Android 使用内容提供者登录详细信息，带来许多循环

我想在登录

活动

上创建一个

Toast

文本（关于我尚未在数据库中注册）。然而，当我把这个

Toast

文本放进去时，出现了一个问题。如果我将它放入while循环

Cursor.MoveToNext（）

，它将循环它所拥有的条目数的倍

循环内部

 if(cursor!=null)
                    {
                        {
                            int i = 0;
                            while(cursor.moveToNext())
                            {
                                if(cursor.getString(i).equals(input_email) && cursor.getString(i).equals(input_password))
                                {
                                    Log.d(TAG, "Udah masuk belum " );
                                    Toast.makeText(getApplicationContext(),"Login Successful!", Toast.LENGTH_SHORT).show();
                                    Intent intent =new Intent(LoginActivity.this, RegisterActivity.class);
                                    startActivity(intent);
                                    finish();
                                    i = i + 1;
                                }
                                else
                                {
                                    Toast.makeText(getApplicationContext(),"You haven't Registered yet!", Toast.LENGTH_SHORT).show();
                                    Intent intent =new Intent(LoginActivity.this, RegisterActivity.class);
                                    startActivity(intent);
                                    finish();
                                }
                            }
                            cursor.close();
                        }
                    }

       String [] projection ={ServiceProvidersContract.Columns.SEmail, ServiceProvidersContract.Columns.spPassword};
                   Cursor cursor = contentResolver.query(ServiceProvidersContract.CONTENT_URI, projection, null, null, null);

                   Log.d(TAG, "Checking Cursor" + cursor );
                    if(cursor!=null)
                    {
                        {
                            int i = 0;
                            while(cursor.moveToNext())
                            {
                                if(cursor.getString(i).equals(input_email) && cursor.getString(i).equals(input_password))
                                {
                                    Log.d(TAG, "Udah masuk belum " );
                                    Toast.makeText(getApplicationContext(),"Login Successful!", Toast.LENGTH_SHORT).show();
                                    Intent intent =new Intent(LoginActivity.this, RegisterActivity.class);
                                    startActivity(intent);
                                    finish();
                                    i = i + 1;
                                }
                            }
                            cursor.close();
                            if(!cursor.getString(i).equals(input_email) && cursor.getString(i).equals(input_password))
                            {
                                Toast.makeText(getApplicationContext(),"You haven't Registered yet!", Toast.LENGTH_SHORT).show();
                                Intent intent =new Intent(LoginActivity.this, RegisterActivity.class);
                                startActivity(intent);
                                finish();

                            }
                        }

                    }

但当我把球打到圈外时，它会带来错误。你知道这个问题的解决方案是什么吗

在循环之外

 if(cursor!=null)
                    {
                        {
                            int i = 0;
                            while(cursor.moveToNext())
                            {
                                if(cursor.getString(i).equals(input_email) && cursor.getString(i).equals(input_password))
                                {
                                    Log.d(TAG, "Udah masuk belum " );
                                    Toast.makeText(getApplicationContext(),"Login Successful!", Toast.LENGTH_SHORT).show();
                                    Intent intent =new Intent(LoginActivity.this, RegisterActivity.class);
                                    startActivity(intent);
                                    finish();
                                    i = i + 1;
                                }
                                else
                                {
                                    Toast.makeText(getApplicationContext(),"You haven't Registered yet!", Toast.LENGTH_SHORT).show();
                                    Intent intent =new Intent(LoginActivity.this, RegisterActivity.class);
                                    startActivity(intent);
                                    finish();
                                }
                            }
                            cursor.close();
                        }
                    }

       String [] projection ={ServiceProvidersContract.Columns.SEmail, ServiceProvidersContract.Columns.spPassword};
                   Cursor cursor = contentResolver.query(ServiceProvidersContract.CONTENT_URI, projection, null, null, null);

                   Log.d(TAG, "Checking Cursor" + cursor );
                    if(cursor!=null)
                    {
                        {
                            int i = 0;
                            while(cursor.moveToNext())
                            {
                                if(cursor.getString(i).equals(input_email) && cursor.getString(i).equals(input_password))
                                {
                                    Log.d(TAG, "Udah masuk belum " );
                                    Toast.makeText(getApplicationContext(),"Login Successful!", Toast.LENGTH_SHORT).show();
                                    Intent intent =new Intent(LoginActivity.this, RegisterActivity.class);
                                    startActivity(intent);
                                    finish();
                                    i = i + 1;
                                }
                            }
                            cursor.close();
                            if(!cursor.getString(i).equals(input_email) && cursor.getString(i).equals(input_password))
                            {
                                Toast.makeText(getApplicationContext(),"You haven't Registered yet!", Toast.LENGTH_SHORT).show();
                                Intent intent =new Intent(LoginActivity.this, RegisterActivity.class);
                                startActivity(intent);
                                finish();

