android - 如何调整图库中的图像大小？

Question

第一个文件允许用户从图库中选择一张照片并将其发送到将处理它的 Activity 。问题是图片对于手机屏幕来说太大了，所以你只能看到图片的上角(好像被放大了一样)。

Button useGallery = (Button)findViewById(R.id.loadfromgallery);
        useGallery.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View arg0) {

                Intent photoPickerIntent = new Intent(Intent.ACTION_PICK);
                photoPickerIntent.setType("image/*");
                startActivityForResult(photoPickerIntent, SELECT_PHOTO); 
            }}) ;

 @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent imageReturnedIntent) { 
        super.onActivityResult(requestCode, resultCode, imageReturnedIntent); 

        switch(requestCode) { 
        case SELECT_PHOTO:
            if(resultCode == RESULT_OK){  
                Uri selectedImage = imageReturnedIntent.getData();
                InputStream imageStream = null;
                try {
                    imageStream = getContentResolver().openInputStream(selectedImage);
                } catch (FileNotFoundException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
                Bitmap yourSelectedImage = BitmapFactory.decodeStream(imageStream);
                Intent intent = new Intent(mContext, DisplayUndistortedBitmapFromGalleryActivity.class);
                intent.setData(selectedImage);
                startActivity(intent);

                if(yourSelectedImage != null){
                Log.e(TAG,"pic ok");
                }else{
                     Log.e(TAG,"pic not ok");
                }
            }
        }

.第二个文件是从 Intent 接收图像数据并将其放置在派生位图的 URI 中的 Activity 。

public class DisplayUndistortedBitmapFromGalleryActivity extends Activity {

    private static final String TAG = "*********DUBFGActivity";
    private Context mContext = this;
    Uri uri;
    private Bitmap mbitmap = null;

    @Override 
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        requestWindowFeature(Window.FEATURE_NO_TITLE);
        getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
                WindowManager.LayoutParams.FLAG_FULLSCREEN);


         uri = getIntent().getData();
        if(uri != null){
            Log.e(TAG, "uri ok");
        }else {
            Log.e(TAG, "uri not ok");
        }


        try {
              mbitmap = Media.getBitmap(getContentResolver(), uri);
             //setMbitmap(bitmap);
        } catch (FileNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

.

我有第三个文件，它是 Activity 的自定义 View 。下面的行从它的 Activity 中检索位图并显示它。有没有办法缩小位图以使其适合屏幕？谢谢。

Bitmap bm = ((DisplayUndistortedBitmapFromGalleryActivity)getContext()).getMbitmap();

Answer 1

这是我通常调整位图大小的方法，也是最简单的方法。

public class bitmaptest extends Activity {
@Override
public void onCreate(Bundle icicle) {
    super.onCreate(icicle);
    LinearLayout linLayout = new LinearLayout(this);

    // load the origial BitMap (500 x 500 px)
    Bitmap bitmapOrg = BitmapFactory.decodeResource(getResources(),
           R.drawable.android);

    int width = bitmapOrg.width();
    int height = bitmapOrg.height();
    int newWidth = 200;
    int newHeight = 200;

    // calculate the scale - in this case = 0.4f
    float scaleWidth = ((float) newWidth) / width;
    float scaleHeight = ((float) newHeight) / height;

    // createa matrix for the manipulation
    Matrix matrix = new Matrix();
    // resize the bit map
    matrix.postScale(scaleWidth, scaleHeight);
    // rotate the Bitmap


    // recreate the new Bitmap
    Bitmap resizedBitmap = Bitmap.createBitmap(bitmapOrg, 0, 0,
                      width, height, matrix, true);

    // make a Drawable from Bitmap to allow to set the BitMap
    // to the ImageView, ImageButton or what ever
    BitmapDrawable bmd = new BitmapDrawable

编辑:

这是另一种选择。

  int targetWidth  = bitmapOrg.getWidth() - 15; //change this to control the size
  int targetHeight = bitmapOrg.getHeight() - 15 ;
  Matrix matrix = new Matrix();
  matrix.postScale(1f, 1f);
  Bitmap resizedBitmap = Bitmap.createBitmap(bmp, 0, 0, targetWidth, targetHeight, matrix, true);