如何暂停画布以特定角度旋转2秒? [英] How to pause canvas from rotating for 2 secs at specific angles?
问题描述
我做了一个旋钮，但是我想将旋钮以特定角度停下来2秒钟.我想将其停在260f和-20f上.
I made a rotating knob ,but I want to stop the knob at specific angles for 2 seconds. I want to stop it on 260f and -20f.
有人可以建议怎么做吗?
Can anyone suggest how to do it ?
这是博客中的代码.我根据自己的要求进行了许多更改.
This is the code from a blog. I made many changes according to my requirements.
public class RotatoryKnobView extends ImageView {
private float angle = -20f;
private float theta_old=0f;
private RotaryKnobListener listener;
public interface RotaryKnobListener {
public void onKnobChanged(float arg);
}
public void setKnobListener(RotaryKnobListener l )
{
listener = l;
}
public RotatoryKnobView(Context context) {
super(context);
initialize();
}
public RotatoryKnobView(Context context, AttributeSet attrs)
{
super(context, attrs);
initialize();
}
public RotatoryKnobView(Context context, AttributeSet attrs, int defStyle)
{
super(context, attrs, defStyle);
initialize();
}
private float getTheta(float x, float y)
{
float sx = x - (getWidth() / 2.0f);
float sy = y - (getHeight() / 2.0f);
float length = (float)Math.sqrt( sx*sx + sy*sy);
float nx = sx / length;
float ny = sy / length;
float theta = (float)Math.atan2( ny, nx );
final float rad2deg = (float)(180.0/Math.PI);
float thetaDeg = theta*rad2deg;
return (thetaDeg < 0) ? thetaDeg + 360.0f : thetaDeg;
}
public void initialize()
{
this.setImageResource(R.drawable.rotoron);
setOnTouchListener(new OnTouchListener()
{
@Override
public boolean onTouch(View v, MotionEvent event) {
float x = event.getX(0);
float y = event.getY(0);
float theta = getTheta(x,y);
switch(event.getAction() & MotionEvent.ACTION_MASK)
{
case MotionEvent.ACTION_POINTER_DOWN:
theta_old = theta;
break;
case MotionEvent.ACTION_MOVE:
invalidate();
float delta_theta = theta - theta_old;
theta_old = theta;
int direction = (delta_theta > 0) ? 1 : -1;
angle += 5*direction;
notifyListener(angle+20);
break;
}
return true;
}
});
}
private void notifyListener(float arg)
{
if (null!=listener)
listener.onKnobChanged(arg);
}
protected void onDraw(Canvas c)
{if(angle==257f){
try {
synchronized (c) {
c.wait(5000);
angle=260f;
}
} catch (InterruptedException e) {
}
}
else if(angle==-16f)
{
try {
synchronized (c) {
c.wait(5000);
angle=-20f;
}
} catch (InterruptedException e) {
}
}
else
if(angle>260f)
{
angle=-20f;
}
else if(angle<-20f)
{
angle=260f;
}
else{
c.rotate(angle,getWidth()/2,getHeight()/2);
}
super.onDraw(c);
}
}
推荐答案
我认为，这里的最终答案是通过扩展SurfaceView然后覆盖onDraw(Canvas canvas)
I think the ultimate answer here is to implement your own class by extending SurfaceView and then overriding onDraw( Canvas canvas )
然后您可以使用Canvas例程来呈现控件.
You can then use the Canvas routines to render your control.
如果您使用google，还有很多很好的例子.
There are a lot of good examples out there if you google.
要开始初始化表面视图:
To get started initialize the surface view:
// So things actually render
setDrawingCacheEnabled(true);
setWillNotDraw(false);
setZOrderOnTop(true);
// Controls the drawing thread.
getHolder().addCallback(new CallbackSurfaceView());
重写onDraw并添加您的渲染例程.您可以将它们分层 随你去.
Override onDraw and add your rendering routines. You can layer them as you go.
public void onDraw(Canvas canvas) {
// Always Draw
super.onDraw(canvas);
drawBackground(canvas);
drawKnobIndentWell(canvas);
drawKnob(canvas);
drawKnobLED( canvas ); //etc....
}
回调和更新线程的示例:
An example of a Callback and an update thread:
/**
* This is the drawing callback.
* It handles the creation and destruction of the drawing thread when the
* surface for drawing is created and destroyed.
*/
class CallbackSurfaceView implements SurfaceHolder.Callback {
Thread threadIndeterminant;
RunnableProgressUpdater runnableUpdater;
boolean done = false;
/**
* Kills the running thread.
*/
public void done() {
done = true;
if (null != runnableUpdater) {
runnableUpdater.done();
}
}
/**
* Causes the UI to render once.
*/
public void needRedraw() {
if (runnableUpdater != null) {
runnableUpdater.needRedraw();
}
}
/**
* When the surface is created start the drawing thread.
* @param holder
*/
@Override
public void surfaceCreated(SurfaceHolder holder) {
if (!done) {
threadIndeterminant = new Thread(runnableUpdater = new RunnableProgressUpdater());
threadIndeterminant.start();
}
}
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
}
/**
* When the surface is destroyed stop the drawing thread.
* @param holder
*/
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
if (null != runnableUpdater) {
runnableUpdater.done();
threadIndeterminant = null;
runnableUpdater = null;
}
}
}
/**
* This is the runnable for the drawing operations. It is started and stopped by the callback class.
*/
class RunnableProgressUpdater implements Runnable {
boolean surfaceExists = true;
boolean needRedraw = false;
public void done() {
surfaceExists = false;
}
public void needRedraw() {
needRedraw = true;
}
@Override
public void run() {
canvasDrawAndPost();
while (surfaceExists) {
// Renders continuously during a download operation.
// Otherwise only renders when requested.
// Necessary so that progress bar and cirlce activity update.
if (syncContext.isRunning()) {
canvasDrawAndPost();
needRedraw = true;
} else if (needRedraw) {
canvasDrawAndPost();
needRedraw = false;
}
try {
Thread.sleep(100);
} catch (InterruptedException e) {
// Don't care
}
}
// One final update
canvasDrawAndPost();
}
/**
* Routine the redraws the controls on each loop.
*/
private synchronized void canvasDrawAndPost() {
Canvas canvas = getHolder().lockCanvas();
if (canvas != null) {
try {
draw(canvas);
} finally {
getHolder().unlockCanvasAndPost(canvas);
}
}
}
}
如果您决定采用这种方法，则可以使用以下命令从XML中自定义控件 自定义值.
If you decide to go this route you can customize your control from XML using custom values.
<com.killerknob.graphics.MultimeterVolumeControl
android:id="@+id/volume_control"
android:layout_below="@id/divider_one"
android:background="@android:color/white"
android:layout_width="match_parent"
android:layout_height="60dp"
android:minHeight="60dp"
custom:ledShadow="#357BBB"
custom:ledColor="#357BBB"
custom:knobBackground="@color/gray_level_13"
custom:knobColor="@android:color/black"
/>
创建自定义控件时，请按其程序包名称进行引用. 您在/values下的资源文件中创建自定义变量，然后引用 他们在你班上.
When you create a custom control you reference it by its package name. You create custom variable in a resource file under /values and then reference them in your class.
此处有更多详细信息:
http://developer.android.com/training/custom- views/create-view.html
这可能比您想做的工作还要多，但是我认为您最终将获得更加专业的外观控制，并且动画会更加流畅.
This may be more work then you want to do, but I think you will end up with a more professional looking control and the animations will be smoother.
无论如何，它看起来是一个有趣的项目.祝你好运.
At any rate, looks like a fun project. Good Luck.
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