Most efficient way to show frame by frame animatio

问题:

I am trying to show frame by frame animation by changing images in a imageview. I tried animation drawable in xml and also changing the bitmap of the imageview inside a Handler. I also tried to store only three bitmaps inside a arraylist(to avoid out of memory) as a caching mechanism but really low improvement. I need to iterate 36 images for a full animation. The problem i am facing is that in all the methods I used I cannot complete the animation in the given timeframe of 50ms. The images range from 250 kb smallest to 540 kb maximum. The fps of animation is really low. As the ios version of the app is ready I am constrained to show animation consistent to the ios version. I am a noob in renderscript and opengl. Is there any way to show a smooth animation for large images in 50-60ms. Any hints or suggestions is highly appreciated. Heres a snapshot of the animation: Here's the link to my images for any one intrested.

回答1:

I wrote a simple activity that does the most basic thing:

Loads all bitmaps in a Thread, then posts a change to an ImageView every 40ms.

package mk.testanimation;

import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Bundle;
import android.os.Handler;
import android.util.Log;
import android.widget.ImageView;
import java.util.ArrayList;

public class MainActivity extends Activity {
    ImageView mImageView;

    private int mImageRes[] = new int[]{
        R.drawable.s0,
        R.drawable.s1,
        R.drawable.s2,
        R.drawable.s3,
        R.drawable.s4,
        R.drawable.s5,
        R.drawable.s6,
        R.drawable.s7,
        R.drawable.s8,
        R.drawable.s9,
        R.drawable.s10,
        R.drawable.s11,
        R.drawable.s12,
        R.drawable.s13,
        R.drawable.s14,
        R.drawable.s15,
        R.drawable.s16,
        R.drawable.s17,
        R.drawable.s18,
        R.drawable.s19,
        R.drawable.s20,
        R.drawable.s21,
        R.drawable.s22,
        R.drawable.s23,
        R.drawable.s24,
        R.drawable.s25,
        R.drawable.s26,
        R.drawable.s27,
        R.drawable.s28,
        R.drawable.s29,
        R.drawable.s30,
        R.drawable.s31,
        R.drawable.s32,
        R.drawable.s33,
        R.drawable.s34,
        R.drawable.s35,
    };

    private ArrayList<Bitmap> mBitmaps = new ArrayList<Bitmap>(mImageRes.length);

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        final Handler handler = new Handler();
        mImageView = new ImageView(this);
        setContentView(mImageView);
        Thread important = new Thread() {
            @Override
            public void run() {
                long timestamp = System.currentTimeMillis();
                for (int i = 0; i < mImageRes.length; i++) {
                    mBitmaps.add(BitmapFactory.decodeResource(getResources(), mImageRes[i]));
                }
                Log.d("ANIM-TAG", "Loading all bitmaps took " + (System.currentTimeMillis() - timestamp) + "ms");
                for (int i = 0; i < mBitmaps.size(); i++) {
                    final int idx = i;
                    handler.postDelayed(new Runnable() {
                        @Override
                        public void run() {
                            mImageView.setImageBitmap(mBitmaps.get(idx));
                        }
                    }, i * 40);
                }
            }
        };
        important.setPriority(Thread.MAX_PRIORITY);
        important.start();
    }
}

This looked pretty decent on my Nexus 7, but it did take a little over 4s to load all the bitmaps.

Can you load the bitmaps in advance?

Also, it won't save a ton, but your pngs have a bunch of padding around the transparent space. You can crop them and reduce the memory a bit. Otherwise compressing the images will also help (like limiting the number of colors used).

Ideally, in the above solution, you'd recycle the bitmaps immediately after they're no longer used.

Also, if that's too memory-heavy, you could do as you mentioned, and have a Bitmap buffer, but I'm pretty sure it'll need to be more than 3 images large.

Good luck.

