当我从图库中选择图像并将其缩放以适合视图时,有时图像显示会自动旋转 -90 度。这很奇怪。而且我注意到它仅在所选图像太大时发生。代码或 android 可能有什么问题?
我使用了以下代码 -
public class MainActivity extends Activity {
TextView textTargetUri;
ImageView targetImage;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button buttonLoadImage = (Button)findViewById(R.id.loadimage);
textTargetUri = (TextView)findViewById(R.id.targeturi);
targetImage = (ImageView)findViewById(R.id.targetimage);
buttonLoadImage.setOnClickListener(new Button.OnClickListener(){
@Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
Intent intent = new Intent(Intent.ACTION_PICK,
android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
startActivityForResult(intent, 0);
}});
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
// TODO Auto-generated method stub
super.onActivityResult(requestCode, resultCode, data);
if (resultCode == RESULT_OK){
Uri targetUri = data.getData();
textTargetUri.setText(targetUri.toString());
Toast.makeText(getApplicationContext(),
"ImageView: " + targetImage.getWidth() + " x " + targetImage.getHeight(),
Toast.LENGTH_LONG).show();
Bitmap bitmap;
bitmap = decodeSampledBitmapFromUri(
targetUri,
targetImage.getWidth(), targetImage.getHeight());
if(bitmap == null){
Toast.makeText(getApplicationContext(), "the image data could not be decoded", Toast.LENGTH_LONG).show();
}else{
Toast.makeText(getApplicationContext(),
"Decoded Bitmap: " + bitmap.getWidth() + " x " + bitmap.getHeight(),
Toast.LENGTH_LONG).show();
targetImage.setImageBitmap(bitmap);
}
}
}
/*
* How to "Loading Large Bitmaps Efficiently"?
* Refer: http://developer.android.com/training/displaying-bitmaps/load-bitmap.html
*/
public Bitmap decodeSampledBitmapFromUri(Uri uri, int reqWidth, int reqHeight) {
Bitmap bm = null;
try{
// First decode with inJustDecodeBounds=true to check dimensions
final BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
BitmapFactory.decodeStream(getContentResolver().openInputStream(uri), null, options);
// Calculate inSampleSize
options.inSampleSize = calculateInSampleSize(options, reqWidth, reqHeight);
options.inJustDecodeBounds = false;
bm = BitmapFactory.decodeStream(getContentResolver().openInputStream(uri), null, options);
} catch (FileNotFoundException e) {
e.printStackTrace();
Toast.makeText(getApplicationContext(), e.toString(), Toast.LENGTH_LONG).show();
}
return bm;
}
public int calculateInSampleSize(
BitmapFactory.Options options, int reqWidth, int reqHeight) {
// Raw height and width of image
final int height = options.outHeight;
final int width = options.outWidth;
int inSampleSize = 1;
if (height > reqHeight || width > reqWidth) {
if (width > height) {
inSampleSize = Math.round((float)height / (float)reqHeight);
} else {
inSampleSize = Math.round((float)width / (float)reqWidth);
}
}
return inSampleSize;
}
}
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="@string/hello_world" />
<Button
android:id="@+id/loadimage"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="Load Image" />
<TextView
android:id="@+id/targeturi"
android:layout_width="fill_parent"
android:layout_height="wrap_content" />
<ImageView
android:id="@+id/targetimage"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:scaleType="centerCrop" />
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.androidselectimage"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="15" />
<application
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity android:screenOrientation="portrait"
android:name=".MainActivity"
android:label="@string/title_activity_main" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>