使用php和mysql为Android构建登录，注册系统，但应用程序可以运行

Question

I currently work with an login and registration system for android app.I use mysql as database,php to doing that,but after doing all the system files,the app just stop when clicking to login button..pls help,below is all the code i made

main.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:background="@drawable/images" >

    <LinearLayout
        android:id="@+id/linearLayout1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_alignParentLeft="true"
        android:layout_marginBottom="22dp"
        android:layout_marginLeft="19dp"
        android:orientation="vertical" >

        <TextView
            android:id="@+id/textView1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentBottom="true"
            android:layout_alignParentLeft="true"
            android:layout_marginBottom="2dp"
            android:text="Plot Out"
            android:textAppearance="?android:attr/textAppearanceLarge" />

        <TextView
            android:id="@+id/textView2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignLeft="@+id/textView1"
            android:layout_alignTop="@+id/textView1"
            android:layout_marginTop="1dp"
            android:text="Bring Me Out"
            android:textAppearance="?android:attr/textAppearanceLarge" />
    </LinearLayout>

    <LinearLayout
        android:id="@+id/linearLayout2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="84dp"
        android:orientation="vertical" >

        <ImageView
            android:id="@+id/imageView1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginBottom="10dp"
            android:layout_marginLeft="53dp"
            android:layout_marginTop="2dp"
            android:src="@drawable/logo" />

        <Button
            android:id="@+id/btnLogin"
            android:layout_width="wrap_content"
            android:layout_height="match_parent"
            android:layout_marginBottom="1dp"
            android:layout_marginLeft="40dp"
            android:text="Login"
            android:width="100sp" />

        <Button
            android:id="@+id/btnRegister"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginBottom="10dp"
            android:layout_marginLeft="40dp"
            android:text="Register"
            android:width="100sp" />

        <TextView
            android:id="@+id/link_to_forgotpassword"
            android:clickable="true"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_below="@+id/linearLayout2"
            android:layout_centerHorizontal="true"
            android:text="Forgot Your Password?"
            android:textAppearance="?android:attr/textAppearanceMedium" />
    </LinearLayout>

</RelativeLayout>

login.xml

<?xml version="1.0" encoding="utf-8"?>
<ScrollView
  xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_width="fill_parent"
  android:layout_height="fill_parent"
  android:fillViewport="true">
  <RelativeLayout
        android:layout_width="fill_parent"
        android:layout_height="wrap_content" 
        android:background="#ffffff">

       <!--  Header Starts-->

<LinearLayout
    android:id="@+id/header"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:background="@layout/header_gradient"
    android:orientation="vertical"
    android:paddingBottom="5dip"
    android:paddingTop="5dip" >

        <!-- Logo Start-->
        <ImageView android:src="@drawable/logo"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginLeft="10dip"/>
        <!-- Logo Ends -->
</LinearLayout>
<!--  Header Ends -->

       <!-- Footer Start -->
<LinearLayout android:orientation="horizontal"
    android:id="@+id/footer"
    android:layout_width="fill_parent"
    android:layout_height="90dip"
    android:background="@layout/footer_repeat"
    android:layout_alignParentBottom="true">
</LinearLayout>
<!-- Footer Ends -->

        <!-- Login Form -->
        <LinearLayout

          android:orientation="vertical"
          android:layout_width="match_parent"
          android:layout_height="wrap_content"
          android:padding="10dip"
          android:layout_below="@id/header">
          <!--  Email Label -->
          <TextView android:layout_width="fill_parent"
                android:id="@+id/loginEmail"
                android:layout_height="wrap_content"
                android:textColor="#372c24"
                android:text="Email"/>
          <EditText android:layout_width="fill_parent"
                android:layout_height="wrap_content"
                android:layout_marginTop="5dip"
                android:layout_marginBottom="20dip"
                android:singleLine="true" />

          <!--  Password Label -->
          <TextView android:layout_width="fill_parent"
                android:layout_height="wrap_content"
                android:textColor="#372c24"
                android:text="Password"/>