EDIT: Attempt 2. First, I cropped all the images to 590x590. This shaved about 1mb off the images. Then I created a new class, which is a bit "busy" and doesn't have a fixed frame rate but renders the images as soon as they are ready:

package mk.testanimation;

import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Bundle;
import android.os.Handler;
import android.util.Log;
import android.widget.ImageView;

import java.util.ArrayList;

public class MainActivity extends Activity {
    ImageView mImageView;

    private int mImageRes[] = new int[]{R.drawable.s0, R.drawable.s1, R.drawable.s2, R.drawable.s3, R.drawable.s4, R.drawable.s5, R.drawable.s6, R.drawable.s7, R.drawable.s8, R.drawable.s9, R.drawable.s10, R.drawable.s11, R.drawable.s12, R.drawable.s13, R.drawable.s14, R.drawable.s15, R.drawable.s16, R.drawable.s17, R.drawable.s18, R.drawable.s19, R.drawable.s20, R.drawable.s21, R.drawable.s22, R.drawable.s23, R.drawable.s24, R.drawable.s25, R.drawable.s26, R.drawable.s27, R.drawable.s28, R.drawable.s29, R.drawable.s30, R.drawable.s31, R.drawable.s32, R.drawable.s33, R.drawable.s34, R.drawable.s35};

    private ArrayList<Bitmap> mBitmaps = new ArrayList<Bitmap>(mImageRes.length);

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        final long timestamp = System.currentTimeMillis();
        final Handler handler = new Handler();
        mImageView = new ImageView(this);
        setContentView(mImageView);
        Thread important = new Thread() {
            @Override
            public void run() {
                for (int i = 0; i < mImageRes.length; i++) {
                    mBitmaps.add(BitmapFactory.decodeResource(getResources(), mImageRes[i]));
                }
            }
        };
        important.setPriority(Thread.MAX_PRIORITY);
        important.start();
        Thread drawing = new Thread() {
            @Override
            public void run() {
                int i = 0;
                while (i < mImageRes.length) {
                    if (i >= mBitmaps.size()) {
                        Thread.yield();
                    } else {
                        final Bitmap bitmap = mBitmaps.get(i);
                        handler.post(new Runnable() {
                            @Override
                            public void run() {
                                mImageView.setImageBitmap(bitmap);
                            }
                        });
                        i++;
                    }
                }
                Log.d("ANIM-TAG", "Time to render all frames:" + (System.currentTimeMillis() - timestamp) + "ms");
            }
        };
        drawing.setPriority(Thread.MAX_PRIORITY);
        drawing.start();
    }
}

The above got the rendering to start nearly immediately, and it took less than 4s on my 2012 Nexus 7.

As a last effort, I converted all the images to 8-bit PNGs instead of 32-bit. This brought the rendering to under 2 seconds!

I'll bet any solution you end up with will benefit from making the images as small as possible.

Again -- Good Luck!

回答2:

I'm facing the same problem and I have solved it by overriding an AnimationDrawable. So, if the problem is you that can't load all images in array because it is too big for the memory to hold it, then load the image when you need it. My AnimationDrawable is this:

public abstract class MyAnimationDrawable extends AnimationDrawable {

    private Context context;
    private int current;
    private int reqWidth;
    private int reqHeight;
    private int totalTime;

    public MyAnimationDrawable(Context context, int reqWidth, int reqHeight) {
        this.context = context;
        this.current = 0;
        //In my case size of screen to scale Drawable
        this.reqWidth = reqWidth;
        this.reqHeight = reqHeight;
        this.totalTime = 0;
    }

    @Override
    public void addFrame(Drawable frame, int duration) {
        super.addFrame(frame, duration);
        totalTime += duration;
    }

