Switcher.java

/* Modifications to allow more than one move in either direction and also
 * to allow the swipe motion to be used for switching tabs when used as TabContentView
 * 
 * Modifications Copyright (C) 2009 Justin Shapcott, nEx.Software
 *
 * 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.
 */

/* Original Copyright Information
 * 
 * Copyright (C) 2008 The Android Open Source Project
 *
 * 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 my.android.widget;

import android.content.Context;
import android.util.AttributeSet;
import android.view.GestureDetector;
import android.view.MotionEvent;
import android.view.View;
import android.view.animation.TranslateAnimation;
import android.widget.FrameLayout;

class Switcher extends FrameLayout
	{
	private static final int MAJOR_MOVE = 60;
	private static final int ANIM_DURATION = 1000;

	private GestureDetector mGestureDetector;
	private int mCurrentView;
	private View children[];

	private int mWidth;
	private TranslateAnimation inLeft;
	private TranslateAnimation outLeft;

	private TranslateAnimation inRight;
	private TranslateAnimation outRight;

	public Switcher(Context context, AttributeSet attrs)
		{
		super(context, attrs);
		mCurrentView = 0;
		mGestureDetector = new GestureDetector(context, new GestureDetector.SimpleOnGestureListener()
			{
				public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY)
					{
					int dx = (int) (e2.getX() - e1.getX());
					if(Math.abs(dx) > MAJOR_MOVE && Math.abs(velocityX) > Math.abs(velocityY))
						{
						if(velocityX > 0)
							{
							moveRight();
							}
						else
							{
							moveLeft();
							}
						return true;
						}
					else
						{
						return false;
						}
					}
			});
		}

	@Override
	public void onSizeChanged(int w, int h, int oldW, int oldH)
		{
		mWidth = w;
		inLeft = new TranslateAnimation(mWidth, 0, 0, 0);
		outLeft = new TranslateAnimation(0, -mWidth, 0, 0);
		inRight = new TranslateAnimation(-mWidth, 0, 0, 0);
		outRight = new TranslateAnimation(0, mWidth, 0, 0);

		inLeft.setDuration(ANIM_DURATION);
		outLeft.setDuration(ANIM_DURATION);
		inRight.setDuration(ANIM_DURATION);
		outRight.setDuration(ANIM_DURATION);

		}

	protected void onFinishInflate()
		{
		int count = getChildCount();
		children = new View[count];
		for(int i = 0; i < count; ++i)
			{
			children[i] = getChildAt(i);
			if(i != mCurrentView)
				{
				children[i].setVisibility(View.GONE);
				}
			}
		}

	@Override
	public boolean onTouchEvent(MotionEvent event)
		{
		mGestureDetector.onTouchEvent(event);
		return true;
		}

	@Override
	public boolean onInterceptTouchEvent(MotionEvent event)
		{
		return mGestureDetector.onTouchEvent(event);
		}

	void moveLeft()
		{
		try
			{
			if(this.getParent().getParent() instanceof my.android.widget.TabHost)
				{
				my.android.widget.TabHost MyTabHost = ((my.android.widget.TabHost) Switcher.this.getParent().getParent());
				if(mCurrentView < MyTabHost.getTabWidget().getTabCount() - 1)
					{
					MyTabHost.setCurrentTab(mCurrentView + 1);
					// mCurrentView++;
					}
				}
			else
				{
				if(mCurrentView < children.length - 1 /*
													 * && mPreviousMove != LEFT
													 */)
					{
					children[mCurrentView + 1].setVisibility(View.VISIBLE);
					children[mCurrentView + 1].startAnimation(inLeft);
					children[mCurrentView].startAnimation(outLeft);
					children[mCurrentView].setVisibility(View.GONE);

					mCurrentView++;
					}
				}
			}
		catch(Exception e)
			{
			}
		}

	void moveRight()
		{
		try
			{
			// Switch the tab on the Parent TabHost
			if(this.getParent().getParent() instanceof my.android.widget.TabHost)
				{
				my.android.widget.TabHost MyTabHost = ((my.android.widget.TabHost) Switcher.this.getParent().getParent());
				if(mCurrentView > 0)
					{
					MyTabHost.setCurrentTab(mCurrentView - 1);
					// mCurrentView--;
					}
				}
			else
				{
				if(mCurrentView > 0 /* && mPreviousMove != RIGHT */)
					{
					children[mCurrentView - 1].setVisibility(View.VISIBLE);
					children[mCurrentView - 1].startAnimation(inRight);
					children[mCurrentView].startAnimation(outRight);
					children[mCurrentView].setVisibility(View.GONE);

					mCurrentView--;
					}
				}
			}
		catch(Exception e)
			{
			}
		}

	public int getCurrentIndex()
		{
		return mCurrentView;
		}

	// Added so the TabHost tell us what the current tab is...
	public void setCurrentIndex(int index)
		{
		mCurrentView = index;
		}
	}