Android 实现QQ扩展listview(expandlistview)

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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"
    tools:context="com.example.yzj.android_8_2.ExpandListActivity">

    <ExpandableListView
        android:id="@+id/elv"
        android:layout_width="match_parent"
        android:layout_height="match_parent"></ExpandableListView>
</RelativeLayout>

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <TextView
        android:id="@+id/tv"
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:text="30dp"/>
</LinearLayout>

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="horizontal"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <com.example.yzj.android_8_2.CircleImageView
        android:id="@+id/civ"
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:src="@mipmap/ic_launcher"/>
    <TextView
        android:id="@+id/tv"
        android:layout_width="wrap_content"
        android:layout_height="match_parent" />
</LinearLayout>

package com.example.yzj.android_8_2;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseExpandableListAdapter;
import android.widget.ExpandableListView;
import android.widget.ImageView;
import android.widget.TextView;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class ExpandListActivity extends AppCompatActivity {
    private MyAdapter myAdapter;
    private ExpandableListView elv;
    private String[] parentsData = {"农大炮友", "北科炮友", "美国炮友"};
    private String[][] childData = {{"张三", "李四", "王五"}, {"赵六", "李七", "林八"}, {"Alice", "lucy"}};
    private int[][] imgs = {{R.drawable.a, R.drawable.b, R.drawable.c}, {R.drawable.a, R.drawable.b, R.drawable.c}, {R.drawable.a, R.drawable.b}};

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_expand_list);
        init();
        myAdapter=new MyAdapter();
        elv.setAdapter(myAdapter);
    }

    private void init() {
        elv = (ExpandableListView) findViewById(R.id.elv);
    }

    private class MyAdapter extends BaseExpandableListAdapter {

        @Override
        public int getGroupCount() {
            return parentsData.length;
        }

        @Override
        public int getChildrenCount(int groupPosition) {
            return childData.length;
        }

        @Override
        public Object getGroup(int groupPosition) {
            return null;
        }

        @Override
        public Object getChild(int groupPosition, int childPosition) {
            return null;
        }

        @Override
        public long getGroupId(int groupPosition) {
            return 0;
        }

        @Override
        public long getChildId(int groupPosition, int childPosition) {
            return 0;
        }

        @Override
        public boolean hasStableIds() {
            return false;
        }

        @Override
        public View getGroupView(int groupPosition, boolean isExpanded, View convertView, ViewGroup parent) {
            TextView tv = null;
            if (convertView == null) {
                convertView = View.inflate(ExpandListActivity.this, R.layout.layout_parents, null);
                tv =(TextView)convertView.findViewById(R.id.tv);
                convertView.setTag(tv);
            } else {
                tv = (TextView) convertView.getTag();
            }
                tv.setText(parentsData[groupPosition]);
            return convertView;
        }

        @Override
        public View getChildView(int groupPosition, int childPosition, boolean isLastChild, View convertView, ViewGroup parent) {
            ViewHolder holder=null;
            if(convertView==null){
                convertView=View.inflate(ExpandListActivity.this,R.layout.layout_child,null);
                holder=new ViewHolder();
                holder.img=(CircleImageView)convertView.findViewById(R.id.civ);
                holder.tv=(TextView)convertView.findViewById(R.id.tv);
                convertView.setTag(holder);
            }
            else{
                holder = (ViewHolder)convertView.getTag();
            }
            holder.img.setImageResource(imgs[groupPosition][childPosition]);
            holder.tv.setText(childData[groupPosition][childPosition]);
            return convertView;
        }

        @Override
        public boolean isChildSelectable(int groupPosition, int childPosition) {
            return true;
        }
    }
    private class ViewHolder{
        CircleImageView img;
        TextView tv;
    }
}

//这是一个圆形的View的代码，用来绘制圆形View
/*
 * Copyright 2014 - 2016 Henning Dodenhof
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.example.yzj.android_8_2;

