android自定义适配屏幕的ImageView

package org.angryfun.view;
import android.content.Context;
import android.graphics.Bitmap;
import android.util.AttributeSet;
import android.view.ViewGroup.LayoutParams;
import android.widget.ImageView;

public class FitImageView extends ImageView {
	private Bitmap mBitmap;
	private int mBitmapWidth;
	private int mBitmapHeight;

	private boolean mReady;
	private boolean mSetupPending;

	public FitImageView(Context context) {
		super(context);
		init();
	}

	public FitImageView(Context context, AttributeSet attrs) {
		this(context, attrs, 0);
	}

	public FitImageView(Context context, AttributeSet attrs, int defStyle) {
		super(context, attrs, defStyle);
		init();
	}

	private void init() {
		mReady = true;

		if (mSetupPending) {
			setup();
			mSetupPending = false;
		}
	}

	private void reSize() {
		int width = getResources().getDisplayMetrics().widthPixels;
		int height = (int) (getResources().getDisplayMetrics().heightPixels * 0.8);
		int imgH = mBitmapHeight;
		int imgW = mBitmapWidth;
		int lastH = imgH;
		int lastW = imgW;
		double radio = 1.0;
		radio = (width * 1.0) / imgW;
		if (imgH * radio > height) {
			radio = (height * 1.0) / imgH;
		}
		lastH = (int) (radio * imgH);
		lastW = (int) (radio * imgW);
		LayoutParams lp = this.getLayoutParams();
		lp.width = lastW;
		lp.height = lastH;
		this.setLayoutParams(lp);
	}

	@Override
	public void setImageBitmap(Bitmap bm) {
		super.setImageBitmap(bm);
		mBitmap = bm;
		setup();
		reSize();
	}

	private void setup() {
		if (!mReady) {
			mSetupPending = true;
			return;
		}

		if (mBitmap == null) {
			return;
		}

		mBitmapHeight = mBitmap.getHeight();
		mBitmapWidth = mBitmap.getWidth();

		invalidate();
	}

}
 
  
 
  
 
  
 
  
 从网络上下载后的图片加载在页面上按照ImageView自带的属性根本就设置不准确，所以自己重新封装了一个ImageView来实现屏幕自适配，其实原理就是重载 
  setImageBitmap函数，获得bitmap的宽度和高度然后根据手机屏幕大小自动调整ImageView控件的大小 
  
 
  
               android:id="@+id/img_art_real"
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
             android:contentDescription="@null"
             android:scaleType="fitXY"
             android:layout_centerHorizontal="true" />