          <EditText android:layout_width="fill_parent"
                android:id="@+id/loginPassword"
                android:layout_height="wrap_content"
                android:layout_marginTop="5dip"
                android:singleLine="true"
                android:password="true"/>

           <!--  Error message -->
        <TextView android:id="@+id/login_error"
                    android:layout_width="fill_parent"
                    android:layout_height="wrap_content"
                    android:textColor="#e30000"
                    android:padding="10dip"
                    android:textStyle="bold"/>

          <!-- Login button -->
          <Button android:id="@+id/btnLogin"
                android:layout_width="fill_parent"
                android:layout_height="wrap_content"
                android:layout_marginTop="10dip"
                android:text="Login"/>
          <!-- Link to Registration Screen -->

          <TextView
              android:id="@+id/link_to_register"
              android:layout_width="fill_parent"
              android:layout_height="wrap_content"
              android:layout_marginBottom="40dip"
              android:layout_marginTop="40dip"
              android:gravity="center"
              android:text="New to Plot Out?Register here"
              android:textColor="#0b84aa"
              android:textSize="20sp" />

</LinearLayout>
<!-- Login Form Ends -->

  </RelativeLayout>
</ScrollView>

register.xml

<?xml version="1.0" encoding="utf-8"?>
<ScrollView
  xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_width="fill_parent"
  android:layout_height="fill_parent"
  android:fillViewport="true">
  <RelativeLayout
        android:layout_width="fill_parent"
        android:layout_height="wrap_content" android:background="#fff">

        <!--  Header  Starts-->
        <LinearLayout android:id="@+id/header"
                android:layout_width="fill_parent"
                android:layout_height="wrap_content"
                android:background="@layout/header_gradient"
                android:paddingTop="5dip"
                android:paddingBottom="5dip">
                <!-- Logo Start-->
                <ImageView android:src="@drawable/logo"
                            android:layout_width="wrap_content"
                            android:layout_height="wrap_content"
                            android:layout_marginLeft="10dip"/>
                <!-- Logo Ends -->
        </LinearLayout>
        <!--  Header Ends -->
        <!-- Footer Start -->
        <LinearLayout android:id="@+id/footer"
                android:orientation="horizontal"
                android:layout_width="fill_parent"
                android:layout_height="90dip"
                android:background="@layout/footer_repeat"
                android:layout_alignParentBottom="true">
        </LinearLayout>
        <!-- Footer Ends -->

        <!-- Registration Form -->
        <!-- Registration Form Ends -->

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_alignParentBottom="true"
            android:layout_alignParentLeft="true"
            android:orientation="vertical"
            android:padding="10dip" >

            <TextView
                android:layout_width="fill_parent"
                android:layout_height="wrap_content"
                android:text="Full Name"
                android:textColor="#372c24" />

            <EditText
                android:id="@+id/registerName"
                android:layout_width="fill_parent"
                android:layout_height="wrap_content"
                android:layout_marginBottom="20dip"
                android:layout_marginTop="5dip"
                android:singleLine="true" >

                <requestFocus />
            </EditText>

            <TextView
                android:layout_width="fill_parent"
                android:layout_height="wrap_content"
                android:text="Email"
                android:textColor="#372c24" />

            <EditText
                android:id="@+id/registerEmail"
                android:layout_width="fill_parent"
                android:layout_height="wrap_content"
                android:layout_marginBottom="20dip"
                android:layout_marginTop="5dip"
                android:singleLine="true" />

            <TextView
                android:layout_width="fill_parent"
                android:layout_height="wrap_content"
                android:text="Password"
                android:textColor="#372c24" />

            <EditText
                android:id="@+id/registerPassword"
                android:layout_width="fill_parent"
                android:layout_height="wrap_content"
                android:layout_marginTop="5dip"
                android:password="true"
                android:singleLine="true" />

           <!--  Error message -->
        <TextView android:id="@+id/register_error"
                    android:layout_width="fill_parent"
                    android:layout_height="wrap_content"
                    android:textColor="#e30000"
                    android:padding="10dip"
                    android:textStyle="bold"/>

