/*
* Copyright 2017 Rozdoum
*
* 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.rozdoum.socialcomponents.views;
/**
* Created by alexey on 21.12.16.
*/
import android.annotation.TargetApi;
import android.content.Context;
import android.content.res.TypedArray;
import android.os.Build;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.text.TextUtils;
import android.util.AttributeSet;
import android.util.SparseBooleanArray;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewGroup;
import android.view.animation.AlphaAnimation;
import android.view.animation.Animation;
import android.view.animation.Transformation;
import android.widget.LinearLayout;
import android.widget.TextView;
import com.rozdoum.socialcomponents.R;
public class ExpandableTextView extends LinearLayout implements View.OnClickListener {
private static final String TAG = ExpandableTextView.class.getSimpleName();
/* The default number of lines */
private static final int MAX_COLLAPSED_LINES = 8;
/* The default animation duration */
private static final int DEFAULT_ANIM_DURATION = 300;
/* The default alpha value when the animation starts */
private static final float DEFAULT_ANIM_ALPHA_START = 0.7f;
/* The default text of collapse button */
private static final String COLLAPS_BUTTON_TEXT = "show less";
/* The default text of expand button */
private static final String EXPAND_BUTTON_TEXT = "show more";
protected TextView mTv;
protected TextView mButton; // Button to expand/collapse
private boolean mRelayout;
private boolean mCollapsed = true; // Show short version as default.
private int mCollapsedHeight;
private int mTextHeightWithMaxLines;
private int mMaxCollapsedLines;
private int mMarginBetweenTxtAndBottom;
private String mExpandText;
private String mCollapseText;
private int mAnimationDuration;
private float mAnimAlphaStart;
private boolean mAnimating;
/* Listener for callback */
private OnExpandStateChangeListener mListener;
/* For saving collapsed status when used in ListView */
private SparseBooleanArray mCollapsedStatus;
private int mPosition;
public ExpandableTextView(Context context) {
this(context, null);
}
public ExpandableTextView(Context context, AttributeSet attrs) {
super(context, attrs);
init(attrs);
}
@TargetApi(Build.VERSION_CODES.HONEYCOMB)
public ExpandableTextView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
init(attrs);
}
@Override
public void setOrientation(int orientation) {
if (LinearLayout.HORIZONTAL == orientation) {
throw new IllegalArgumentException("ExpandableTextView only supports Vertical Orientation.");
}
super.setOrientation(orientation);
}
@Override
public void onClick(View view) {
if (mButton.getVisibility() != View.VISIBLE) {
return;
}
mCollapsed = !mCollapsed;
mButton.setText(mCollapsed ? mExpandText : mCollapseText);
if (mCollapsedStatus != null) {
mCollapsedStatus.put(mPosition, mCollapsed);
}
// mark that the animation is in progress
mAnimating = true;
Animation animation;
if (mCollapsed) {
animation = new ExpandCollapseAnimation(this, getHeight(), mCollapsedHeight);
} else {
animation = new ExpandCollapseAnimation(this, getHeight(), getHeight() +
mTextHeightWithMaxLines - mTv.getHeight());
}
animation.setFillAfter(true);
animation.setAnimationListener(new Animation.AnimationListener() {
@Override
public void onAnimationStart(Animation animation) {
applyAlphaAnimation(mTv, mAnimAlphaStart);
}
@Override
public void onAnimationEnd(Animation animation) {
// clear animation here to avoid repeated applyTransformation() calls
clearAnimation();
// clear the animation flag
mAnimating = false;
// notify the listener
if (mListener != null) {
mListener.onExpandStateChanged(mTv, !mCollapsed);
}
if (mCollapsed) {
mTv.setMaxLines(mMaxCollapsedLines);
}
}
@Override
public void onAnimationRepeat(Animation animation) {
}
});
clearAnimation();
startAnimation(animation);
}
@Override
public boolean onInterceptTouchEvent(MotionEvent ev) {
// while an animation is in progress, intercept all the touch events to children to
// prevent extra clicks during the animation
return mAnimating;
}
@Override
protected void onFinishInflate() {
findViews();
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
// If no change, measure and return
if (!mRelayout || getVisibility() == View.GONE) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
return;
}
mRelayout = false;
// Setup with optimistic case
// i.e. Everything fits. No button needed
mButton.setVisibility(View.GONE);
mTv.setMaxLines(Integer.MAX_VALUE);
// Measure
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
// If the text fits in collapsed mode, we are done.
if (mTv.getLineCount() <= mMaxCollapsedLines) {
return;
}
// Saves the text height w/ max lines
mTextHeightWithMaxLines = getRealTextViewHeight(mTv);
// Doesn't fit in collapsed mode. Collapse text view as needed. Show
// button.
