2

我创建了这个演示，它从图库中检索图像并将其显示在 ImageView 中（在重新采样图像本身之后）https://github.com/svappdroid/BitmapDemo

在 Galaxy Nexus 上，我无法打开尺寸为 4307x2894 的图像，logcat 说“位图太大，无法在纹理中上传”；奇怪的是，模拟 Galaxy Nexus 我可以打开相同的图像；为什么会出现这种行为以及如何在实际设备上解决它？

活动代码为：


    package com.example.bitmapdemo;

    import java.io.FileNotFoundException;

    import android.app.Activity;
    import android.content.Intent;
    import android.graphics.Bitmap;
    import android.graphics.BitmapFactory;
    import android.net.Uri;
    import android.os.Bundle;
    import android.util.DisplayMetrics;
    import android.view.View;
    import android.view.View.OnClickListener;
    import android.widget.Button;
    import android.widget.ImageView;
    import android.widget.LinearLayout;
    import android.widget.Toast;

    public class MainActivity extends Activity {
        public ImageView canvasImageView;
        public Button selectImageButton;
        public LinearLayout ll;
        public Bitmap image;

        //REQUEST CODE
        public static final int SELECT_IMAGE_REQ_CODE = 1;

        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
            ll = (LinearLayout) this.findViewById(R.id.LinearLayout1);
            canvasImageView = (ImageView) this.findViewById(R.id.canvasImageView);
            selectImageButton = (Button) this.findViewById(R.id.selectImageButton);

            selectImageButton.setOnClickListener(new OnClickListener(){

                @Override
                public void onClick(View v)
                {
                    Intent selectImageIntent = new Intent(Intent.ACTION_GET_CONTENT);
                    selectImageIntent.setType("image/*");
                    startActivityForResult(selectImageIntent, SELECT_IMAGE_REQ_CODE);
                }
            });
        }

        @Override
        protected void onActivityResult(int requestCode, int resultCode, Intent data) {
            super.onActivityResult(requestCode, resultCode, data);
            if(requestCode == SELECT_IMAGE_REQ_CODE)
            {
                switch(resultCode)
                {
                    case(RESULT_OK):
                        Uri imageUri = data.getData();

                        try
                        {
                            int inSampleSize = calculateInSampleSize(imageUri);
                            image = resampleImage(imageUri, inSampleSize);
                            canvasImageView.setImageBitmap(image);

                        }
                        catch(FileNotFoundException e){}
                }
            }
        }

        public int calculateInSampleSize(Uri imageUri) throws FileNotFoundException
        {
            BitmapFactory.Options opts = new BitmapFactory.Options();
            opts.inJustDecodeBounds = true;
            BitmapFactory.decodeStream(getContentResolver().openInputStream(imageUri), null, opts);
            int imageWidth = opts.outWidth;
            int imageHeight = opts.outHeight;
            int inSampleSize = 4;

            //Get display dimension in order to calculate image ratio
            DisplayMetrics displayMetrics = new DisplayMetrics();
            getWindowManager().getDefaultDisplay().getMetrics(displayMetrics);

            int reqWidth = displayMetrics.widthPixels;
            int reqHeight = displayMetrics.heightPixels;

            if(imageHeight > reqHeight || imageWidth > reqWidth)
            {
                final int heightRatio = Math.round((float)imageHeight / (float) reqHeight);
                final int widthRatio = Math.round((float) imageWidth / (float) reqWidth);

                inSampleSize = heightRatio

And here is the xml code for the layout: 




<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/LinearLayout1"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity" >

    <ImageView
        android:id="@+id/canvasImageView"
        android:layout_width="wrap_content"
        android:layout_height="0dp"
        android:layout_weight="1"
        android:layout_gravity="center"
        android:src="@drawable/ic_launcher" />

    <Button
        android:id="@+id/selectImageButton"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="@string/select_image_button" />

</LinearLayout>

4

2 回答 2

4

您需要调整要在视图上显示的位图大小。

Bitmap b = BitmapFactory.decodeByteArray(imageAsBytes, 0, imageAsBytes.length)
profileImage.setImageBitmap(Bitmap.createScaledBitmap(sourceBitmap, width, height, false));

有一个很好的文档可用于在 adnroid 中处理位图。请参考：http: //developer.android.com/training/displaying-bitmaps/index.html

在 SO 上，您也可以找到许多解释。请参阅下文，这将有所帮助：https ://stackoverflow.com/a/10703256/2035885 https://stackoverflow.com/a/4837803/2035885

于 2013-10-26T14:18:15.807 回答
0

试试这个代码

public static Bitmap getImageFromFile(String filePath) {

        try {
            File file = new File(filePath);
            if (!file.exists()) {
                return null;
            }
            // decode image size
            BitmapFactory.Options bitmapTempOption = new BitmapFactory.Options();
            bitmapTempOption.inJustDecodeBounds = true;
            BitmapFactory.decodeStream(new FileInputStream(file), null, bitmapTempOption);

            // Find the correct scale value. It should be the power of 2.
            final int REQUIRED_SIZE = 200;
            int width_tmp = bitmapTempOption.outWidth, height_tmp = bitmapTempOption.outHeight;
            int scale = 1;
            while (true) {
                if (width_tmp / 2 < REQUIRED_SIZE || height_tmp / 2 < REQUIRED_SIZE)
                    break;
                width_tmp /= 2;
                height_tmp /= 2;
                scale *= 2;
            }

            // decode with inSampleSize
            BitmapFactory.Options bitmapOption = new BitmapFactory.Options();
            bitmapOption.inSampleSize = scale;

            try {
                return BitmapFactory.decodeStream(new FileInputStream(file), null, bitmapOption);
            } catch (OutOfMemoryError e) {
                DebugHelper.printError(e);
            } catch (Error e) {
                DebugHelper.printError(e);
            }
        } catch (Exception exception) {
            DebugHelper.printException(exception);
        }
        return null;
    }

您还可以使用此代码缩小图像

ImageView iv  = (ImageView)waypointListView.findViewById(R.id.waypoint_picker_photo);
Bitmap d = new BitmapDrawable(ctx.getResources() , w.photo.getAbsolutePath()).getBitmap();
int nh = (int) ( d.getHeight() * (512.0 / d.getWidth()) );
Bitmap scaled = Bitmap.createScaledBitmap(d, 512, nh, true);
iv.setImageBitmap(scaled);
于 2013-10-28T18:11:35.220 回答