Android TabLayout 指示器宽度自定义教程

要自定义TabLayout指示器的宽度，可以通过设置自定义的TabIndicator类来实现。下面是一个示例：

1. 创建一个自定义的TabIndicator类，继承自TabLayout中的TabIndicator类，并重写draw方法：

public class CustomTabIndicator extends TabLayout.TabIndicator {

    private Paint mPaint;
    private int mIndicatorWidth;
    private int mIndicatorHeight;

    public CustomTabIndicator(TabLayout tabLayout) {
        super(tabLayout);
        mPaint = new Paint();
        mPaint.setColor(Color.RED);
        mIndicatorWidth = 100;
        mIndicatorHeight = 5;
    }

    @Override
    public void draw(Canvas canvas) {
        int indicatorLeft = getLeft() + (getWidth() - mIndicatorWidth) / 2;
        int indicatorRight = indicatorLeft + mIndicatorWidth;
        int indicatorTop = getTop() + (getHeight() - mIndicatorHeight) / 2;
        int indicatorBottom = indicatorTop + mIndicatorHeight;
        canvas.drawRect(indicatorLeft, indicatorTop, indicatorRight, indicatorBottom, mPaint);
    }
}

2. 在TabLayout中设置自定义的TabIndicator：

TabLayout tabLayout = findViewById(R.id.tab_layout);
CustomTabIndicator customTabIndicator = new CustomTabIndicator(tabLayout);
tabLayout.setSelectedTabIndicator(customTabIndicator);

这样就可以自定义TabLayout指示器的宽度了。在CustomTabIndicator类中，可以根据自己的需求设置指示器的颜色、宽度和高度等属性。