if (mCollapsed) {
mTv.setMaxLines(mMaxCollapsedLines);
}
mButton.setVisibility(View.VISIBLE);
// Re-measure with new setup
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
if (mCollapsed) {
// Gets the margin between the TextView's bottom and the ViewGroup's bottom
mTv.post(new Runnable() {
@Override
public void run() {
mMarginBetweenTxtAndBottom = getHeight() - mTv.getHeight();
}
});
// Saves the collapsed height of this ViewGroup
mCollapsedHeight = getMeasuredHeight();
}
}
public void setOnExpandStateChangeListener(@Nullable OnExpandStateChangeListener listener) {
mListener = listener;
}
public void setText(@Nullable CharSequence text) {
mRelayout = true;
mTv.setText(text);
setVisibility(TextUtils.isEmpty(text) ? View.GONE : View.VISIBLE);
}
public void setText(@Nullable CharSequence text, @NonNull SparseBooleanArray collapsedStatus, int position) {
mCollapsedStatus = collapsedStatus;
mPosition = position;
boolean isCollapsed = collapsedStatus.get(position, true);
clearAnimation();
mCollapsed = isCollapsed;
mButton.setText(mCollapsed ? mExpandText : mCollapseText);
setText(text);
getLayoutParams().height = ViewGroup.LayoutParams.WRAP_CONTENT;
requestLayout();
}
@Nullable
public CharSequence getText() {
if (mTv == null) {
return "";
}
return mTv.getText();
}
private void init(AttributeSet attrs) {
TypedArray typedArray = getContext().obtainStyledAttributes(attrs, R.styleable.ExpandableTextView);
mMaxCollapsedLines = typedArray.getInt(R.styleable.ExpandableTextView_maxCollapsedLines, MAX_COLLAPSED_LINES);
mAnimationDuration = typedArray.getInt(R.styleable.ExpandableTextView_animDuration, DEFAULT_ANIM_DURATION);
mAnimAlphaStart = typedArray.getFloat(R.styleable.ExpandableTextView_animAlphaStart, DEFAULT_ANIM_ALPHA_START);
mExpandText = typedArray.getString(R.styleable.ExpandableTextView_expandText);
mCollapseText = typedArray.getString(R.styleable.ExpandableTextView_collapseText);
if (mExpandText == null) {
mExpandText = EXPAND_BUTTON_TEXT;
}
if (mCollapseText == null) {
mCollapseText = COLLAPS_BUTTON_TEXT;
}
typedArray.recycle();
// enforces vertical orientation
setOrientation(LinearLayout.VERTICAL);
// default visibility is gone
setVisibility(GONE);
}
private void findViews() {
mTv = (TextView) findViewById(R.id.expandable_text);
// TODO: 12.05.17 for enabling expand/collapse comment by click on text remove comment
// mTv.setOnClickListener(this);
mButton = (TextView) findViewById(R.id.expand_collapse);
mButton.setText(mCollapsed ? mExpandText : mCollapseText);
mButton.setOnClickListener(this);
}
private static boolean isPostHoneycomb() {
return Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB;
}
@TargetApi(Build.VERSION_CODES.HONEYCOMB)
private static void applyAlphaAnimation(View view, float alpha) {
if (isPostHoneycomb()) {
view.setAlpha(alpha);
} else {
AlphaAnimation alphaAnimation = new AlphaAnimation(alpha, alpha);
// make it instant
alphaAnimation.setDuration(0);
alphaAnimation.setFillAfter(true);
view.startAnimation(alphaAnimation);
}
}
private static int getRealTextViewHeight(@NonNull TextView textView) {
int textHeight = textView.getLayout().getLineTop(textView.getLineCount());
int padding = textView.getCompoundPaddingTop() + textView.getCompoundPaddingBottom();
return textHeight + padding;
}
class ExpandCollapseAnimation extends Animation {
private final View mTargetView;
private final int mStartHeight;
private final int mEndHeight;
public ExpandCollapseAnimation(View view, int startHeight, int endHeight) {
mTargetView = view;
mStartHeight = startHeight;
mEndHeight = endHeight;
setDuration(mAnimationDuration);
}
@Override
protected void applyTransformation(float interpolatedTime, Transformation t) {
final int newHeight = (int) ((mEndHeight - mStartHeight) * interpolatedTime + mStartHeight);
mTv.setMaxHeight(newHeight - mMarginBetweenTxtAndBottom);
if (Float.compare(mAnimAlphaStart, 1.0f) != 0) {
applyAlphaAnimation(mTv, mAnimAlphaStart + interpolatedTime * (1.0f - mAnimAlphaStart));
}
mTargetView.getLayoutParams().height = newHeight;
mTargetView.requestLayout();
}
@Override
public void initialize(int width, int height, int parentWidth, int parentHeight) {
super.initialize(width, height, parentWidth, parentHeight);
}
@Override
public boolean willChangeBounds() {
return true;
}
}
public interface OnExpandStateChangeListener {
/**
* Called when the expand/collapse animation has been finished
*
* @param textView - TextView being expanded/collapsed
* @param isExpanded - true if the TextView has been expanded
*/
void onExpandStateChanged(TextView textView, boolean isExpanded);
}
}
