Java tutorial
/* * Copyright (C) 2016 The Android Open Source Project * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package com.example.vivek.team; import android.app.AlertDialog; import android.app.LoaderManager; import android.content.ContentValues; import android.content.CursorLoader; import android.content.DialogInterface; import android.content.Intent; import android.content.Loader; import android.database.Cursor; import android.database.sqlite.SQLiteDatabase; import android.net.Uri; import android.os.Bundle; import android.support.v4.app.NavUtils; import android.support.v7.app.AppCompatActivity; import android.text.TextUtils; import android.view.Menu; import android.view.MenuItem; import android.view.MotionEvent; import android.view.View; import android.widget.AdapterView; import android.widget.ArrayAdapter; import android.widget.EditText; import android.widget.Spinner; import android.widget.Toast; import com.example.vivek.team.Data.UserContract.UserDB; import com.example.vivek.team.Data.UserHelper; import static com.example.vivek.team.Data.UserContract.UserDB.GENDER_FEMALE; import static com.example.vivek.team.Data.UserContract.UserDB.GENDER_MALE; import static com.example.vivek.team.Data.UserContract.UserDB.GENDER_SELECT; /** * Allows user to create a new user or edit an existing one. */ public class EditorActivity extends AppCompatActivity implements LoaderManager.LoaderCallbacks<Cursor> { private UserHelper mDbHelper; private static final int EXISTING_USER_LOADER = 0; /** EditText field to enter the user's name */ private EditText mNameEditText; /** EditText field to enter the user's id */ private EditText mUserIdEditText; /** EditText field to enter the user birthday */ private EditText mBirthdayEditText; /** EditText field to enter the user's gender */ private Spinner mGenderSpinner; /** * Gender of the USER. The possible values are: * 0 for unknown gender, 1 for male, 2 for female. */ private int mGender = GENDER_SELECT; private Uri mCurrentUserUri; private boolean mUserHasChanged = false; private View.OnTouchListener mTouchListener = new View.OnTouchListener() { @Override public boolean onTouch(View view, MotionEvent motionEvent) { mUserHasChanged = true; return false; } }; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_editor); Intent intent = getIntent(); mCurrentUserUri = intent.getData(); if (mCurrentUserUri == null) { setTitle(getString(R.string.editor_Newuser_title)); invalidateOptionsMenu(); } else { setTitle(getString(R.string.editor_update_title)); getLoaderManager().initLoader(EXISTING_USER_LOADER, null, this); } // Find all relevant views that we will need to read user input from mNameEditText = (EditText) findViewById(R.id.edit_name); mUserIdEditText = (EditText) findViewById(R.id.edit_userid); mBirthdayEditText = (EditText) findViewById(R.id.edit_birthday); mGenderSpinner = (Spinner) findViewById(R.id.spinner_gender); mNameEditText.setOnTouchListener(mTouchListener); mUserIdEditText.setOnTouchListener(mTouchListener); mBirthdayEditText.setOnTouchListener(mTouchListener); mGenderSpinner.setOnTouchListener(mTouchListener); setupSpinner(); } /** * Setup the dropdown spinner that allows the user to select the gender of the user. */ private void setupSpinner() { // Create adapter for spinner. The list options are from the String array it will use // the spinner will use the default layout ArrayAdapter genderSpinnerAdapter = ArrayAdapter.createFromResource(this, R.array.array_gender_options, android.R.layout.simple_spinner_item); // Specify dropdown layout style - simple list view with 1 item per line genderSpinnerAdapter.setDropDownViewResource(android.R.layout.simple_dropdown_item_1line); // Apply the adapter to the spinner mGenderSpinner.setAdapter(genderSpinnerAdapter); // Set the integer mSelected to the constant values mGenderSpinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() { @Override public void onItemSelected(AdapterView<?> parent, View view, int position, long id) { String selection = (String) parent.getItemAtPosition(position); if (!TextUtils.isEmpty(selection)) { if (selection.equals(getString(R.string.gender_male))) { mGender = GENDER_MALE; // Male } else if (selection.equals(getString(R.string.gender_female))) { mGender = GENDER_FEMALE; // Female } else { mGender = GENDER_SELECT; } } } // Because AdapterView is an abstract class, onNothingSelected must be defined @Override public void onNothingSelected(AdapterView<?