Java tutorial
// Copyright 2015 The Project Buendia Authors // // 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 distrib- // uted 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 // specific language governing permissions and limitations under the License. package org.projectbuendia.client.ui; import android.animation.Animator; import android.animation.AnimatorListenerAdapter; import android.os.Bundle; import android.support.annotation.Nullable; import android.support.v4.app.Fragment; import android.util.Log; import android.view.Gravity; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.LinearLayout; import android.widget.ProgressBar; import android.widget.RelativeLayout; import android.widget.TextView; import com.android.volley.Response; import com.android.volley.VolleyError; import com.google.common.base.Charsets; import org.projectbuendia.client.App; import org.projectbuendia.client.R; import java.util.ArrayList; import java.util.List; /** * A {@link Fragment} that shows a spinner or progress bar when fragment content is not ready to * be displayed. */ public abstract class ProgressFragment extends Fragment implements Response.ErrorListener { public enum State { LOADING, LOADED, ERROR } protected View mContent; protected RelativeLayout mFrame; protected TextView mErrorTextView; // Fancy progress bar. protected View mProgressBarLayout; protected ProgressBar mProgressBar; protected TextView mProgressBarLabel; // Indeterminate progress bar. protected ProgressBar mIndeterminateProgressBar; protected int mShortAnimationDuration; private State mState = State.LOADING; private List<ChangeStateSubscriber> mSubscribers = new ArrayList<ChangeStateSubscriber>(); public ProgressFragment() { } /** Subscriber for listening for state changes. */ public interface ChangeStateSubscriber { /** Called whenever the state is changed. */ public void onChangeState(State newState); } @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); mShortAnimationDuration = getResources().getInteger(android.R.integer.config_shortAnimTime); } @Override public void onErrorResponse(VolleyError error) { changeErrorState(error.toString()); Log.e("server", new String(error.networkResponse.data, Charsets.UTF_8)); } @Override public void onDestroy() { super.onDestroy(); App.getServer().cancelPendingRequests(); } @Override public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) { super.onCreateView(inflater, container, savedInstanceState); mFrame = new RelativeLayout(getActivity()); RelativeLayout.LayoutParams layoutParams = new RelativeLayout.LayoutParams( RelativeLayout.LayoutParams.MATCH_PARENT, RelativeLayout.LayoutParams.MATCH_PARENT); mFrame.setLayoutParams(layoutParams); RelativeLayout.LayoutParams relativeLayout = new RelativeLayout.LayoutParams( LinearLayout.LayoutParams.WRAP_CONTENT, LinearLayout.LayoutParams.WRAP_CONTENT); relativeLayout.addRule(RelativeLayout.CENTER_IN_PARENT, RelativeLayout.TRUE); mIndeterminateProgressBar = new ProgressBar(getActivity()); mIndeterminateProgressBar.setLayoutParams(relativeLayout); mProgressBarLayout = inflater.inflate(R.layout.progress_fragment_measured_progress_view, null); mProgressBarLayout.setLayoutParams(relativeLayout); mProgressBar = (ProgressBar) mProgressBarLayout.findViewById(R.id.progress_fragment_progress_bar); mProgressBarLabel = (TextView) mProgressBarLayout.findViewById(R.id.progress_fragment_label); RelativeLayout.LayoutParams fullLayout = new RelativeLayout.LayoutParams( LinearLayout.LayoutParams.MATCH_PARENT, LinearLayout.LayoutParams.MATCH_PARENT); fullLayout.addRule(RelativeLayout.CENTER_IN_PARENT, RelativeLayout.TRUE); mErrorTextView = new TextView(getActivity()); mErrorTextView.setLayoutParams(fullLayout); mErrorTextView.setGravity(Gravity.CENTER); mContent.setVisibility(View.GONE); mProgressBarLayout.setVisibility(View.GONE); mFrame.addView(mIndeterminateProgressBar); mFrame.addView(mProgressBarLayout); mFrame.addView(mContent); mFrame.addView(mErrorTextView); return mFrame; } @Override public void onDestroyView() { super.onDestroyView(); if (mFrame != null) { mFrame.removeAllViewsInLayout(); } } /** Registers a {@link ChangeStateSubscriber}. */ public void registerSubscriber(ChangeStateSubscriber subscriber) { mSubscribers.add(subscriber); } /** Unregisters a {@link ChangeStateSubscriber} if the subscriber is currently registered. */ public void unregisterSubscriber(ChangeStateSubscriber subscriber) { if (mSubscribers.contains(subscriber)) { mSubscribers.remove(subscriber); } } public State getState() { return mState; } protected void setContentView(int layout) { mContent = LayoutInflater.from(getActivity()).inflate(layout, null, false); } protected void changeErrorState(String message) { mErrorTextView.setText(message); changeState(State.ERROR); } /** Changes the state of this fragment, hiding or showing the spinner as necessary. */ public void changeState(State state) { mState = state; // On state change, always start with the indeterminate loader. mProgressBarLayout.setVisibility(View.GONE); mIndeterminateProgressBar.setVisibility(state == State.LOADING ? View.VISIBLE : View.GONE); mContent.setVisibility(state == State.LOADED ? View.VISIBLE : View.GONE); mErrorTextView.setVisibility(state == State.ERROR ? View.VISIBLE : View.GONE); for (ChangeStateSubscriber subscriber : mSubscribers) { subscriber.onChangeState(mState); } } protected void incrementProgressBy(int progress) { switchToHorizontalProgressBar(); mProgressBar.incrementProgressBy(progress); } protected void setProgress(int progress) { switchToHorizontalProgressBar(); mProgressBar.setProgress(progress); } protected void setProgressLabel(String label) { switchToHorizontalProgressBar(); mProgressBarLabel.setText(label); } protected void switchToHorizontalProgressBar() { if (mState == State.LOADING) { mIndeterminateProgressBar.setVisibility(View.GONE); mProgressBarLayout.setVisibility(View.VISIBLE); } } protected void switchToCircularProgressBar() { if (mState == State.LOADING) { mIndeterminateProgressBar.setVisibility(View.VISIBLE); mProgressBarLayout.setVisibility(View.GONE); } } private void crossfade(View inView, final View outView) { // Set the content view to 0% opacity but visible, so that it is visible // (but fully transparent) during the animation. inView.setAlpha(0f); inView.setVisibility(View.VISIBLE); // Animate the content view to 100% opacity, and clear any animation // listener set on the view. inView.animate().alpha(1f).setDuration(mShortAnimationDuration).setListener(null); // Animate the loading view to 0% opacity. After the animation ends, // set its visibility to GONE as an optimization step (it won't // participate in layout passes, etc.) if (outView != null) { outView.animate().alpha(0f).setDuration(mShortAnimationDuration) .setListener(new AnimatorListenerAdapter() { @Override public void onAnimationEnd(Animator animation) { outView.setVisibility(View.GONE); } }); } } }