FlowIndicator 自定义左右图片切换

<?xml version="1.0" encoding="utf-8"?>
<resources>
    
    <declare-styleable name="FlowIndicator">
        <attr name="count" format="integer" />
        <attr name="space" format="dimension" />
        <attr name="point_size" format="dimension" />
        <attr name="point_seleted_color" format="color|reference" />
        <attr name="point_normal_color" format="color|reference" />
        <attr name="point_radius" format="dimension" />
    </declare-styleable>
</resources>

public class FlowIndicator extends View {
	
	private int count;
	private float space, radius;
	private int point_normal_color, point_seleted_color;
	
	// 选中
	private int seleted = 0;

	public FlowIndicator(Context context, AttributeSet attrs) {
		super(context, attrs);
		// TODO Auto-generated constructor stub
		
		//提供TypedArray（用于Drawable对象数组）的XML资源。
		TypedArray typedArray = context.obtainStyledAttributes(attrs,R.styleable.FlowIndicator);
		
		count = typedArray.getInteger(R.styleable.FlowIndicator_count,4);
		space = typedArray.getDimension(R.styleable.FlowIndicator_space, 9);
		radius = typedArray.getDimension(R.styleable.FlowIndicator_point_radius, 9);
		
		point_normal_color = typedArray.getColor(R.styleable.FlowIndicator_point_normal_color, 0x000000);
		point_seleted_color = typedArray.getColor(R.styleable.FlowIndicator_point_seleted_color, 0xffff07);
		
		int sum = attrs.getAttributeCount();
		if(Constans.DEBUG){
			String str = "";
			for(int i=0;i<sum;i++){
				String name = attrs.getAttributeName(i);
				String value = attrs.getAttributeValue(i);
				str += "sttr_name:" + name +": " + value +"\n";
			}
			Log.i("attribute", str);
		}
		typedArray.recycle();
	}
	
	public void setSeletion(int index){
		this.seleted = index;
		//重绘
		invalidate();
	}
	
	public void setCount(int count){
		this.count = count;
		invalidate();
	}
	
	public void next(){
		if(seleted < count-1){
			seleted++;
		}else{
			seleted = 0;
		}
		invalidate();
	}
	
	public void previous(){
		if(seleted > 0 ){
			seleted--;
		}else{
			seleted = count-1;
		}
		invalidate();
	}

	@Override
	protected void onDraw(Canvas canvas) {
		// TODO Auto-generated method stub
		super.onDraw(canvas);
		
		Paint paint = new Paint();
		paint.setAntiAlias(true);
		
		float width = (getWidth() - ((radius * 2 * count) + (space * (count - 1))))/2.f;
		for (int i = 0; i < count; i++) {
			if (i == seleted)
				paint.setColor(point_seleted_color);
			else
				paint.setColor(point_normal_color);
			canvas.drawCircle(width + getPaddingLeft() + radius + i
					* (space + radius + radius), getHeight() / 2, radius, paint);

		}
	}
	
	@Override
	protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
		setMeasuredDimension(measureWidth(widthMeasureSpec),
				measureHeight(heightMeasureSpec));
	}

	private int measureWidth(int measureSpec) {
		int result = 0;
		int specMode = MeasureSpec.getMode(measureSpec);
		int specSize = MeasureSpec.getSize(measureSpec);

		if (specMode == MeasureSpec.EXACTLY) {
			result = specSize;
		} else {
			result = (int) (getPaddingLeft() + getPaddingRight()
					+ (count * 2 * radius) + (count - 1) * radius + 1);
			if (specMode == MeasureSpec.AT_MOST) {
				result = Math.min(result, specSize);
			}
		}
		return result;
	}

	private int measureHeight(int measureSpec) {
		int result = 0;
		int specMode = MeasureSpec.getMode(measureSpec);
		int specSize = MeasureSpec.getSize(measureSpec);

		if (specMode == MeasureSpec.EXACTLY) {
			result = specSize;
		} else {
			result = (int) (2 * radius + getPaddingTop() + getPaddingBottom() + 1);
			if (specMode == MeasureSpec.AT_MOST) {
				result = Math.min(result, specSize);
			}
		}
		return result;
	}


