android 适配器模式训练（一）前期布局

package com.example.asus.ndk.circlemenulayout;

import android.content.Context;
import android.util.AttributeSet;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TextView;

import com.example.asus.ndk.R;

public class CircleMenuLayout extends ViewGroup {
    //圆形直径
    private int mRadius;
    //该容器内child item 默认尺寸
    private static final float RADIO_DEFAULT_CHILD_DIMENSION = 1 / 4f;
    private static final float RADIO_PADDING_LAYOUT = 1 / 12f;
    private float mPadding;
    private double mStartAngle = 0;
    private String[] itemText;
    private int[] itemImgs;
    private int mMenuItemCount;
    private int mMenuLayoutId = R.layout.circle_menu_item;
    
    public CircleMenuLayout(Context context) {
        super(context);
    }
    
    public CircleMenuLayout(Context context, AttributeSet attrs) {
        super(context, attrs);
        setPadding(0,0,0,0);
    }
    public void setMenuItemIconsAndText(String[] text,int[] img){
        if (text == null && img == null){
            throw new IllegalArgumentException("菜单设置项最少一项");
        }
        itemText = text;
        itemImgs = img;
        mMenuItemCount = itemImgs == null ? text.length : img.length;
        if (img != null && text != null){
            mMenuItemCount = Math.min(img.length,text.length);
        }
        buildMenuItem();
    }

    private void buildMenuItem() {
        for (int i = 0;i<mMenuItemCount;++i){
            View view = inflateMenuView(i);
            initMenuItem(view,i);
            addView(view);

        };
    }
    private View inflateMenuView(int childView){
        LayoutInflater inflater = LayoutInflater.from(getContext());
        View itemView = inflater.inflate(mMenuLayoutId,this,false);
        return itemView;
    }
    //初始化菜单
    private void initMenuItem(View view,int position){
        ImageView imageView = view.findViewById(R.id.circle_menu_img);
        TextView textView = view.findViewById(R.id.circle_menu_text);
        imageView.setVisibility(VISIBLE);
        imageView.setImageResource(itemImgs[position]);
        textView.setVisibility(VISIBLE);
        textView.setText(itemText[position]);
    }
    //设置menu itemView id
    public void setMenuItemLayoutId(int layoutId){
        mMenuLayoutId = layoutId;
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        //丈量自身尺寸
        measureMyself(widthMeasureSpec,heightMeasureSpec);
        //丈量自布局
        measureChildView();


    }
    private void measureMyself(int widthMeasureSpec,int heightMeasureSpec){
        int resWidth = 0;
        int resHeight = 0;
        int width = MeasureSpec.getSize(widthMeasureSpec);
        int height = MeasureSpec.getSize(heightMeasureSpec);
        int widthMode = MeasureSpec.getMode(widthMeasureSpec);
        int heightMode = MeasureSpec.getMode(heightMeasureSpec);
        if (widthMode == MeasureSpec.EXACTLY || heightMode == MeasureSpec.EXACTLY){
            resWidth = getSuggestedMinimumWidth();
            resWidth = resWidth == 0 ? getWidth() : resWidth;
            resHeight = getSuggestedMinimumHeight();
            resHeight = resHeight == 0 ? getHeight() : resHeight;
        }else {
            resWidth = resHeight = Math.min(width,height);
        }
        setMeasuredDimension(resWidth,resHeight);
    }
    private void measureChildView(){
        mRadius = Math.max(getMeasuredWidth(),getMeasuredHeight());
        //menu 数量
        int menuCount = getChildCount();
        //menu 尺寸
        int childSize = (int) (mRadius * RADIO_DEFAULT_CHILD_DIMENSION);
        int childMode = MeasureSpec.EXACTLY;
        for (int i=0;i<menuCount;++i){
            View child = getChildAt(i);
            if (child.getVisibility() == GONE){
                continue;
            }
            //计算menu item的尺寸，以及设置好的模式，对item进行测量
            int makeMeasureSpec = -1;
            makeMeasureSpec = MeasureSpec.makeMeasureSpec(childSize,childMode);
            child.measure(makeMeasureSpec,makeMeasureSpec);
        };
        mPadding = RADIO_PADDING_LAYOUT * mRadius;

    }
    @Override
    protected void onLayout(boolean changed, int l, int t, int r, int b) {
        int childCount = getChildCount();
        int left,top;
        int itemWidth = (int) (mRadius * RADIO_DEFAULT_CHILD_DIMENSION);
        float angleDelay = 360/childCount;
        for (int i=0;i<childCount;++i){
            View child = getChildAt(i);
            if (child.getVisibility() == GONE){
                continue;
            }
            mStartAngle %= 360;
            int distanceFromCenter = (int) (mRadius/2f - itemWidth/2 - mPadding);
            left = mRadius/2 + (int) Math.round(distanceFromCenter * Math.cos(Math.toRadians(mStartAngle))-1/2f*itemWidth);
            top = mRadius/2 + (int) Math.round(distanceFromCenter*Math.sin(Math.toRadians(mStartAngle))-1/2f*itemWidth);
            child.layout(left,top,left+itemWidth,top+itemWidth);
            mStartAngle += angleDelay;
        }
    }


}