私は Android 開発を始めたばかりで、AppInventor を少し試した後、Android Studio を使用しています。
アクティビティの開始と結果の取得について読み、例を調べました。
MainActivity には、LoginActivity を起動するログイン ボタンがあります。例のために、次のように、呼び出し元のアクティビティ (MainActivity) から呼び出されたアクティビティ (LoginActivity) に「余分な」を渡します。戻り時に (実際にはどこにもログインしません)、2 つの追加パラメーターを設定します。 MainActivity に戻されます。
My LoginActivity は、New Activity Wizard によって作成されたテンプレートを少し変更したバージョンです。基本的に、OUTPARAM 静的文字列 (追加パラメーターの名前) を定義し、着信パラメーターを読み取り、発信パラメーターを設定するコードを追加しました。
package com.example.testapp.ui;
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;
import android.view.MenuItem;
import android.support.v4.app.NavUtils;
/**
* Activity which displays a login screen to the user, offering registration as
* well.
*/
public class LoginActivity extends Activity {
// DEGT : Activity parameters passed via intent.putExtra
static public final String INPARAM_METHOD = "com.example.testapp.ui.loginMethod";
static public final String OUTPARAM_USERID = "com.example.testapp.ui.userId";
static public final String OUTPARAM_PASSW = "com.example.testapp.ui.password";
/**
* 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_login);
setupActionBar();
// Set up the login form.
mEmail = getIntent().getStringExtra(EXTRA_EMAIL); // TODO modify
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();
}
});
}
/**
* Set up the {@link android.app.ActionBar}, if the API is available.
*/
@TargetApi(Build.VERSION_CODES.HONEYCOMB)
private void setupActionBar() {
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {
// Show the Up button in the action bar.
getActionBar().setDisplayHomeAsUpEnabled(true);
}
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case android.R.id.home:
// This ID represents the Home or Up button. In the case of this
// activity, the Up button is shown. Use NavUtils to allow users
// to navigate up one level in the application structure. For
// more details, see the Navigation pattern on Android Design:
//
// http://developer.android.com/design/patterns/navigation.html#up-vs-back
//
// TODO: If Settings has multiple levels, Up should navigate up
// that hierarchy.
NavUtils.navigateUpFromSameTask(this);
return true;
}
return super.onOptionsItemSelected(item);
}
@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);
// TODO DEGT
// 1. Use Server setting to select Login Service URL
// 2. Download list of exhibition rooms to populate spinner on MainActivity
} catch (InterruptedException e) {
return false;
}
// get the intent extras (parameters passed to activity)
android.content.Intent intent = getIntent();
if (intent.getStringExtra(LoginActivity.INPARAM_METHOD).equalsIgnoreCase("manual"))
{
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);
// get the intent extras passed to the activity by calling activity
android.content.Intent intent = getIntent();
if (success) {
// TO-TEST pass the credentials back to the calling activity
intent.putExtra(OUTPARAM_USERID, mEmailView.getText());
intent.putExtra(OUTPARAM_PASSW, mPasswordView.getText());
setResult(RESULT_OK, intent); // otherwise it returns RESULT_CANCELED
setIntent(intent);
finish();
} else {
// TO-TEST pass the credentials back to the calling activity
intent.putExtra(OUTPARAM_USERID, "");
intent.putExtra(OUTPARAM_PASSW, "");
setIntent(intent);
mPasswordView.setError(getString(R.string.error_incorrect_password));
mPasswordView.requestFocus();
}
}
@Override
protected void onCancelled() {
mAuthTask = null;
showProgress(false);
}
}
}
UserLoginTask クラス (LoginActivity クラス内で定義) で、doInBackground() メソッドの入力パラメーター (INPARAM_*) を確認します。デバッグ ブレークポイントは、MainActivity によって設定された正しい値を取得していることを示しています。
onPostExecute() メソッドで、両方の OUTPARAM エクストラを設定しています。デバッグ中に、これらの値が実際にインテントのバンドルに挿入されていることを確認しました。ただし、コントロールが (呼び出し元の) MainActivity に戻されると、すべてのパラメーター (INPARAM、OUTPARAM) は、onActivityResult メソッドの data パラメーターで渡された Intent から ABSENT になります。
(呼び出し元の) MainActivity は次のとおりです。
package com.example.testapp.ui;
import android.os.Bundle;
import android.app.Activity;
import android.provider.ContactsContract;
import android.view.Menu;
import android.widget.Button; // Button
import android.view.View; // View
import android.content.Intent; // Intent
import android.widget.TextView;
public class MainActivity extends Activity {
static public final int AUTHENTICATE_TICKET = 2; // Login to server
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Create the Login button onClick to start LoginActivity
Button button= (Button) findViewById(R.id.buttonLogin);
button.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
//startActivity(new Intent(MainActivity.this, LoginActivity.class));
Intent intent = new Intent(MainActivity.this, LoginActivity.class);
intent.putExtra(LoginActivity.INPARAM_METHOD, "manual"); // DEGT dummy for now
startActivityForResult(intent, AUTHENTICATE_TICKET);
}
});
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
// Check which request we're responding to
if (requestCode == AUTHENTICATE_TICKET)
{ // Successful LoginActivity result.
if (resultCode == RESULT_OK)
{
// Get a reference to the TextView we will update
final TextView txtMainMessage = (TextView)findViewById(R.id.textViewMainMessage);
// Update the TextView with a personalized message. TODO Localize
String userId = data.getExtras().getString(LoginActivity.OUTPARAM_USERID);
String msg = "Hello " + userId + ". Now select the exhibition room please.";
txtMainMessage.setText(msg);
}
}
}
}
