在android中要加载一张大图片到内存中如果通过如下方式进行:
Bitmap bitmap= BitmapFactory.decodeFile("/sdcard/a.jpg");
iv.setImageBitmap(bitmap);
则会抛出内存溢出异常Caused by: java.lang.OutOfMemoryError
正确的做法应该是这样的:
public class MainActivity extends Activity {
private ImageView iv;
private int windowHeight;
private int windowWidth;@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
iv = (ImageView) findViewById(R.id.iv);
WindowManager win = (WindowManager) getSystemService(WINDOW_SERVICE);
windowHeight = win.getDefaultDisplay().getHeight();
windowWidth = win.getDefaultDisplay().getWidth();
}@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}public void load(View view) {
/* Bitmap bitmap= BitmapFactory.decodeFile("/sdcard/a.jpg");
iv.setImageBitmap(bitmap);*/// 图片解析的配置
BitmapFactory.Options options = new Options();
// 不去真的解析图片,只是获取图片的头部信息宽,高
options.inJustDecodeBounds = true;
BitmapFactory.decodeFile("/sdcard/a.jpg", options);
int imageHeight = options.outHeight;
int imageWidth = options.outWidth;
// 计算缩放比例
int scaleX = imageWidth / windowWidth;
int scaleY = imageHeight / windowHeight;
int scale = 1;
if (scaleX > scaleY & scaleY >= 1) {
scale = scaleX;}else if (scaleY > scaleX & scaleX >= 1) {
scale = scaleY;}
//真的解析图片
options.inJustDecodeBounds=false;
//设置采样率
options.inSampleSize=scale;
Bitmap bitmap=BitmapFactory.decodeFile("/sdcard/a.jpg", options);
iv.setImageBitmap(bitmap);
}}
在这种情况下,是将大分辨率的图片按照一定的比例缩小然后加载进内存,就不会出现内存溢出的现象了。
转载请注明出处:http://www.cnblogs.com/yydcdut/p/3744876.html
参考:http://blog.csdn.net/zhong1113/article/details/23824933
Android -- 加载大图片的方法,布布扣,bubuko.com