FragmentBreadCrumbs.java

package org.holoeverywhere.preference;

import org.holoeverywhere.LayoutInflater;
import org.holoeverywhere.widget.LinearLayout;

import android.animation.LayoutTransition;
import android.annotation.SuppressLint;
import android.content.Context;
import android.os.Build.VERSION;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentManager.BackStackEntry;
import android.util.AttributeSet;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

public class FragmentBreadCrumbs extends ViewGroup implements
        FragmentManager.OnBackStackChangedListener {
    public interface OnBreadCrumbClickListener {
        public boolean onBreadCrumbClick(BackStackEntry backStack, int flags);
    }

    FragmentActivity mActivity;
    LinearLayout mContainer;
    LayoutInflater mInflater;
    int mMaxVisible = -1;
    private OnBreadCrumbClickListener mOnBreadCrumbClickListener;

    private OnClickListener mOnClickListener = new OnClickListener() {
        @Override
        public void onClick(View v) {
            if (v.getTag() instanceof BackStackEntry) {
                BackStackEntry bse = (BackStackEntry) v.getTag();
                if (bse == mParentEntry) {
                    if (mParentClickListener != null) {
                        mParentClickListener.onClick(v);
                    }
                } else {
                    if (mOnBreadCrumbClickListener != null) {
                        if (mOnBreadCrumbClickListener.onBreadCrumbClick(
                                bse == mTopEntry ? null : bse, 0)) {
                            return;
                        }
                    }
                    if (bse == mTopEntry) {
                        mActivity.getSupportFragmentManager().popBackStack();
                    } else {
                        mActivity.getSupportFragmentManager().popBackStack(
                                bse.getId(), 0);
                    }
                }
            }
        }
    };

    private OnClickListener mParentClickListener;
    BackStackEntry mParentEntry;
    BackStackEntry mTopEntry;

    public FragmentBreadCrumbs(Context context) {
        this(context, null);
    }

    public FragmentBreadCrumbs(Context context, AttributeSet attrs) {
        this(context, attrs, android.R.style.Widget_FragmentBreadCrumbs);
    }

    public FragmentBreadCrumbs(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
    }

    private BackStackEntry createBackStackEntry(final CharSequence title,
            final CharSequence shortTitle) {
        if (title == null) {
            return null;
        }
        return new BackStackEntry() {
            @Override
            public CharSequence getBreadCrumbShortTitle() {
                return shortTitle;
            }

            @Override
            public int getBreadCrumbShortTitleRes() {
                return 0;
            }

            @Override
            public CharSequence getBreadCrumbTitle() {
                return title;
            }

            @Override
            public int getBreadCrumbTitleRes() {
                return 0;
            }

            @Override
            public int getId() {
                return 2837452;
            }

            @Override
            public String getName() {
                return "backstackentry";
            }
        };
    }

    private BackStackEntry getPreEntry(int index) {
        if (mParentEntry != null) {
            return index == 0 ? mParentEntry : mTopEntry;
        } else {
            return mTopEntry;
        }
    }

    private int getPreEntryCount() {
        return (mTopEntry != null ? 1 : 0) + (mParentEntry != null ? 1 : 0);
    }

    @Override
    public void onBackStackChanged() {
        updateCrumbs();
    }

    @Override
    protected void onLayout(boolean changed, int l, int t, int r, int b) {
        final int childCount = getChildCount();
        for (int i = 0; i < childCount; i++) {
            final View child = getChildAt(i);
            int childRight = getPaddingLeft() + child.getMeasuredWidth()
                    - getPaddingRight();
            int childBottom = getPaddingTop() + child.getMeasuredHeight()
                    - getPaddingBottom();
            child.layout(getPaddingLeft(), getPaddingTop(), childRight,
                    childBottom);
        }
    }