                            }
                        }

                    }

---

只是想澄清一下，我最终在我的登录部分使用For和While成功登录了。 另一个问题来自Toast文本（我无法将失败的Toast文本放入循环）。这是我的密码：

private static final String TAG = "LoginActivity";
private Button btnLogin, btnLinkToRegister;
private SessionManager session;
private EditText password, email;


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



        // Defining everything
        email = (EditText) findViewById(R.id.email);
        password = (EditText) findViewById(R.id.password);
        btnLinkToRegister = (Button) findViewById(R.id.btnLinkToRegister);
        btnLogin = (Button) findViewById(R.id.btnLogin);


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

            public void onClick(View view) {
                ContentResolver contentResolver = getContentResolver() ;

                String input_email = email.getText().toString().trim();
                String input_password = password.getText().toString().trim();
                Log.d(TAG, "onClick: " + input_email  + input_password);

                // Check for empty data in the form
               if (!input_email.isEmpty() && !input_password.isEmpty()) {
                   Log.d(TAG, "onClick: if statement succeseful");

               //      checking from the database
                   String [] projection ={ServiceProvidersContract.Columns.SEmail, ServiceProvidersContract.Columns.spPassword};
                   Cursor cursor = contentResolver.query(ServiceProvidersContract.CONTENT_URI, projection, null, null, null);

                   Log.d(TAG, "Checking Cursor" + cursor );
                    if(cursor!=null)
                    {
                        cursor.moveToFirst();
                        while(cursor.moveToNext())
                        {
                            Log.d(TAG, "while process");
                            for(int i=0; i<cursor.getColumnCount(); i++)
                            {
                                Log.d(TAG, "for process " + cursor.getString(i));
                                if (cursor.getString(0).equals(input_email) && cursor.getString(1).equals(input_password)) {
                                        Log.d(TAG, "if process");
                                        Toast.makeText(getApplicationContext(), "Login Successful!", Toast.LENGTH_SHORT).show();
                                        Intent intent = new Intent(LoginActivity.this, RegisterActivity.class);
                                        startActivity(intent);
                                        finish();
                                    break;
                                }
                            }
                        }
                        if (!cursor.getString(0).equals(input_email) && cursor.getString(1).equals(input_password)) {
                            Log.d(TAG, "if process");
                            Toast.makeText(getApplicationContext(), "You haven't registered yet!", Toast.LENGTH_SHORT).show();
                            Intent intent = new Intent(LoginActivity.this, RegisterActivity.class);
                            startActivity(intent);
                            finish();
                        }
                        cursor.close();
                    }
                } else {
                    // Prompt user to enter credentials
                    Toast.makeText(getApplicationContext(),
                            "Please enter the credentials!", Toast.LENGTH_LONG)
                            .show();
                }
            }
        });

            btnLinkToRegister.setOnClickListener(new View.OnClickListener() {

            public void onClick(View view){
                    Intent i = new Intent(LoginActivity.this, RegisterActivity.class);
                    startActivity(i);
                    finish();
                }
        });
    }

private static final String TAG=“LoginActivity”；
私人按钮btnLogin，btnLinkToRegister；
私人会话管理器会话；
私人编辑文本密码、电子邮件；
@凌驾
创建时受保护的void（Bundle savedInstanceState）{
super.onCreate（savedInstanceState）；
setContentView（R.layout.activity\u登录）；
//定义一切
email=（EditText）findviewbyd（R.id.email）；
密码=（EditText）findViewById（R.id.password）；
btnLinkToRegister=（按钮）findViewById（R.id.btnLinkToRegister）；
btnLogin=（按钮）findViewById（R.id.btnLogin）；
//登录按钮点击事件
btnLogin.setOnClickListener（新视图.OnClickListener（）{
公共void onClick（视图）{
ContentResolver ContentResolver=getContentResolver（）；
String input_email=email.getText（）.toString（）.trim（）；
字符串输入_password=password.getText（）.toString（）.trim（）；
Log.d（标记“onClick:”+输入电子邮件+输入密码）；
//检查表单中是否有空数据
如果（！input_email.isEmpty（）&&！input_password.isEmpty（））{
Log.d（标记“onClick:if语句成功”）；
//从数据库中检查
String[]projection={ServiceProvidersContract.Columns.SEmail，ServiceProvidersContract.Columns.spPassword}；
Cursor Cursor=contentResolver.query（ServiceProvidersContract.CONTENT\u URI，projection，null，null）；
Log.d（标记“检查光标”+光标）；
如果（光标！=null）
{
cursor.moveToFirst（）；
while（cursor.moveToNext（））
{
Log.d（标记“while process”）；
for（int i=0；i您得到的错误是什么？当您在循环中进行迭代时，cusror有100个值，因此对于所有值，如果它不输入，则将执行条件else，因此将生成100次toast。是的，我很抱歉。我没有将for循环放在这里，因此它无法工作。