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package com.android.deskclock;
import android.content.Context;
import android.content.res.Resources;
import android.util.AttributeSet;
import android.view.View;
import android.widget.Button;
import android.widget.FrameLayout;
import android.widget.TextView;
/**
* This class adjusts the locations of child buttons and text of this view group by adjusting the
* margins of each item. The left and right buttons are aligned with the bottom of the circle. The
* stop button and label text are located within the circle with the stop button near the bottom and
* the label text near the top. The maximum text size for the label text view is also calculated.
*/
public class CircleButtonsLayout extends FrameLayout {
private float mDiamOffset;
private View mCircleView;
private Button mResetAddButton;
private TextView mLabel;
@SuppressWarnings("unused")
public CircleButtonsLayout(Context context) {
this(context, null);
}
public CircleButtonsLayout(Context context, AttributeSet attrs) {
super(context, attrs);
final Resources res = getContext().getResources();
final float strokeSize = res.getDimension(R.dimen.circletimer_circle_size);
mDiamOffset = strokeSize * 2;
}
@Override
public void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
// We must call onMeasure both before and after re-measuring our views because the circle
// may not always be drawn here yet. The first onMeasure will force the circle to be drawn,
// and the second will force our re-measurements to take effect.
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
remeasureViews();
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
}
protected void remeasureViews() {
if (mLabel == null) {
mCircleView = findViewById(R.id.timer_time);
mLabel = (TextView) findViewById(R.id.timer_label);
mResetAddButton = (Button) findViewById(R.id.reset_add);
}
final int frameWidth = mCircleView.getMeasuredWidth();
final int frameHeight = mCircleView.getMeasuredHeight();
final int minBound = Math.min(frameWidth, frameHeight);
final int circleDiam = (int) (minBound - mDiamOffset);
if (mResetAddButton != null) {
final MarginLayoutParams resetAddParams = (MarginLayoutParams) mResetAddButton
.getLayoutParams();
resetAddParams.bottomMargin = circleDiam / 6;
if (minBound == frameWidth) {
resetAddParams.bottomMargin += (frameHeight - frameWidth) / 2;
}
}
if (mLabel != null) {
MarginLayoutParams labelParams = (MarginLayoutParams) mLabel.getLayoutParams();
labelParams.topMargin = circleDiam/6;
if (minBound == frameWidth) {
labelParams.topMargin += (frameHeight-frameWidth)/2;
}
/* The following formula has been simplified based on the following:
* Our goal is to calculate the maximum width for the label frame.
* We may do this with the following diagram to represent the top half of the circle:
* ___
* . | .
* ._________| .
* . ^ | .
* / x | \
* |_______________|_______________|
*
* where x represents the value we would like to calculate, and the final width of the
* label will be w = 2 * x.
*
* We may find x by drawing a right triangle from the center of the circle:
* ___
* . | .
* ._________| .
* . . | .
* / . | }y \
* |_____________.t|_______________|
*
* where t represents the angle of that triangle, and y is the height of that triangle.
*
* If r = radius of the circle, we know the following trigonometric identities:
* cos(t) = y / r
* and sin(t) = x / r
* => r * sin(t) = x
* and sin^2(t) = 1 - cos^2(t)
* => sin(t) = +/- sqrt(1 - cos^2(t))
* (note: because we need the positive value, we may drop the +/-).
*
* To calculate the final width, we may combine our formulas:
* w = 2 * x
* => w = 2 * r * sin(t)
* => w = 2 * r * sqrt(1 - cos^2(t))
* => w = 2 * r * sqrt(1 - (y / r)^2)
*
* Simplifying even further, to mitigate the complexity of the final formula:
* sqrt(1 - (y / r)^2)
* => sqrt(1 - (y^2 / r^2))
* => sqrt((r^2 / r^2) - (y^2 / r^2))
* => sqrt((r^2 - y^2) / (r^2))
* => sqrt(r^2 - y^2) / sqrt(r^2)
* => sqrt(r^2 - y^2) / r
* => sqrt((r + y)*(r - y)) / r
*
* Placing this back in our formula, we end up with, as our final, reduced equation:
* w = 2 * r * sqrt(1 - (y / r)^2)
* => w = 2 * r * sqrt((r + y)*(r - y)) / r
* => w = 2 * sqrt((r + y)*(r - y))
*/
// Radius of the circle.
int r = circleDiam / 2;
// Y value of the top of the label, calculated from the center of the circle.
int y = frameHeight / 2 - labelParams.topMargin;
// New maximum width of the label.
double w = 2 * Math.sqrt((r + y) * (r - y));
mLabel.setMaxWidth((int) w);
}
}
}
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