2

OK、LoginActivity があります。ユーザーがサインインすると、ユーザーがサインアウトしない限り、アクティビティが再び表示されることはありません。どうすればいいですか？私はアンドロイドにかなり慣れていないので、ご容赦ください。これは、後でデータベース機能を追加する予定の ADT の単なる例ですが、今のところ、テスト目的でそのままにしておきます。

package com.example.imet;

import android.animation.Animator;
import android.animation.AnimatorListenerAdapter;
import android.annotation.TargetApi;
import android.app.Activity;
import android.os.AsyncTask;
import android.os.Build;
import android.os.Bundle;
import android.text.TextUtils;
import android.view.KeyEvent;
import android.view.Menu;
import android.view.View;
import android.view.inputmethod.EditorInfo;
import android.widget.EditText;
import android.widget.TextView;

/**
* Activity which displays a login screen to the user, offering registration as
* well.
*/
public class MainActivity extends Activity {
/**
 * A dummy authentication store containing known user names and passwords.
 * TODO: remove after connecting to a real authentication system.
 */
private static final String[] DUMMY_CREDENTIALS = new String[] {
        "foo@example.com:hello", "bar@example.com:world" };

/**
 * The default email to populate the email field with.
 */
public static final String EXTRA_EMAIL = "com.example.android.authenticatordemo.extra.EMAIL";

/**
 * Keep track of the login task to ensure we can cancel it if requested.
 */
private UserLoginTask mAuthTask = null;

// Values for email and password at the time of the login attempt.
private String mEmail;
private String mPassword;

// UI references.
private EditText mEmailView;
private EditText mPasswordView;
private View mLoginFormView;
private View mLoginStatusView;
private TextView mLoginStatusMessageView;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    setContentView(R.layout.activity_main);

    // Set up the login form.
    mEmail = getIntent().getStringExtra(EXTRA_EMAIL);
    mEmailView = (EditText) findViewById(R.id.email);
    mEmailView.setText(mEmail);

    mPasswordView = (EditText) findViewById(R.id.password);
    mPasswordView
            .setOnEditorActionListener(new TextView.OnEditorActionListener() {
                @Override
                public boolean onEditorAction(TextView textView, int id,
                        KeyEvent keyEvent) {
                    if (id == R.id.login || id == EditorInfo.IME_NULL) {
                        attemptLogin();
                        return true;
                    }
                    return false;
                }
            });

    mLoginFormView = findViewById(R.id.login_form);
    mLoginStatusView = findViewById(R.id.login_status);
    mLoginStatusMessageView = (TextView) findViewById(R.id.login_status_message);

    findViewById(R.id.sign_in_button).setOnClickListener(
            new View.OnClickListener() {
                @Override
                public void onClick(View view) {
                    attemptLogin();
                }
            });
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    super.onCreateOptionsMenu(menu);
    getMenuInflater().inflate(R.menu.login, menu);
    return true;
}

/**
 * Attempts to sign in or register the account specified by the login form.
 * If there are form errors (invalid email, missing fields, etc.), the
 * errors are presented and no actual login attempt is made.
 */
public void attemptLogin() {
    if (mAuthTask != null) {
        return;
    }

    // Reset errors.
    mEmailView.setError(null);
    mPasswordView.setError(null);

    // Store values at the time of the login attempt.
    mEmail = mEmailView.getText().toString();
    mPassword = mPasswordView.getText().toString();

    boolean cancel = false;
    View focusView = null;

    // Check for a valid password.
    if (TextUtils.isEmpty(mPassword)) {
        mPasswordView.setError(getString(R.string.error_field_required));
        focusView = mPasswordView;
        cancel = true;
    } else if (mPassword.length() < 4) {
        mPasswordView.setError(getString(R.string.error_invalid_password));
        focusView = mPasswordView;
        cancel = true;
    }

