在Android中，自定義ProgressDrawable的形狀可以通過創建一個新的類并繼承自ProgressDrawable來實現。以下是一個簡單的示例，展示了如何創建一個帶有自定義形狀的ProgressDrawable：

1. 首先，創建一個新的類，繼承自ProgressDrawable：

import android.graphics.Canvas;
import android.graphics.ColorFilter;
import android.graphics.Paint;
import android.graphics.PixelFormat;
import android.graphics.Rect;
import android.graphics.drawable.Drawable;
import android.os.Build;

public class CustomProgressDrawable extends Drawable {
    private Paint paint;

    public CustomProgressDrawable() {
        paint = new Paint();
        paint.setAntiAlias(true);
        paint.setStyle(Paint.Style.STROKE);
        paint.setStrokeWidth(10);
    }

    @Override
    protected void onBoundsChange(Rect bounds) {
        super.onBoundsChange(bounds);
    }

    @Override
    public void draw(Canvas canvas) {
        // 在這里繪制你的自定義形狀
        Rect bounds = getBounds();
        int centerX = bounds.centerX();
        int centerY = bounds.centerY();
        int radius = Math.min(centerX, centerY) - (int) paint.getStrokeWidth() / 2;

        paint.setColor(0xFF009688);
        canvas.drawCircle(centerX, centerY, radius, paint);

        paint.setColor(0xFFFF5722);
        canvas.drawArc(bounds.left, bounds.top, bounds.right, bounds.bottom, 270, 120, false, paint);
    }

    @Override
    public void setAlpha(int alpha) {
        paint.setAlpha(alpha);
    }

    @Override
    public void setColorFilter(ColorFilter colorFilter) {
        paint.setColorFilter(colorFilter);
    }

    @Override
    public int getOpacity() {
        return PixelFormat.TRANSLUCENT;
    }
}

2. 然后，在你的布局文件中使用這個自定義的ProgressDrawable：

    android:id="@+id/progressBar"
    style="?android:attr/progressBarStyleHorizontal"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:indeterminate="false"
    android:max="100"
    android:progress="50" />

3. 最后，在你的Activity或Fragment中設置自定義的ProgressDrawable：

ProgressBar progressBar = findViewById(R.id.progressBar);
CustomProgressDrawable customProgressDrawable = new CustomProgressDrawable();
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
    progressBar.setProgressDrawable(customProgressDrawable);
} else {
    progressBar.setIndeterminateDrawable(customProgressDrawable);
}

這樣，你就可以看到一個帶有自定義形狀的ProgressBar了。你可以根據需要修改CustomProgressDrawable類中的draw()方法，以繪制你想要的形狀。