基于我之前的问题“如何在camera2 Android api中创建一个BottomBar作为StickyBottomCaptureLayout？“，我创建了一个布局StickyBar(SB) 始终锁定在系统栏上方/附近。我设置了 SB 和其他布局的默认位置和坐标onLayout()（确切地作为我的回答).
上面的布局是简单的自定义DrawView其中有一个 ArrayListPath由用户绘制。当设备旋转时，它会调用onDraw()并多次致电canvas.drawPath()。但是，那Paths 使用与之前相同的坐标重新绘制，但位置和布局大小不同。这些屏幕截图展示了实际行为：
left: portrait - right: landscape
但我想在方向改变时保持相同的坐标和位置，如下所示：
left: same portrait as above - right: landscape with "portrait" coordinates
锁定我的活动android:orientation="portrait"不是预期的解决方案。我用android:configChanges="orientation" and an OrientationListener检测旋转并防止完全重新创建Activity.
onLayout()但显然，这不是正确的方式。我之前尝试过转换倍数Path像这样：
for (Path path : mPathList) {
Matrix matrix = new Matrix();
RectF bounds = new RectF();
path.computeBounds(bounds, true);
// center points to rotate
final float px = bounds.centerX();
final float py = bounds.centerY();
// distance points to move
final float dx; // ?
final float dy; // ?
/** I tried many calculations without success, it's
not worth to paste these dumb calculations here... **/
matrix.postRotate(rotation, px, py); // rotation is 90°, -90° or 0
matrix.postTranslate(dx, dy); // ?
path.transform(matrix);
}
我还尝试按如下方式旋转画布：
@Override
protected void onDraw(Canvas canvas) {
canvas.save();
canvas.rotate(rotation); // rotation is 90°, -90° or 0
canvas.drawColor(mDrawHelper.getBackgroundViewColor());
for (int i=0; i < mPathList.size(); i++) {
canvas.drawPath(mPathList.get(i), mPaintList.get(i));
}
if (mPath != null && mPaint != null)
canvas.drawPath(mPath, mPaint);
canvas.restore();
}
无论如何，我尝试了很多操作，但在这种特定情况下似乎没有任何效果。有人有一个聪明绝妙的想法可以分享，可以引导我走向正确的方向吗？
先谢谢您的帮助。
Update:方法已经简化并且更容易遵循。示例应用程序已更新。
我想我明白你想做什么。您希望图形保持其与对象的关系StickyCaptureLayout你已经定义了。我喜欢使用的方法Path and Matrix转变。
确定设备经历的旋转后，创建一个Matrix进行适当的旋转并绕图形中心旋转。
mMatrix.postRotate(rotationDegrees, oldBounds.centerX(), oldBounds.centerY());
Here oldBounds是定位之前图形的边界。我们将使用它来确定旋转图形的边距。继续进行旋转
mPath.transform(mMatrix)
图形已旋转，但其位置不正确。它处于旧位置但已旋转。创建翻译Matrix移动Path到适当的位置。实际计算取决于旋转。对于 90 度旋转，计算为
transY = -newBounds.bottom; // move bottom of graphic to top of View
transY += getHeight(); // move to bottom of rotated view
transY -= (getHeight() - oldBounds.right); // finally move up by old right margin
transX = -newBounds.left; // Pull graphic to left of container
transX += getWidth() - oldBounds.bottom; // and pull right for margin
where transY是 Y 平移并且transX是 X 平移。oldBounds是预旋转边界，newBounds是旋转后的边界。这里需要注意的是getWidth()会给你“旧”View身高和getHeight()会给你旧的View width.