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Bitmap;
import android.graphics.BitmapShader;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.ColorFilter;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.graphics.RectF;
import android.graphics.Shader;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.ColorDrawable;
import android.graphics.drawable.Drawable;
import android.net.Uri;
import android.support.annotation.ColorInt;
import android.support.annotation.ColorRes;
import android.support.annotation.DrawableRes;
import android.util.AttributeSet;
import android.widget.ImageView;

public class CircleImageView extends ImageView {

    private static final ScaleType SCALE_TYPE = ScaleType.CENTER_CROP;

    private static final Bitmap.Config BITMAP_CONFIG = Bitmap.Config.ARGB_8888;
    private static final int COLORDRAWABLE_DIMENSION = 2;

    private static final int DEFAULT_BORDER_WIDTH = 0;
    private static final int DEFAULT_BORDER_COLOR = Color.BLACK;
    private static final int DEFAULT_FILL_COLOR = Color.TRANSPARENT;
    private static final boolean DEFAULT_BORDER_OVERLAY = false;

    private final RectF mDrawableRect = new RectF();
    private final RectF mBorderRect = new RectF();

    private final Matrix mShaderMatrix = new Matrix();
    private final Paint mBitmapPaint = new Paint();
    private final Paint mBorderPaint = new Paint();
    private final Paint mFillPaint = new Paint();

    private int mBorderColor = DEFAULT_BORDER_COLOR;
    private int mBorderWidth = DEFAULT_BORDER_WIDTH;
    private int mFillColor = DEFAULT_FILL_COLOR;

    private Bitmap mBitmap;
    private BitmapShader mBitmapShader;
    private int mBitmapWidth;
    private int mBitmapHeight;

    private float mDrawableRadius;
    private float mBorderRadius;

    private ColorFilter mColorFilter;

    private boolean mReady;
    private boolean mSetupPending;
    private boolean mBorderOverlay;
    private boolean mDisableCircularTransformation;

    public CircleImageView(Context context) {
        super(context);

        init();
    }

    public CircleImageView(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public CircleImageView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);

        TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.CircleImageView, defStyle, 0);

        mBorderWidth = a.getDimensionPixelSize(R.styleable.CircleImageView_civ_border_width, DEFAULT_BORDER_WIDTH);
        mBorderColor = a.getColor(R.styleable.CircleImageView_civ_border_color, DEFAULT_BORDER_COLOR);
        mBorderOverlay = a.getBoolean(R.styleable.CircleImageView_civ_border_overlay, DEFAULT_BORDER_OVERLAY);
        mFillColor = a.getColor(R.styleable.CircleImageView_civ_fill_color, DEFAULT_FILL_COLOR);

        a.recycle();

        init();
    }

    private void init() {
        super.setScaleType(SCALE_TYPE);
        mReady = true;

        if (mSetupPending) {
            setup();
            mSetupPending = false;
        }
    }

    @Override
    public ScaleType getScaleType() {
        return SCALE_TYPE;
    }

    @Override
    public void setScaleType(ScaleType scaleType) {
        if (scaleType != SCALE_TYPE) {
            throw new IllegalArgumentException(String.format("ScaleType %s not supported.", scaleType));
        }
    }

    @Override
    public void setAdjustViewBounds(boolean adjustViewBounds) {
        if (adjustViewBounds) {
            throw new IllegalArgumentException("adjustViewBounds not supported.");
        }
    }

    @Override
    protected void onDraw(Canvas canvas) {
        if (mDisableCircularTransformation) {
            super.onDraw(canvas);
            return;
        }

        if (mBitmap == null) {
            return;
        }

        if (mFillColor != Color.TRANSPARENT) {
            canvas.drawCircle(mDrawableRect.centerX(), mDrawableRect.centerY(), mDrawableRadius, mFillPaint);
        }
        canvas.drawCircle(mDrawableRect.centerX(), mDrawableRect.centerY(), mDrawableRadius, mBitmapPaint);
        if (mBorderWidth > 0) {
            canvas.drawCircle(mBorderRect.centerX(), mBorderRect.centerY(), mBorderRadius, mBorderPaint);
        }
    }

    @Override
    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
        super.onSizeChanged(w, h, oldw, oldh);
        setup();
    }

    @Override
    public void setPadding(int left, int top, int right, int bottom) {
        super.setPadding(left, top, right, bottom);
        setup();
    }

