Radar animation
So here's what. I am tracking specific distances and I would like to display them in radar animation. A basic radar image would be something like this (not really)
where each circle represents a range of distances. The idea is that the point moves towards the circles as the distance changes. My initial approach was to take different images of the same radar with a dot on each circle and just switch them by distance. But then I wonder if there is a chance (performer and this works great at different resolutions) to have one base radar image and just move the dot. Hopefully I'm clearing it up and if anyone has an idea I'll be very grateful
I am not posting any code because I need an idea and then a bad fight with the implementation
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Have you tried these examples?
https://github.com/jfabrix101/RadarCustomVIew
https://github.com/gpfduoduo/RadarScanView
i.e
Radar.java
public class RadarView extends View {
private final String LOG = "RadarView";
private final int POINT_ARRAY_SIZE = 25;
private int fps = 100;
private boolean showCircles = true;
float alpha = 0;
Point latestPoint[] = new Point[POINT_ARRAY_SIZE];
Paint latestPaint[] = new Paint[POINT_ARRAY_SIZE];
public RadarView(Context context) {
this(context, null);
}
public RadarView(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}
public RadarView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
Paint localPaint = new Paint();
localPaint.setColor(Color.GREEN);
localPaint.setAntiAlias(true);
localPaint.setStyle(Paint.Style.STROKE);
localPaint.setStrokeWidth(1.0F);
localPaint.setAlpha(0);
int alpha_step = 255 / POINT_ARRAY_SIZE;
for (int i=0; i < latestPaint.length; i++) {
latestPaint[i] = new Paint(localPaint);
latestPaint[i].setAlpha(255 - (i* alpha_step));
}
}
android.os.Handler mHandler = new android.os.Handler();
Runnable mTick = new Runnable() {
@Override
public void run() {
invalidate();
mHandler.postDelayed(this, 1000 / fps);
}
};
public void startAnimation() {
mHandler.removeCallbacks(mTick);
mHandler.post(mTick);
}
public void stopAnimation() {
mHandler.removeCallbacks(mTick);
}
public void setFrameRate(int fps) { this.fps = fps; }
public int getFrameRate() { return this.fps; };
public void setShowCircles(boolean showCircles) { this.showCircles = showCircles; }
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
int width = getWidth();
int height = getHeight();
int r = Math.min(width, height);
//canvas.drawRect(0, 0, getWidth(), getHeight(), localPaint);
int i = r / 2;
int j = i - 1;
Paint localPaint = latestPaint[0]; // GREEN
if (showCircles) {
canvas.drawCircle(i, i, j, localPaint);
canvas.drawCircle(i, i, j, localPaint);
canvas.drawCircle(i, i, j * 3 / 4, localPaint);
canvas.drawCircle(i, i, j >> 1, localPaint);
canvas.drawCircle(i, i, j >> 2, localPaint);
}
alpha -= 0.5;
if (alpha < -360) alpha = 0;
double angle = Math.toRadians(alpha);
int offsetX = (int) (i + (float)(i * Math.cos(angle)));
int offsetY = (int) (i - (float)(i * Math.sin(angle)));
latestPoint[0]= new Point(offsetX, offsetY);
for (int x=POINT_ARRAY_SIZE-1; x > 0; x--) {
latestPoint[x] = latestPoint[x-1];
}
int lines = 0;
for (int x = 0; x < POINT_ARRAY_SIZE; x++) {
Point point = latestPoint[x];
if (point != null) {
canvas.drawLine(i, i, point.x, point.y, latestPaint[x]);
}
}
lines = 0;
for (Point p : latestPoint) if (p != null) lines++;
boolean debug = false;
if (debug) {
StringBuilder sb = new StringBuilder(" >> ");
for (Point p : latestPoint) {
if (p != null) sb.append(" (" + p.x + "x" + p.y + ")");
}
Log.d(LOG, sb.toString());
// " - R:" + r + ", i=" + i +
// " - Size: " + width + "x" + height +
// " - Angle: " + angle +
// " - Offset: " + offsetX + "," + offsetY);
}
}
}
in your activity .xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_gravity="center"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:background="@android:color/black">
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="start"
android:onClick="startAniamtion"/>
<frusso.radartest.RadarView
android:id="@+id/radarView"
android:layout_width="240dp"
android:layout_height="240dp"
android:layout_gravity="center_horizontal"
/>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="stop"
android:onClick="stopAnimation"/>
Activity.java
public class MainActivity extends Activity {
RadarView mRadarView = null;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mRadarView = (RadarView) findViewById(R.id.radarView);
mRadarView.setShowCircles(true);
}
public void stopAnimation(View view) {
if (mRadarView != null) mRadarView.stopAnimation();
}
public void startAnimation(View view) {
if (mRadarView != null) mRadarView.startAnimation();
}
}
Hope this helps you with your requirements.
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"I control certain distances." What does it mean?
To make a radar, create a class that extends ImageView. Flip onDraw (canvas canvas) and set image resource to radar background.
@Override
public void onDraw(Canvas canvas) {
//draw background
super.onDraw(canvas);
for(PointF p : points)
{
//draw each point as an image. Maybe, translate by width/2 and height/2
}
}
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