一直想要实现一个这样的效果,终于弄出来了做个记录。
public class MyProgressView extends View {
private Paint mPaint;
private int viewWidth, viewHeight;
private float maxProgress = 100;
private float progress = 0;
private Bitmap progressBitmap, textBitmap;
private Canvas proCanvas, textCanvas;
private RectF dstRect, srcRect;
private Xfermode xfermode = new PorterDuffXfermode(PorterDuff.Mode.XOR);
public MyProgressView(Context context) {
this(context, null);
}
public MyProgressView(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}
public MyProgressView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
init(context);
}
private void init(Context context) {
mPaint = new Paint();
mPaint.setAntiAlias(true);
mPaint.setTextSize(100);
}
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
super.onSizeChanged(w, h, oldw, oldh);
viewWidth = w;
viewHeight = h;
progressBitmap = Bitmap.createBitmap(viewWidth, viewHeight, Bitmap.Config.ARGB_8888);
textBitmap = Bitmap.createBitmap(viewWidth, viewHeight, Bitmap.Config.ARGB_8888);
proCanvas = new Canvas(progressBitmap);
textCanvas = new Canvas(textBitmap);
srcRect = new RectF(0, 0, w, h);
dstRect = new RectF(0, 0, w, h);
}
public MyProgressView setMaxProgress(float maxProgress) {
this.maxProgress = maxProgress;
return this;
}
public void setProgress(float progress) {
this.progress = progress;
proCanvas.drawColor(Color.WHITE, PorterDuff.Mode.CLEAR);
mPaint.setColor(Color.BLUE);
proCanvas.drawRect(0, 0, viewWidth * (progress / maxProgress), viewHeight, mPaint);
String text = String.format(Locale.getDefault(), "%.2f%%", progress);
mPaint.setColor(Color.RED);
Paint.FontMetrics metrics = mPaint.getFontMetrics();
float fontHeight = metrics.bottom - metrics.top;
float textBaseY = viewHeight - (viewHeight - fontHeight) / 2 - metrics.bottom;
textCanvas.drawColor(Color.WHITE, PorterDuff.Mode.CLEAR);
textCanvas.drawText(text, (viewWidth - mPaint.measureText(text)) / 2, textBaseY, mPaint);
invalidate();
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
int saveCount = canvas.saveLayer(srcRect, mPaint, Canvas.ALL_SAVE_FLAG);
//这里先绘制底部的进度条
canvas.drawBitmap(progressBitmap, null, srcRect, mPaint);
//设置混合模式
mPaint.setXfermode(xfermode);
//在回事文本
canvas.drawBitmap(textBitmap, null, dstRect, mPaint);
mPaint.setXfermode(null);
canvas.restoreToCount(saveCount);
}
}