Android 自定义imageview 图片高度固定大小宽度按比例自适应

最新推荐文章于 2021-06-14 14:59:57 发布

dst123965

最新推荐文章于 2021-06-14 14:59:57 发布

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文章标签： android imageview 图片

本文链接：https://blog.youkuaiyun.com/dst123965/article/details/50264553

AdaptiveImageView_Width_Wrap_content 是一个Android自定义ImageView，实现图片高度固定，宽度按比例自适应。通过测量控件默认尺寸、获取图片比例并调整布局参数来达到效果。

package com.common.common.wediget;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.Drawable;
import android.graphics.drawable.NinePatchDrawable;
import android.util.AttributeSet;
import android.view.ViewGroup.LayoutParams;
import android.widget.ImageView;

public class AdaptiveImageView_Width_Wrap_content extends ImageView {

// 控件默认长、宽

private int defaultWidth = 0;

private int defaultHeight = 0;

// 比例

private float scale = 0;

public AdaptiveImageView_Width_Wrap_content(Context context) {

super(context);

}

public AdaptiveImageView_Width_Wrap_content(Context context, AttributeSet attrs) {

super(context, attrs);

}

public AdaptiveImageView_Width_Wrap_content(Context context, AttributeSet attrs, int defStyle) {

super(context, attrs, defStyle);

}

@Override
protected void onDraw(Canvas canvas) {

Drawable drawable = getDrawable();

if (drawable == null) {

return;

}

if (getWidth() == 0 || getHeight() == 0) {

return;

}

this.measure(0, 0);

if (drawable.getClass() == NinePatchDrawable.class)

return;

Bitmap b = ((BitmapDrawable) drawable).getBitmap();

Bitmap bitmap = b.copy(Bitmap.Config.ARGB_8888, true);

if (bitmap.getWidth() == 0 || bitmap.getHeight() == 0) {

return;

}

if (defaultWidth == 0) {

defaultWidth = getWidth();

}

if (defaultHeight == 0) {

defaultHeight = getHeight();

}

scale = (float) defaultHeight / (float) bitmap.getHeight();

defaultWidth = Math.round(bitmap.getWidth() * scale);

LayoutParams params = this.getLayoutParams();

params.width = defaultWidth;

params.height = defaultHeight;

this.setLayoutParams(params);

super.onDraw(canvas);

}

}