android 文字滚动，全屏字幕滚动APP实现

android 一款文字滚动App

• 下载app体验

https://download.csdn.net/download/qq_38355313/88063389
新增自定义文字大小和自定义滚动速度

• 先上效果图

核心就是自定义文字滚动的类

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.util.AttributeSet;
import android.view.View;

import androidx.annotation.ColorInt;
import androidx.annotation.Nullable;

import com.example.baselibrary.CommonParameters;
import com.example.baselibrary.utils.SPUtil;


/**
 * @Author MUZI102
 * @Date 2022/2/717:58
 * @Version 1.0
 * 

 * 

 * 所有属性 尽量用Builder 来控制
 */
public class ScrollTextView extends View {


    public static final int SCROLLDIRECTION_LEFT_TO_RIGHT = 0;
    public static final int SCROLLDIRECTION_RIGHT_TO_LEFT = 1;
    public static final int SCROLLDIRECTION_NO_MOVE = 2;


    public static final int TEXT_SIZE_SMALL = 3;
    public static final int TEXT_SIZE_MEDIUM = 4;
    public static final int TEXT_SIZE_LAGRE = 5;
    public static final int TEXT_SIZE_EXTRA_LARGE = 55;


    public static final int SCROLL_SPEED_SLOW = 6;
    public static final int SCROLL_SPEED_MEDIUM = 7;
    public static final int SCROLL_SPEED_FAST = 8;
    public static final int SCROLL_SPEED_PARTICULARLY_FAST = 9;


    public static final int SCROLL_SELECT_WHITE = 10; //#FFFFFF
    public static final int SCROLL_SELECT_BLACK = 11;//#000000
    public static final int SCROLL_SELECT_RED = 12;//红色
    public static final int SCROLL_SELECT_FUCHISA = 13;//红色
    public static final int SCROLL_SELECT_LAWNGREEN = 14;//红色
    public static final int SCROLL_SELECT_YELLOW = 16;//红色
    public static final int SCROLL_SELECT_LIME = 17;//红色
    public static final int SCROLL_SELECT_BLUE = 18;//红色


    private Paint mPaint;
    private int width;
    private int higth;
    private float stringWidth;
    private float currentTextX;
    private float currentTextY;

    private String drawString = "";
    private Builder mBuilder;
    private static final int CYCLE_INDEX = 100;
    private boolean isScroll = true;
    private int currentSpeed = 0;
    private int scrollDirection = SCROLLDIRECTION_LEFT_TO_RIGHT;
    private boolean isStart = false;

    private Context context;

    public Builder getBuilder() {
        if (mBuilder == null) {
            mBuilder = new Builder();
        }
        return mBuilder;
    }

    public void setBuilder(Builder mBuilder) {
        this.mBuilder = mBuilder;
        measureTextlLocation();
        SPUtil.getInstance(context).setBean(CommonParameters.SP_KEY_SCROLLTEXTVIEW_BUILDER, mBuilder);
    }


    public ScrollTextView(Context context) {
        super(context);
        initPaint();
        this.context = context;
    }

    public ScrollTextView(Context context, @Nullable AttributeSet attrs) {
        super(context, attrs);
        initPaint();
        this.context = context;
    }

    public ScrollTextView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        initPaint();
        this.context = context;
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
    }

    @Override
    protected void onFinishInflate() {
        super.onFinishInflate();
    }


    /**
     * 初始化画笔设置
     */
    private void initPaint() {
        mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
        mPaint.setAntiAlias(true);
    }


    private void measureTextlLocation() {
        width = getMeasuredWidth();
        higth = getMeasuredHeight();

        if (mBuilder.getTextSize() == TEXT_SIZE_SMALL) {
            mPaint.setTextSize(context.getResources().getDimensionPixelSize(com.example.resourcelibrary.R.dimen.sp_100));
        } else if (mBuilder.getTextSize() == TEXT_SIZE_MEDIUM) {
            mPaint.setTextSize(context.getResources().getDimensionPixelSize(com.example.resourcelibrary.R.dimen.sp_130));
        } else if (mBuilder.getTextSize() == TEXT_SIZE_LAGRE) {
            mPaint.setTextSize(context.getResources().getDimensionPixelSize(com.example.resourcelibrary.R.dimen.sp_160));
        } else if (mBuilder.getTextSize() == TEXT_SIZE_EXTRA_LARGE) {
            mPaint.setTextSize(context.getResources().getDimensionPixelSize(com.example.resourcelibrary.R.dimen.sp_200));
        } else {
            mPaint.setTextSize(context.getResources().getDimensionPixelSize(com.example.resourcelibrary.R.dimen.sp_250));
        }

