Android ImageView调整父级高度和适配宽度

Android ImageView adjusting parent#39;s height and fitting width(Android ImageView调整父级高度和适配宽度)

问题描述

更新:我使用 这个答案

我有点纠结这个问题，我认为应该很简单.

I'm a bit stuck with this issue, which I think should be pretty simple.

所以我的应用程序下载了一张图片，并在 ImageView(RelativeLayout 的一个子元素)中呈现位图.我希望 ImageView 适合父宽度，并调整它的大小以保持纵横比.

So my app downloads an image, and renders the bitmap in an ImageView, a child element of a RelativeLayout. I would like the ImageView to fit the parent width, and to adapt it's size to keep the aspect ratio.

这是我的 XML:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
<RelativeLayout android:id="@+id/banner" android:layout_width="fill_parent" android:layout_height="wrap_content"></RelativeLayout>
<TextView  
android:layout_width="fill_parent" 
android:layout_height="wrap_content" 
android:text="@string/hello"
/>
</LinearLayout>

还有代码:

public void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);


    RelativeLayout banner = (RelativeLayout) findViewById(R.id.banner);
    ImageView imgV = new ImageView(this);

    imgV.setScaleType(ImageView.ScaleType.CENTER_CROP);
    // I tried all the scale types : CENTER_INSIDE : same effect, FIT_CENTER : same effect... 

    imgV.setBackgroundColor(0x00FFFF00);

    imgV.setAdjustViewBounds(Color.BLUE);


    RelativeLayout.LayoutParams params = new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.FILL_PARENT, RelativeLayout.LayoutParams.WRAP_CONTENT);

    banner.addView(imgV,params);

    // Some code downloading the image stream

    bitmap = BitmapFactory.decodeStream(stream);


    imgV.setImageBitmap(bitmap);

    }

期望:

结果:

推荐答案

感谢@Julien 和@js.这是 ImageView 的完整解决方案，即使位图小于 ImageView，也会拉伸位图高度保持纵横比.

Thanks to @Julien and @js. Here is complete solution of ImageView that will stretch bitmap height preserving aspect ratio even if bitmap is smaller than ImageView.

public class ResizableImageView extends ImageView {

    public ResizableImageView(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    @Override 
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec){
         Drawable d = getDrawable();

         if(d!=null){
                 // ceil not round - avoid thin vertical gaps along the left/right edges
                 int width = MeasureSpec.getSize(widthMeasureSpec);
                 int height = (int) Math.ceil((float) width * (float) d.getIntrinsicHeight() / (float) d.getIntrinsicWidth());
                 setMeasuredDimension(width, height);
         }else{
                 super.onMeasure(widthMeasureSpec, heightMeasureSpec);
         }
    }

}

你可以在你的 xml 布局中使用这个类来代替 ImageView.

You can use this class in your xml layouts instead ImageView.

<com.example.ResizableImageView
    android:id="@+id/banner"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:src="@drawable/banner" />

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