在Android中显示Toast消息时出现问题

Question

According to my requirement in android, if the user presses only "space" and clicks "post" button a toast should be displayed. So i have the code as below, but the toast doesnt get displayed. please can anybody tell why it is not displaying ?

   mEditText.addTextChangedListener(mTextEditorWatcher);    
  Button button = (Button) findViewById(R.id.button1);

 button.setOnClickListener(new View.OnClickListener() {

    public void onClick(View v) {
        // TODO Auto-generated method stub
        String result =mEditText.getText().toString();
         if(result.contains ("\\s"))
           Toast.makeText(getApplicationContext(), "Space ", Toast.LENGTH_LONG).show();
    }
});
}

Answer 1

I dont think contains get you the best result, try this:

if(result.equals(" "))
    Toast.makeText(getApplicationContext(), "Space ", Toast.LENGTH_LONG).show();

Answer 2

Looks like you are trying to use regex with String.contains method. String.contains method works with String . It doesn't work with regex .

See this question for more details: How to use regex in String.contains() method in Java

By the way, you should not check for just one space. You should handle any number of spaces.

if(result.length()!=0 && result.trim().equals(""))
    ShowToast();

Answer 3

Try this..

if(result.contains (" "))
           Toast.makeText(getApplicationContext(), "Space ", Toast.LENGTH_LONG).show();

Answer 4

You have a two way of solutions

1.You should check this condition by " " --> if(result.contains ("\\s"))

Example:

if(result.contains(" "))

2.You Should Check with Pattern

Example:

String result =ed.getText().toString();
       Pattern pattern = Pattern.compile("\\s");
   Matcher matcher = pattern.matcher(result);
   boolean found = matcher.find();
   if(found)
         Toast.makeText(getApplicationContext(), "Space ", Toast.LENGTH_LONG).show();

Please use any of these solutions.It will work.

Answer 5

I changed the if condition to space and i am getting a Toast message successfully.

public class MainActivity extends Activity implements OnClickListener{

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

    Button button = (Button) findViewById(R.id.Button1);
    final EditText mEditText = (EditText) findViewById(R.id.EditText1);

    button.setOnClickListener(new View.OnClickListener() {

       public void onClick(View v) {
           // TODO Auto-generated method stub
           String result =mEditText.getText().toString();
           Log.e("Test Message", result);
           if(result.contains (" "))
             Toast.makeText(getApplicationContext(), "Space ", Toast.LENGTH_LONG).show();
       }
   });
}

Please try and let me know if you are still facing the issue ...

Thanks