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这期内容当中小编将会给大家带来有关怎么在Android中利用ImageView实现一个放大缩小动画,文章内容丰富且以专业的角度为大家分析和叙述,阅读完这篇文章希望大家可以有所收获。

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;
}
}