这是一个完成我上面描述的内容的示例程序。下面的几个图形显示了使用此示例应用程序进行的 90 度旋转。
Demo app
package com.example.rotatetranslatedemo;
import android.app.Activity;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.RectF;
import android.os.Bundle;
import android.view.Display;
import android.view.Surface;
import android.view.View;
import android.view.WindowManager;
public class MainActivity extends Activity {
private DrawingView dv;
private Paint mPaint;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
dv = new DrawingView(this);
setContentView(dv);
mPaint = new Paint();
mPaint.setAntiAlias(true);
mPaint.setDither(true);
mPaint.setColor(Color.GREEN);
mPaint.setStyle(Paint.Style.STROKE);
mPaint.setStrokeJoin(Paint.Join.ROUND);
mPaint.setStrokeCap(Paint.Cap.ROUND);
mPaint.setStrokeWidth(12);
}
public class DrawingView extends View {
private Bitmap mBitmap;
private Path mPath;
private Paint mBitmapPaint;
Context context;
private Paint paint;
Matrix mMatrix = new Matrix();
RectF oldBounds = new RectF();
RectF newBounds = new RectF();
public DrawingView(Context c) {
super(c);
context = c;
mBitmapPaint = new Paint(Paint.DITHER_FLAG);
paint = new Paint();
paint.setAntiAlias(true);
paint.setColor(Color.BLUE);
paint.setStyle(Paint.Style.STROKE);
paint.setStrokeJoin(Paint.Join.MITER);
paint.setStrokeWidth(4f);
}
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
super.onSizeChanged(w, h, oldw, oldh);
mBitmap = Bitmap.createBitmap(w, h, Bitmap.Config.ARGB_8888);
}
@Override
protected void onDraw(Canvas canvas) {
Display display = ((WindowManager) context.getSystemService(Context.WINDOW_SERVICE))
.getDefaultDisplay();
int rotationDegrees = 0;
float transX = 0;
float transY = 0;
super.onDraw(canvas);
canvas.drawBitmap(mBitmap, 0, 0, mBitmapPaint);
// Determine the rotation of the screen.
switch (display.getRotation()) {
case Surface.ROTATION_0:
break;
case Surface.ROTATION_90:
rotationDegrees = 270;
break;
case Surface.ROTATION_180:
rotationDegrees = 180;
break;
case Surface.ROTATION_270:
rotationDegrees = 90;
break;
default:
rotationDegrees = 0;
break;
}
if (mPath == null) { // Just define what we are drawing/moving
mPath = setupGraphic();
}
// Reposition the graphic taking into account the current rotation.
if (rotationDegrees != 0) {
mMatrix.reset();
// Rotate the graphic by its center and in place.
mPath.computeBounds(oldBounds, true);
mMatrix.postRotate(rotationDegrees, oldBounds.centerX(), oldBounds.centerY());
mPath.transform(mMatrix);
// Get the bounds of the rotated graphic
mPath.computeBounds(newBounds, true);
mMatrix.reset();
if (rotationDegrees == 90) {
transY = -newBounds.bottom; // move bottom of graphic to top of View
transY += getHeight(); // move to bottom of rotated view
transY -= (getHeight() - oldBounds.right); // finally move up by old right margin
transX = -newBounds.left; // Pull graphic to left of container
transX += getWidth() - oldBounds.bottom; // and pull right for margin
} else if (rotationDegrees == 270) {
transY = -newBounds.top; // pull top of graphic to the top of View
transY += getHeight() - oldBounds.right; // move down for old right margin
transX = getWidth() - newBounds.right; // Pull to right side of View
transX -= getHeight() - oldBounds.right; // Reestablish right margin
}
mMatrix.postTranslate(transX, transY);
mPath.transform(mMatrix);
}
canvas.drawPath(mPath, mPaint);
}
// Define the graphix that we will draw and move.
private Path setupGraphic() {
int startX;
int startY;
final int border = 20;
Path path;
if (getHeight() > getWidth()) {
startX = getWidth() - border - 1;
startY = getHeight() - border - 1;
} else {
startX = getHeight() - border - 1;
startY = getWidth() - border - 1;
}
startX = startX - 200;
Pt[] myLines = {
new Pt(startX, startY),
new Pt(startX, startY - 500),
new Pt(startX, startY),
new Pt(startX - 100, startY),
new Pt(startX, startY - 500),
new Pt(startX - 50, startY - 400),
new Pt(startX, startY - 500),
new Pt(startX + 50, startY - 400),
new Pt(startX + 200, startY),
new Pt(startX + 200, startY - 500)
};
// Create the final Path
path = new Path();
for (int i = 0; i < myLines.length; i = i + 2) {
path.moveTo(myLines[i].x, myLines[i].y);
path.lineTo(myLines[i + 1].x, myLines[i + 1].y);
}
return path;
}
private static final String TAG = "DrawingView";
}
// Class to hold ordered pair
private class Pt {
float x, y;
Pt(float _x, float _y) {
x = _x;
y = _y;
}
}
}
Portrait
景观
