我面临两个问题
我需要一些有关在活动中正确实现意图的指示。
MainActivity.java ：
package com.example.yusuf.futurestep;
import android.content.Intent;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;
import com.example.yusuf.futurestep.data.User;
import com.example.yusuf.futurestep.data.UserDBHelper;
public class MainActivity extends AppCompatActivity {
private EditText usernameEditText = (EditText)
findViewById(R.id.lUsername_edit_text);
private EditText passwordEditText = (EditText) findViewById(R.id.lPassword_edit_text);
public void init() {
TextView signUpTextView = (TextView) findViewById(R.id.signup_text_view);
signUpTextView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent i = new Intent(MainActivity.this, SignUpActivity.class);
startActivity(i);
}
});
Button loginButton = findViewById(R.id.login_button);
loginButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
String usernameString = usernameEditText.getText().toString().trim();
String passwordString = passwordEditText.getText().toString().trim();
if (authenticate(usernameString, passwordString)) {
Toast.makeText(MainActivity.this, "Sign in Sucessful", Toast.LENGTH_LONG).show();
Intent j = new Intent(MainActivity.this, HomescreenActivity.class);
startActivity(j);
finish();
} else {
Toast.makeText(MainActivity.this, "Wrong Id or Password!!!", Toast.LENGTH_LONG).show();
setContentView(R.layout.activity_main);
}
}
});
}
public boolean authenticate(String username, String password) {
UserDBHelper myDb = new UserDBHelper(this);
SQLiteDatabase db = myDb.getReadableDatabase();
User user = new User();
Cursor cursor = db.query(TABLE_NAME,// Selecting Table
new String[]{_ID, COLUMN_USER_USERNAME, COLUMN_USER_PASSWORD,
COLUMN_USER_MOBILE},//Selecting columns want to query
COLUMN_USER_USERNAME + "=?",
new String[]{username},//Where clause
null, null, null);
if (cursor != null && cursor.moveToFirst() && cursor.getCount() > 0) {
// if cursor has value then in user database there is
// user associated with this given email
User user1 = new User(cursor.getString(0), cursor.getString(1), cursor.getString(2), cursor.getString(3));
//Match both passwords check they are same or not
if (password.equalsIgnoreCase(user1.getPassword())) {
return true;
}
}
//if user password does not matches or there is no record with that email then return @false
return false;
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
init();
}
}
User.java ：
package com.example.yusuf.futurestep.data;
public class User {
private String mUsername;
private String mPassword;
private String mName;
private String mMobile;
public User(String username, String password, String name, String mobile){
mUsername = username;
mPassword = password;
mName = name;
mMobile = mobile;
}
public User(){
mUsername = this.mUsername;
mPassword = this.mPassword;
mName = this.mName;
mMobile = this.mMobile;
}
public String getUsername() {
return mUsername;
}
public String getPassword() {
return mPassword;
}
public String getName() {
return mName;
}
public String getMobile() {
return mMobile;
}
}
SignUpActivity.java ：
package com.example.yusuf.futurestep;
import android.content.ContentValues;
import android.content.Intent;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import com.example.yusuf.futurestep.data.UserContract.UserEntry;
import android.widget.TextView;
import android.widget.Toast;
import com.example.yusuf.futurestep.data.UserDBHelper;
public class SignUpActivity extends AppCompatActivity {
/** EditText field to enter the pet's name */
private EditText mUserNameEditText;
/** EditText field to enter the pet's breed */
private EditText mPasswordEditText;
/** EditText field to enter the pet's weight */
private EditText mNameEditText;
/** EditText field to enter the pet's gender */
private EditText mMobileEditText;
private UserDBHelper mDbHelper;
SQLiteDatabase db;
public void init(){
TextView signUpTextView = (TextView) findViewById(R.id.signup_text_view);
signUpTextView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent i = new Intent(SignUpActivity.this, MainActivity.class);
startActivity(i);
finish();
}
});
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_sign_up);
init();
mDbHelper = new UserDBHelper(this);
mUserNameEditText = (EditText) findViewById(R.id.username_edit_text);
mPasswordEditText = (EditText) findViewById(R.id.password_edit_text);
mNameEditText = (EditText) findViewById(R.id.name_edit_text);
mMobileEditText = (EditText) findViewById(R.id.mobile_edit_text);
Button button = (Button) findViewById(R.id.signup_button);
button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
insertUser();
}
});
}
@Override
protected void onStart() {
super.onStart();
}
private void insertUser() {
// Read from input fields
// Use trim to eliminate leading or trailing white space
String usernameString = mUserNameEditText.getText().toString().trim();
String passwordString = mPasswordEditText.getText().toString().trim();
String nameString = mNameEditText.getText().toString().trim();
String mobileString = mMobileEditText.getText().toString().trim();
int mobileInt = Integer.parseInt(mobileString);
// Create database helper
mDbHelper = new UserDBHelper(this);
// Gets the database in write mode
db = mDbHelper.getWritableDatabase();
// Create a ContentValues object where column names are the keys,
// and pet attributes from the editor are the values.