            <Button
                android:id="@+id/btnRegister"
                android:layout_width="fill_parent"
                android:layout_height="wrap_content"
                android:layout_marginTop="10dip"
                android:text="Register New Account" />

            <TextView
                android:id="@+id/link_to_login"
                android:layout_width="fill_parent"
                android:layout_height="wrap_content"
                android:layout_marginBottom="40dip"
                android:layout_marginTop="40dip"
                android:gravity="center"
                android:text="Already has account! Login here"
                android:textColor="#ffffff"
                android:textSize="15sp" />
        </LinearLayout>

  </RelativeLayout>
</ScrollView>

LoginActivity.java

package com.plotout.loginandregister;

import java.util.HashMap;

import org.json.JSONException;
import org.json.JSONObject;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

import com.plotout.loginandregister.library.DatabaseHandler;
import com.plotout.loginandregister.library.UserFunctions;

public class LoginActivity extends Activity {
    Button btnLogin;
    EditText inputEmail;
    EditText inputPassword;
    TextView loginErrorMsg;
    TextView link_to_register;

    // JSON Response node names
    private static String KEY_SUCCESS = "success";
    private static String KEY_ERROR = "error";
    private static String KEY_ERROR_MSG = "error_msg";
    private static String KEY_UID = "uid";
    private static String KEY_NAME = "name";
    private static String KEY_EMAIL = "email";
    private static String KEY_CREATED_AT = "created_at";

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.login);

        // Importing all assets like buttons, text fields
        inputEmail = (EditText) findViewById(R.id.loginEmail);
        inputPassword = (EditText) findViewById(R.id.loginPassword);
        btnLogin = (Button) findViewById(R.id.btnLogin);
        link_to_register = (TextView) findViewById (R.id.link_to_register);
        loginErrorMsg = (TextView) findViewById(R.id.login_error);

        // Login button Click Event
        btnLogin.setOnClickListener(new View.OnClickListener() {

            public void onClick(View view) {
                String email = inputEmail.getText().toString();
                String password = inputPassword.getText().toString();
                UserFunctions userFunction = new UserFunctions();
                JSONObject json = userFunction.loginUser(email, password);

                // check for login response
                try {
                    if (json.getString(KEY_SUCCESS) != null) {
                        loginErrorMsg.setText("");
                        String res = json.getString(KEY_SUCCESS); 
                        if(Integer.parseInt(res) == 1){
                            // user successfully logged in
                            // Store user details in SQLite Database
                            DatabaseHandler db = new DatabaseHandler(getApplicationContext());
                            JSONObject json_user = json.getJSONObject("user");

                            // Clear all previous data in database
                            userFunction.logoutUser(getApplicationContext());
                            db.addUser(json_user.getString(KEY_NAME), json_user.getString(KEY_EMAIL), json.getString(KEY_UID), json_user.getString(KEY_CREATED_AT));                        

                            // Launch Dashboard Screen
                            Intent dashboard = new Intent(getApplicationContext(), DashboardActivity.class);

                            // Close all views before launching Dashboard
                            dashboard.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
                            startActivity(dashboard);

                            // Close Login Screen
                            finish();
                        }else{
                            // Error in login
                            loginErrorMsg.setText("Incorrect username/password");
                        }
                    }
                } catch (JSONException e) {
                    e.printStackTrace();
                }
            }
        });

        TextView registerScreen = (TextView) findViewById(R.id.link_to_login);

        // Listening to register new account link
        registerScreen.setOnClickListener(new View.OnClickListener() {

            public void onClick(View v) {
                // Switching to Register screen
                Intent i = new Intent(getApplicationContext(), RegisterActivity.class);
                startActivity(i);
            }
        });
    }
}

RegisterAvtivity.java

package com.plotout.loginandregister;

import org.json.JSONException;
import org.json.JSONObject;

import com.plotout.loginandregister.library.DatabaseHandler;
import com.plotout.loginandregister.library.UserFunctions;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

public class RegisterActivity extends Activity {
    Button btnRegister;
    TextView link_to_login;
    EditText inputFullName;
    EditText inputEmail;
    EditText inputPassword;
    TextView registerErrorMsg;

