Elite Technority: October 2016

Menus are a common user interface component in many types of applications. To provide a familiar and consistent user experience, you should use the Menu APIs to present user actions and other options in your activities.
Although the design and user experience for some menu items have changed, the semantics to define a set of actions and options is still based on the Menu APIs.

A ViewGroup is a special view that can contain other views (called children.) The view group is the base class for layouts and views containers. This class also defines the ViewGroup.LayoutParams class which serves as the base class for layouts parameters.

void onLayout (boolean changed, int left, int top, int right, int bottom) method is called from layout when this view should assign a size and position to each of its children. Derived classes with children should override this method and call layout on each of their children.

void onMeasure (int widthMeasureSpec, int heightMeasureSpec) method measure the view and its content to determine the measured width and the measured height. This method is invoked by measure(int, int) and should be overridden by subclasses to provide accurate and efficient measurement of their contents.
When overriding this method, you must call setMeasuredDimension(int, int) to store the measured width and height of this view. Failure to do so will trigger an IllegalStateException, thrown by measure(int, int). Calling the superclass' onMeasure(int, int) is a valid use.
The base class implementation of measure defaults to the background size, unless a larger size is allowed by the MeasureSpec. Subclasses should override onMeasure(int, int) to provide better measurements of their content.
If this method is overridden, it is the subclass's responsibility to make sure the measured height and width are at least the view's minimum height and width (getSuggestedMinimumHeight() and getSuggestedMinimumWidth()).

Using these two methods we can create our circular view and add the child views in the layout arranging into circular layout. Finally, we can have circular menu UI which can give attractive look and feel to out applications.

Refer the below link for complete sample code:-

Download Sample Code

Have a look on few code snippets,

//activity_cicularmenu2.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:gravity="center_vertical"
    android:background="#590100"
    android:orientation="horizontal" >

    <circlemenulayout.CircleMenuLayout
        android:id="@+id/id_menulayout"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:padding="100dp"
        android:background="@drawable/circle_bg3" >

        <RelativeLayout
            android:id="@id/id_circle_menu_item_center"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content" >
            <TextView
                android:id="@+id/tv_circlemenu"
                android:textSize="25sp"
                android:textStyle="bold"
                android:textColor="#a5f406"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_centerInParent="true"/>
        </RelativeLayout>
    </circlemenulayout.CircleMenuLayout>

</LinearLayout>

//circle_menu_item.xml

<?xml version="1.0" encoding="UTF-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:gravity="center"
    android:orientation="vertical" >

    <ImageView
        android:id="@+id/id_circle_menu_item_image"
        android:layout_width="wrap_content"
        android:visibility="gone"
        android:layout_height="wrap_content" />

    <TextView
        android:id="@+id/id_circle_menu_item_text"
        android:layout_width="wrap_content"
        android:visibility="gone"
        android:layout_height="wrap_content"
        android:textColor="@android:color/white"
        android:text="text"
        android:textSize="16sp" />

</LinearLayout>

//CircleActivity.java

package com.example.harshalbenake.circularlayout;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.animation.Animation;
import android.view.animation.RotateAnimation;
import android.widget.TextView;
import android.widget.Toast;

import circlemenulayout.CircleMenuLayout;
import circlemenulayout.CircleMenuLayout.OnMenuItemClickListener;

/**
 * <pre>


 * </pre>
 */
public class CircleActivity extends Activity {

    private CircleMenuLayout mCircleMenuLayout;

    private String[] mItemTexts = new String[]{"Item 0", "Item 1", "Item 2", "Item 3",
            "Item 4", "Item 5", "Item 6"};
    private int[] mItemImgs = new int[]{
            R.drawable.ic_launcher,
            R.drawable.ic_launcher,
            R.drawable.ic_launcher,
            R.drawable.ic_launcher,
            R.drawable.ic_launcher,
            R.drawable.ic_launcher,
            R.drawable.ic_launcher};
    private TextView mtv_circlemenu;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_cicularmenu2);

        mCircleMenuLayout = (CircleMenuLayout) findViewById(R.id.id_menulayout);
        mtv_circlemenu = (TextView) findViewById(R.id.tv_circlemenu);

        mCircleMenuLayout.setMenuItemIconsAndTexts(mItemImgs, mItemTexts);
        mCircleMenuLayout.setOnMenuItemClickListener(new OnMenuItemClickListener() {