> parent) { mGender = 0; // Unknown } }); } @Override public boolean onCreateOptionsMenu(Menu menu) { // Inflate the menu options from the res/menu/menu_editor.xml file. // This adds menu items to the app bar. getMenuInflater().inflate(R.menu.menu_editor, menu); return true; } @Override public boolean onPrepareOptionsMenu(Menu menu) { super.onPrepareOptionsMenu(menu); // If this is a new user, hide the "Delete" menu item. if (mCurrentUserUri == null) { MenuItem menuItem = menu.findItem(R.id.delete); menuItem.setVisible(false); } return true; } @Override public boolean onOptionsItemSelected(MenuItem item) { // User clicked on a menu option in the app bar overflow menu switch (item.getItemId()) { // Respond to a click on the "Save" menu option case R.id.save: // insert values from editor page saveUser(); finish(); return true; // Respond to a click on the "Delete" menu option case R.id.delete: showDeleteConfirmationDialog(); return true; // Respond to a click on the "Up" arrow button in the app bar case android.R.id.home: // If the user hasn't changed, continue with navigating up to parent activity // which is the {@link CatalogActivity}. if (!mUserHasChanged) { NavUtils.navigateUpFromSameTask(EditorActivity.this); return true; } // Otherwise if there are unsaved changes, setup a dialog to warn the user. // Create a click listener to handle the user confirming that // changes should be discarded. DialogInterface.OnClickListener discardButtonClickListener = new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialogInterface, int i) { // User clicked "Discard" button, navigate to parent activity. NavUtils.navigateUpFromSameTask(EditorActivity.this); } }; // Show a dialog that notifies the user they have unsaved changes showUnsavedChangesDialog(discardButtonClickListener); return true; } return super.onOptionsItemSelected(item); } private void showUnsavedChangesDialog(DialogInterface.OnClickListener discardButtonClickListener) { // Create an AlertDialog.Builder and set the message, and click listeners // for the positive and negative buttons on the dialog. AlertDialog.Builder builder = new AlertDialog.Builder(this); builder.setMessage(R.string.unsaved_changes_dialog_msg); builder.setPositiveButton(R.string.discard, discardButtonClickListener); builder.setNegativeButton(R.string.keep_editing, new DialogInterface.OnClickListener() { public void onClick(DialogInterface dialog, int id) { // User clicked the "Keep editing" button, so dismiss the dialog // and continue editing the user. if (dialog != null) { dialog.dismiss(); } } }); // Create and show the AlertDialog AlertDialog alertDialog = builder.create(); alertDialog.show(); } @Override public void onBackPressed() { // If the user hasn't changed, continue with handling back button press if (!mUserHasChanged) { super.onBackPressed(); return; } // Otherwise if there are unsaved changes, setup a dialog to warn the user. // Create a click listener to handle the user confirming that changes should be discarded. DialogInterface.OnClickListener discardButtonClickListener = new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialogInterface, int i) { // User clicked "Discard" button, close the current activity. finish(); } }; // Show dialog that there are unsaved changes showUnsavedChangesDialog(discardButtonClickListener); } private void showDeleteConfirmationDialog() { // Create an AlertDialog.Builder and set the message, and click listeners // for the postivie and negative buttons on the dialog. AlertDialog.Builder builder = new AlertDialog.Builder(this); builder.setMessage(R.string.delete_dialog_msg); builder.setPositiveButton(R.string.delete, new DialogInterface.OnClickListener() { public void onClick(DialogInterface dialog, int id) { // User clicked the "Delete" button, so delete the user. deleteUser(); } }); builder.setNegativeButton(R.string.cancel, new DialogInterface.OnClickListener() { public void onClick(DialogInterface dialog, int id) { // User clicked the "Cancel" button, so dismiss the dialog // and continue editing the user. if (dialog != null) { dialog.dismiss(); } } }); // Create and show the AlertDialog AlertDialog alertDialog = builder.create(); alertDialog.show(); } private void deleteUser() { if (mCurrentUserUri != null) { int rowsDeleted = getContentResolver().delete(mCurrentUserUri, null, null); if (rowsDeleted == 0) { // If no rows were deleted, then there was an error with the delete. Toast.makeText(this, getString(R.string.editor_delete_user_failed), Toast.LENGTH_SHORT).show(); } else { // Otherwise, the delete was successful and we can display a toast. Toast.makeText(this, getString(R.string.editor_delete_user_successful), Toast.LENGTH_SHORT).show(); } } finish(); } private void saveUser() { mDbHelper = new UserHelper(this); String userName = mNameEditText.getText().toString().trim(); String userID = mUserIdEditText.getText().toString().trim(); //int Birthday =Integer.parseInt( String Birthday = mBirthdayEditText.getText().toString().trim(); SQLiteDatabase db = mDbHelper.getWritableDatabase(); if ((mCurrentUserUri == null) && TextUtils.isEmpty(userName) && TextUtils.isEmpty(userID) && TextUtils.isEmpty(Birthday)) { return; } ContentValues values = new ContentValues(); values.put(UserDB.COLUMN_NAME, userName); values.put(UserDB.COLUMN_USERID, userID); values.put(UserDB.COLUMN_GENDER, mGender); int BDay = 0; if (!TextUtils.isEmpty(Birthday)) { BDay = Integer.parseInt(Birthday); } values.put(UserDB.COLUMN_BIRTHDAY, BDay); if (mCurrentUserUri == null) { // This is a NEW user, so insert a new user into the provider, // returning the content URI for the new user. Uri newUri = getContentResolver().insert(UserDB.content_URI, values); // Show a toast message depending on whether or not the insertion was successful. if (newUri == null) { // If the new content URI is null, then there was an error with insertion. Toast.makeText(this, getString(R.string.editor_insert_user_failed), Toast.LENGTH_SHORT).show(); } else { // Otherwise, the insertion was successful and we can display a toast. Toast.makeText(this, getString(R.string.editor_insert_user_successful), Toast.LENGTH_SHORT).show(); } } else { int rowsAffected = getContentResolver().update(mCurrentUserUri, values, null, null); // Show a toast message depending on whether or not the update was successful. if (rowsAffected == 0) { // If no rows were affected, then there was an error with the update. Toast.makeText(this, getString(R.string.editor_update_user_failed), Toast.LENGTH_SHORT).show(); } else { // Otherwise, the update was successful and we can display a toast. Toast.makeText(this, getString(R.string.editor_update_user_successful), Toast.LENGTH_SHORT).show(); } } } @Override public Loader<Cursor> onCreateLoader(int id, Bundle args) { String[] projection = { UserDB._ID, UserDB.COLUMN_NAME, UserDB.COLUMN_USERID, UserDB.COLUMN_GENDER, UserDB.COLUMN_BIRTHDAY }; return new CursorLoader(this, mCurrentUserUri, projection, null, null, null); } @Override public void onLoadFinished(Loader<Cursor> loader, Cursor cursor) { if (cursor.moveToFirst()) { // Find the columns of user attributes that we're interested in int nameColumnIndex = cursor.getColumnIndex(UserDB.COLUMN_NAME); int userIdColumnIndex = cursor.getColumnIndex(UserDB.COLUMN_USERID); int genderColumnIndex = cursor.getColumnIndex(UserDB.COLUMN_GENDER); int birthdayColumnIndex = cursor.getColumnIndex(UserDB.COLUMN_BIRTHDAY); // Extract out the value from the Cursor for the given column index String name = cursor.getString(nameColumnIndex); String userId = cursor.getString(userIdColumnIndex); int gender = cursor.getInt(genderColumnIndex); int birthday = cursor.getInt(birthdayColumnIndex); // Update the views on the screen with the values from the database mNameEditText.setText(name); mUserIdEditText.setText(userId); mBirthdayEditText.setText(Integer.toString(birthday)); switch (gender) { case GENDER_MALE: mGenderSpinner.setSelection(1); break; case GENDER_FEMALE: mGenderSpinner.setSelection(2); break; default: mGenderSpinner.setSelection(0); break; } } } @Override public void onLoaderReset(Loader<Cursor> loader) { // If the loader is invalidated, clear out all the data from the input fields. mNameEditText.setText(""); mUserIdEditText.setText(""); mBirthdayEditText.setText(""); mGenderSpinner.setSelection(0); // Select "Unknown" gender } }