        if (mBuilder.getScrollSpeed() == SCROLL_SPEED_SLOW) {
            currentSpeed = context.getResources().getDimensionPixelSize(com.example.resourcelibrary.R.dimen.dp_5);
        } else if (mBuilder.getScrollSpeed() == SCROLL_SPEED_MEDIUM) {
            currentSpeed = context.getResources().getDimensionPixelSize(com.example.resourcelibrary.R.dimen.dp_7);
        } else if (mBuilder.getScrollSpeed() == SCROLL_SPEED_FAST) {
            currentSpeed = context.getResources().getDimensionPixelSize(com.example.resourcelibrary.R.dimen.dp_9);
        } else if (mBuilder.getScrollSpeed() == SCROLL_SPEED_PARTICULARLY_FAST) {
            currentSpeed = context.getResources().getDimensionPixelSize(com.example.resourcelibrary.R.dimen.dp_11);
        } else {
            currentSpeed = 10;
        }
        mPaint.setColor(Color.parseColor(getColor(mBuilder.getTextColor())));
        this.isScroll = mBuilder.isScroll();
        this.scrollDirection = mBuilder.getScrollDirection();
        StringBuilder StringBuilder = new StringBuilder();
        for (int i = 0; i < CYCLE_INDEX; i++) {
            StringBuilder.append(mBuilder.getMsg()).append("  ");
        }
        if (mBuilder.getScrollDirection() == SCROLLDIRECTION_LEFT_TO_RIGHT) {
            //左往右
            //文字反转
            drawString = StringBuilder.reverse().toString();
            //文字的y轴坐标
            Paint.FontMetrics fontMetrics = mPaint.getFontMetrics();
            stringWidth = mPaint.measureText(drawString);
            currentTextY = getMeasuredHeight() / 2 + (Math.abs(fontMetrics.ascent) - fontMetrics.descent) / 2;
            currentTextX = -stringWidth;
        } else if (mBuilder.getScrollDirection() == SCROLLDIRECTION_RIGHT_TO_LEFT) {
            //右往左
            drawString = StringBuilder.toString();
            //文字的y轴坐标
            Paint.FontMetrics fontMetrics = mPaint.getFontMetrics();
            stringWidth = mPaint.measureText(drawString);
            currentTextY = getMeasuredHeight() / 2 + (Math.abs(fontMetrics.ascent) - fontMetrics.descent) / 2;

            currentTextX = width;
        } else {
            //禁止不动
            drawString = mBuilder.getMsg();
            //文字的y轴坐标
            Paint.FontMetrics fontMetrics = mPaint.getFontMetrics();
            currentTextY = getMeasuredHeight() / 2 + (Math.abs(fontMetrics.ascent) - fontMetrics.descent) / 2;
            currentTextX = getWidth() / 2 - mPaint.measureText(drawString) / 2;
        }
        invalidate();
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        if (isStart) {
            if (mBuilder != null) {
                if (!isScroll) {
                    //不滚动，则居中显示
                    canvas.drawText(drawString, currentTextX, currentTextY, mPaint);
                } else {
                    //滚动
                    canvas.drawText(drawString, currentTextX, currentTextY, mPaint);
                    if (scrollDirection == SCROLLDIRECTION_LEFT_TO_RIGHT) {
                        //左往右
                        currentTextX = currentTextX + currentSpeed;
                        if (currentTextX >= 0) {
                            measureTextlLocation();
                            return;
                        }

                    } else if (scrollDirection == SCROLLDIRECTION_RIGHT_TO_LEFT) {
                        //右往左
                        currentTextX = currentTextX - currentSpeed;
                        if (0 > currentTextX + stringWidth) {
                            measureTextlLocation();
                            return;
                        }
                    }
                    invalidate();
                }
            }
        }
    }


    public boolean isStart() {
        return isStart;
    }

    public void setStart(boolean start) {
        isStart = start;
        if (isStart) {
            invalidate();
        }
    }

    public static class Builder {
        private String msg = "欢迎使用字幕滚动app！";
        private int textSize = ScrollTextView.TEXT_SIZE_MEDIUM;
        private int scrollDirection = ScrollTextView.SCROLLDIRECTION_RIGHT_TO_LEFT;
        private int textColor = SCROLL_SELECT_WHITE;
        private int scrollSpeed = ScrollTextView.SCROLL_SPEED_MEDIUM;
        private boolean isScroll = true;
        private int bgColor = SCROLL_SELECT_BLACK;

