LinearBreadcrumb.java

package com.alorma.github.ui.view;

import android.annotation.TargetApi;
import android.app.Activity;
import android.content.Context;
import android.graphics.drawable.Drawable;
import android.os.Build;
import android.support.annotation.NonNull;
import android.support.v4.view.ViewCompat;
import android.util.AttributeSet;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.HorizontalScrollView;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.TextView;
import com.alorma.github.R;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.List;

/**
 * @author Aidan Follestad (afollestad)
 */
public class LinearBreadcrumb extends HorizontalScrollView implements View.OnClickListener {

  private List<Crumb> mCrumbs;
  private LinearLayout mChildFrame;
  private int mActive;
  private SelectionCallback mCallback;

  public LinearBreadcrumb(Context context) {
    super(context);
    init();
  }

  public LinearBreadcrumb(Context context, AttributeSet attrs) {
    super(context, attrs);
    init();
  }

  public LinearBreadcrumb(Context context, AttributeSet attrs, int defStyleAttr) {
    super(context, attrs, defStyleAttr);
    init();
  }

  private void init() {
    setMinimumHeight((int) getResources().getDimension(R.dimen.breadcrumb_height));
    setClipToPadding(false);
    mCrumbs = new ArrayList<>();
    mChildFrame = new LinearLayout(getContext());
    addView(mChildFrame, new ViewGroup.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.MATCH_PARENT));
  }

  @TargetApi(Build.VERSION_CODES.JELLY_BEAN)
  private void setAlpha(View view, int alpha) {
    if (view instanceof ImageView && Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {
      ((ImageView) view).setImageAlpha(alpha);
    } else {
      ViewCompat.setAlpha(view, alpha);
    }
  }

  public void addPath(@NonNull String path, @NonNull String separator) {
    clearCrumbs();
    initRootCrumb();
    String[] paths = path.split(separator);
    Crumb lastCrumb = null;
    for (String splitPath : paths) {
      lastCrumb = new Crumb(splitPath);
      addCrumb(lastCrumb, false);
    }

    if (lastCrumb != null) {
      setActive(lastCrumb);
    }
  }

  public void addCrumb(@NonNull Crumb crumb, boolean refreshLayout) {
    LinearLayout view = (LinearLayout) LayoutInflater.from(getContext()).inflate(R.layout.bread_crumb, this, false);
    view.setTag(mCrumbs.size());
    view.setOnClickListener(this);

    ImageView iv = (ImageView) view.getChildAt(1);
    Drawable arrow = getResources().getDrawable(R.drawable.ic_right_arrow);
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
      if (arrow != null) {
        arrow.setAutoMirrored(true);
      }
    }
    iv.setImageDrawable(arrow);
    iv.setVisibility(View.GONE);

    mChildFrame.addView(view, new ViewGroup.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT));
    mCrumbs.add(crumb);
    if (refreshLayout) {
      mActive = mCrumbs.size() - 1;
      requestLayout();
    }
    invalidateActivatedAll();
  }

  @Override
  protected void onLayout(boolean changed, int l, int t, int r, int b) {
    super.onLayout(changed, l, t, r, b);
    //RTL works fine like this
    View child = mChildFrame.getChildAt(mActive);
    if (child != null) smoothScrollTo(child.getLeft(), 0);
  }

  public Crumb findCrumb(@NonNull String forDir) {
    for (int i = 0; i < mCrumbs.size(); i++) {
      if (mCrumbs.get(i).getPath().equals(forDir)) return mCrumbs.get(i);
    }
    return null;
  }

  public void clearCrumbs() {
    try {
      mCrumbs.clear();
      mChildFrame.removeAllViews();
    } catch (IllegalStateException e) {
      e.printStackTrace();
    }
  }

  public Crumb getCrumb(int index) {
    return mCrumbs.get(index);
  }

  public void setCallback(SelectionCallback callback) {
    mCallback = callback;
  }

  public boolean setActive(Crumb newActive) {
    mActive = mCrumbs.indexOf(newActive);
    invalidateActivatedAll();
    boolean success = mActive > -1;
    if (success) requestLayout();
    return success;
  }

