缩放图像以填充ImageView宽度并保持纵横比
缩放图像以填充ImageView宽度并保持纵横比
提问于 2013-08-06 18:15:49
我有一台GridView。GridView的数据是从服务器请求的。
以下是GridView中的项目布局
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="@drawable/analysis_micon_bg"
android:gravity="center_horizontal"
android:orientation="vertical"
android:paddingBottom="@dimen/half_activity_vertical_margin"
android:paddingLeft="@dimen/half_activity_horizontal_margin"
android:paddingRight="@dimen/half_activity_horizontal_margin"
android:paddingTop="@dimen/half_activity_vertical_margin" >
<ImageView
android:id="@+id/ranking_prod_pic"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:adjustViewBounds="true"
android:contentDescription="@string/app_name"
android:scaleType="centerCrop" />
<TextView
android:id="@+id/ranking_rank_num"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
<TextView
android:id="@+id/ranking_prod_num"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
<TextView
android:id="@+id/ranking_prod_name"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</LinearLayout>我从服务器请求数据，获取图像url并将图像加载到Bitmap
public static Bitmap loadBitmapFromInputStream(InputStream is) {
return BitmapFactory.decodeStream(is);
}
public static Bitmap loadBitmapFromHttpUrl(String url) {
try {
return loadBitmapFromInputStream((InputStream) (new URL(url).getContent()));
} catch (Exception e) {
Log.e(TAG, e.getMessage());
return null;
}
}在适配器中有getView(int position, View convertView, ViewGroup parent)方法的代码
Bitmap bitmap = BitmapUtil.loadBitmapFromHttpUrl(product.getHttpUrl());
prodImg.setImageBitmap(bitmap);图像大小为210*210。我在我的Nexus4上运行我的应用程序。图像确实填充了ImageView宽度，但ImageView高度没有缩放。ImageView不会显示整个图像。
我该如何解决这个问题？
回答 14
Stack Overflow用户
发布于 2013-11-22 21:26:02
我喜欢arnefm的回答，但他犯了一个小错误(见评论)，我会努力改正：
import android.content.Context;
import android.graphics.drawable.Drawable;
import android.util.AttributeSet;
import android.widget.ImageView;
/**
* ImageView that keeps aspect ratio when scaled
*/
public class ScaleImageView extends ImageView {
public ScaleImageView(Context context) {
super(context);
}
public ScaleImageView(Context context, AttributeSet attrs) {
super(context, attrs);
}
public ScaleImageView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
try {
Drawable drawable = getDrawable();
if (drawable == null) {
setMeasuredDimension(0, 0);
} else {
int measuredWidth = MeasureSpec.getSize(widthMeasureSpec);
int measuredHeight = MeasureSpec.getSize(heightMeasureSpec);
if (measuredHeight == 0 && measuredWidth == 0) { //Height and width set to wrap_content
setMeasuredDimension(measuredWidth, measuredHeight);
} else if (measuredHeight == 0) { //Height set to wrap_content
int width = measuredWidth;
int height = width * drawable.getIntrinsicHeight() / drawable.getIntrinsicWidth();
setMeasuredDimension(width, height);
} else if (measuredWidth == 0){ //Width set to wrap_content
int height = measuredHeight;
int width = height * drawable.getIntrinsicWidth() / drawable.getIntrinsicHeight();
setMeasuredDimension(width, height);
} else { //Width and height are explicitly set (either to match_parent or to exact value)
setMeasuredDimension(measuredWidth, measuredHeight);
}
}
} catch (Exception e) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
}
}
}因此，如果(例如)放在ScrollView中，您的ImageView将被适当地缩放，并且不会有尺寸问题
Stack Overflow用户
发布于 2013-08-06 18:32:01
我曾经遇到过类似的问题。我通过制作一个定制的ImageView解决了这个问题。
public class CustomImageView extends ImageView然后覆盖图像视图的onMeasure方法。我做了这样的事情，我相信：
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
try {
Drawable drawable = getDrawable();
if (drawable == null) {
setMeasuredDimension(0, 0);
} else {
float imageSideRatio = (float)drawable.getIntrinsicWidth() / (float)drawable.getIntrinsicHeight();
float viewSideRatio = (float)MeasureSpec.getSize(widthMeasureSpec) / (float)MeasureSpec.getSize(heightMeasureSpec);
if (imageSideRatio >= viewSideRatio) {
// Image is wider than the display (ratio)
int width = MeasureSpec.getSize(widthMeasureSpec);
int height = (int)(width / imageSideRatio);
setMeasuredDimension(width, height);
} else {
// Image is taller than the display (ratio)
int height = MeasureSpec.getSize(heightMeasureSpec);
int width = (int)(height * imageSideRatio);
setMeasuredDimension(width, height);
}
}
} catch (Exception e) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
}这将拉伸图像以适合屏幕，同时保持纵横比。
Stack Overflow用户
发布于 2014-10-06 21:11:37
使用android:scaleType="centerCrop"。
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/18077325
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