            @Override
            public void itemClick(final View view, int pos) {
                mtv_circlemenu.setText(mItemTexts[pos]);
                Animation rotateAnimation = new RotateAnimation(0, 360, view.getWidth() / 2, view.getHeight() / 2);
                rotateAnimation.setDuration(250);
                view.startAnimation(rotateAnimation);
            }

            @Override
            public void itemCenterClick(View view) {
                Toast.makeText(CircleActivity.this, "Middle Item Clicked", Toast.LENGTH_SHORT).show();

            }
        });

    }

}

//CircleMenuLayout.java

package circlemenulayout;

import android.content.Context;
import android.util.AttributeSet;
import android.util.DisplayMetrics;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewGroup;
import android.view.WindowManager;
import android.widget.ImageView;
import android.widget.TextView;
import com.example.harshalbenake.circularlayout.R;


public class CircleMenuLayout extends ViewGroup {
    private int mRadius;
    private static final float RADIO_DEFAULT_CHILD_DIMENSION = 1 / 4f;
    private float RADIO_DEFAULT_CENTERITEM_DIMENSION = 1 / 3f;
    private static final float RADIO_PADDING_LAYOUT = 1 / 12f;
    private static final int FLINGABLE_VALUE = 300;
    private static final int NOCLICK_VALUE = 3;
    private int mFlingableValue = FLINGABLE_VALUE;
    private float mPadding;
    private double mStartAngle = 0;
    private String[] mItemTexts;
    private int[] mItemImgs;
    private int mMenuItemCount;
    private float mTmpAngle;
    private long mDownTime;
    private boolean isFling;
    private int mMenuItemLayoutId = R.layout.circle_menu_item;

    public CircleMenuLayout(Context context, AttributeSet attrs) {
        super(context, attrs);
        setPadding(0, 0, 0, 0);
    }


    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        int resWidth = 0;
        int resHeight = 0;


        int width = MeasureSpec.getSize(widthMeasureSpec);
        int widthMode = MeasureSpec.getMode(widthMeasureSpec);

        int height = MeasureSpec.getSize(heightMeasureSpec);
        int heightMode = MeasureSpec.getMode(heightMeasureSpec);


        if (widthMode != MeasureSpec.EXACTLY
                || heightMode != MeasureSpec.EXACTLY) {
            resWidth = getSuggestedMinimumWidth();
            resWidth = resWidth == 0 ? getDefaultWidth() : resWidth;

            resHeight = getSuggestedMinimumHeight();
            resHeight = resHeight == 0 ? getDefaultWidth() : resHeight;
        } else {
            resWidth = resHeight = Math.min(width, height);
        }

        setMeasuredDimension(resWidth, resHeight);

        mRadius = Math.max(getMeasuredWidth(), getMeasuredHeight());

        final int count = getChildCount();
        int childSize = (int) (mRadius * RADIO_DEFAULT_CHILD_DIMENSION);
        int childMode = MeasureSpec.EXACTLY;

        for (int i = 0; i < count; i++) {
            final View child = getChildAt(i);

            if (child.getVisibility() == GONE) {
                continue;
            }

            int makeMeasureSpec = -1;

            if (child.getId() == R.id.id_circle_menu_item_center) {
                makeMeasureSpec = MeasureSpec.makeMeasureSpec(
                        (int) (mRadius * RADIO_DEFAULT_CENTERITEM_DIMENSION),
                        childMode);
            } else {
                makeMeasureSpec = MeasureSpec.makeMeasureSpec(childSize,
                        childMode);
            }
            child.measure(makeMeasureSpec, makeMeasureSpec);
        }

        mPadding = RADIO_PADDING_LAYOUT * mRadius;

