Java tutorial
package com.locution.hereyak; import java.io.IOException; import java.net.MalformedURLException; import java.util.HashMap; import java.util.Map; import org.json.JSONException; import org.json.JSONObject; import com.google.android.gms.common.GooglePlayServicesUtil; import android.animation.Animator; import android.animation.AnimatorListenerAdapter; import android.annotation.TargetApi; import android.app.Activity; import android.app.AlertDialog; import android.content.Context; import android.content.Intent; import android.content.SharedPreferences; import android.net.Uri; import android.os.AsyncTask; import android.os.Build; import android.os.Bundle; import android.text.TextUtils; import android.util.Log; import android.view.Gravity; import android.view.KeyEvent; import android.view.Menu; import android.view.MenuItem; import android.view.View; import android.view.inputmethod.EditorInfo; import android.widget.EditText; import android.widget.TextView; import android.widget.Toast; public class LoginActivity extends Activity { 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); SharedPreferences prefs = getSharedPreferences(Constants.PREFS_FILE_NAME, MODE_PRIVATE); if (prefs.getString("username", null) != null && prefs.getString("access_token", null) != null && prefs.getString("device_key", null) != null) { Intent i = new Intent(getApplicationContext(), MainActivity.class); i.putExtra("username", ObscureData.unObscureIt(this, prefs.getString("username", null))); i.putExtra("access_token", ObscureData.unObscureIt(this, prefs.getString("access_token", null))); i.putExtra("device_key", ObscureData.unObscureIt(this, prefs.getString("device_key", null))); startActivityForResult(i, 1); setResult(RESULT_OK); finish(); } setContentView(R.layout.activity_login); // Set up the login form. //mEmail = getIntent().getStringExtra(); 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(); } }); findViewById(R.id.sign_up_text).setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { Constants.logMessage(1, "sign_up_text_onClick", "Switching to sign up activity"); Intent i = new Intent(getApplicationContext(), SignUpActivity.class); mEmail = mEmailView.getText().toString(); i.putExtra("email", mEmail); startActivityForResult(i, 1); } }); findViewById(R.id.forgot_password_text).setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { lostPassword(); } }); } @Override public boolean onCreateOptionsMenu(Menu menu) { super.onCreateOptionsMenu(menu); getMenuInflater().inflate(R.menu.login, menu); MenuItem item = menu.findItem(R.id.action_forgot_password); if (item != null) { item.setOnMenuItemClickListener(new MenuItem.OnMenuItemClickListener() { public boolean onMenuItemClick(MenuItem item) { lostPassword(); return true; } }); } return true; } @Override public boolean onOptionsItemSelected(MenuItem item) { switch (item.getItemId()) { case R.id.menu_legalnotices: String LicenseInfo = GooglePlayServicesUtil.getOpenSourceSoftwareLicenseInfo(getApplicationContext()); AlertDialog.Builder LicenseDialog = new AlertDialog.Builder(this); LicenseDialog.setTitle("Legal Notices"); LicenseDialog.setMessage(LicenseInfo); LicenseDialog.show(); return true; } return super.onOptionsItemSelected(item); } private void lostPassword() { Intent i = new Intent(Intent.ACTION_VIEW, Uri.parse("https://hereyak.com/users/password/new")); startActivity(i); } 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() < 6) { 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); } } @Override protected void onActivityResult(int requestCode, int resultCode, Intent data) { super.onActivityResult(requestCode, resultCode, data); if (resultCode == RESULT_OK && requestCode == 1) { setResult(RESULT_OK); finish(); } } /** * Represents an asynchronous login task used to authenticate * the user. */ public class UserLoginTask extends AsyncTask<Void, Void, Map<String, Object>> { @Override protected Map<String, Object> doInBackground(Void... params) { try { YakHttpClient yakClient = new YakHttpClient("sign_in"); Map<String, Object> ret = new HashMap<String, Object>(); ret = yakClient.sign_in(mEmail, mPassword); Constants.logMessage(1, "UserLoginTask", ret.toString()); return ret; } catch (MalformedURLException e) { Constants.logMessage(2, "UserLoginTask", e.getMessage()); } catch (IOException e) { Constants.logMessage(2, "UserLoginTask", e.getMessage()); } catch (Exception e) { Constants.logMessage(2, "UserLoginTask", e.getMessage()); } return null; } @Override protected void onPostExecute(final Map<String, Object> ret) { mAuthTask = null; showProgress(false); Boolean success = false; if ((ret != null) && Integer.parseInt(((String) ret.get("status"))) == 0) { success = true; } if (success) { Constants.logMessage(1, "onPostExecute", "Success!"); Intent i = new Intent(getApplicationContext(), MainActivity.class); JSONObject json = (JSONObject) (ret.get("data")); try { i.putExtra("username", json.getString("username")); i.putExtra("access_token", json.getString("access_token")); i.putExtra("device_key", json.getString("device_key")); startActivityForResult(i, 1); setResult(RESULT_OK); finish(); } catch (JSONException e) { Context context = getApplicationContext(); CharSequence text = getString(R.string.error_server); int duration = Toast.LENGTH_SHORT; Toast toast = Toast.makeText(context, text, duration); toast.setGravity(Gravity.CENTER_VERTICAL, 0, 0); toast.show(); } } else { Context context = getApplicationContext(); CharSequence text = getString(R.string.error_incorrect_credentials); if ((ret != null) && (Integer.parseInt((String) ret.get("status")) == 2)) { text = getString(R.string.error_server); } int duration = Toast.LENGTH_SHORT; Toast toast = Toast.makeText(context, text, duration); toast.setGravity(Gravity.CENTER_VERTICAL, 0, 0); toast.show(); } } @Override protected void onCancelled() { mAuthTask = null; showProgress(false); } } }