java - 自定义底部导航 View

Question

我使用 OpenCV 开发了一个 Android 应用程序。用户界面有底部导航 View 。当我按下底部导航 View 中的项目时，它会实时将不同的过滤器应用于 JavaCameraView。

我的问题是底部导航看起来很平坦。我想让按钮等项目从其位置升高，这样它们就不会与用户界面的其余部分处于同一平面。

我知道底部工作表，但这对我没有帮助。我已经完全开发了该应用程序并完成了设计。除了底部导航 View 之外，我无法使用任何 View 。

我可以在 BottomNavigationView 对象上使用任何 XML 属性或任何方法来使项目从其位置提升吗？

导航 View :

<android.support.design.widget.BottomNavigationView
  android:id="@+id/navigation"
  android:layout_width="match_parent"
  android:layout_height="45dp"
  android:layout_gravity="start"
  app:itemTextColor="@color/cardview_light_background"
  android:background="?android:attr/windowBackground"
  app:menu="@menu/nav" />

商品代码:

<?xml version="1.0" encoding="utf-8"?>
  <menu xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto">
    <item android:id="@+id/fiter1" android:title="Filter 1" />
    <item android:id="@+id/filter2" android:title="Filter 2" />
    <item android:id="@+id/filter3" android:title="Filter 3" />
  </menu>

Answer 1

使用自定义类，我们可以在弯曲底部导航 View 中绘制弯曲的自定义形状。通过使用下面的 XML

<android.tutorial.curvedbottombar.CurvedBottomNavigationView
            android:id="@+id/customBottomBar"
            android:layout_width="match_parent"
            android:layout_height="62dp"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="parent" />

对于 Java 类来说是

public class CurvedBottomNavigationView extends BottomNavigationView {
    private Path mPath;
    private Paint mPaint;


    /** the CURVE_CIRCLE_RADIUS represent the radius of the fab button */
    public final int CURVE_CIRCLE_RADIUS = 256 / 3;
    // the coordinates of the first curve
    public Point mFirstCurveStartPoint = new Point();
    public Point mFirstCurveEndPoint = new Point();
    public Point mFirstCurveControlPoint2 = new Point();
    public Point mFirstCurveControlPoint1 = new Point();

    //the coordinates of the second curve
    @SuppressWarnings("FieldCanBeLocal")
    public Point mSecondCurveStartPoint = new Point();
    public Point mSecondCurveEndPoint = new Point();
    public Point mSecondCurveControlPoint1 = new Point();
    public Point mSecondCurveControlPoint2 = new Point();
    public int mNavigationBarWidth;
    public int mNavigationBarHeight;

    public CurvedBottomNavigationView(Context context) {
        super(context);
        init();
    }

    public CurvedBottomNavigationView(Context context, AttributeSet attrs) {
        super(context, attrs);
        init();
    }

    public CurvedBottomNavigationView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        init();
    }

    private void init() {
        mPath = new Path();
        mPaint = new Paint();
        mPaint.setStyle(Paint.Style.FILL_AND_STROKE);
        mPaint.setColor(Color.WHITE);
        setBackgroundColor(Color.TRANSPARENT);
    }

    @Override
    protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
        super.onLayout(changed, left, top, right, bottom);

    }

    @Override
    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
        super.onSizeChanged(w, h, oldw, oldh);
        // get width and height of navigation bar
        // Navigation bar bounds (width & height)
         mNavigationBarWidth = getWidth();
         mNavigationBarHeight = getHeight();
        // the coordinates (x,y) of the start point before curve
        mFirstCurveStartPoint.set((mNavigationBarWidth / 2) - (CURVE_CIRCLE_RADIUS * 2) - (CURVE_CIRCLE_RADIUS / 3), 0);
        // the coordinates (x,y) of the end point after curve
        mFirstCurveEndPoint.set(mNavigationBarWidth / 2, CURVE_CIRCLE_RADIUS + (CURVE_CIRCLE_RADIUS / 4));
        // same thing for the second curve
        mSecondCurveStartPoint = mFirstCurveEndPoint;
        mSecondCurveEndPoint.set((mNavigationBarWidth / 2) + (CURVE_CIRCLE_RADIUS * 2) + (CURVE_CIRCLE_RADIUS / 3), 0);

        // the coordinates (x,y)  of the 1st control point on a cubic curve
        mFirstCurveControlPoint1.set(mFirstCurveStartPoint.x + CURVE_CIRCLE_RADIUS + (CURVE_CIRCLE_RADIUS / 4), mFirstCurveStartPoint.y);
        // the coordinates (x,y)  of the 2nd control point on a cubic curve
        mFirstCurveControlPoint2.set(mFirstCurveEndPoint.x - (CURVE_CIRCLE_RADIUS * 2) + CURVE_CIRCLE_RADIUS, mFirstCurveEndPoint.y);

        mSecondCurveControlPoint1.set(mSecondCurveStartPoint.x + (CURVE_CIRCLE_RADIUS * 2) - CURVE_CIRCLE_RADIUS, mSecondCurveStartPoint.y);
        mSecondCurveControlPoint2.set(mSecondCurveEndPoint.x - (CURVE_CIRCLE_RADIUS + (CURVE_CIRCLE_RADIUS / 4)), mSecondCurveEndPoint.y);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        mPath.reset();
        mPath.moveTo(0, 0);
        mPath.lineTo(mFirstCurveStartPoint.x, mFirstCurveStartPoint.y);

        mPath.cubicTo(mFirstCurveControlPoint1.x, mFirstCurveControlPoint1.y,
                mFirstCurveControlPoint2.x, mFirstCurveControlPoint2.y,
                mFirstCurveEndPoint.x, mFirstCurveEndPoint.y);

        mPath.cubicTo(mSecondCurveControlPoint1.x, mSecondCurveControlPoint1.y,
                mSecondCurveControlPoint2.x, mSecondCurveControlPoint2.y,
                mSecondCurveEndPoint.x, mSecondCurveEndPoint.y);

        mPath.lineTo(mNavigationBarWidth, 0);
        mPath.lineTo(mNavigationBarWidth, mNavigationBarHeight);
        mPath.lineTo(0, mNavigationBarHeight);
        mPath.close();

        canvas.drawPath(mPath, mPaint);
    }
}

您可以从Here下载完整的源代码