【ANDROID自定义控件】可扩展的TextView,ExpandableTextView与Scroller类的使用

package com.sahadev.sildingfinishlayout;

import android.content.Context;
import android.util.AttributeSet;
import android.view.View;
import android.widget.Button;
import android.widget.RelativeLayout;
import android.widget.Scroller;
import android.widget.TextView;

public class ExpandableTextView extends RelativeLayout {
        private TextView mTextView;
        private Button mButton;
        private int mTextViewId = 567576458;// 这里注意不要随便填一个简单的数字,可能会和R中的ID冲突造成无效
        private Scroller mScroller;
        private int mHeight, mWidthMeasureSpec, mButtonHeight, paddingSize = 1;
        private boolean isExpanded, WSettedFlag, HSettedFlag, onceFlag;
        private int times = 2;// 缩小的倍数,默认2倍

        public ExpandableTextView(Context context) {
                this(context, null);
        }

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

        public ExpandableTextView(Context context, AttributeSet attrs, int defStyle) {
                super(context, attrs, defStyle);
                mTextView = new TextView(context);
                mTextView.setId(mTextViewId);

                mButton = new Button(context);
                mButton.setText("扩    展");
                mScroller = new Scroller(context);

                LayoutParams lp = new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.WRAP_CONTENT, RelativeLayout.LayoutParams.WRAP_CONTENT);

                lp.addRule(RelativeLayout.BELOW, mTextViewId);
                lp.addRule(RelativeLayout.ALIGN_PARENT_LEFT, TRUE);
                lp.addRule(RelativeLayout.ALIGN_PARENT_RIGHT, TRUE);

                mButton.setOnClickListener(new OnClickListener() {

                        @Override
                        public void onClick(View v) {
                                if (!isExpanded) {
                                        // 展开来
                                        mScroller.startScroll(0, mHeight / times, 0, mHeight / times);
                                        postInvalidate();
                                        isExpanded = true;
                                } else {
                                        // 收回去
                                        mScroller.startScroll(0, mHeight, 0, -mHeight / times);
                                        postInvalidate();
                                        isExpanded = false;
                                }
                        }
                });

                addView(mTextView);
                addView(mButton, lp);

        }

        @Override
        public void computeScroll() {
                super.computeScroll();
                if (mScroller.computeScrollOffset()) {

                        mTextView.setHeight(mScroller.getCurrY());
                        postInvalidate();
                        return;
                }
        }

        public void setTimes(int times) {
                if (times == 0) {
                        throw new ArithmeticException("倍数不能为0");
                }
                this.times = times;
        }

        public void setTextViewPadding(int pixels) {
                mTextView.setPadding(pixels, pixels, pixels, 0);
                paddingSize = pixels;
        }

        public void setButtonTips(CharSequence text) {
                mButton.setText(text);
        }

        public void setText(CharSequence text) {
                mTextView.setText(text);
        }

        public void setTextColor(int color) {
                mTextView.setTextColor(color);
        }

        public void setTextSize(float size) {
                mTextView.setTextSize(size);
        }

        public void setBackgroundColor(int color) {
                mTextView.setBackgroundColor(color);
        }

        public void setWidth(int width) {
                mWidthMeasureSpec = width;
                mTextView.setWidth(width - paddingSize * 2);
                WSettedFlag = true;
        }

        public void setHeight(int height) {
                mHeight = (height - mButtonHeight) * 2;
                HSettedFlag = true;
        }

        /* onMeasure方法在重绘的时候会一直被调用 */
        @Override
        protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
                super.onMeasure(widthMeasureSpec, heightMeasureSpec);

                /* 此步骤只用执行一次，获取到textView的宽度以及Button的高度以及一些初始化的值 */
                if (!WSettedFlag) {
                        WSettedFlag = true;
                        mWidthMeasureSpec = mTextView.getMeasuredWidth();
                }

                if (!HSettedFlag) {
                        HSettedFlag = true;
                        mHeight = mTextView.getMeasuredHeight();
                        OtherTools.showLog("mHeight----" + mHeight);
                }

                if (!onceFlag) {
                        onceFlag = true;
                        mButtonHeight = mButton.getMeasuredHeight();
                        OtherTools.showLog("mButtonHeight----" + mButtonHeight);
                        // mTextView.setHeight(mHeight / times + mButtonHeight >
                        // heightMeasureSpec ? heightMeasureSpec - mButtonHeight : mHeight /
                        // times);
                        mTextView.setHeight(mHeight / times);
                }
                // int tempHeight = mHeight / 2 + mButtonHeight;
                // tempHeight = tempHeight > heightMeasureSpec ? heightMeasureSpec :
                // tempHeight;
                setMeasuredDimension(mWidthMeasureSpec, mButtonHeight + mTextView.getMeasuredHeight());
        }
}