); 
      } 
     }); 



     ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(this, 
       R.array.userTypeArray, android.R.layout.simple_spinner_item); 
     adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item); 
     userTypeSpinner.setAdapter(adapter); 
     userTypeSpinner.setOnItemSelectedListener(this); 
    } 

    @Override 
    public void onItemSelected(AdapterView<?> adapterView, View view, int i, long l) { 
     String item = adapterView.getItemAtPosition(i).toString(); 

     Toast.makeText(adapterView.getContext(), "Selected: " + item, Toast.LENGTH_SHORT).show(); 
    } 

    @Override 
    public void onNothingSelected(AdapterView<?> adapterView) { 

    } 
} 

Answer 1

吐司需要显示。最后使用.show()。

Toast.makeText(getApplicationContext(), "Button is Selected", Toast.LENGTH_SHORT).show();