关于android获得图片的总结

1，已将图片保存到drawable目录下
[color=cyan]a)通过图片id获得Drawable[/color]
Resource res=gerResource();
Drawable drawable=res.getDrawable(id);//id为R.drawable.图片名称

[color=cyan]b)通过图片id获得Bitmap[/color]
Resource res=gerResource();
Bitmap bitmap=BitmapFactory.decodeResource(res, id);

c)若只知道图片的名称，可以通过图片的名称获得图片的id
//name:图片的名称 defType：图片的类型（png,jpeg),defPackage:工程的包名
int id =int id =res.getIdentifier(name, defType, defPackage);
获得id之后可以根据你的需要来获得Bitmap或Drawable

2,已将图片保存到assest目录下
[color=cyan]a)知道图片的名称，通过inputstream打开图片[/color]
AssetManager asm=getAssetMg();
InputStream is=asm.open(name);//name:图片的名称

//获得Drawable
Drawable da = Drawable.createFromStream(is, null);
//获得Bitmap
Bitmap bitmap=BitmapFactory.decodeStream(is);

3,图片保存在sdcard,已知图片的路径
//图片路径
String path = Environment.getExternalStorageDirectory().toString()
+ "/DCIM/device.png";
RandomAccessFile mMiniThumbFile；
File imgfile = new File(path);
try {
mMiniThumbFile = new RandomAccessFile(imgfile, "rw");
} catch (IOException ex) {
// Open as read-only so we can at least read the existing
// thumbnails.
try {
mMiniThumbFile = new RandomAccessFile(imgfile, "r");
} catch (IOException ex2) {
// ignore exception
System.out.println(ex2.toString());
}
}

data= new byte[10553];
try {
mMiniThumbFile.seek(0);
int got = mMiniThumbFile.read(data, 0, 10552);
System.out.println("got="+got);

} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
System.out.println(e.toString());
}

if (data != null) {
//通过data获得bitmap
Bitmap bitmap = BitmapFactory.decodeByteArray(data, 0,
data.length);