Bitmap的使用 防止OOM异常

public class MainActivity extends Activity {ImageView captruepic;int requestCode = 0;String path = "/mnt/sdcard/pic.jpg";int height = 0;int width = 0;File file = new File(path);@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);captruepic = (ImageView) findViewById(R.id.captruepic);Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);intent.putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(file));startActivityForResult(intent, requestCode);}@Overrideprotected void onActivityResult(int requestCode, int resultCode, Intent data) {try {if (requestCode == this.requestCode && resultCode == RESULT_OK) {// Bundle bundle = data.getExtras();// (Bitmap)bundle.get("data");Bitmap bit = null;BitmapFactory.Options options = new BitmapFactory.Options();// options.inJustDecodeBounds = true; 表示只返回照片的尺寸值 不解码照片本身options.inJustDecodeBounds = true;bit = BitmapFactory.decodeFile(file.getAbsolutePath(), options);// 这时候options.outHeight options.outWidth 记录的就是照片的尺寸height = options.outHeight;width = options.outWidth;Display display = this.getWindowManager().getDefaultDisplay();if (options.outHeight > 0 && options.outWidth > 0) {// 一般手机拍照的照片的尺寸都比手机屏幕的尺寸大 所以这边用照片的高 宽 除以 屏幕的高 宽int Height = options.outHeight / display.getHeight();int Width = options.outWidth / display.getWidth();// inSampleSize If set to a value > 1, requests the decoder// to subsample the original image, returning a smaller// image to save memory 简单的说就是inSampleSize > 1// 时候返回的照片是原照片的1/inSampleSize倍options.inSampleSize = Height > Width ? Height : Width;}// options.inJustDecodeBounds = false; 表示解码照片本身options.inJustDecodeBounds = false;bit = BitmapFactory.decodeFile(file.getAbsolutePath(), options);captruepic.setImageBitmap(bit);}} catch (Exception e) {e.printStackTrace();}}}

使用Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE); 开启Camera

如果直接执行startActivityForResult(intent, requestCode);那么在 onActivityResult(int requestCode, int resultCode, Intent data)中的data参数会返回拍的照片

使用Bundle bundle = data.getExtras();    

        Bitmap bit  = (Bitmap)bundle.get("data");获得

如果使用Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE); 开启Camera

然后设置了intent.putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(file));照片保存的文件的Uri  那么在 onActivityResult(int requestCode, int resultCode, Intent data)中的data参数不会返回拍的照片，要想获得照片可以通过 BitmapFactory.decodeFile(file.getAbsolutePath(), options);

补充说明:

intent.putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(file));

这句话中的MediaStore.EXTRA_OUTPUT是为了告诉android设备不要将返回的图片压缩成很小的尺寸，而且它将告诉应用程序，你想将图片保存在哪个位置。