android 自定义进度条控件

Android中自定义进度条控件可以通过继承ProgressBar来实现。以下是一个示例代码：

public class CustomProgressBar extends ProgressBar {

    private Paint paint;
    private RectF rectF;

    public CustomProgressBar(Context context) {
        super(context);
        init();
    }

    public CustomProgressBar(Context context, AttributeSet attrs) {
        super(context, attrs);
        init();
    }

    public CustomProgressBar(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        init();
    }

    private void init() {
        paint = new Paint();
        paint.setAntiAlias(true);
        paint.setStyle(Paint.Style.FILL);
        paint.setColor(Color.BLUE);
        rectF = new RectF();
    }

    @Override
    protected synchronized void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        rectF.left = getPaddingLeft();
        rectF.top = getPaddingTop();
        rectF.right = getWidth() - getPaddingRight();
        rectF.bottom = getHeight() - getPaddingBottom();
        float progress = (float) getProgress() / (float) getMax();
        float secondaryProgress = (float) getSecondaryProgress() / (float) getMax();
        canvas.drawRoundRect(rectF, 10, 10, paint); // 绘制背景
        canvas.drawRoundRect(rectF.left, rectF.top, rectF.right * progress, rectF.bottom, 10, 10, paint); // 绘制进度条
        canvas.drawRoundRect(rectF.left, rectF.top, rectF.right * secondaryProgress, rectF.bottom, 10, 10, paint); // 绘制第二进度条
    }

}

以上代码绘制了一个圆角矩形的进度条，可以自定义颜色、圆角大小等属性。在布局文件中引用该控件即可：

<com.example.CustomProgressBar
    android:id="@+id/progress_bar"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:max="100"
    android:progress="50"
    android:secondaryProgress="75" />