单击“无法在按钮上使用操作”-Java和Android Studio

Question

I feel like an idiot for having to ask this, but I am working on a simple application that requires login. If the correct credentials are entered, it redirects to the settings/preferences activity. If not, it displays an error. Simple, right? However, I whenever I click the button, nothing happens.

login.java

 import android.app.AlertDialog;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;

public class login extends AppCompatActivity {
    EditText userName;
    EditText password;
    Boolean verified = false;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_login);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);
        Button loginButton = (Button) findViewById(R.id.loginButton);
        userName = (EditText) findViewById(R.id.userNameField);
        password = (EditText) findViewById(R.id.passwordField);

        loginButton.setOnClickListener(new Button.OnClickListener() {
            @Override
            public void onClick(View v) {
                if ((userName.getText().toString() != "bkAdmin") || (password.getText().toString() != "midAmBK")) {
                    verified = false;
                } else {
                    verified = true;
                }
            }
        });
        SharedPreferences preferences = getSharedPreferences("config.xml", MODE_PRIVATE);
        if (verified) {
            Intent intent = new Intent(this, midamcorp.com.burgerkingapp.preferences.class);
            SharedPreferences.Editor editor = preferences.edit();
            editor.putBoolean("loggedIn", true);
            editor.commit();
            if (preferences.getBoolean("config", false)) {
                editor.putBoolean("config", true);
                editor.commit();
            }
            startActivity(intent);
        } else {
            AlertDialog.Builder builder = new AlertDialog.Builder(this);
            builder.setMessage("Invalid Username or Password");

            builder.setPositiveButton("Accept", new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface dialog, int which) {
                    dialog.dismiss();
                }
            });
            FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
            fab.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {
                    Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
                            .setAction("Action", null).show();
                }
            });

        }

    }
}

content_login.xml

   <?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    app:layout_behavior="@string/appbar_scrolling_view_behavior"
    tools:context="midamcorp.com.burgerkingapp.login"
    tools:showIn="@layout/activity_login">
<TableLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent">
    <TableRow android:layout_marginBottom="50dp">
        <TextView
            android:layout_height="wrap_content"
            android:layout_width="wrap_content"
            android:minWidth="200dp"
            android:text=" Username:" />
    <EditText
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/userNameField"
        android:minWidth="200dp"
       />

    </TableRow>
    <TableRow android:layout_marginBottom="50dp">
        <TextView
            android:layout_height="wrap_content"
            android:layout_width="wrap_content"
            android:minWidth="200dp"
            android:text=" Password:" />
    <EditText
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:inputType="textPassword"

        android:minWidth="200dp"
        android:id="@+id/passwordField"
/>
</TableRow>
<TableRow>
    <Button
        android:id="@+id/loginButton"
        android:text = "Login!" />

</TableRow>
</TableLayout>
</RelativeLayout>

I truly, truly appreciate any help!

Answer 1

Try something like this. wrap you code in a method and call it inside your button click event.

loginButton.setOnClickListener(new Button.OnClickListener() {
            @Override
            public void onClick(View v) {
                if ((userName.getText().toString() != "bkAdmin") || (password.getText().toString() != "midAmBK")) {
                    verified = false;
                } else {
                    verified = true;
                }
                completeRegistration(verified);
            }
        });
}

Wrap this in a method

private void completeRegistration(boolean verified){
        if (verified) {
            Intent intent = new Intent(this, midamcorp.com.burgerkingapp.preferences.class);
            SharedPreferences.Editor editor = preferences.edit();
            editor.putBoolean("loggedIn", true);
            editor.commit();
            if (preferences.getBoolean("config", false)) {
                editor.putBoolean("config", true);
                editor.commit();
            }
            startActivity(intent);
        } else {
            AlertDialog.Builder builder = new AlertDialog.Builder(this);
            builder.setMessage("Invalid Username or Password");

            builder.setPositiveButton("Accept", new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface dialog, int which) {
                    dialog.dismiss();
                }
            });
            FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
            fab.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {
                    Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
                            .setAction("Action", null).show();
                }
            });

        }
}

Answer 2

The onCreate method is where you initialize the activity. Your verified variable will always be false. The callback of button click is executed after the onCreate was finished. Move your logic to other method or put inside the button callback.

Answer 3

使用View.OnClickListener而不是Button.onClickListener

Answer 4

You have to write the code for navigating to the settings screen or showing the error dialog inside OnClickListener . At present it is outside it. Try this -

 import android.app.AlertDialog;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;

public class login extends AppCompatActivity {
    EditText userName;
    EditText password;
    Boolean verified = false;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_login);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);
        Button loginButton = (Button) findViewById(R.id.loginButton);
        userName = (EditText) findViewById(R.id.userNameField);
        password = (EditText) findViewById(R.id.passwordField);
loginButton.setOnClickListener(new Button.OnClickListener() {
            @Override
            public void onClick(View v) {
                if ((userName.getText().toString() != "bkAdmin") || (password.getText().toString() != "midAmBK")) {
                    verified = false;
                } else {
                    verified = true;
                }

 SharedPreferences preferences = getSharedPreferences("config.xml", MODE_PRIVATE);
        if (verified) {
            Intent intent = new Intent(login.this, midamcorp.com.burgerkingapp.preferences.class);
            SharedPreferences.Editor editor = preferences.edit();
            editor.putBoolean("loggedIn", true);
            editor.commit();
            if (preferences.getBoolean("config", false)) {
                editor.putBoolean("config", true);
                editor.commit();
            }
            startActivity(intent);
        } else {
            AlertDialog.Builder builder = new AlertDialog.Builder(login.this);
            builder.setMessage("Invalid Username or Password");

            builder.setPositiveButton("Accept", new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface dialog, int which) {
                    dialog.dismiss();
                }
            });
            FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
            fab.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {
                    Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
                            .setAction("Action", null).show();
                }
            });

        }
            }
        });