Android的绘制动画线 [英] Android drawing an animated line

问题描述

我目前正在与图形和路径，我可以successufully显示我想做的事情。

I'm currently working with graphics and paths, and I can successufully display whatever I want.

而不是直接在我的SurfaceView画一条线，我想逐步绘制的动画。

But instead of drawing a line directly on my SurfaceView, I'd like to draw it progressively in an animation.

我到目前为止，完成的是创建一个路径，然后使用PathMeasure检索坐标逐渐沿路径。这基本上是我到目前为止，完成

What I've done so far is to create a Path and then to use PathMeasure to retrieve the coordinates progressively along the path. Here is basically what I've done so far

PathMeasure pm = new PathMeasure(myPath, false);

    float position = 0;
    float end = pm.getLength();
    float[] coord = {0,0,0,0,0,0,0,0,0};

    while (position < end){
        Matrix m = new Matrix();
        // put the current path position coordinates into the matrix
        pm.getMatrix(position, m, PathMeasure.POSITION_MATRIX_FLAG | PathMeasure.TANGENT_MATRIX_FLAG);
        // put the matrix data into the coord array (coord[2] = x and coord[5] = y)
        m.getValues(coord);
        ????
        position += 1;

    }

中的问号就是我坚持。我想画的路径逐步看到它的动画在屏幕上。我找不到关于它在互联网上的很多信息，因此任何线索将是非常美联社preciated如果你已经遇到了同样的情况。最终效果我想创建像铅笔画自动逐步文本。

The question marks is where I'm stuck. I want to draw the path progressively and see it animated on the screen. I couldn't find much info about it on the internet, so any clue would be much appreciated if you have already come across the same situation. The final effect I want to create is like a pencil drawing progressively a text automatically.

推荐答案

我只是解决此问题，在这里我做的：

I just have resolve this problem, here what I do:

private float[] mIntervals = { 0f, 0f };
private float drawSpeed = 2f;
private int currentPath = -1;
private PathMeasure mPathMeasure = new PathMeasure();
private ArrayList<Path> mListPath = new ArrayList<Path>(this.pathCount);


@Override
protected void onDraw(Canvas canvas) {
   if (mIntervals[1] <= 0f && currentPath < (pathCount - 1)) {
     // Set the current path to draw
     // getPath(int num) a function to return a path.
     Path newPath = this.getPath(mListPath.size());
     this.mListPath.add(newPath);
     this.mPathMeasure.setPath(newPath, false);
     mIntervals[0] = 0;
     mIntervals[1] = this.mPathMeasure.getLength();
   }

  if (mIntervals[1] > 0) {
     // draw the previous path
     int last = this.mListPath.size();
     for (int i = 0; i < last; i++) {
        canvas.drawPath(this.mListPath.get(i), mPaint);
     }
     // partially draw the last path
     this.mPaint.setPathEffect(new DashPathEffect(mIntervals, 0f));

     canvas.drawPath(this.mListPath.get(last), mPaint);

     // Update the path effects values, to draw a little more
     // on the path.
     mIntervals[0] += drawSpeed;
     mIntervals[1] -= drawSpeed;

     super.invalidate();
  } else {
     // The drawing have been done, draw it entirely
     for (int i = 0; i < this.mListPath.size(); i++) {
        canvas.drawPath(this.mListPath.get(i), mPaint);
     }
  }
}

这个例子，是我做了什么适应（简化的例子）。希望大家能够理解。因为我刚刚做这个功能的工作，它缺乏优化之类的东西了。

This example, is an adaptation of what I've done (to simplify the example). Hope you will understand it. Since I've just made this function working, It lacks of optimizations and things like that.

希望这会有所帮助; - ）

Hope it will help ;-)

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