    // JSON Response node names
    private static String KEY_SUCCESS = "success";
    private static String KEY_ERROR = "error";
    private static String KEY_ERROR_MSG = "error_msg";
    private static String KEY_UID = "uid";
    private static String KEY_NAME = "name";
    private static String KEY_EMAIL = "email";
    private static String KEY_CREATED_AT = "created_at";

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.register);

        // Importing all assets like buttons, text fields
        inputFullName = (EditText) findViewById(R.id.registerName);
        inputEmail = (EditText) findViewById(R.id.registerEmail);
        inputPassword = (EditText) findViewById(R.id.registerPassword);
        btnRegister = (Button) findViewById(R.id.btnRegister);
        link_to_login= (TextView) findViewById(R.id.link_to_login);
        registerErrorMsg = (TextView) findViewById(R.id.register_error);

        // Register Button Click event
        btnRegister.setOnClickListener(new View.OnClickListener() {         
            public void onClick(View view) {
                String name = inputFullName.getText().toString();
                String email = inputEmail.getText().toString();
                String password = inputPassword.getText().toString();
                UserFunctions userFunction = new UserFunctions();
                JSONObject json = userFunction.registerUser(name, email, password);

                // check for login response
                try {
                    if (json.getString(KEY_SUCCESS) != null) {
                        registerErrorMsg.setText("");
                        String res = json.getString(KEY_SUCCESS); 
                        if(Integer.parseInt(res) == 1){
                            // user successfully registred
                            // Store user details in SQLite Database
                            DatabaseHandler db = new DatabaseHandler(getApplicationContext());
                            JSONObject json_user = json.getJSONObject("user");

                            // Clear all previous data in database
                            userFunction.logoutUser(getApplicationContext());
                            db.addUser(json_user.getString(KEY_NAME), json_user.getString(KEY_EMAIL), json.getString(KEY_UID), json_user.getString(KEY_CREATED_AT));                        
                            // Launch Dashboard Screen
                            Intent dashboard = new Intent(getApplicationContext(), DashboardActivity.class);
                            // Close all views before launching Dashboard
                            dashboard.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
                            startActivity(dashboard);
                            // Close Registration Screen
                            finish();
                        }else{
                            // Error in registration
                            registerErrorMsg.setText("Error occured in registration");
                        }
                    }
                } catch (JSONException e) {
                    e.printStackTrace();
                }
            }
        });

        TextView loginScreen = (TextView) findViewById(R.id.link_to_login);

        // Listening to Login Screen link
        loginScreen.setOnClickListener(new View.OnClickListener() {

            public void onClick(View arg0) {
                                // Closing registration screen
                // Switching to Login Screen/closing register screen
                finish();
            }
        });
    }
}

Below is the logcat shown in ecplise

i just change the id of edit text in login xml,is solve the ClassCastException error.. <

EditText android:layout_width="fill_parent"
                android:id="@+id/loginEmail"
                android:layout_height="wrap_content"
                android:layout_marginTop="5dip"
                android:layout_marginBottom="20dip"
                android:singleLine="true" />

Now is become a new error, "java.lang.NullPointerException"..So where is the reason again ya??

All experts here pls take a look ya.pls help..thank you

Answer 1

Your button doesn't do anything because the following two lines in LoginActivity throw a ClassCastException because you can't cast from an Android.widget.TextView to an Android.widget.EditView .

inputEmail = (EditText) findViewById(R.id.loginEmail);
inputPassword = (EditText) findViewById(R.id.loginPassword);

In main.xml change the first two <TextView ... /> to <EditText ... /> :

<TextView
    android:id="@+id/textView1"
    ...
    android:textAppearance="?android:attr/textAppearanceLarge" />

Change to :

<EditText
    android:id="@+id/textView2"
    ...
    android:textAppearance="?android:attr/textAppearanceLarge" />