    // Check for a valid email address.
    if (TextUtils.isEmpty(mEmail)) {
        mEmailView.setError(getString(R.string.error_field_required));
        focusView = mEmailView;
        cancel = true;
    } else if (!mEmail.contains("@")) {
        mEmailView.setError(getString(R.string.error_invalid_email));
        focusView = mEmailView;
        cancel = true;
    }

    if (cancel) {
        // There was an error; don't attempt login and focus the first
        // form field with an error.
        focusView.requestFocus();
    } else {
        // Show a progress spinner, and kick off a background task to
        // perform the user login attempt.
        mLoginStatusMessageView.setText(R.string.login_progress_signing_in);
        showProgress(true);
        mAuthTask = new UserLoginTask();
        mAuthTask.execute((Void) null);
    }
}

/**
 * Shows the progress UI and hides the login form.
 */
@TargetApi(Build.VERSION_CODES.HONEYCOMB_MR2)
private void showProgress(final boolean show) {
    // On Honeycomb MR2 we have the ViewPropertyAnimator APIs, which allow
    // for very easy animations. If available, use these APIs to fade-in
    // the progress spinner.
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB_MR2) {
        int shortAnimTime = getResources().getInteger(
                android.R.integer.config_shortAnimTime);

        mLoginStatusView.setVisibility(View.VISIBLE);
        mLoginStatusView.animate().setDuration(shortAnimTime)
                .alpha(show ? 1 : 0)
                .setListener(new AnimatorListenerAdapter() {
                    @Override
                    public void onAnimationEnd(Animator      animation) {
                        mLoginStatusView.setVisibility(show ? View.VISIBLE
                                : View.GONE);
                    }
                });

        mLoginFormView.setVisibility(View.VISIBLE);
        mLoginFormView.animate().setDuration(shortAnimTime)
                .alpha(show ? 0 : 1)
                .setListener(new AnimatorListenerAdapter() {
                    @Override
                    public void onAnimationEnd(Animator animation) {
                        mLoginFormView.setVisibility(show ? View.GONE
                                : View.VISIBLE);
                    }
                });
    } else {
        // The ViewPropertyAnimator APIs are not available, so simply show
        // and hide the relevant UI components.
        mLoginStatusView.setVisibility(show ? View.VISIBLE : View.GONE);
        mLoginFormView.setVisibility(show ? View.GONE : View.VISIBLE);
    }
}

/**
 * Represents an asynchronous login/registration task used to authenticate
 * the user.
 */
public class UserLoginTask extends AsyncTask<Void, Void, Boolean> {
    @Override
    protected Boolean doInBackground(Void... params) {
        // TODO: attempt authentication against a network service.

        try {
            // Simulate network access.
            Thread.sleep(2000);
        } catch (InterruptedException e) {
            return false;
        }

        for (String credential : DUMMY_CREDENTIALS) {
            String[] pieces = credential.split(":");
            if (pieces[0].equals(mEmail)) {
                // Account exists, return true if the password matches.
                return pieces[1].equals(mPassword);
            }
        }

        // TODO: register the new account here.
        return true;
    }

    @Override
    protected void onPostExecute(final Boolean success) {
        mAuthTask = null;
        showProgress(false);

        if (success) {
            finish();
        } else {
            mPasswordView
                    .setError(getString(R.string.error_incorrect_password));
            mPasswordView.requestFocus();
        }
    }

    @Override
    protected void onCancelled() {
        mAuthTask = null;
        showProgress(false);
    }
}

}

4

2 に答える 2

0

最も簡単な方法は、ユーザーの状態を のブール変数に保持することですSharedPreferences。次に、ユーザーがアプリを開くたびに値を確認し、それに応じてログイン アクティビティまたはユーザー ログイン後に表示する次のアクティビティのいずれかを表示します。続行する前に、次のスレッドとブログを確認することをお勧めします。

共有設定を使用した Android ユーザー セッション管理

Android は以前にログインしたユーザーをチェックし、それ以外の場合はログイン アクティビティを開始します

すべてのアクティビティでログインを確認する

お役に立てれば。

于 2013-06-11T02:23:06.967 に答える