/**
 * 获取签名工具类
 */
public class AppSigning {
    public final static String MD5 = "MD5";
    public final static String SHA1 = "SHA1";
    public final static String SHA256 = "SHA256";
    private static HashMap<String, ArrayList<String>> mSignMap = new HashMap<>();

    /**
     * 返回一个签名的对应类型的字符串
     *
     * @param context
     * @param type
     * @return 因为一个安装包可以被多个签名文件签名，所以返回一个签名信息的list
     */
    public static ArrayList<String> getSignInfo(Context context, String type) {
        if (context == null || type == null) {
            return null;
        }
        String packageName = context.getPackageName();
        if (packageName == null) {
            return null;
        }
        if (mSignMap.get(type) != null) {
            return mSignMap.get(type);
        }
        ArrayList<String> mList = new ArrayList<String>();
        try {
            Signature[] signs = getSignatures(context, packageName);
            for (Signature sig : signs) {
                String tmp = "error!";
                if (MD5.equals(type)) {
                    tmp = getSignatureByteString(sig, MD5);
                } else if (SHA1.equals(type)) {
                    tmp = getSignatureByteString(sig, SHA1);
                } else if (SHA256.equals(type)) {
                    tmp = getSignatureByteString(sig, SHA256);
                }
                mList.add(tmp);
            }
        } catch (Exception e) {
            LogUtil.e(e.toString());
        }
        mSignMap.put(type, mList);
        return mList;
    }

    /**
     * 获取签名sha1值
     *
     * @param context
     * @return
     */
    public static String getSha1(Context context) {
        String res = "";
        ArrayList<String> mlist = getSignInfo(context, SHA1);
        if (mlist != null && mlist.size() != 0) {
            res = mlist.get(0);
        }
        return res;
    }

    /**
     * 获取签名MD5值
     *
     * @param context
     * @return
     */
    public static String getMD5(Context context) {
        String res = "";
        ArrayList<String> mlist = getSignInfo(context, MD5);
        if (mlist != null && mlist.size() != 0) {
            res = mlist.get(0);
        }
        return res;
    }

    /**
     * 获取签名SHA256值
     *
     * @param context
     * @return
     */
    public static String getSHA256(Context context) {
        String res = "";
        ArrayList<String> mlist = getSignInfo(context, SHA256);
        if (mlist != null && mlist.size() != 0) {
            res = mlist.get(0);
        }
        return res;
    }

    /**
     * 返回对应包的签名信息
     *
     * @param context
     * @param packageName
     * @return
     */
    private static Signature[] getSignatures(Context context, String packageName) {
        PackageInfo packageInfo = null;
        try {
            packageInfo = context.getPackageManager().getPackageInfo(packageName, PackageManager.GET_SIGNATURES);
            return packageInfo.signatures;
        } catch (Exception e) {
            LogUtil.e(e.toString());
        }
        return null;
    }

    /**
     * 获取相应的类型的字符串（把签名的byte[]信息转换成16进制）
     *
     * @param sig
     * @param type
     * @return
     */
    private static String getSignatureString(Signature sig, String type) {
        byte[] hexBytes = sig.toByteArray();
        String fingerprint = "error!";
        try {
            MessageDigest digest = MessageDigest.getInstance(type);
            if (digest != null) {
                byte[] digestBytes = digest.digest(hexBytes);
                StringBuilder sb = new StringBuilder();
                for (byte digestByte : digestBytes) {
                    sb.append((Integer.toHexString((digestByte & 0xFF) | 0x100)).substring(1, 3));
                }
                fingerprint = sb.toString();
            }
        } catch (Exception e) {
            LogUtil.e(e.toString());
        }

        return fingerprint;
    }

    /**
     * 获取相应的类型的字符串（把签名的byte[]信息转换成 95:F4:D4:FG 这样的字符串形式）
     *
     * @param sig
     * @param type
     * @return
     */
    private static String getSignatureByteString(Signature sig, String type) {
        byte[] hexBytes = sig.toByteArray();
        String fingerprint = "error!";
        try {
            MessageDigest digest = MessageDigest.getInstance(type);
            if (digest != null) {
                byte[] digestBytes = digest.digest(hexBytes);
                StringBuilder sb = new StringBuilder();
                for (byte digestByte : digestBytes) {
                    sb.append(((Integer.toHexString((digestByte & 0xFF) | 0x100)).substring(1, 3)).toUpperCase());
                    sb.append(":");
                }
                fingerprint = sb.substring(0, sb.length() - 1).toString();
            }
        } catch (Exception e) {
            LogUtil.e(e.toString());
        }

