如何自定义一个带有首尾间距得跑马灯效果

定义跑马灯效果我们使用Textview，根据画布得高宽和文字得高宽来设置跑马灯效果

直接上代码

public class HorizontalTextview extends AppCompatTextView {
    private float textLength = 0f;
    private float drawTextX = 0f;// 文本的横坐标
    public boolean isStarting = false;// 是否开始滚动
    private Paint paint = null;
    private String text = "";
    private long waitTime = 1000; //开始时等待的时间
    private int scrollTile = 2; //文字的滚动速度
    private int baseline;
    private float baselinex;
    private float drawTextx2;
    private float distance=160;//间距


    public HorizontalTextview(Context context) {
        super(context);
        initView(context);
    }

    public HorizontalTextview(Context context, AttributeSet attrs) {
        super(context, attrs);
        initView(context);
    }

    public HorizontalTextview(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        initView(context);
    }


    @Override
    public void invalidate() {

        super.invalidate();
    }

    private void initView(Context context) {
        setMaxWidth(context.getResources().getDisplayMetrics().widthPixels / 2); //因为需求需要所以设置了最大宽度，如果不需要此功能可以删除掉

        paint = getPaint();
        paint.setColor(getTextColors().getColorForState(getDrawableState(), 0));
        text = getText().toString();
        if (TextUtils.isEmpty(text)) {
            return;
        }
        textLength = paint.measureText(text);
        isStarting = true;
    }

    @Override
    public void setTextColor(int color) {
        super.setTextColor(color);
        paint.setColor(color);
        start();
    }

    @Override
    public void setText(CharSequence text, BufferType type) {
        super.setText(text, type);
        this.text = text.toString();
        this.textLength = getPaint().measureText(text.toString());
        drawTextX = 0;//第一次跑马灯
        drawTextx2=-textLength-distance;//第二次跑马灯
        start();
    }

    public void start() {
        isStarting = true;
        invalidate();
    }

    @Override
    public void setGravity(int gravity) {

        super.setGravity(gravity);
    }

    public void stop() {
        isStarting = false;
        invalidate();
    }

    @Override
    public void onDraw(Canvas canvas) {
        final Paint.FontMetricsInt fontMetrics = paint.getFontMetricsInt();
        baseline = (canvas.getHeight() - fontMetrics.bottom - fontMetrics.top) / 2;

        if (textLength <= canvas.getWidth()) {
            baselinex=canvas.getWidth()/2-textLength/2;

            canvas.drawText(text, baselinex, baseline, paint);

            return;
        }
        canvas.drawText(text, -drawTextX, baseline, paint);
        canvas.drawText(text, -drawTextx2, baseline, paint);


        if (!isStarting) {
            return;
        }
        if (drawTextX == 0) {
            postDelayed(() -> {
                drawTextX = 1;
                drawTextx2= -textLength-distance;
                isStarting = true;
                invalidate();
            }, waitTime);
            isStarting = false;
            return;
        }
        drawTextX += scrollTile;
        drawTextx2+=scrollTile;
        //判断是否滚动结束
        if (drawTextX > textLength) {
//            drawTextX = -canvas.getWidth()-30;
            drawTextX=-textLength-2*distance;
            drawTextx2=-distance;

        }
        invalidate();
    }

}

在xml直接引用即可

<com.example.xmltest.HorizontalTextview
            android:id="@+id/roll_text"
            android:layout_width="match_parent"
            android:layout_marginTop="10dp"
            android:layout_marginBottom="10dp"
            android:layout_height="40dp"
            android:layout_marginLeft="10dp"
            android:layout_marginRight="10dp"
            android:layout_alignRight="@id/text_img"
            android:layout_alignParentEnd="true"
            android:layout_toEndOf="@+id/text_img"

            android:text="1111" />

到这里简单得有首尾间距得跑马灯效果实现，谢谢支持！

标签：自定义,textLength,text,void,private,跑马灯,context,public,首尾
来源： https://blog.csdn.net/weixin_40138348/article/details/111604111