Android 如何减少两个可绘制动画的启动时间？

我已经为我的应用程序准备了可绘制动画的数量。所有都工作正常。当应用程序启动时，可绘制动画将启动，我有两个按钮（下一个和上一个）在同一活动中。当我单击“下一步”或“上一步”按钮时，动画将被更改。它工作正常。但当我单击“下一步”或“上一步”按钮时，更改动画需要时间。这是我的代码

mImgLetter.clearAnimation();
        Log.d("before clear","------");
        mImgLetter.setBackgroundResource(resID);
        Log.d("after clear","------");
        mImgLetter.post(new Runnable() {

            public void run() {

                loadingAnimation = (AnimationDrawable) mImgLetter
                        .getBackground();
                loadingAnimation.start();
            }
        });

当我点击按钮时，如何减少两个可绘制动画的开始时间。请帮助我

Logcat是

02-21 17:52:57.278: D/before clear(813): ------
02-21 17:52:57.337: D/dalvikvm(813): GC freed 285 objects / 12160 bytes in 47ms
02-21 17:52:57.568: D/dalvikvm(813): GC freed 255 objects / 13568 bytes in 50ms
02-21 17:52:57.798: D/dalvikvm(813): GC freed 24 objects / 1016 bytes in 49ms
02-21 17:52:58.018: D/dalvikvm(813): GC freed 24 objects / 1016 bytes in 48ms
02-21 17:52:58.808: D/dalvikvm(813): GC freed 24 objects / 1024 bytes in 52ms
02-21 17:52:59.447: D/dalvikvm(813): GC freed 24 objects / 1016 bytes in 327ms
02-21 17:53:00.127: D/dalvikvm(813): GC freed 26 objects / 1160 bytes in 51ms
02-21 17:53:00.358: D/dalvikvm(813): GC freed 24 objects / 1032 bytes in 49ms
02-21 17:53:01.138: D/dalvikvm(813): GC freed 26 objects / 1552 bytes in 48ms
02-21 17:53:01.678: D/after clear(813): ------

GC将花费大量时间。请告诉我如何减少GC时间