加载图片 获取屏幕宽高

 

 1 package com.itheima.getimage;
 2 
 3 import android.app.Activity;
 4 import android.content.Intent;
 5 import android.database.Cursor;
 6 import android.graphics.Bitmap;
 7 import android.graphics.BitmapFactory;
 8 import android.graphics.BitmapFactory.Options;
 9 import android.net.Uri;
10 import android.os.Bundle;
11 import android.view.View;
12 import android.view.WindowManager;
13 import android.widget.ImageView;
14 
15 public class MainActivity extends Activity {
16 
17     private ImageView iv;
18 
19     @Override
20     protected void onCreate(Bundle savedInstanceState) {
21         super.onCreate(savedInstanceState);
22         setContentView(R.layout.activity_main);
23         
24         iv = (ImageView) findViewById(R.id.iv);
25     }
26     
27     public void open(View v) {
28         Intent intent = new Intent(Intent.ACTION_PICK);
29         intent.setType("image/*");
30         startActivityForResult(intent, 100);
31     }
32     
33     @Override
34     protected void onActivityResult(int requestCode, int resultCode, Intent intent) {
35         Uri uri = intent.getData();
36         String path = getAbsolutePath(uri);
37         Bitmap bm = getUsableBitmap(path);
38         iv.setImageBitmap(bm);
39         System.out.println(bm.getWidth() + ", " + bm.getHeight());
40     }
41     
42     public String getAbsolutePath(Uri uri) {
43         Cursor c = getContentResolver().query(uri, new String[] { "_data" }, null, null, null);
44         c.moveToNext();
45         return c.getString(0);
46     }
47     
48     @SuppressWarnings("deprecation")
49     private Bitmap getUsableBitmap(String path) {
50         Options opts = new Options();
51         opts.inJustDecodeBounds = true;            // 设置只加载图片大小
52         BitmapFactory.decodeFile(path, opts);
53         
54         WindowManager manager = (WindowManager) getSystemService(WINDOW_SERVICE);
55         int width = manager.getDefaultDisplay().getWidth();        // 屏幕宽度
56         int height = manager.getDefaultDisplay().getHeight();    // 屏幕高度
57         
58         int xScale = opts.outWidth / width;
59         int yScale = opts.outHeight / height;
60         int scale = xScale > yScale ? xScale : yScale;    // 计算缩放比例
61         
62         opts.inJustDecodeBounds = false;                // 设置不只加载图片大小
63         opts.inSampleSize = scale;                        // 设置缩放比例
64         return BitmapFactory.decodeFile(path, opts);    // 按照设置加载图片(缩放)
65     }
66 
67 }
68