Java tutorial
/** * Copyright Google Inc. All Rights Reserved. * <p/> * 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 * <p/> * http://www.apache.org/licenses/LICENSE-2.0 * <p/> * 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.google.firebase.codelab.friendlychat.ui.messages; import android.content.Context; import android.content.Intent; import android.os.Bundle; import android.support.annotation.NonNull; import android.support.v4.content.ContextCompat; import android.support.v7.widget.LinearLayoutManager; import android.support.v7.widget.RecyclerView; import android.text.Editable; import android.text.TextWatcher; import android.util.Log; import android.view.Menu; import android.view.MenuInflater; import android.view.MenuItem; import android.view.View; import android.widget.Button; import android.widget.EditText; import android.widget.ProgressBar; import android.widget.Toast; import com.bumptech.glide.Glide; import com.firebase.ui.database.FirebaseRecyclerAdapter; import com.google.android.gms.common.ConnectionResult; import com.google.android.gms.common.api.GoogleApiClient; import com.google.firebase.auth.FirebaseAuth; import com.google.firebase.auth.FirebaseUser; import com.google.firebase.codelab.friendlychat.R; import com.google.firebase.codelab.friendlychat.ui.base.BaseActivity; import com.google.firebase.codelab.friendlychat.ui.signin.SignInActivity; import com.google.firebase.codelab.friendlychat.model.FriendlyMessage; import com.google.firebase.database.DatabaseReference; import com.google.firebase.database.FirebaseDatabase; public class MessagesActivity extends BaseActivity implements GoogleApiClient.OnConnectionFailedListener { private DatabaseReference mFirebaseDatabaseReference; private FirebaseRecyclerAdapter<FriendlyMessage, MessageViewHolder> mFirebaseAdapter; public static Intent newIntent(Context context) { return new Intent(context, SignInActivity.class); } private static final String TAG = "MainActivity"; public static final String MESSAGES_CHILD = "messages"; public static final String ANONYMOUS = "anonymous"; private String mUsername; private String mPhotoUrl; private FirebaseAuth mFirebaseAuth; private Button mSendButton; private RecyclerView mMessageRecyclerView; private LinearLayoutManager mLinearLayoutManager; private ProgressBar mProgressBar; private EditText mMessageEditText; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); // Initialize ProgressBar and RecyclerView. mProgressBar = (ProgressBar) findViewById(R.id.progressBar); mMessageRecyclerView = (RecyclerView) findViewById(R.id.messageRecyclerView); mLinearLayoutManager = new LinearLayoutManager(this); mLinearLayoutManager.setStackFromEnd(true); mMessageRecyclerView.setLayoutManager(mLinearLayoutManager); FirebaseDatabase.getInstance().setPersistenceEnabled(true); mFirebaseDatabaseReference = FirebaseDatabase.getInstance().getReference(); mFirebaseAdapter = new FirebaseRecyclerAdapter<FriendlyMessage, MessageViewHolder>(FriendlyMessage.class, R.layout.item_message, MessageViewHolder.class, mFirebaseDatabaseReference.child(MESSAGES_CHILD)) { @Override protected void populateViewHolder(MessageViewHolder viewHolder, FriendlyMessage friendlyMessage, int position) { mProgressBar.setVisibility(ProgressBar.INVISIBLE); viewHolder.bind(friendlyMessage); } }; mFirebaseAdapter.registerAdapterDataObserver(new RecyclerView.AdapterDataObserver() { @Override public void onItemRangeInserted(int positionStart, int itemCount) { super.onItemRangeInserted(positionStart, itemCount); int friendlyMessageCount = mFirebaseAdapter.getItemCount(); int lastVisiblePosition = mLinearLayoutManager.findLastCompletelyVisibleItemPosition(); // If the recycler view is initially being loaded or the // user is at the bottom of the list, scroll to the bottom // of the list to show the newly added message. if (lastVisiblePosition == -1 || (positionStart >= (friendlyMessageCount - 1) && lastVisiblePosition == (positionStart - 1))) { mMessageRecyclerView.scrollToPosition(positionStart); } } }); mMessageRecyclerView.setLayoutManager(mLinearLayoutManager); mMessageRecyclerView.setAdapter(mFirebaseAdapter); mMessageEditText = (EditText) findViewById(R.id.messageEditText); mMessageEditText.addTextChangedListener(new TextWatcher() { @Override public void beforeTextChanged(CharSequence charSequence, int i, int i1, int i2) { } @Override public void onTextChanged(CharSequence charSequence, int i, int i1, int i2) { if (charSequence.toString().trim().length() > 0) { mSendButton.setEnabled(true); } else { mSendButton.setEnabled(false); } } @Override public void afterTextChanged(Editable editable) { } }); mSendButton = (Button) findViewById(R.id.sendButton); mSendButton.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { FriendlyMessage friendlyMessage = new FriendlyMessage(mMessageEditText.getText().toString(), mUsername, mPhotoUrl); mFirebaseDatabaseReference.child(MESSAGES_CHILD).push().setValue(friendlyMessage); mMessageEditText.setText(""); } }); } @Override public void onStart() { super.onStart(); // Check if user is signed in. // TODO: Add code to check if user is signed in. } @Override public void onPause() { super.onPause(); } @Override public void onResume() { super.onResume(); } @Override public void onDestroy() { super.onDestroy(); } @Override public boolean onCreateOptionsMenu(Menu menu) { MenuInflater inflater = getMenuInflater(); inflater.inflate(R.menu.main_menu, menu); return true; } @Override public boolean onOptionsItemSelected(MenuItem item) { switch (item.getItemId()) { case R.id.sign_out_menu: mFirebaseAuth.signOut(); mUsername = ANONYMOUS; startActivity(new Intent(this, SignInActivity.class)); return true; default: return super.onOptionsItemSelected(item); } } @Override public void onConnectionFailed(@NonNull ConnectionResult connectionResult) { // An unresolvable error has occurred and Google APIs (including Sign-In) will not // be available. Log.d(TAG, "onConnectionFailed:" + connectionResult); Toast.makeText(this, "Google Play Services error.", Toast.LENGTH_SHORT).show(); } }