Android使用ImageView淡入淡出

时间:2012-01-04 00:29:12

标签: android animation imageview fadein fadeout

我在制作幻灯片时遇到了一些麻烦。

我在xml中创建了2个用于淡入和淡出的动画:

fadein.xml

    <?xml version="1.0" encoding="UTF-8"?>
       <set xmlns:android="http://schemas.android.com/apk/res/android">
         <alpha android:fromAlpha="0.0" android:toAlpha="1.0" 
          android:interpolator="@android:anim/accelerate_interpolator" 
          android:duration="2000"/>
     </set>

fadeout.xml

    <?xml version="1.0" encoding="UTF-8"?>
       <set xmlns:android="http://schemas.android.com/apk/res/android">
         <alpha android:fromAlpha="1.0" android:toAlpha="0.0" 
          android:interpolator="@android:anim/accelerate_interpolator" 
          android:duration="2000"/>
     </set>

我正在做的是使用淡入淡出效果从ImageView更改图像,因此当前显示的图像将淡出,另一个将淡入。 考虑到我已经设置了一个图像,我可以毫无问题地逐渐淡出这个图像:

    Animation fadeInAnimation = AnimationUtils.loadAnimation(this, R.anim.your_fade_in_anim);
    imageView.startAnimation(fadeoutAnim);

但是,我设置了下一个要显示的图像:

    imageView.setImageBitmap(secondImage);

它只是出现在imageView中,当我设置动画时它会隐藏图像,淡入它...有没有办法解决这个问题,我的意思是,当我做 imageView.setImageBitmap( secondImage); 命令,图像不会立即显示,只有在执行淡入动画时才会显示?

10 个答案:

答案 0 :(得分:95)

我想实现与你相同的目标,所以我编写了以下方法,如果你传递一个ImageView和一个对图像drawables的引用列表,我就会这样做。

ImageView demoImage = (ImageView) findViewById(R.id.DemoImage);
int imagesToShow[] = { R.drawable.image1, R.drawable.image2,R.drawable.image3 };

animate(demoImage, imagesToShow, 0,false);  



  private void animate(final ImageView imageView, final int images[], final int imageIndex, final boolean forever) {

  //imageView <-- The View which displays the images
  //images[] <-- Holds R references to the images to display
  //imageIndex <-- index of the first image to show in images[] 
  //forever <-- If equals true then after the last image it starts all over again with the first image resulting in an infinite loop. You have been warned.

    int fadeInDuration = 500; // Configure time values here
    int timeBetween = 3000;
    int fadeOutDuration = 1000;

    imageView.setVisibility(View.INVISIBLE);    //Visible or invisible by default - this will apply when the animation ends
    imageView.setImageResource(images[imageIndex]);

    Animation fadeIn = new AlphaAnimation(0, 1);
    fadeIn.setInterpolator(new DecelerateInterpolator()); // add this
    fadeIn.setDuration(fadeInDuration);

    Animation fadeOut = new AlphaAnimation(1, 0);
    fadeOut.setInterpolator(new AccelerateInterpolator()); // and this
    fadeOut.setStartOffset(fadeInDuration + timeBetween);
    fadeOut.setDuration(fadeOutDuration);

    AnimationSet animation = new AnimationSet(false); // change to false
    animation.addAnimation(fadeIn);
    animation.addAnimation(fadeOut);
    animation.setRepeatCount(1);
    imageView.setAnimation(animation);

    animation.setAnimationListener(new AnimationListener() {
        public void onAnimationEnd(Animation animation) {
            if (images.length - 1 > imageIndex) {
                animate(imageView, images, imageIndex + 1,forever); //Calls itself until it gets to the end of the array
            }
            else {
                if (forever){
                animate(imageView, images, 0,forever);  //Calls itself to start the animation all over again in a loop if forever = true
                }
            }
        }
        public void onAnimationRepeat(Animation animation) {
            // TODO Auto-generated method stub
        }
        public void onAnimationStart(Animation animation) {
            // TODO Auto-generated method stub
        }
    });
}

答案 1 :(得分:64)