        return fingerprint;
    }
}

/**
 * 可自定义设置drawable宽高的TextView
 */
public class DrawableTextView extends AppCompatTextView {
    private Drawable drawableLeft;
    private Drawable drawableRight;
    private Drawable drawableTop;
    private int leftWidth;
    private int rightWidth;
    private int topWidth;
    private int leftHeight;
    private int rightHeight;
    private int topHeight;
    private Context mContext;

    public DrawableTextView(Context context) {
        super(context);
        this.mContext = context;
        init(context, null);
    }

    public DrawableTextView(Context context, AttributeSet attrs) {
        super(context, attrs);
        this.mContext = context;
        init(context, attrs);
    }

    public DrawableTextView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        this.mContext = context;
        init(context, attrs);
    }

    private void init(Context context, AttributeSet attrs) {
        TypedArray typedArray = context.obtainStyledAttributes(attrs, R.styleable.DrawableTextView);
        drawableLeft = typedArray.getDrawable(R.styleable.DrawableTextView_leftDrawable);
        drawableRight = typedArray.getDrawable(R.styleable.DrawableTextView_rightDrawable);
        drawableTop = typedArray.getDrawable(R.styleable.DrawableTextView_topDrawable);
        if (drawableLeft != null) {
            leftWidth = typedArray.getDimensionPixelOffset(R.styleable.DrawableTextView_leftDrawableWidth, dip2px(context, 20));
            leftHeight = typedArray.getDimensionPixelOffset(R.styleable.DrawableTextView_leftDrawableHeight, dip2px(context, 20));
        }
        if (drawableRight != null) {
            rightWidth = typedArray.getDimensionPixelOffset(R.styleable.DrawableTextView_rightDrawableWidth, dip2px(context, 20));
            rightHeight = typedArray.getDimensionPixelOffset(R.styleable.DrawableTextView_rightDrawableHeight, dip2px(context, 20));
        }
        if (drawableTop != null) {
            topWidth = typedArray.getDimensionPixelOffset(R.styleable.DrawableTextView_topDrawableWidth, dip2px(context, 20));
            topHeight = typedArray.getDimensionPixelOffset(R.styleable.DrawableTextView_topDrawableHeight, dip2px(context, 20));
        }
    }


    public int dip2px(Context context, float dpValue) {
        final float scale = context.getResources().getDisplayMetrics().density;
        return (int) (dpValue * scale + 0.5f);
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        if (drawableLeft != null) {
            drawableLeft.setBounds(0, 0, leftWidth, leftHeight);
        }
        if (drawableRight != null) {
            drawableRight.setBounds(0, 0, rightWidth, rightHeight);
        }
        if (drawableTop != null) {
            drawableTop.setBounds(0, 0, topWidth, topHeight);
        }
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        this.setCompoundDrawables(drawableLeft, drawableTop, drawableRight, null);

    }

    /**
     * 设置左侧图片并重绘
     */
    public void setDrawableLeft(Drawable drawableLeft) {
        this.drawableLeft = drawableLeft;
        invalidate();
    }

    /**
     * 设置左侧图片并重绘
     */
    public void setDrawableLeft(int drawableLeftRes) {
        this.drawableLeft = mContext.getResources().getDrawable(drawableLeftRes);
        invalidate();
    }

    /**
     * 设置右侧图片并重绘
     */
    public void setDrawableRight(Drawable drawableRight) {
        this.drawableRight = drawableLeft;
        invalidate();
    }

    /**
     * 设置右侧图片并重绘
     */
    public void setDrawableRight(int drawableRightRes) {
        this.drawableRight = mContext.getResources().getDrawable(drawableRightRes);
        invalidate();
    }

    /**
     * 设置上部图片并重绘
     */
    public void setDrawable(Drawable drawableTop) {
        this.drawableTop = drawableTop;
        invalidate();
    }

    /**
     * 设置右侧图片并重绘
     */
    public void setDrawableTop(int drawableTopRes) {
        this.drawableTop = mContext.getResources().getDrawable(drawableTopRes);
        invalidate();
    }
}

<TextView 
	    android:id="@+id/test_shadow"
	    android:layout_width="wrap_content"
	    android:layout_height="wrap_content"
	    android:textSize="60sp"
	    android:textColor="#cc000000"
	    android:text="Test Shadow"
	    android:layout_gravity="center"
	    android:shadowColor="#aa22ff22"
	    android:shadowRadius="10"
	    android:shadowDx="0"
	    android:shadowDy="0"
	    />