    @Override
    public void start() {
        super.start();
        new Handler().postDelayed(new Runnable() {

            public void run() {
                onAnimationFinish();
            }
        }, totalTime);
    }

    public int getTotalTime() {
        return totalTime;
    }

    @Override
    public void draw(Canvas canvas) {
        try {
            //Loading image from assets, you could make it from resources 
            Bitmap bmp = BitmapFactory.decodeStream(context.getAssets().open("presentation/intro_000"+(current < 10 ? "0"+current : current)+".jpg"));
            //Scaling image to fitCenter
            Matrix m = new Matrix();
            m.setRectToRect(new RectF(0, 0, bmp.getWidth(), bmp.getHeight()), new RectF(0, 0, reqWidth, reqHeight), Matrix.ScaleToFit.CENTER);
            bmp = Bitmap.createBitmap(bmp, 0, 0, bmp.getWidth(), bmp.getHeight(), m, true);
            //Calculating the start 'x' and 'y' to paint the Bitmap 
            int x = (reqWidth - bmp.getWidth()) / 2;
            int y = (reqHeight - bmp.getHeight()) / 2;
            //Painting Bitmap in canvas
            canvas.drawBitmap(bmp, x, y, null);
            //Jump to next item
            current++;
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    abstract void onAnimationFinish();

}

Now to play animation you need to do what next

    //Get your ImageView
    View image = MainActivity.this.findViewById(R.id.presentation);

    //Create AnimationDrawable
    final AnimationDrawable animation = new MyAnimationDrawable(this, displayMetrics.widthPixels, displayMetrics.heightPixels) {

        @Override
        void onAnimationFinish() {
            //Do something when finish animation
        }

    };
    animation.setOneShot(true); //dont repeat animation
    //This is just to say that my AnimationDrawable has 72 frames with 50 milliseconds interval
    try {
        //Always load same bitmap, anyway you load the right one in draw() method in MyAnimationDrawable
        Bitmap bmp = BitmapFactory.decodeStream(MainActivity.this.getAssets().open("presentation/intro_00000.jpg"));
        for (int i = 0; i < 72; i++) {
            animation.addFrame(new BitmapDrawable(getResources(), bmp), 50);
        }
    } catch (IOException e) {
        e.printStackTrace();
    }

    //Set AnimationDrawable to ImageView
    if (Build.VERSION.SDK_INT < 16) {
        image.setBackgroundDrawable(animation);
    } else {
        image.setBackground(animation);
    }

    //Start animation
    image.post(new Runnable() {

        @Override
        public void run() {
            animation.start();
        }

    });

That is all, and works OK form me!!!

回答3:

Try using an AnimationDrawable for your ImageView. See my answer here for example.

回答4:

The most efficient way to show fram by frame animation in android is using OpenGL with NDK.

回答5:

Create an imageView using programming and then rotate it with an angle and then make another one and then rotate it.. do it for number of imageView you want to show. you only have to add only one image for it. you can rotate an image like this..

Matrix matrix=new Matrix();
imageView.setScaleType(ScaleType.MATRIX);   //required
matrix.postRotate((float) angle, pivX, pivY);
imageView.setImageMatrix(matrix);

回答6:

Maybe stupid answer but it may help you. Make the animation using another tool and save it as a high quality video and then just play the video.

回答7:

Try exporting your images to a GIF? Android does support decoding GIF files.

Have a look : Supported Media Formats.

回答8:

Loading the bitmaps from assets instead of resources saved 40% decoding time for me. You might want to try that.

So this went from 5 seconds with resources to 3 seconds on your pictures on my 2012 Nexus 7:

long time = System.currentTimeMillis();
try {
    for (int i = 0; i < 35; i++) {
        InputStream assetStream = getAssets().open(
                "_step" + (i + 1) + ".png");
        try {
            Bitmap bitmap = BitmapFactory.decodeStream(assetStream);
            if (bitmap == null) {
                throw new RuntimeException("Could not load bitmap");
            }
            mBitmaps.add(bitmap);
        } finally {
            assetStream.close();
        }
    }
} catch (Exception e) {
    throw new RuntimeException(e);
}
Log.d("ANIM", "Loading bitmaps elapsed "+(System.currentTimeMillis() - time)+"ms");