    }

    public interface OnMenuItemClickListener {
        void itemClick(View view, int pos);

        void itemCenterClick(View view);
    }


    private OnMenuItemClickListener mOnMenuItemClickListener;

    /**
     *
     * @param mOnMenuItemClickListener
     */
    public void setOnMenuItemClickListener(
            OnMenuItemClickListener mOnMenuItemClickListener) {
        this.mOnMenuItemClickListener = mOnMenuItemClickListener;
    }


    @Override
    protected void onLayout(boolean changed, int l, int t, int r, int b) {
        int layoutRadius = mRadius;

        // Laying out the child views
        final int childCount = getChildCount();

        int left, top;
        // menu item
        int cWidth = (int) (layoutRadius * RADIO_DEFAULT_CHILD_DIMENSION);

        float angleDelay = 360 / (getChildCount() - 1);

        for (int i = 0; i < childCount; i++) {
            final View child = getChildAt(i);

            if (child.getId() == R.id.id_circle_menu_item_center)
                continue;

            if (child.getVisibility() == GONE) {
                continue;
            }

            mStartAngle %= 360;

            float tmp = layoutRadius / 2f - cWidth / 2 - mPadding;

            left = layoutRadius
                    / 2
                    + (int) Math.round(tmp
                    * Math.cos(Math.toRadians(mStartAngle)) - 1 / 2f
                    * cWidth);
            top = layoutRadius
                    / 2
                    + (int) Math.round(tmp
                    * Math.sin(Math.toRadians(mStartAngle)) - 1 / 2f
                    * cWidth);

            child.layout(left, top, left + cWidth, top + cWidth);
            mStartAngle += angleDelay;
        }

        View cView = findViewById(R.id.id_circle_menu_item_center);
        if (cView != null) {
            cView.setOnClickListener(new OnClickListener() {
                @Override
                public void onClick(View v) {

                    if (mOnMenuItemClickListener != null) {
                        mOnMenuItemClickListener.itemCenterClick(v);
                    }
                }
            });
            int cl = layoutRadius / 2 - cView.getMeasuredWidth() / 2;
            int cr = cl + cView.getMeasuredWidth();
            cView.layout(cl, cl, cr, cr);
        }

    }

    private float mLastX;
    private float mLastY;


    private AutoFlingRunnable mFlingRunnable;

    @Override
    public boolean dispatchTouchEvent(MotionEvent event) {
        float x = event.getX();
        float y = event.getY();

        // Log.e("TAG", "x = " + x + " , y = " + y);

        switch (event.getAction()) {
            case MotionEvent.ACTION_DOWN:

                mLastX = x;
                mLastY = y;
                mDownTime = System.currentTimeMillis();
                mTmpAngle = 0;

                if (isFling) {
                    removeCallbacks(mFlingRunnable);
                    isFling = false;
                    return true;
                }

                break;
            case MotionEvent.ACTION_MOVE:

                float start = getAngle(mLastX, mLastY);

                float end = getAngle(x, y);

                // Log.e("TAG", "start = " + start + " , end =" + end);
                if (getQuadrant(x, y) == 1 || getQuadrant(x, y) == 4) {
                    mStartAngle += end - start;
                    mTmpAngle += end - start;
                } else
                {
                    mStartAngle += start - end;
                    mTmpAngle += start - end;
                }
                requestLayout();

                mLastX = x;
                mLastY = y;

                break;
            case MotionEvent.ACTION_UP:

                float anglePerSecond = mTmpAngle * 1000
                        / (System.currentTimeMillis() - mDownTime);