/**
 * ShadowLayout.java
 * <p>
 * Created by lijiankun on 17/8/11.
 */

public class ShadowLayout extends RelativeLayout {

    public static final int ALL = 0x1111;

    public static final int LEFT = 0x0001;

    public static final int TOP = 0x0010;

    public static final int RIGHT = 0x0100;

    public static final int BOTTOM = 0x1000;

    private Paint mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);

    private RectF mRectF = new RectF();

    /**
     * 阴影的颜色
     */
    private int mShadowColor = Color.TRANSPARENT;

    /**
     * 阴影的大小范围
     */
    private float mShadowRadius = 0;

    /**
     * 阴影 x 轴的偏移量
     */
    private float mShadowDx = 0;

    /**
     * 阴影 y 轴的偏移量
     */
    private float mShadowDy = 0;

    /**
     * 阴影显示的边界
     */
    private int mShadowSide = ALL;

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

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

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

    /**
     * 获取绘制阴影的位置，并为 ShadowLayout 设置 Padding 以为显示阴影留出空间
     */
    @Override
    protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
        super.onLayout(changed, left, top, right, bottom);

        float effect = mShadowRadius + dip2px(5);
        float rectLeft = 0;
        float rectTop = 0;
        float rectRight = this.getWidth();
        float rectBottom = this.getHeight();
        int paddingLeft = 0;
        int paddingTop = 0;
        int paddingRight = 0;
        int paddingBottom = 0;

        if (((mShadowSide & LEFT) == LEFT)) {
            rectLeft = effect;
            paddingLeft = (int) effect;
        }
        if (((mShadowSide & TOP) == TOP)) {
            rectTop = effect;
            paddingTop = (int) effect;
        }
        if (((mShadowSide & RIGHT) == RIGHT)) {
            rectRight = this.getWidth() - effect;
            paddingRight = (int) effect;
        }
        if (((mShadowSide & BOTTOM) == BOTTOM)) {
            rectBottom = this.getHeight() - effect;
            paddingBottom = (int) effect;
        }
        if (mShadowDy != 0.0f) {
            rectBottom = rectBottom - mShadowDy;
            paddingBottom = paddingBottom + (int) mShadowDy;
        }
        if (mShadowDx != 0.0f) {
            rectRight = rectRight - mShadowDx;
            paddingRight = paddingRight + (int) mShadowDx;
        }
        mRectF.left = rectLeft;
        mRectF.top = rectTop;
        mRectF.right = rectRight;
        mRectF.bottom = rectBottom;
        this.setPadding(paddingLeft, paddingTop, paddingRight, paddingBottom);
    }

    /**
     * 真正绘制阴影的方法
     */
    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        canvas.drawRect(mRectF, mPaint);
    }

    /**
     * 读取设置的阴影的属性
     *
     * @param attrs 从其中获取设置的值
     */
    private void init(AttributeSet attrs) {
        setLayerType(View.LAYER_TYPE_SOFTWARE, null);  // 关闭硬件加速
        this.setWillNotDraw(false);                    // 调用此方法后，才会执行 onDraw(Canvas) 方法

        TypedArray typedArray = getContext().obtainStyledAttributes(attrs, R.styleable.ShadowLayout);
        if (typedArray != null) {
            mShadowColor = typedArray.getColor(R.styleable.ShadowLayout_shadowColor,
                    ContextCompat.getColor(getContext(), android.R.color.black));
            mShadowRadius = typedArray.getDimension(R.styleable.ShadowLayout_shadowRadius, dip2px(0));
            mShadowDx = typedArray.getDimension(R.styleable.ShadowLayout_shadowDx, dip2px(0));
            mShadowDy = typedArray.getDimension(R.styleable.ShadowLayout_shadowDy, dip2px(0));
            mShadowSide = typedArray.getInt(R.styleable.ShadowLayout_shadowSide, ALL);
            typedArray.recycle();
        }
        mPaint.setAntiAlias(true);
        mPaint.setColor(Color.TRANSPARENT);
        mPaint.setShadowLayer(mShadowRadius, mShadowDx, mShadowDy, mShadowColor);
    }

    /**
     * dip2px dp 值转 px 值
     *
     * @param dpValue dp 值
     * @return px 值
     */
    private float dip2px(float dpValue) {
        DisplayMetrics dm = getContext().getResources().getDisplayMetrics();
        float scale = dm.density;
        return (dpValue * scale + 0.5F);
    }
}