    @Override
    public void setPaddingRelative(int start, int top, int end, int bottom) {
        super.setPaddingRelative(start, top, end, bottom);
        setup();
    }

    public int getBorderColor() {
        return mBorderColor;
    }

    public void setBorderColor(@ColorInt int borderColor) {
        if (borderColor == mBorderColor) {
            return;
        }

        mBorderColor = borderColor;
        mBorderPaint.setColor(mBorderColor);
        invalidate();
    }

    /**
     * @deprecated Use {@link #setBorderColor(int)} instead
     */
    @Deprecated
    public void setBorderColorResource(@ColorRes int borderColorRes) {
        setBorderColor(getContext().getResources().getColor(borderColorRes));
    }

    /**
     * Return the color drawn behind the circle-shaped drawable.
     *
     * @return The color drawn behind the drawable
     *
     * @deprecated Fill color support is going to be removed in the future
     */
    @Deprecated
    public int getFillColor() {
        return mFillColor;
    }

    /**
     * Set a color to be drawn behind the circle-shaped drawable. Note that
     * this has no effect if the drawable is opaque or no drawable is set.
     *
     * @param fillColor The color to be drawn behind the drawable
     *
     * @deprecated Fill color support is going to be removed in the future
     */
    @Deprecated
    public void setFillColor(@ColorInt int fillColor) {
        if (fillColor == mFillColor) {
            return;
        }

        mFillColor = fillColor;
        mFillPaint.setColor(fillColor);
        invalidate();
    }

    /**
     * Set a color to be drawn behind the circle-shaped drawable. Note that
     * this has no effect if the drawable is opaque or no drawable is set.
     *
     * @param fillColorRes The color resource to be resolved to a color and
     *                     drawn behind the drawable
     *
     * @deprecated Fill color support is going to be removed in the future
     */
    @Deprecated
    public void setFillColorResource(@ColorRes int fillColorRes) {
        setFillColor(getContext().getResources().getColor(fillColorRes));
    }

    public int getBorderWidth() {
        return mBorderWidth;
    }

    public void setBorderWidth(int borderWidth) {
        if (borderWidth == mBorderWidth) {
            return;
        }

        mBorderWidth = borderWidth;
        setup();
    }

    public boolean isBorderOverlay() {
        return mBorderOverlay;
    }

    public void setBorderOverlay(boolean borderOverlay) {
        if (borderOverlay == mBorderOverlay) {
            return;
        }

        mBorderOverlay = borderOverlay;
        setup();
    }

    public boolean isDisableCircularTransformation() {
        return mDisableCircularTransformation;
    }

    public void setDisableCircularTransformation(boolean disableCircularTransformation) {
        if (mDisableCircularTransformation == disableCircularTransformation) {
            return;
        }

        mDisableCircularTransformation = disableCircularTransformation;
        initializeBitmap();
    }

    @Override
    public void setImageBitmap(Bitmap bm) {
        super.setImageBitmap(bm);
        initializeBitmap();
    }

    @Override
    public void setImageDrawable(Drawable drawable) {
        super.setImageDrawable(drawable);
        initializeBitmap();
    }

    @Override
    public void setImageResource(@DrawableRes int resId) {
        super.setImageResource(resId);
        initializeBitmap();
    }

    @Override
    public void setImageURI(Uri uri) {
        super.setImageURI(uri);
        initializeBitmap();
    }

    @Override
    public void setColorFilter(ColorFilter cf) {
        if (cf == mColorFilter) {
            return;
        }

        mColorFilter = cf;
        applyColorFilter();
        invalidate();
    }

    @Override
    public ColorFilter getColorFilter() {
        return mColorFilter;
    }

    private void applyColorFilter() {
        if (mBitmapPaint != null) {
            mBitmapPaint.setColorFilter(mColorFilter);
        }
    }

    private Bitmap getBitmapFromDrawable(Drawable drawable) {
        if (drawable == null) {
            return null;
        }

        if (drawable instanceof BitmapDrawable) {
            return ((BitmapDrawable) drawable).getBitmap();
        }

        try {
            Bitmap bitmap;

            if (drawable instanceof ColorDrawable) {
                bitmap = Bitmap.createBitmap(COLORDRAWABLE_DIMENSION, COLORDRAWABLE_DIMENSION, BITMAP_CONFIG);
            } else {
                bitmap = Bitmap.createBitmap(drawable.getIntrinsicWidth(), drawable.getIntrinsicHeight(), BITMAP_CONFIG);
            }