}

public class MainActivity extends Activity {
	
	private static final int SCROLL_ACTION = 0;
	
	private TextView textView;
	private Gallery mGallery;
	private FlowIndicator myView;
	Timer mTimer;
	private GalleryAdapter galleryAdapter;
	
	private String[] titles = {"标题1","标题2","标题3","标题4","标题5","标题6","标题7","标题8","标题9"};

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.header_view);
		viewInit();
		
		//定时滚动
		mTimer = new Timer();
		mTimer.scheduleAtFixedRate(new MyTask(), 0, 5000);
	}
	
	private void viewInit(){
		textView = (TextView) findViewById(R.id.tv_gal_title);
		mGallery = (Gallery) findViewById(R.id.home_gallery);
		myView = (FlowIndicator) findViewById(R.id.myview);
		galleryAdapter = new GalleryAdapter(this);
		
		myView.setCount(galleryAdapter.getCount());
		mGallery.setAdapter(galleryAdapter);
		
		mGallery.setOnItemSelectedListener(new OnItemSelectedListener() {

			@Override
			public void onItemSelected(AdapterView<?> arg0, View arg1,
					int arg2, long arg3) {
				// TODO Auto-generated method stub
				textView.setText(titles[arg2]);
				myView.setSeletion(arg2);
			}

			@Override
			public void onNothingSelected(AdapterView<?> arg0) {
				// TODO Auto-generated method stub
				
			}
		});
	}
	
	private class GalleryAdapter extends BaseAdapter{
		
		Context mContext;
		int[] res = new int[] { R.drawable.t1, R.drawable.t2,
				R.drawable.t3, R.drawable.t1, R.drawable.t2,
				R.drawable.t3, R.drawable.t1, R.drawable.t2,
				R.drawable.t3 };

		public GalleryAdapter(Context cnt) {
			this.mContext = cnt;
		}
		
		@Override
		public int getCount() {
			// TODO Auto-generated method stub
			return res.length;
		}

		@Override
		public Object getItem(int arg0) {
			// TODO Auto-generated method stub
			return res[arg0];
		}

		@Override
		public long getItemId(int arg0) {
			// TODO Auto-generated method stub
			return arg0;
		}

		@Override
		public View getView(int position, View convertView, ViewGroup parent) {
			// TODO Auto-generated method stub
			if(convertView == null){
				convertView = LayoutInflater.from(mContext).inflate(R.layout.gallery_item, null);
			}
			
			ImageView imageView = (ImageView) convertView.findViewById(R.id.home_img);
			imageView.setImageResource(res[position]);
			return convertView;
		}
		
	}
	
	private class MyTask extends TimerTask {
		@Override
		public void run() {
			mHandler.sendEmptyMessage(SCROLL_ACTION);
		}
	}
	
	Handler mHandler = new Handler() {
		@Override
		public void handleMessage(Message msg) {
			// TODO Auto-generated method stub
			super.handleMessage(msg);
			switch (msg.what) {
			case SCROLL_ACTION:
				MotionEvent e1 = MotionEvent.obtain(SystemClock.uptimeMillis(),
						SystemClock.uptimeMillis(), MotionEvent.ACTION_DOWN,
						89.333336f, 265.33334f, 0);
				MotionEvent e2 = MotionEvent.obtain(SystemClock.uptimeMillis(),
						SystemClock.uptimeMillis(), MotionEvent.ACTION_UP,
						300.0f, 238.00003f, 0);

				mGallery.onFling(e1, e2, -1300, 0);
				break;

			default:
				break;
			}
		}
	};

}

public class Constans {
	public static boolean DEBUG = true;

}