要以您开始的方式实现此功能,您需要添加AnimationListener,以便检测动画的开头和结尾。当调用用于淡出的onAnimationEnd()时,可以将ImageView对象的可见性设置为View.INVISIBLE,切换图像并开始淡入淡出动画 - 这里也需要另一个AnimationListener。当您收到onAnimationEnd()用于淡入淡出动画时,将ImageView设置为View.VISIBLE,这样可以为您提供所需的效果。

之前我已经实现了类似的效果,但是我使用了ViewSwitcher和2个ImageView而不是单个ImageView。您可以使用淡入和淡出为ViewSwitcher设置“in”和“out”动画,以便它可以管理AnimationListener实现。然后你需要做的就是在2个ImageViews之间交替。

修改 为了更有用,这里有一个如何使用ViewSwitcher的快速示例。我已将完整的来源包含在https://github.com/aldryd/imageswitcher

<强> activity_main.xml中

    <ViewSwitcher
        android:id="@+id/switcher"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true"
        android:inAnimation="@anim/fade_in"
        android:outAnimation="@anim/fade_out" >

        <ImageView
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:scaleType="fitCenter"
            android:src="@drawable/sunset" />

        <ImageView
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:scaleType="fitCenter"
            android:src="@drawable/clouds" />
    </ViewSwitcher>

<强> MainActivity.java

    // Let the ViewSwitcher do the animation listening for you
    ((ViewSwitcher) findViewById(R.id.switcher)).setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View v) {
            ViewSwitcher switcher = (ViewSwitcher) v;

            if (switcher.getDisplayedChild() == 0) {
                switcher.showNext();
            } else {
                switcher.showPrevious();
            }
        }
    });

答案 2 :(得分:42)

您是否考虑过使用TransitionDrawable而不是自定义动画? https://developer.android.com/reference/android/graphics/drawable/TransitionDrawable.html

实现目标的一种方法是:

// create the transition layers
Drawable[] layers = new Drawable[2];
layers[0] = new BitmapDrawable(getResources(), firstBitmap);
layers[1] = new BitmapDrawable(getResources(), secondBitmap);

TransitionDrawable transitionDrawable = new TransitionDrawable(layers);
imageView.setImageDrawable(transitionDrawable);
transitionDrawable.startTransition(FADE_DURATION);

答案 3 :(得分:4)

我使用旧的fadeIn动画替换旧图像的新图像

ObjectAnimator.ofFloat(imageView, View.ALPHA, 0.2f, 1.0f).setDuration(1000).start();

答案 4 :(得分:3)

基于Aladin Q的解决方案,这是我写的一个辅助函数,它会在运动中淡出/淡出动画时改变图像视图中的图像:

public static void ImageViewAnimatedChange(Context c, final ImageView v, final Bitmap new_image) {
        final Animation anim_out = AnimationUtils.loadAnimation(c, android.R.anim.fade_out); 
        final Animation anim_in  = AnimationUtils.loadAnimation(c, android.R.anim.fade_in); 
        anim_out.setAnimationListener(new AnimationListener()
        {
            @Override public void onAnimationStart(Animation animation) {}
            @Override public void onAnimationRepeat(Animation animation) {}
            @Override public void onAnimationEnd(Animation animation)
            {
                v.setImageBitmap(new_image); 
                anim_in.setAnimationListener(new AnimationListener() {
                    @Override public void onAnimationStart(Animation animation) {}
                    @Override public void onAnimationRepeat(Animation animation) {}
                    @Override public void onAnimationEnd(Animation animation) {}
                });
                v.startAnimation(anim_in);
            }
        });
        v.startAnimation(anim_out);
    }

答案 5 :(得分:1)

我正在使用这种例程以编程方式链接动画。

    final Animation anim_out = AnimationUtils.loadAnimation(context, android.R.anim.fade_out); 
    final Animation anim_in  = AnimationUtils.loadAnimation(context, android.R.anim.fade_in); 

    anim_out.setAnimationListener(new AnimationListener()
    {
        @Override
        public void onAnimationStart(Animation animation) {}

        @Override
        public void onAnimationRepeat(Animation animation) {}

        @Override
        public void onAnimationEnd(Animation animation)
        {
            ////////////////////////////////////////
            // HERE YOU CHANGE YOUR IMAGE CONTENT //
            ////////////////////////////////////////
            //ui_image.setImage...

            anim_in.setAnimationListener(new AnimationListener()
            {
                @Override
                public void onAnimationStart(Animation animation) {}

                @Override
                public void onAnimationRepeat(Animation animation) {}

                @Override
                public void onAnimationEnd(Animation animation) {}
            });

            ui_image.startAnimation(anim_in);
        }
    });

    ui_image.startAnimation(anim_out);

答案 6 :(得分:1)

最好也是最简单的方法,对我来说就是这个......