            Canvas canvas = new Canvas(bitmap);
            drawable.setBounds(0, 0, canvas.getWidth(), canvas.getHeight());
            drawable.draw(canvas);
            return bitmap;
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }

    private void initializeBitmap() {
        if (mDisableCircularTransformation) {
            mBitmap = null;
        } else {
            mBitmap = getBitmapFromDrawable(getDrawable());
        }
        setup();
    }

    private void setup() {
        if (!mReady) {
            mSetupPending = true;
            return;
        }

        if (getWidth() == 0 && getHeight() == 0) {
            return;
        }

        if (mBitmap == null) {
            invalidate();
            return;
        }

        mBitmapShader = new BitmapShader(mBitmap, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP);

        mBitmapPaint.setAntiAlias(true);
        mBitmapPaint.setShader(mBitmapShader);

        mBorderPaint.setStyle(Paint.Style.STROKE);
        mBorderPaint.setAntiAlias(true);
        mBorderPaint.setColor(mBorderColor);
        mBorderPaint.setStrokeWidth(mBorderWidth);

        mFillPaint.setStyle(Paint.Style.FILL);
        mFillPaint.setAntiAlias(true);
        mFillPaint.setColor(mFillColor);

        mBitmapHeight = mBitmap.getHeight();
        mBitmapWidth = mBitmap.getWidth();

        mBorderRect.set(calculateBounds());
        mBorderRadius = Math.min((mBorderRect.height() - mBorderWidth) / 2.0f, (mBorderRect.width() - mBorderWidth) / 2.0f);

        mDrawableRect.set(mBorderRect);
        if (!mBorderOverlay && mBorderWidth > 0) {
            mDrawableRect.inset(mBorderWidth - 1.0f, mBorderWidth - 1.0f);
        }
        mDrawableRadius = Math.min(mDrawableRect.height() / 2.0f, mDrawableRect.width() / 2.0f);

        applyColorFilter();
        updateShaderMatrix();
        invalidate();
    }

    private RectF calculateBounds() {
        int availableWidth  = getWidth() - getPaddingLeft() - getPaddingRight();
        int availableHeight = getHeight() - getPaddingTop() - getPaddingBottom();

        int sideLength = Math.min(availableWidth, availableHeight);

        float left = getPaddingLeft() + (availableWidth - sideLength) / 2f;
        float top = getPaddingTop() + (availableHeight - sideLength) / 2f;

        return new RectF(left, top, left + sideLength, top + sideLength);
    }

    private void updateShaderMatrix() {
        float scale;
        float dx = 0;
        float dy = 0;

        mShaderMatrix.set(null);

        if (mBitmapWidth * mDrawableRect.height() > mDrawableRect.width() * mBitmapHeight) {
            scale = mDrawableRect.height() / (float) mBitmapHeight;
            dx = (mDrawableRect.width() - mBitmapWidth * scale) * 0.5f;
        } else {
            scale = mDrawableRect.width() / (float) mBitmapWidth;
            dy = (mDrawableRect.height() - mBitmapHeight * scale) * 0.5f;
        }

        mShaderMatrix.setScale(scale, scale);
        mShaderMatrix.postTranslate((int) (dx + 0.5f) + mDrawableRect.left, (int) (dy + 0.5f) + mDrawableRect.top);

        mBitmapShader.setLocalMatrix(mShaderMatrix);
    }

}

//圆形的xml，注意这个xml要放在res/values里面

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <declare-styleable name="CircleImageView">
        <attr name="civ_border_width" format="dimension" />
        <attr name="civ_border_color" format="color" />
        <attr name="civ_border_overlay" format="boolean" />
        <attr name="civ_fill_color" format="color" />
    </declare-styleable>
</resources>