[英]Android Pinch Zoom ImageView (PhotoView) with ScrollView
[英]Android PhotoView Keep Zoom After Orientation Change
我正在使用Chris Banes的PhotoView類能夠放大圖像並看到它,但我想這樣做,以便當我改變方向時,照片仍將在更改后放大。
我理解如何執行此操作的基礎知識,當檢測到方向更改時,將調用onSaveInstanceState,因此我嘗試將實例保存在那里,然后在調用onCreate時將其放回到PhotoView中。
public class MainActivity extends ActionBarActivity
{
PhotoView mPhotoView;
@Override
protected void onCreate( Bundle aSavedInstanceState )
{
super.onCreate( aSavedInstanceState );
mPhotoView = new PhotoView(this);
mPhotoView.setMaximumScale( 12 );
setContentView( mPhotoView );
mPhotoView.setImageResource( R.drawable.vm_app_icon);
if (aSavedInstanceState != null)
{
RectF theRect = aSavedInstanceState.getParcelable( "Rect" );
if ( theRect != null)
{
Matrix theMatrix = new Matrix();
theMatrix.setScale( theRect.bottom, theRect.left, theRect.right, theRect.top );
mPhotoView.setDisplayMatrix( theMatrix );
}
}
}
@Override
protected void onSaveInstanceState( final Bundle outState )
{
super.onSaveInstanceState( outState );
RectF theRect = mPhotoView.getDisplayRect();
if (theRect != null)
{
outState.putParcelable( "Rect", theRect );
}
}
}
但這不起作用。 我應該在捆綁中存儲什么才能應用回PhotoView以保持縮放級別?
好吧,經過10個小時的嘗試,我已經弄清楚了。
為了保存縮放級別,我需要在Bundle,Scale(縮放級別)和DisplayRect(RectF類型)中保存兩件事。
縮放級別 - MinScale和MaxScale之間的數字,在我的實例中介於1和16之間
RectF包含四個值,由於某種原因,這些值是當前視圖相對於當前屏幕方向的左上角的坐標。 即使它保持左上角坐標我不想圍繞它旋轉,我想圍繞中心旋轉,所以我需要找到矩形的中心,然后將該值除以“ScreenBase”,這是一個將標准化值並使其能夠轉換為差異平面的值。 這是我如何保存它:
@Override
protected void onSaveInstanceState( final Bundle outState )
{
super.onSaveInstanceState( outState );
Matrix theMatrix = mPhotoView.getDisplayMatrix();
float[] theFloat = new float[9];
theMatrix.getValues( theFloat );
RectF theRect = mPhotoView.getDisplayRect();
if (theRect != null)
{
if( theRect.left > ( mViewWidth / 2 ) || ( theRect.left >= 0 ) )
{
theRect.left = 0;
}
else
{
theRect.left = ( theRect.left - ( mViewWidth / 2 ) ) / mScreenBase;
}
if( theRect.top > ( mViewHeight / 2 ) || ( theRect.top >= 0 ) )
{
theRect.top = 0;
}
else
{
theRect.top = ( theRect.top - ( mViewHeight / 2 ) ) / mScreenBase;
}
outState.putParcelable( "RectF", theRect );
outState.putFloat( "ZoomLevel", mPhotoView.getScale() );
}
}
然后當我們在另一側拾取它時,我們必須對數字進行大量操作,以使新屏幕空間的左上角居中於同一位置(如果出現邊界問題則操縱它),這里是我是怎么做到的
@Override
protected void onCreate( final Bundle aSavedInstanceState )
{
super.onCreate( aSavedInstanceState );
mPhotoView = new PhotoView( this );
mPhotoView.setMaximumScale( 16 );
setContentView( mPhotoView );
mPhotoView.setImageResource( R.drawable.vm_app_icon );
mPhotoView.getViewTreeObserver().addOnPreDrawListener( new ViewTreeObserver.OnPreDrawListener()
{
public boolean onPreDraw()
{
mPhotoView.getViewTreeObserver().removeOnPreDrawListener( this );
mViewHeight = mPhotoView.getMeasuredHeight();
mViewWidth = mPhotoView.getMeasuredWidth();
Matrix theMatrix = mPhotoView.getDisplayMatrix();
theMatrix.getValues( mBaseMatrixValues );
mScreenBase = mBaseMatrixValues[ 0 ];
int theWidth = mPhotoView.getWidth();
Log.e(TAG, theWidth + "");
if( aSavedInstanceState != null )
{
float[] theFloats = new float[ 9 ];
float theZoom = aSavedInstanceState.getFloat( "ZoomLevel" );
RectF theRect = aSavedInstanceState.getParcelable( "RectF" );
theFloats[ 0 ] = theZoom;
theFloats[ 4 ] = theZoom;
theFloats[ 2 ] = ( theRect.left * mScreenBase ) - ( theZoom * mBaseMatrixValues[ 2 ] ) + ( mViewWidth / 2 ); //Left
theFloats[ 5 ] = ( theRect.top * mScreenBase ) - ( theZoom * mBaseMatrixValues[ 5 ] ) + ( mViewHeight / 2 ); //Top
theFloats[ 8 ] = (float) 1.0;
theFloats = CheckBoundaries( theZoom, theFloats, theRect );
theMatrix.setValues( theFloats );
mPhotoView.setDisplayMatrix( theMatrix ); //Sets the mSuppMatrix in the PhotoViewAttacher
Matrix theImageViewMatrix = mPhotoView.getDisplayMatrix(); //Gets the new mDrawMatrix
mPhotoView.setImageMatrix( theImageViewMatrix ); //And applies it to the PhotoView (catches out of boundaries problems)
}
return true;
}
} );
}
private float[] CheckBoundaries(final float aZoom, float[] aFloats, final RectF aRect )
{
if( aZoom == 1.0 ) //If the zoom is all the way out
{
aFloats[ 2 ] = 0;
aFloats[ 5 ] = 0;
return aFloats;
}
theMaxLeftValue = ( ( mViewHeight * aZoom ) - mViewWidth + ( aZoom * mBaseMatrixValues[ 2 ] ) );
theMaxTopValue = ( ( mViewWidth * aZoom ) - mViewHeight + ( aZoom * mBaseMatrixValues[ 5 ] ) );
if( Math.abs( aFloats[ 2 ] ) > ( theMaxLeftValue ) )
{
aFloats[ 2 ] = -Math.abs( theMaxLeftValue ) + 10;
}
else if( Math.abs( aFloats[ 2 ] ) < ( aZoom * mBaseMatrixValues[ 2 ] ) )
{
aFloats[ 2 ] = -( aZoom * mBaseMatrixValues[ 2 ] );
}
if( Math.abs( aFloats[ 5 ] ) > ( theMaxTopValue ) )
{
aFloats[ 5 ] = -Math.abs( theMaxTopValue ) + 10;
}
else if( Math.abs( aFloats[ 5 ] ) < ( aZoom * mBaseMatrixValues[ 5 ] ) )
{
aFloats[ 5 ] = -( aZoom * mBaseMatrixValues[ 5 ] );
}
if( aFloats[ 2 ] > 0 )
aFloats[ 2 ] = -( mViewWidth / 2 );
else if( aFloats[ 5 ] > 0 )
aFloats[ 5 ] = -( mViewHeight / 2 );
return aFloats;
}
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