                // Log.e("TAG", anglePrMillionSecond + " , mTmpAngel = " +
                // mTmpAngle);

                if (Math.abs(anglePerSecond) > mFlingableValue && !isFling) {
                    post(mFlingRunnable = new AutoFlingRunnable(anglePerSecond));

                    return true;
                }

                if (Math.abs(mTmpAngle) > NOCLICK_VALUE) {
                    return true;
                }

                break;
        }
        return super.dispatchTouchEvent(event);
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        return true;
    }

    /**
     *
     * @param xTouch
     * @param yTouch
     * @return
     */
    private float getAngle(float xTouch, float yTouch) {
        double x = xTouch - (mRadius / 2d);
        double y = yTouch - (mRadius / 2d);
        return (float) (Math.asin(y / Math.hypot(x, y)) * 180 / Math.PI);
    }

    /**
     *
     * @param x
     * @param y
     * @return
     */
    private int getQuadrant(float x, float y) {
        int tmpX = (int) (x - mRadius / 2);
        int tmpY = (int) (y - mRadius / 2);
        if (tmpX >= 0) {
            return tmpY >= 0 ? 4 : 1;
        } else {
            return tmpY >= 0 ? 3 : 2;
        }

    }

    /**
     *
     * @param resIds
     */
    public void setMenuItemIconsAndTexts(int[] resIds, String[] texts) {
        mItemImgs = resIds;
        mItemTexts = texts;

        if (resIds == null && texts == null) {
            throw new IllegalArgumentException("IllegalArgumentException");
        }

        mMenuItemCount = resIds == null ? texts.length : resIds.length;

        if (resIds != null && texts != null) {
            mMenuItemCount = Math.min(resIds.length, texts.length);
        }

        addMenuItems();

    }

    /**
     *
     * @param mMenuItemLayoutId
     */
    public void setMenuItemLayoutId(int mMenuItemLayoutId) {
        this.mMenuItemLayoutId = mMenuItemLayoutId;
    }

    /**
     */
    private void addMenuItems() {
        LayoutInflater mInflater = LayoutInflater.from(getContext());


        for (int i = 0; i < mMenuItemCount; i++) {
            final int j = i;
            View view = mInflater.inflate(mMenuItemLayoutId, this, false);
            ImageView iv = (ImageView) view
                    .findViewById(R.id.id_circle_menu_item_image);
            TextView tv = (TextView) view
                    .findViewById(R.id.id_circle_menu_item_text);

            if (iv != null) {
                iv.setVisibility(View.VISIBLE);
                iv.setImageResource(mItemImgs[i]);
                iv.setOnClickListener(new OnClickListener() {
                    @Override
                    public void onClick(View v) {

                        if (mOnMenuItemClickListener != null) {
                            mOnMenuItemClickListener.itemClick(v, j);
                        }
                    }
                });
            }
            if (tv != null) {
                tv.setVisibility(View.VISIBLE);
                tv.setText(mItemTexts[i]);
            }

            addView(view);
        }
    }

    /**
     *
     * @param mFlingableValue
     */
    public void setFlingableValue(int mFlingableValue) {
        this.mFlingableValue = mFlingableValue;
    }

    /**
     *
     * @param mPadding
     */
    public void setPadding(float mPadding) {
        this.mPadding = mPadding;
    }

    /**
     *
     * @return
     */
    private int getDefaultWidth() {
        WindowManager wm = (WindowManager) getContext().getSystemService(
                Context.WINDOW_SERVICE);
        DisplayMetrics outMetrics = new DisplayMetrics();
        wm.getDefaultDisplay().getMetrics(outMetrics);
        return Math.min(outMetrics.widthPixels, outMetrics.heightPixels);
    }


    public class AutoFlingRunnable implements Runnable {

        private float angelPerSecond;

        public AutoFlingRunnable(float velocity) {
            this.angelPerSecond = velocity;
        }

        public void run() {
            if ((int) Math.abs(angelPerSecond) < 20) {
                isFling = false;
                return;
            }
            isFling = true;
            mStartAngle += (angelPerSecond / 30);
            angelPerSecond /= 1.0666F;
            postDelayed(this, 30);
            requestLayout();
        }
    }

}