如果文本字段为空,则禁用Android按钮

Question

有人可以告诉我如何禁用Android中的按钮,除非所有三个editText字段都填满了吗？我不知道在这里包含条件语句的位置以及如何将它放在按钮侦听器的上下文中.

这是我的主要活动代码.

package com.amritayalur.mypowerschool;



import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.text.method.ScrollingMovementMethod;
import android.view.Gravity;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.inputmethod.InputMethodManager;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;



public class MyPowerSchoolActivity extends Activity {
Button buttonSubmit;
TextView textViewTitle;
TextView textViewDesc;
EditText editTextURL, editTextUser, editTextPass;

String url = "";
 String str;
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);


    buttonSubmit = (Button) findViewById(R.id.buttonSubmit);
    textViewTitle = (TextView) findViewById(R.id.textViewTitle);
    textViewDesc = (TextView) findViewById(R.id.textViewDesc);

    editTextURL = (EditText) findViewById(R.id.editTextURL);
    editTextUser = (EditText) findViewById(R.id.editTextUser);
    editTextPass = (EditText) findViewById(R.id.editTextPass);
    //Start TextView
    textViewTitle.setText("MyPowerSchool");


    //button listener
    buttonSubmit.setOnClickListener(new View.OnClickListener() {


        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub
            Intent i = new Intent( MyPowerSchoolActivity.this, creds.class);    
            i.putExtra("pschoolurl", editTextURL.getText().toString());
            i.putExtra("pschooluser", editTextUser.getText().toString());
            i.putExtra("pschoolpass", editTextPass.getText().toString());
            // get the text here
            final int result = 1;
            startActivityForResult(i, result); 

        };




    });




}       
}

Answer 1

您可以使用TextChangeListener

    EditText ed = //your EditText
    ed.addTextChangedListener(new TextWatcher() {

        @Override
        public void onTextChanged(CharSequence s, int start, int before, int count) {
            //Check if 's' is empty 

        }

        @Override
        public void beforeTextChanged(CharSequence s, int start, int count,
                int after) {
            // TODO Auto-generated method stub

        }

        @Override
        public void afterTextChanged(Editable s) {
            // TODO Auto-generated method stub

        }
    });