package com.loaderman.customviewdemo;

import android.content.Context;

import android.graphics.*;

import android.util.AttributeSet;

import android.view.SurfaceHolder;

import android.view.SurfaceView;

public class AnimationSurfaceView extends SurfaceView {

    private SurfaceHolder surfaceHolder;

    private boolean flag = false;// 线程标识

    private Bitmap bitmap_bg;// 背景图

    private float mSurfaceWindth, mSurfaceHeight;// 屏幕宽高

    private int mBitposX;//开始绘制的图片的X坐标

    private Canvas mCanvas;

    private Thread thread;

    // 背景移动状态

    private enum State {

        LEFT, RINGHT

    }

    // 默认为向左

    private State state = State.LEFT;

    private final int BITMAP_STEP = 10;// 背景画布移动步伐.

    public AnimationSurfaceView(Context context, AttributeSet attrs) {

        super(context, attrs);

        surfaceHolder = getHolder();

        surfaceHolder.addCallback(new SurfaceHolder.Callback() {

            @Override

            public void surfaceCreated(SurfaceHolder holder) {

                flag = true;

                startAnimation();

            }

            @Override

            public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {

            }

            @Override

            public void surfaceDestroyed(SurfaceHolder holder) {

                flag = false;

            }

        });

    }

    private void startAnimation() {

        mSurfaceWindth = getWidth();

        mSurfaceHeight = getHeight();

        int mWindth = (int) (mSurfaceWindth * 3 / 2);

        /***

         * 将图片缩放到屏幕的3/2倍.

         */

        Bitmap bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.scenery);

        bitmap_bg = Bitmap.createScaledBitmap(bitmap, mWindth, (int) mSurfaceHeight, true);

        //开始绘图

        thread = new Thread(new Runnable() {

            @Override

            public void run() {

                while (flag) {

                    mCanvas = surfaceHolder.lockCanvas();

                    DrawView();

                    surfaceHolder.unlockCanvasAndPost(mCanvas);

                    try {

                        Thread.sleep(50);

                    } catch (InterruptedException e) {

                        e.printStackTrace();

                    }

                }

            }

        });

        thread.start();

    }

    /***

     * 进行绘制.

     */

    protected void DrawView() {

        //绘制背景

        mCanvas.drawColor(Color.TRANSPARENT, PorterDuff.Mode.CLEAR);// 清屏幕.

        mCanvas.drawBitmap(bitmap_bg, mBitposX, 0, null);// 绘制当前屏幕背景

        /** 图片滚动效果 **/

        switch (state) {

            case LEFT:

                mBitposX -= BITMAP_STEP;// 画布左移

                break;

            case RINGHT:

                mBitposX += BITMAP_STEP;// 画布右移

                break;

            default:

                break;

        }

        if (mBitposX <= -mSurfaceWindth / 2) {

            state = State.RINGHT;

        }

        if (mBitposX >= 0) {

            state = State.LEFT;

        }

    }

}