![enter image description here](https://istack.dev59.com/yquFk.webp)
我写了一个简单的活动,只做最基本的事情:
在一个线程中加载所有位图,然后每40毫秒将更改发布到ImageView。
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();
}
}
在我的Nexus 7上看起来还不错,但加载所有位图需要超过4秒的时间。
你能提前加载位图吗?
另外,虽然不能节省很多空间,但是你的png图片周围有很多填充透明空间。你可以裁剪它们并减少一些内存。否则压缩图像也会有帮助(例如限制使用的颜色数量)。
理想情况下,在上述解决方案中,当位图不再使用时,应立即回收它们。
此外,如果内存占用过高,您可以像您所提到的那样使用位图缓冲区,但我相信它需要比3个图像更大。
祝你好运。
编辑:尝试2。 首先,我将所有图像裁剪为590x590。这减少了约1mb的图像大小。然后我创建了一个新类,该类有点“忙碌”,没有固定的帧速率,但在图像准备就绪后立即呈现它们:
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();
}
}
上述方法使得渲染几乎立即开始,在我2012年的Nexus 7上只花费不到4秒钟。
最后,我将所有图片转换为8位PNG格式而非32位。这将渲染时间缩短至不到2秒钟!
我敢打赌,你最终使用的任何解决方案都会受益于尽可能地减小图片大小。
再次祝好运!
我遇到了同样的问题,通过重写AnimationDrawable来解决了它。所以,如果问题是由于数组中的图片太大而导致内存不足无法加载所有图片,那么可以在需要时再加载图片。 我的AnimationDrawable代码如下:
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();
}
//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();
}
});
尝试为您的ImageView
使用AnimationDrawable
。 例如,请参见此处中的答案。
Matrix matrix=new Matrix();
imageView.setScaleType(ScaleType.MATRIX); //required
matrix.postRotate((float) angle, pivX, pivY);
imageView.setImageMatrix(matrix);
从 assets 中加载位图而不是资源,为我节省了 40% 的解码时间。你可能想试试。
因此,在我的2012年版Nexus 7上,这个过程的时间从使用资源的5秒变成了3秒:
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");