ContentValues values = new ContentValues();
values.put(UserEntry.COLUMN_USER_USERNAME, usernameString);
values.put(UserEntry.COLUMN_USER_PASSWORD, passwordString);
values.put(UserEntry.COLUMN_USER_NAME, nameString);
values.put(UserEntry.COLUMN_USER_MOBILE, mobileInt);
// Insert a new row for pet in the database, returning the ID of that new row.
long newRowId = db.insert(UserEntry.TABLE_NAME, null, values);
// Show a toast message depending on whether or not the insertion was successful
if (newRowId == -1) {
// If the row ID is -1, then there was an error with insertion.
Toast.makeText(this, "Server Error", Toast.LENGTH_SHORT).show();
} else {
// Otherwise, the insertion was successful and we can display a toast with the row ID.
Toast.makeText(this, "Registration Successful: " +newRowId, Toast.LENGTH_SHORT).show();
}
}
public void displayDatabaseInfo() {
// Create and/or open a database to read from it
SQLiteDatabase db = mDbHelper.getReadableDatabase();
// Define a projection that specifies which columns from the database
// you will actually use after this query.
String[] projection = {
UserEntry._ID,
UserEntry.COLUMN_USER_USERNAME,
UserEntry.COLUMN_USER_PASSWORD,
UserEntry.COLUMN_USER_NAME,
UserEntry.COLUMN_USER_MOBILE };
// Perform a query on the pets table
Cursor cursor = db.query(
UserEntry.TABLE_NAME, // The table to query
projection, // The columns to return
null, // The columns for the WHERE clause
null, // The values for the WHERE clause
null, // Don't group the rows
null, // Don't filter by row groups
null); // The sort order
TextView displayView = (TextView) findViewById(R.id.text);
try {
// Create a header in the Text View that looks like this:
//
// The pets table contains <number of rows in Cursor> pets.
// _id - name - breed - gender - weight
//
// In the while loop below, iterate through the rows of the cursor and display
// the information from each column in this order.
displayView.setText("The pets table contains " + cursor.getCount() + " pets.\n\n");
displayView.append(UserEntry._ID + " - " +
UserEntry.COLUMN_USER_USERNAME + " - " +
UserEntry.COLUMN_USER_PASSWORD + " - " +
UserEntry.COLUMN_USER_NAME + " - " +
UserEntry.COLUMN_USER_MOBILE + "\n");
// Figure out the index of each column
int idColumnIndex = cursor.getColumnIndex(UserEntry._ID);
int usernameColumnIndex = cursor.getColumnIndex(UserEntry.COLUMN_USER_USERNAME);
int passwordColumnIndex = cursor.getColumnIndex(UserEntry.COLUMN_USER_PASSWORD);
int nameColumnIndex = cursor.getColumnIndex(UserEntry.COLUMN_USER_NAME);
int mobileColumnIndex = cursor.getColumnIndex(UserEntry.COLUMN_USER_MOBILE);
// Iterate through all the returned rows in the cursor
while (cursor.moveToNext()) {
// Use that index to extract the String or Int value of the word
// at the current row the cursor is on.
int currentID = cursor.getInt(idColumnIndex);
String currentUserName = cursor.getString(usernameColumnIndex);
String currentPassword = cursor.getString(passwordColumnIndex);
int currentName = cursor.getInt(nameColumnIndex);
int currentMobile = cursor.getInt(mobileColumnIndex);
// Display the values from each column of the current row in the cursor in the TextView
displayView.append(("\n" + currentID + " - " +
currentUserName + " - " +
currentPassword + " - " +
currentName + " - " +
currentMobile));
}
} finally {
// Always close the cursor when you're done reading from it. This releases all its
// resources and makes it invalid.
cursor.close();
}
}
}
UserDBHelper.java ：
package com.example.yusuf.futurestep.data;
import android.content.ContentValues;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.view.View;
import android.widget.EditText;
import android.widget.Toast;
import com.example.yusuf.futurestep.R;
import com.example.yusuf.futurestep.data.UserContract.UserEntry;
public class UserDBHelper extends SQLiteOpenHelper {
/*****
/** EditText field to enter the pet's name */
private EditText mUserNameEditText;
/**
* EditText field to enter the pet's breed
*/
private EditText mPasswordEditText;
/**
* EditText field to enter the pet's weight
*/
private EditText mNameEditText;
/**
* EditText field to enter the pet's gender
*/
private EditText mMobileEditText;
public static final String LOG_TAG = UserDBHelper.class.getSimpleName();
/*Name of the database file */
private static final String DATABASE_NAME = "futurestep.db";
/**
* Database version. If you change the database schema, you must increment the database version.
*/
private static final int DATABASE_VERSION = 1;
public UserDBHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
@Override
public void onCreate(SQLiteDatabase db) {
// Create a String that contains the SQL statement to create the pets table
String SQL_CREATE_USERINFO_TABLE = "CREATE TABLE " + UserEntry.TABLE_NAME + " ("
+ UserEntry._ID + " INTEGER PRIMARY KEY AUTOINCREMENT, "
+ UserEntry.COLUMN_USER_USERNAME + " TEXT NOT NULL, "
+ UserEntry.COLUMN_USER_PASSWORD + " TEXT, "
+ UserEntry.COLUMN_USER_NAME + " TEXT NOT NULL, "
+ UserEntry.COLUMN_USER_MOBILE + " INTEGER NOT NULL );";
db.execSQL(SQL_CREATE_USERINFO_TABLE);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
String query = "DROP TABLE IF EXISTS " + UserEntry.TABLE_NAME;
db.execSQL(query);
this.onCreate(db);
}
//inserting in database
}