com.woodblockwithoutco.quickcontroldock.ui.view.pager.PagerSwitcher.java Source code

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Here is the source code for com.woodblockwithoutco.quickcontroldock.ui.view.pager.PagerSwitcher.java

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/*******************************************************************************
 * Copyright 2014 Alexander Leontyev
 *
 * 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.woodblockwithoutco.quickcontroldock.ui.view.pager;

import java.lang.reflect.Field;

import com.woodblockwithoutco.quickcontroldock.prefs.resolvers.ColorsResolver;
import com.woodblockwithoutco.quickcontroldock.R;

import android.content.Context;
import android.content.res.TypedArray;
import android.support.v4.view.ViewPager;
import android.support.v4.view.ViewPager.OnPageChangeListener;
import android.util.AttributeSet;
import android.util.Log;
import android.widget.ImageView;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.view.ViewParent;

public class PagerSwitcher extends ImageView implements OnClickListener, OnPageChangeListener {

    private static enum Direction {
        LEFT, RIGHT
    }

    private static final String TAG = "PagerSwitcher";

    private ViewPager mControlledPager;
    private Direction mDirection = Direction.LEFT;

    private int mActiveColor;
    private int mPressedColor;

    private int mPagerId;

    public PagerSwitcher(Context context) {
        this(context, null, 0);
    }

    public PagerSwitcher(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
    }

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

        mActiveColor = ColorsResolver.getActiveColor(getContext());
        mPressedColor = ColorsResolver.getPressedColor(getContext());

        setColorFilter(mActiveColor);

        if (attrs != null) {
            TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.PagerSwitcher, defStyle, 0);
            mPagerId = a.getResourceId(R.styleable.PagerSwitcher_controlledPager, 0);
            int direction = a.getInt(R.styleable.PagerSwitcher_direction, 0);
            switch (direction) {
            case 0:
                mDirection = Direction.LEFT;
                break;
            case 1:
                mDirection = Direction.RIGHT;
                break;
            }
            a.recycle();
        }

        switch (mDirection) {
        case LEFT:
            setImageResource(R.drawable.ic_left);
            break;
        case RIGHT:
            setImageResource(R.drawable.ic_right);
            break;
        }

        setClickable(true);
        setLongClickable(true);
        setOnClickListener(this);
    }

    @Override
    public void onAttachedToWindow() {
        super.onAttachedToWindow();

        if (mControlledPager == null && mPagerId != 0) {
            ViewParent parent = getParent();
            if (parent != null && parent instanceof ViewGroup) {
                ViewGroup parentView = (ViewGroup) parent;
                mControlledPager = (ViewPager) parentView.findViewById(mPagerId);
                if (mControlledPager != null) {
                    OnPageChangeListener l = getPageChangeListener(mControlledPager);
                    if (l == null) {
                        l = new MultiPageChangeListener();
                    }
                    ((MultiPageChangeListener) l).addOnPageChangeListener(this);
                    mControlledPager.setOnPageChangeListener(l);
                } else {
                    Log.e(TAG, "Can't find given ViewPager!");
                }
            } else {
                Log.e(TAG, "Can't find given ViewPager!");
            }
            checkIfNeedToHideOrShow(mControlledPager.getCurrentItem());
        }

    }

    private void checkIfNeedToHideOrShow(int page) {
        if (mControlledPager != null) {
            int max = mControlledPager.getAdapter().getCount();
            int visibility = View.VISIBLE;

            switch (mDirection) {
            case LEFT:
                if (page == 0) {
                    visibility = View.INVISIBLE;
                } else {
                    visibility = View.VISIBLE;
                }
                break;
            case RIGHT:
                if (page == max - 1) {
                    visibility = View.INVISIBLE;
                } else {
                    visibility = View.VISIBLE;
                }
                break;
            }

            setVisibility(visibility);
        }
    }

    @Override
    public void onClick(View v) {
        if (mControlledPager != null) {
            int position = mControlledPager.getCurrentItem();
            switch (mDirection) {
            case LEFT:
                if (position - 1 >= 0)
                    mControlledPager.setCurrentItem(position - 1, true);
                break;
            case RIGHT:
                int max = mControlledPager.getAdapter().getCount();
                if (position + 1 <= max - 1)
                    mControlledPager.setCurrentItem(position + 1, true);
                break;
            }
        }
    }

    @Override
    public boolean onTouchEvent(MotionEvent e) {
        switch (e.getAction()) {
        case MotionEvent.ACTION_DOWN:
            setColorFilter(mPressedColor);
            break;
        case MotionEvent.ACTION_UP:
            setColorFilter(mActiveColor);
            break;
        }
        return super.onTouchEvent(e);
    }

    @Override
    public void onPageScrollStateChanged(int state) {
    }

    @Override
    public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
    }

    @Override
    public void onPageSelected(int position) {
        checkIfNeedToHideOrShow(position);
    }

    private static OnPageChangeListener getPageChangeListener(ViewPager v) {
        try {
            Field f = ViewPager.class.getDeclaredField("mOnPageChangeListener");
            f.setAccessible(true);
            Object o;
            o = f.get(v);
            return (OnPageChangeListener) o;
        } catch (NoSuchFieldException e) {
            Log.e(TAG, "Can't find page change listener field!");
        } catch (IllegalAccessException e) {
            Log.e(TAG, "Can't access change listener field!");
        } catch (IllegalArgumentException e) {
            Log.e(TAG, "Can't find page change listener field in given object!");
        }
        return null;
    }

}