  private void invalidateActivatedAll() {
    for (int i = 0; i < mCrumbs.size(); i++) {
      Crumb crumb = mCrumbs.get(i);
      invalidateActivated(mChildFrame.getChildAt(i), mActive == mCrumbs.indexOf(crumb), false, i < mCrumbs.size() - 1).setText(
          crumb.getTitle());
    }
  }

  private void removeCrumbAt(int index) {
    mCrumbs.remove(index);
    mChildFrame.removeViewAt(index);
  }

  private void updateIndices() {
    for (int i = 0; i < mChildFrame.getChildCount(); i++)
      mChildFrame.getChildAt(i).setTag(i);
  }

  private boolean isValidPath(String path) {
    return path == null;
  }

  public int size() {
    return mCrumbs.size();
  }

  private TextView invalidateActivated(View view, boolean isActive, boolean noArrowIfAlone, boolean allowArrowVisible) {
    LinearLayout child = (LinearLayout) view;
    TextView tv = (TextView) child.getChildAt(0);
    tv.setTextColor(getResources().getColor(isActive ? R.color.crumb_active : R.color.crumb_inactive));
    ImageView iv = (ImageView) child.getChildAt(1);
    setAlpha(iv, isActive ? 255 : 109);
    if (noArrowIfAlone && getChildCount() == 1) {
      iv.setVisibility(View.GONE);
    } else if (allowArrowVisible) iv.setVisibility(View.VISIBLE);
    return tv;
  }

  public int getActiveIndex() {
    return mActive;
  }

  @Override
  public void onClick(View v) {
    if (mCallback != null) {
      int index = (Integer) v.getTag();
      if (index >= 0 && index < size()) {
        mCallback.onCrumbSelection(mCrumbs.get(index), getAbsolutePath(mCrumbs.get(index), "/"), mCrumbs.size(), index);
      }
    }
  }

  public SavedStateWrapper getStateWrapper() {
    return new SavedStateWrapper(this);
  }

  public void restoreFromStateWrapper(SavedStateWrapper mSavedState, Activity context) {
    if (mSavedState != null) {
      mActive = mSavedState.mActive;
      for (Crumb c : mSavedState.mCrumbs) {
        addCrumb(c, false);
      }
      requestLayout();
      setVisibility(mSavedState.mVisibility);
    }
  }

  public String getAbsolutePath(Crumb crumb, @NonNull String separator) {
    StringBuilder builder = new StringBuilder();
    if (size() > 1) {
      List<Crumb> crumbs = mCrumbs.subList(1, size());
      for (Crumb mCrumb : crumbs) {
        builder.append(mCrumb.getPath());
        builder.append(separator);
        if (mCrumb.equals(crumb)) {
          break;
        }
      }
      String path = builder.toString();
      return path.substring(0, path.length() - 1);
    } else {
      return null;
    }
  }

  public void initRootCrumb() {
    clearCrumbs();
    addCrumb(new Crumb("/"), true);
  }

  public interface SelectionCallback {

    void onCrumbSelection(Crumb crumb, String absolutePath, int count, int index);
  }

  public static class Crumb implements Serializable {

    private final String mPath;
    private int mScrollY;
    private int mScrollOffset;

    public Crumb(String path) {
      mPath = path;
    }

    public int getScrollY() {
      return mScrollY;
    }

    public void setScrollY(int scrollY) {
      this.mScrollY = scrollY;
    }

    public int getScrollOffset() {
      return mScrollOffset;
    }

    public void setScrollOffset(int scrollOffset) {
      this.mScrollOffset = scrollOffset;
    }

    public String getPath() {
      return mPath;
    }

    public String getTitle() {
      return (mPath != null && mPath.equals("/")) ? "ROOT" : mPath;
    }

    @Override
    public boolean equals(Object o) {
      return (o instanceof Crumb) && ((Crumb) o).getPath().equals(getPath());
    }

    @Override
    public String toString() {
      return getPath();
    }
  }

  public static class SavedStateWrapper implements Serializable {

    public final int mActive;

    public final List<Crumb> mCrumbs;
    public final int mVisibility;

    public SavedStateWrapper(LinearBreadcrumb view) {
      mActive = view.mActive;
      mCrumbs = view.mCrumbs;
      mVisibility = view.getVisibility();
    }
  }
}