使用SD卡上图片资源的ImageView

最新推荐文章于 2025-05-23 23:27:02 发布

原创最新推荐文章于 2025-05-23 23:27:02 发布 · 145 阅读

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#Android #Java #OS

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本文介绍了一个Android应用中从SD卡加载图片并进行缩放显示的方法。通过使用BitmapFactory从文件输入流中解码图片，然后利用Matrix类进行等比例缩放，最后将缩放后的Bitmap设置到ImageView中展示。

这个主要是实现Bitmap和Drawable之间的转换以及SD卡路径的获取问题:


package cn.com;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;

import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Matrix;
import android.os.Bundle;
import android.os.Environment;
import android.widget.ImageView;

public class UserSdCardImage extends Activity {
	/** Called when the activity is first created. */
	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);

		ImageView iv = (ImageView) findViewById(R.id.image);

		showpic(iv);
	}

	private void showpic(ImageView iv) {
		File sdcardDir = Environment.getExternalStorageDirectory();

		String path = sdcardDir.getParent() + sdcardDir.getName();
		System.out.println("________________________" + path);

		File pic = new File(path + java.io.File.separator + "88.jpg");

		FileInputStream is = null;
		try {
			is = new FileInputStream(pic);
			Bitmap bm = BitmapFactory.decodeStream(is, null, null);

			int w = bm.getWidth();
			int h = bm.getHeight();

			double s = 0.6;

			float sw = 1, sh = 1;
			sw = (float) (sw * s);
			sh = (float) (sh * s);
			Matrix mx = new Matrix();
			mx.postScale(sw, sh);

			Bitmap rp = Bitmap.createBitmap(bm, 0, 0, w, h, mx, true);
			iv.setImageBitmap(rp);

		} catch (FileNotFoundException e) {
			e.printStackTrace();
		}
	}
}