    @SuppressLint("NewApi")
    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        final int count = getChildCount();
        int maxHeight = 0;
        int maxWidth = 0;
        int measuredChildState = 0;
        for (int i = 0; i < count; i++) {
            final View child = getChildAt(i);
            if (child.getVisibility() != View.GONE) {
                measureChild(child, widthMeasureSpec, heightMeasureSpec);
                maxWidth = Math.max(maxWidth, child.getMeasuredWidth());
                maxHeight = Math.max(maxHeight, child.getMeasuredHeight());
                if (VERSION.SDK_INT >= 11) {
                    measuredChildState = View.combineMeasuredStates(
                            measuredChildState, child.getMeasuredState());
                } else {
                    measuredChildState = View.combineMeasuredStates(
                            measuredChildState, 0);
                }
            }
        }
        maxWidth += getPaddingLeft() + getPaddingRight();
        maxHeight += getPaddingTop() + getPaddingBottom();
        maxHeight = Math.max(maxHeight, getSuggestedMinimumHeight());
        maxWidth = Math.max(maxWidth, getSuggestedMinimumWidth());
        setMeasuredDimension(View.resolveSizeAndState(maxWidth,
                widthMeasureSpec, measuredChildState),
                View.resolveSizeAndState(maxHeight, heightMeasureSpec,
                        measuredChildState << View.MEASURED_HEIGHT_STATE_SHIFT));
    }

    @SuppressLint("NewApi")
    public void setActivity(FragmentActivity a) {
        mActivity = a;
        mInflater = LayoutInflater.from(a);
        mContainer = (LinearLayout) mInflater.inflate(
                R.layout.fragment_bread_crumbs, this, false);
        addView(mContainer);
        a.getSupportFragmentManager().addOnBackStackChangedListener(this);
        updateCrumbs();
        if (VERSION.SDK_INT >= 11) {
            setLayoutTransition(new LayoutTransition());
        }
    }

    public void setMaxVisible(int visibleCrumbs) {
        if (visibleCrumbs < 1) {
            throw new IllegalArgumentException(
                    "visibleCrumbs must be greater than zero");
        }
        mMaxVisible = visibleCrumbs;
    }

    public void setOnBreadCrumbClickListener(OnBreadCrumbClickListener listener) {
        mOnBreadCrumbClickListener = listener;
    }

    public void setParentTitle(CharSequence title, CharSequence shortTitle,
            OnClickListener listener) {
        mParentEntry = createBackStackEntry(title, shortTitle);
        mParentClickListener = listener;
        updateCrumbs();
    }

    public void setTitle(CharSequence title, CharSequence shortTitle) {
        mTopEntry = createBackStackEntry(title, shortTitle);
        updateCrumbs();
    }

    void updateCrumbs() {
        FragmentManager fm = mActivity.getSupportFragmentManager();
        int numEntries = fm.getBackStackEntryCount();
        int numPreEntries = getPreEntryCount();
        int numViews = mContainer.getChildCount();
        for (int i = 0; i < numEntries + numPreEntries; i++) {
            BackStackEntry bse = i < numPreEntries ? getPreEntry(i) : fm
                    .getBackStackEntryAt(i - numPreEntries);
            if (i < numViews) {
                View v = mContainer.getChildAt(i);
                Object tag = v.getTag();
                if (tag != bse) {
                    for (int j = i; j < numViews; j++) {
                        mContainer.removeViewAt(i);
                    }
                    numViews = i;
                }
            }
            if (i >= numViews) {
                final View item = mInflater.inflate(
                        R.layout.fragment_bread_crumb_item, this, false);
                final TextView text = (TextView) item.findViewById(R.id.title);
                text.setText(bse.getBreadCrumbTitle());
                text.setTag(bse);
                if (i == 0) {
                    item.findViewById(R.id.left_icon).setVisibility(View.GONE);
                }
                mContainer.addView(item);
                text.setOnClickListener(mOnClickListener);
            }
        }
        int viewI = numEntries + numPreEntries;
        numViews = mContainer.getChildCount();
        while (numViews > viewI) {
            mContainer.removeViewAt(numViews - 1);
            numViews--;
        }
        for (int i = 0; i < numViews; i++) {
            final View child = mContainer.getChildAt(i);
            child.findViewById(R.id.title).setEnabled(i < numViews - 1);
            if (mMaxVisible > 0) {
                child.setVisibility(i < numViews - mMaxVisible ? View.GONE
                        : View.VISIBLE);
                final View leftIcon = child.findViewById(R.id.left_icon);
                leftIcon.setVisibility(i > numViews - mMaxVisible && i != 0 ? View.VISIBLE
                        : View.GONE);
            }
        }
    }
}