- &gt;只需使用包含sleep()的Handler创建一个线程。

private ImageView myImageView;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_shape_count); myImageView= (ImageView)findViewById(R.id.shape1);
    Animation myFadeInAnimation = AnimationUtils.loadAnimation(this, R.anim.fadein);
    myImageView.startAnimation(myFadeInAnimation);

    new Thread(new Runnable() {
        private Handler handler = new Handler(){
            @Override
            public void handleMessage(Message msg) {
                Log.w("hendler", "recived");
                    Animation myFadeOutAnimation = AnimationUtils.loadAnimation(getBaseContext(), R.anim.fadeout);
                    myImageView.startAnimation(myFadeOutAnimation);
                    myImageView.setVisibility(View.INVISIBLE);
            }
        };

        @Override
        public void run() {
            try{
                Thread.sleep(2000); // your fadein duration
            }catch (Exception e){
            }
            handler.sendEmptyMessage(1);

        }
    }).start();
}

答案 7 :(得分:1)

你可以通过两个简单的点来改变你的代码

1.在项目动画文件夹的xml中,设置淡入和淡出持续时间不等于

2.在淡出动画开始之前的java类中,设置第二个imageView可见性Gone然后淡出动画后开始设置第二个想要淡入可见的imageView可见性

fadeout.xml

<alpha
    android:duration="4000"
    android:fromAlpha="1.0"
    android:interpolator="@android:anim/accelerate_interpolator"
    android:toAlpha="0.0" />

fadein.xml

<alpha
    android:duration="6000"
    android:fromAlpha="0.0"
    android:interpolator="@android:anim/accelerate_interpolator"
    android:toAlpha="1.0" />

在你的java类

Animation animFadeOut = AnimationUtils.loadAnimation(this, R.anim.fade_out);
    ImageView iv = (ImageView) findViewById(R.id.imageView1);
    ImageView iv2 = (ImageView) findViewById(R.id.imageView2);
    iv.setVisibility(View.VISIBLE);
    iv2.setVisibility(View.GONE);
    animFadeOut.reset();
    iv.clearAnimation();
    iv.startAnimation(animFadeOut);

    Animation animFadeIn = AnimationUtils.loadAnimation(this, R.anim.fade_in);
    iv2.setVisibility(View.VISIBLE);
    animFadeIn.reset();
    iv2.clearAnimation();
    iv2.startAnimation(animFadeIn);

答案 8 :(得分:1)

这可能是您获得的最佳解决方案。简单易行。我在udemy上学到了它。 假设您有两个图像分别具有图像ID的id1和id2,并且当前图像视图设置为id1,并且您希望每次有人点击时将其更改为另一个图像。所以这是MainActivity.java文件中的基本代码< / p>

int clickNum=0;
public void click(View view){
clickNum++;
ImageView a=(ImageView)findViewById(R.id.id1);
ImageView b=(ImageView)findViewById(R.id.id2);
if(clickNum%2==1){
  a.animate().alpha(0f).setDuration(2000); //alpha controls the transpiracy
}
else if(clickNum%2==0){
  b.animate().alpha(0f).setDuration(2000); //alpha controls the transpiracy
}

}

我希望这肯定会有所帮助

答案 9 :(得分:1)

用于无限淡入和淡出

AlphaAnimation fadeIn=new AlphaAnimation(0,1);

AlphaAnimation fadeOut=new AlphaAnimation(1,0);


final AnimationSet set = new AnimationSet(false);

set.addAnimation(fadeIn);
set.addAnimation(fadeOut);
fadeOut.setStartOffset(2000);
set.setDuration(2000);
imageView.startAnimation(set);

set.setAnimationListener(new Animation.AnimationListener() {
    @Override
    public void onAnimationStart(Animation animation) { }
    @Override
    public void onAnimationRepeat(Animation animation) { }
    @Override
    public void onAnimationEnd(Animation animation) {
        imageView.startAnimation(set);
    }
});