editText field is required before moving on to ano

问题:

I have validation for editText. If the editText field is empty it should fail validation and stop the user moving on to another Activity, as a value is required. How to do it? I know this is a basic question, but I can't figure out how to do this.

My code:

btninsert = (Button)findViewById(R.id.btn_insert);
btninsert.setOnClickListener( new View.OnClickListener() {
    public void onClick(View v) {
        insertValues();
        EditText userName = (EditText) findViewById(R.id.editText1);

        if( userName.getText().toString().length() == 0 )
            userName.setError( "First name is required!" );

        Intent i = new Intent(getApplicationContext(), Login.class);
        startActivity(i);
    }
});

When this Button is clicked the user is redirect to next screen, but I need that if validation fails they stay on the current Activity, and only when validation is successful (i.e. a value has been entered) they go to the next Activity.

回答1:

It's easy...check if your EditText is empty as in below example below.

if( TextUtils.isEmpty(userName.getText())){
   /**
    *   You can Toast a message here that the Username is Empty    
    **/

   userName.setError( "First name is required!" );

}else{
   Intent i = new Intent(getApplicationContext(), Login.class);
   startActivity(i);
}

回答2:

Try this:

bt.setOnClickListener(new OnClickListener() {
    public void onClick(View arg0)
    {
        String  str=et.getText().toString();

        if(str.equalsIgnoreCase(""))
        {
            et.setHint("please enter username");//it gives user to hint
            et.setError("please enter username");//it gives user to info message //use any one //
        }
        else
        {
            Intent in=new Intent(getApplicationContext(),second.class);
            startActivity(in);
        }
    }
});

回答3:

You can also try this:

 if ( ( userName.getText().toString().trim().equals("")) ) 
 {
      Toast.makeText(getApplicationContext(), "User name is empty", Toast.LENGTH_SHORT).show();
 }
 else
 {
      Intent i = new Intent(getApplicationContext(), Login.class);
      startActivity(i);
 }

回答4:

I faced a similiar problem. In my case, I had a lot of Edittexts to verify, some them was child of another layouts. Tip: all views must be in same root view. So, to be simple:

...
LinearLayout viewGroup = (LinearLayout) findViewById(R.id.viewGroup);
checkFieldsRequired(viewGroup);
...

public boolean checkFieldsRequired(ViewGroup viewGroup){

    int count = viewGroup.getChildCount();
    for (int i = 0; i < count; i++) {
        View view = viewGroup.getChildAt(i);
        if (view instanceof ViewGroup)
            checkFieldsRequired((ViewGroup) view);
        else if (view instanceof EditText) {
            EditText edittext = (EditText) view;
            if (edittext.getText().toString().trim().equals("")) {                  
                edittext.setError("Required!");                 
            }
        }
    }

    return false;
}

回答5:

Better to test empty textField using If condition for all required or special validation cases and setError to focus.

If(txtName.getText().toString().trim().equals(""))
{
//Your message or any other validation
}

回答6:

I understand it's an old question but may this helps, you can use .isEmpty() instead of .equals()

if( userName.getText().toString().isEmpty()){

   /**
    *   You can Toast a message here that the Username is Empty    
    **/

   userName.setError( "First name is required!" );

}else{
   Intent i = new Intent(getApplicationContext(), Login.class);
   startActivity(i);
}