Question

我在Android应用程序中有一个工作的逐帧动画。这很好 - 但是我如何为这个应用程序添加滚动背景，以便动画在后台运行？我可以找到大量的例子来分别实现这两个过程 - 但不能在一起。任何帮助，将不胜感激！这是动画活动的代码..

import java.util.ArrayList;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.Drawable;
import android.util.AttributeSet;
import android.util.Log;
import android.view.SurfaceView;
import android.widget.ImageView;

/**
 * 
 *
 */
public class MyAnimationView extends ImageView
{
    private static final String TAG = "AnimationTest:AnimationView";
    private Context mContext = null;

    private static final int DELAY = 100; //delay between frames in milliseconds

    private boolean mIsPlaying = false;
    private boolean mStartPlaying = false;

    private ArrayList<Bitmap> mBitmapList = new ArrayList<Bitmap>();

    private int play_frame = 0;
    private long last_tick = 0;

    public MyAnimationView(Context context, AttributeSet attrs)
    {
        super(context, attrs);
        mContext = context;
    }

    @Override
    protected void onDraw(Canvas c)
    {
        Log.d(TAG, "onDraw called");
        if (mStartPlaying)
        {
            Log.d(TAG, "starting animation...");
            play_frame = 0;
            mStartPlaying = false;
            mIsPlaying = true;
            postInvalidate();
        }
        else if (mIsPlaying)
        {

            if (play_frame >= mBitmapList.size())
            {
                mIsPlaying = false;
            }
            else
            {
                long time = (System.currentTimeMillis() - last_tick);
                int draw_x = 0;
                int draw_y = 0;
                if (time >= DELAY) //the delay time has passed. set next frame
                {
                    last_tick = System.currentTimeMillis();
                    c.drawBitmap(mBitmapList.get(play_frame), draw_x, draw_y, null);
                    play_frame++;
                    postInvalidate();
                }
                else //still within delay.  redraw current frame
                {
                    c.drawBitmap(mBitmapList.get(play_frame), draw_x, draw_y, null);
                    postInvalidate();
                }
            }
        }
    }

    /*ideally this should be in a background thread*/
    public void loadAnimation(String prefix, int nframes)
    {
        mBitmapList.clear();
        for (int x = 0; x < nframes; x++)
        {
            String name = prefix + "_" + x;
            Log.d(TAG, "loading animation frame: " + name);
            int res_id = mContext.getResources().getIdentifier(name, "drawable", mContext.getPackageName());
            BitmapDrawable d = (BitmapDrawable) mContext.getResources().getDrawable(res_id);
            mBitmapList.add(d.getBitmap());
        }
    }

    public void playAnimation()
    {
        mStartPlaying = true;
        postInvalidate();
    }
}

Answer 1

＆＃34; draw_x＆＃34;和＆＃34; draw_y＆＃34;是您的位图位置的变量。如果更改这两个变量（或只是其中一个变量），则可以在屏幕上移动（滚动）图片。

如何为逐帧动画添加滚动背景？

1 个答案: