Java 如何在“活动”的运行时逐步绘制线位图

我有画线的示例代码。我需要为运行时逐点绘制线。但现在我得到了执行后只显示活动线。但是，我需要开始活动并逐点显示线条

示例代码

public class MainActivity extends ActionBarActivity {

ImageView drawingImageView;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    drawingImageView = (ImageView) this.findViewById(R.id.DrawingImageView);
    Bitmap bitmap = Bitmap.createBitmap((int) getWindowManager()
            .getDefaultDisplay().getWidth(), (int) getWindowManager()
            .getDefaultDisplay().getHeight(), Bitmap.Config.ARGB_8888);
    Canvas canvas = new Canvas(bitmap);
    drawingImageView.setImageBitmap(bitmap);

    // Line
    Paint paint = new Paint();
    paint.setColor(Color.rgb(255, 153, 51));
    paint.setStrokeWidth(10);
    int startx = 50;
    int starty = 90;
    int endx = 350;
    int endy = 90;
    while(endx>=startx) {
        try {
            Thread.sleep(5);
        }catch (InterruptedException e){
            e.printStackTrace();
        }
        canvas.drawLine(startx, starty, startx+1, endy, paint);
        startx++;
    }
}}

XML

<?xml version="1.0" encoding="utf-8"?>

---

我认为视图中添加了行，但UI没有刷新，所以在线程后添加行。睡眠（5）以刷新UI

getWindow().getDecorView().findViewById(android.R.id.content).invalidate();

或者你可以使用下面的代码-

public class ImgDraw extends Activity {

    ImageView drawingImageView;
    Handler mHandlerAnimation = null;
    Runnable mRunnableAnimation = null;
     Canvas canvas ;
     int startx = 0,starty =0,endx = 0,endy = 0;
     Paint paint;
     Bitmap bitmap ;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_imgdraw);

        drawingImageView = (ImageView)findViewById(R.id.DrawingImageView);

          DisplayMetrics metrics = new DisplayMetrics();
            getWindowManager().getDefaultDisplay().getMetrics(metrics);
           int width = metrics.widthPixels;
           int height = metrics.heightPixels;

          bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);

            canvas = new Canvas(bitmap);
            drawingImageView.setImageBitmap(bitmap);

            // Line
            paint = new Paint();
            paint.setColor(Color.rgb(255, 153, 51));
            paint.setStrokeWidth(10);
             startx = 50;
             starty = 90;
             endx = 350;
             endy = 90;          

          //   canvas.drawLine(startx, starty, startx+1, endy, paint);


                ImgAnimation();


    }

    private void ImgAnimation() {

        mHandlerAnimation = new Handler();

        mRunnableAnimation = new Runnable() {
            public void run() {

                  if(endx>=startx) {
                         canvas.drawLine(startx, starty, startx+1, endy, paint);
                            startx = startx + 10;
                            getWindow().getDecorView().findViewById(android.R.id.content).invalidate();
                     }


                mHandlerAnimation.postDelayed(this, 80);
            }
        };

        mHandlerAnimation.postDelayed(mRunnableAnimation, 80);

    }



}

---

当动画到达端点位置时，使用下面的代码重新启动动画-

private void ImgAnimation() {

        mHandlerAnimation = new Handler();

        mRunnableAnimation = new Runnable() {
            public void run() {

                  if(endx>startx) 
                  {
                         canvas.drawLine(startx, starty, startx+1, endy, paint);
                         startx = startx + 1;
                         getWindow().getDecorView().findViewById(android.R.id.content).invalidate();
                  }
                  else
                  {
                      bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
                      canvas = new Canvas(bitmap);
                      drawingImageView.setImageBitmap(bitmap);
                      startx = 50;
                  }


                mHandlerAnimation.postDelayed(this, 80);
            }
        };

        mHandlerAnimation.postDelayed(mRunnableAnimation, 80);

    }

---

如何将if语句更改为while循环。若我在不响应应用程序的情况下进行更改，若您将if改为while循环，那个么它将直接向您显示上面代码中显示的行。While循环由if+handler.postDelayed覆盖（这是80）；当startx等于endx时。自动startx到达起始位置我没有得到你想要的？当startx等于endx时，你想设置startx=50吗？startx=start+10此条件增加x位置当其再次到达endx位置时，它将到达起始位置（startx=50）。

private void ImgAnimation() {

        mHandlerAnimation = new Handler();

        mRunnableAnimation = new Runnable() {
            public void run() {

                  if(endx>startx) 
                  {
                         canvas.drawLine(startx, starty, startx+1, endy, paint);
                         startx = startx + 1;
                         getWindow().getDecorView().findViewById(android.R.id.content).invalidate();
                  }
                  else
                  {
                      bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
                      canvas = new Canvas(bitmap);
                      drawingImageView.setImageBitmap(bitmap);
                      startx = 50;
                  }


                mHandlerAnimation.postDelayed(this, 80);
            }
        };

        mHandlerAnimation.postDelayed(mRunnableAnimation, 80);

    }