代码实现：
1 public class MainActivity extends AppCompatActivity {
2
3 private ImageView img;
4
5 @Override
6 protected void onCreate(Bundle savedInstanceState) {
7 super.onCreate(savedInstanceState);
8 setContentView(R.layout.activity_main);
9 initView();
10 //从资源文件中得到图片
11 Bitmap rawBitmap = BitmapFactory.decodeResource(getResources(), R.drawable.abc);
12 // 得到图片原始的高宽
13 int rawHeight = rawBitmap.getHeight();
14 int rawWidth = rawBitmap.getWidth();
15 // 新建立矩阵
16 Matrix matrix = new Matrix();
17 matrix.postScale(0.2f, 0.2f);
18
19 Bitmap newBitmap = Bitmap.createBitmap(rawBitmap, 0, 0, rawWidth, rawWidth, matrix, true);
20 BitmapDrawable bitmapDrawable=new BitmapDrawable(newBitmap);
21 img.setImageDrawable(bitmapDrawable);
22 }
23
24 private void initView() {
25 img = (ImageView) findViewById(R.id.img);
26 }
27 }