        public Builder(String msg, int textSize, @ColorInt int textColor, int scrollDirection, int scrollSpeed, boolean isScroll, int bgColor) {
            this.msg = msg;
            this.textSize = textSize;
            this.textColor = textColor;
            this.scrollDirection = scrollDirection;
            this.scrollSpeed = scrollSpeed;
            this.isScroll = isScroll;
            this.bgColor = bgColor;
        }

        public Builder() {
        }

        public Builder(Builder builder) {
            this.msg = builder.getMsg();
            this.textSize = builder.getTextSize();
            this.textColor = builder.getTextColor();
            this.scrollDirection = builder.getScrollDirection();
            this.scrollSpeed = builder.getScrollSpeed();
            this.isScroll = builder.isScroll();
            this.bgColor = builder.getBgColor();
        }

        public String getMsg() {
            return msg;
        }

        public Builder setMsg(String msg) {
            this.msg = msg;
            return this;
        }

        public int getTextSize() {
            return textSize;
        }

        public Builder setTextSize(int textSize) {
            this.textSize = textSize;
            return this;
        }

        public int getTextColor() {
            return textColor;
        }

        public Builder setTextColor(int textColor) {
            this.textColor = textColor;
            return this;
        }

        public int getScrollDirection() {
            return scrollDirection;
        }

        public Builder setScrollDirection(int scrollDirection) {
            this.scrollDirection = scrollDirection;
            return this;
        }

        public int getScrollSpeed() {
            return scrollSpeed;
        }

        public Builder setScrollSpeed(int scrollSpeed) {
            this.scrollSpeed = scrollSpeed;
            return this;
        }

        public boolean isScroll() {
            return isScroll;
        }

        public int getBgColor() {
            return bgColor;
        }

        public void setBgColor(int bgColor) {
            this.bgColor = bgColor;
        }

        public Builder setScroll(boolean scroll) {
            isScroll = scroll;
            return this;
        }

        @Override
        public String toString() {
            return "Builder{" + "msg='" + msg + '\'' + ", textSize=" + textSize + ", scrollDirection=" + scrollDirection + ", textColor=" + textColor + ", scrollSpeed=" + scrollSpeed + ", isScroll=" + isScroll + ", bgColor=" + bgColor + '}';
        }
    }

    /**
     * 设置背景颜色
     *
     * @param type
     */
    public void setBgColor(int type) {
        if (onBgColorChange != null) {
            onBgColorChange.onBgColorChange(type);
        }
        mBuilder.setBgColor(type);
        SPUtil.getInstance(context).setData(CommonParameters.SP_KEY_SCROLLTEXTVIEW_BUILDER, mBuilder);
    }

    public void setOnBgColorChange(OnBgColorChange onBgColorChange) {
        this.onBgColorChange = onBgColorChange;
    }

    private OnBgColorChange onBgColorChange;

    public interface OnBgColorChange {
        void onBgColorChange(int bg);
    }


    public String getColor(int type) {
        if (type == SCROLL_SELECT_WHITE) {
            return "#ffffff";
        } else if (type == SCROLL_SELECT_BLACK) {
            return "#000000";
        } else if (type == SCROLL_SELECT_RED) {
            return "#ff0000";
        } else if (type == SCROLL_SELECT_FUCHISA) {
            return "#ff00ff";
        } else if (type == SCROLL_SELECT_LAWNGREEN) {
            return "#7cfc00";
        } else if (type == SCROLL_SELECT_YELLOW) {
            return "#ffff00";
        } else if (type == SCROLL_SELECT_LIME) {
            return "#00ff00";
        } else if (type == SCROLL_SELECT_BLUE) {
            return "#0000ff";
        } else {
            return "#ffffff";
        }
    }
}

主要属性是通过内部类Builder来控制

    public static class Builder {
        private String msg = "欢迎使用字幕滚动app！";  //需要滚动的文字内容
        private int textSize = ScrollTextView.TEXT_SIZE_MEDIUM; //文字大小
        private int scrollDirection = ScrollTextView.SCROLLDIRECTION_RIGHT_TO_LEFT; //文字滚动的方向
        private int textColor = SCROLL_SELECT_WHITE; //滚动文字的颜色
        private int scrollSpeed = ScrollTextView.SCROLL_SPEED_MEDIUM; //滚动速度
        private boolean isScroll = true; //是否滚动，false则居中显示
        private int bgColor = SCROLL_SELECT_BLACK; //背景颜色