最近，我使用了一个实现来使用 SurfaceView 放大我的 TextureView。缩放效果很好，但视图不会增长到屏幕的尺寸。在我的情况下，TextureView 的尺寸始终为 1080、612。我想修改此缩放比例，以便在捏捏时视图填充屏幕。
这是接收 TextureView 的类的代码：
public class ScaleManager extends BaseInputManager {
private final TextureView mTargetView;
private final ScaleGestureDetector mScaleDetector;
private static final float MIN_SCALE = 1.0f;
private static final float MAX_SCALE = 5.0f;
private float mCurrentScale = MIN_SCALE;
private Matrix mMatrix = new Matrix();
private float[] mMatrixValues = new float[9];
private float mPreviousX;
private float mPreviousY;
private boolean mIsDragInProgress = false;
public ScaleManager(TextureView view) {
mTargetView = view;
mScaleDetector = new ScaleGestureDetector(view.getContext(), new ScaleListener());
mScaleDetector.setQuickScaleEnabled(false);
}
@Override
public boolean handle(KeyEvent event) {
return false;
}
@Override
public boolean handle(MotionEvent event) {
final int index = event.getActionIndex();
final int type = event.getToolType(index);
if (type == MotionEvent.TOOL_TYPE_FINGER || type == MotionEvent.TOOL_TYPE_STYLUS) {
mScaleDetector.onTouchEvent(event);
mMatrix.getValues(mMatrixValues);
boolean isScaling = (mMatrixValues[Matrix.MSCALE_X] != 1.0f && mMatrixValues[Matrix.MSCALE_Y] != 1.0f);
if (isScaling || mScaleDetector.isInProgress()) {
switch (event.getAction()) {
case MotionEvent.ACTION_POINTER_DOWN:
case MotionEvent.ACTION_DOWN:
if (event.getPointerCount() <= 2) {
mPreviousX = event.getX();
mPreviousY = event.getY();
}
if (event.getPointerCount() == 2) {
mIsDragInProgress = true;
}
break;
case MotionEvent.ACTION_MOVE:
if (event.getPointerCount() == 2) {
float x = mMatrixValues[Matrix.MTRANS_X];
float y = mMatrixValues[Matrix.MTRANS_Y];
float width = mTargetView.getWidth();
float height = mTargetView.getHeight();
float right = width * mCurrentScale - width;
float bottom = height * mCurrentScale - height;
float deltaX = event.getX() - mPreviousX;// x difference
float deltaY = event.getY() - mPreviousY;// y difference
float scaledWidth = Math.round(width * mCurrentScale);// width after applying current scale
float scaledHeight = Math.round(height * mCurrentScale);// height after applying current scale
//if scaledWidth is smaller than the views width
//in other words if the image width fits in the view
//limit left and right movement
if (scaledWidth < width) {
deltaX = 0;
if (y + deltaY > 0) {
deltaY = -y;
} else if (y + deltaY < -bottom) {
deltaY = -(y + bottom);
}
//if scaledHeight is smaller than the views height
//in other words if the image height fits in the view
//limit up and down movement
} else if (scaledHeight < height) {
deltaY = 0;
if (x + deltaX > 0) {
deltaX = -x;
} else if (x + deltaX < -right) {
deltaX = -(x + right);
}
//if the image doesn't fit in the width or height
//limit both up and down and left and right
} else {
if (x + deltaX > 0) {
deltaX = -x;
} else if (x + deltaX < -right) {
deltaX = -(x + right);
}
if (y + deltaY > 0) {
deltaY = -y;
} else if (y + deltaY < -bottom) {
deltaY = -(y + bottom);
}
}
//move the image with the matrix
mMatrix.postTranslate(deltaX, deltaY);
mTargetView.setTransform(mMatrix);
mTargetView.invalidate();
mPreviousX = event.getX();
mPreviousY = event.getY();
}
break;
case MotionEvent.ACTION_POINTER_UP:
case MotionEvent.ACTION_UP:
if (event.getPointerCount() == 1) {
mIsDragInProgress = false;
}
break;
}
}
return mScaleDetector.isInProgress() || mIsDragInProgress;
}
return false;
}
private class ScaleListener implements ScaleGestureDetector.OnScaleGestureListener {
@Override
public boolean onScaleBegin(ScaleGestureDetector detector) {
return true;
}
@Override
public boolean onScale(ScaleGestureDetector detector) {
float width = mTargetView.getWidth();
float height = mTargetView.getHeight();
float factor = detector.getScaleFactor();
float scale = mCurrentScale * factor;
if (scale > MAX_SCALE) {
factor = MAX_SCALE / mCurrentScale;
mCurrentScale = MAX_SCALE;
} else if (scale < MIN_SCALE) {
factor = MIN_SCALE / mCurrentScale;
mCurrentScale = MIN_SCALE;
} else {
mCurrentScale = scale;
}
if (width * scale <= width || height * scale <= height) {
mMatrix.postScale(factor, factor, width / 2, height / 2);
} else {
mMatrix.postScale(factor, factor, detector.getFocusX(), detector.getFocusY());
}
if (factor < 1) {
float right = width * mCurrentScale - width;
float bottom = height * mCurrentScale - height;
mMatrix.getValues(mMatrixValues);
float x = mMatrixValues[Matrix.MTRANS_X];
float y = mMatrixValues[Matrix.MTRANS_Y];
if (x < -right) {
mMatrix.postTranslate(-(x + right), 0);
} else if (x > 0) {
mMatrix.postTranslate(-x, 0);
}
if (y < -bottom) {
mMatrix.postTranslate(0, -(y + bottom));
} else if (y > 0) {
mMatrix.postTranslate(0, -y);
}
}
return true;
}
@Override
public void onScaleEnd(ScaleGestureDetector detector) {
}
}
}
当我启动视图时，我使用一个类AspectFrameLayout来确定视图的初始比例。AspectFrameLayout每次修改视图以保持纵横比时都会调用它。按照代码：
<com.examples.views.AspectRatioFrameLayout
android:id="@+id/player_video"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_gravity="center"
android:focusable="true"
android:focusableInTouchMode="true" />
mSurfaceView = layoutInflater.inflate(R.layout.texture_view,
player_video_frame, false)
这是AspectFrameLayout我用来保持纵横比的类：
public final class AspectRatioFrameLayout extends FrameLayout {
private static final float MAX_ASPECT_RATIO_DEFORMATION_FRACTION = 0.01f;
private float mVideoAspectRatio;
public AspectRatioFrameLayout(Context context) {
super(context);
}
public AspectRatioFrameLayout(Context context, AttributeSet attrs) {
super(context, attrs);
}
public void setAspectRatio(float ratio) {
if (this.mVideoAspectRatio != ratio) {
this.mVideoAspectRatio = ratio;
requestLayout();
}
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
if (mVideoAspectRatio == 0) {
// Aspect ratio not set.
return;
}
int width = getMeasuredWidth();
int height = getMeasuredHeight();
float viewAspectRatio = (float) width / height;
float aspectDeformation = mVideoAspectRatio / viewAspectRatio - 1;
if (Math.abs(aspectDeformation) <= MAX_ASPECT_RATIO_DEFORMATION_FRACTION) {
// We're within the allowed tolerance.
return;
}
if (aspectDeformation > 0) {
height = (int) (width / mVideoAspectRatio);
} else {
width = (int) (height * mVideoAspectRatio);
}
super.onMeasure(
MeasureSpec.makeMeasureSpec(width, MeasureSpec.EXACTLY),
MeasureSpec.makeMeasureSpec(height, MeasureSpec.EXACTLY)
);
}
}