ImageView实现自动放大缩小动画 Android自定义ImageView实现自动放大缩小动画
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这篇讲的是如何生成一个自定义的ImageView,实现自动放大缩小动画。
为什么实现这个功能呢?因为我想在ViewPager实现图片放大缩小的动画,但是ViewPager几个页面的动画会一起动,而且放大全屏图片的话会相互覆盖,很诡异。于是上网搜demo,一无所获。迫于无奈。。。
废话不多说,直接贴代码。
1.配置文件直接添加
当直接在布局文件中添加图片的话,可以在自定义View代码中用getDrawable()获取图片资源,然后通过DrawBitmap绘制图片。通过不断绘制图片的位置,达到放大缩小的功能。
第一种情况实在XML布局文件中直接添加的:
public class CoolImageView extends ImageView { private int mLeft = 0; private int mTop = 0; private Handler mHandler; private Bitmap bitmap; private Rect srcRect = new Rect(); private Rect dstRect = new Rect(); private int imgWidth; private int imgHeight; private boolean flag; private boolean istart; public CoolImageView(Context context) { super(context); } public CoolImageView(Context context, AttributeSet attrs) { super(context, attrs); setUp(context, attrs); } public CoolImageView(Context context, AttributeSet attrs, int defStyleAttr) { super(context, attrs, defStyleAttr); setUp(context, attrs); } private void setUp(Context context, AttributeSet attrs) { mHandler = new MoveHandler(); mHandler.sendEmptyMessageDelayed(1, 220L); istart = true; } @Override protected void onDraw(Canvas canvas) { super.onDraw(canvas); int width = getWidth(); int height = getHeight(); //获取图片资源 BitmapDrawable drawable = (BitmapDrawable) getDrawable(); bitmap = drawable.getBitmap(); dstRect.left = 0; dstRect.top = 0; dstRect.right = width; dstRect.bottom = height; if (bitmap != null) { if (istart) { // 获取图片的宽高 imgWidth = bitmap.getWidth(); imgHeight = bitmap.getHeight(); srcRect.left = 0 + mLeft; srcRect.right = imgWidth - mLeft; srcRect.top = 0 + mTop; srcRect.bottom = imgHeight - mTop; canvas.drawBitmap(bitmap, srcRect, dstRect, null); } else { canvas.drawBitmap(bitmap, null, dstRect, null); } } } private class MoveHandler extends Handler { @Override public void handleMessage(Message msg) { switch (msg.what) { case 1: if (imgHeight != 0) { if (mTop == 0) { mTop += 5; mLeft += 5; } else if (mTop == 120) { mTop -= 5; mLeft -= 5; } } postInvalidate(); mHandler.sendEmptyMessageDelayed(1, 250); break; } } } public void start() { mTop = 0; mLeft = 0; istart = true; mHandler.sendEmptyMessageDelayed(1, 220L); } public void stop() { istart = false; } }
2 .通过Glide加载图片的方式
通过Glide加载图片的话,不能直接用getDrawable获取图片资源。Glide加载图片的方式也需要改变。废话不多说,直接上代码。
CoolimageView直接从Glide的缓存中加载图片。
Glide.with(GoodsPagerActivity.this) .load(sList.get(position).img) .override(width, height) .centerCrop() .into(new SimpleTarget<GlideDrawable>() { @Override public void onResourceReady(GlideDrawable resource, GlideAnimation<? super GlideDrawable> glideAnimation) { imageView.setImageDrawable(resource); } });
CoolImageView.java:
唯一不同的是获取图片的方式;
```java
public class CoolImageView extends ImageView { private int mLeft = 0; private int mTop = 0; private Handler mHandler; private Bitmap bitmap; private Rect srcRect = new Rect(); private Rect dstRect = new Rect(); private int imgWidth; private int imgHeight; private boolean flag; private boolean istart; private int width; private int height; public CoolImageView(Context context) { super(context); } public CoolImageView(Context context, AttributeSet attrs) { super(context, attrs); setUp(context, attrs); } public CoolImageView(Context context, AttributeSet attrs, int defStyleAttr) { super(context, attrs, defStyleAttr); setUp(context, attrs); } private void setUp(Context context, AttributeSet attrs) { mHandler = new MoveHandler(); mHandler.sendEmptyMessageDelayed(1, 220L); istart = true; } @Override public void setImageDrawable(@Nullable Drawable drawable) { super.setImageDrawable(drawable); if (mHandler != null) { mHandler.sendEmptyMessageDelayed(1, 220L); } else { mHandler = new MoveHandler(); mHandler.sendEmptyMessageDelayed(1, 220L); istart = true; } } @Override protected void onDraw(Canvas canvas) { super.onDraw(canvas); width = getWidth(); height = getHeight(); GlideBitmapDrawable drawable = (GlideBitmapDrawable) getDrawable(); if (drawable != null) { bitmap = drawable.getBitmap(); } dstRect.left = 0; dstRect.top = 0; dstRect.right = width; dstRect.bottom = height; if (bitmap != null) { if (istart) { imgWidth = bitmap.getWidth(); imgHeight = bitmap.getHeight(); srcRect.left = 0 + mLeft; srcRect.right = imgWidth - mLeft; srcRect.top = 0 + mTop; srcRect.bottom = imgHeight - mTop; canvas.drawBitmap(bitmap, srcRect, dstRect, null); } else { canvas.drawBitmap(bitmap, null, dstRect, null); } } } private class MoveHandler extends Handler { @Override public void handleMessage(Message msg) { switch (msg.what) { case 1: if (imgHeight != 0) { if (mTop == 0) { flag = true; } else if (mTop == 60) { flag = false; } if (!flag) { mTop -= 2; mLeft -= 1; } else { mTop += 2; mLeft += 1; } } postInvalidate(); mHandler.sendEmptyMessageDelayed(1, 200); break; } } } public void start() { mTop = 0; mLeft = 0; istart = true; mHandler.sendEmptyMessageDelayed(1, 220L); } public void stop() { istart = false; } }
如果感觉动画不够流畅可以缩小线程等待时间。
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