使用 Rebound 库向 ImageView 添加与 Facebook Messanger 聊天头相同的自然拖动效果 [英] Adding natural dragging effect to ImageView same as Facebook Messanger chat heads using Rebound library
问题描述
我正在开发一个应用程序,我在 Activity 中拖动我的 ImageView.我已经为最初在 Facebook 中使用的 spring 动画配置了 Facebook Rebound libraryMessenger 的聊天头动画.当我拖动它时,我想将这种动画添加到我的 ImageView 中.视频
I am developing one app where I am dragging around my ImageView in Activity. I have configured Facebook Rebound library for spring animation which is originally used in Facebook Messenger's chat heads animations. I want to add this kind of animations to my ImageView when I drag it. VIDEO
到目前为止,当我触摸 ImageView(在 rootview 上实现 spring)时,我能够获得 spring 动画,这是我的代码.如何将这种自然类型的拖动效果实现到我的 ImageView.
So far I am able to get spring animation when I touch ImageView (implemented spring on rootview), this is my code. How can I implement that natural type of dragging effect to my ImageView.
public class MainTry extends Activity {
int windowwidth;
int windowheight;
private LayoutParams layoutParams;
private final BaseSpringSystem mSpringSystem = SpringSystem.create();
private FrameLayout mRootView;
private Spring spring;
private View mImageView;
private VelocityTracker velocity = null;
private float dx;
private float dy;
private View rootView;
private ImageView img;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.layout);
// Create a system to run the physics loop for a set of springs.
SpringSystem springSystem = SpringSystem.create();
// Add a spring to the system.
spring = springSystem.createSpring();
rootView = getWindow().getDecorView()
.findViewById(android.R.id.content);
windowwidth = getWindowManager().getDefaultDisplay().getWidth();
windowheight = getWindowManager().getDefaultDisplay().getHeight();
img = (ImageView) findViewById(R.id.imageView2);
rootView.setOnTouchListener(new View.OnTouchListener() {
@Override
public boolean onTouch(View v, MotionEvent event) {
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
// spring.setEndValue(1);
break;
case MotionEvent.ACTION_UP:
case MotionEvent.ACTION_CANCEL:
// spring.setEndValue(0);
break;
}
return true;
}
});
// Add a listener to observe the motion of the spring.
spring.addListener(new SimpleSpringListener() {
@Override
public void onSpringUpdate(Spring spring) {
// You can observe the updates in the spring
// state by asking its current value in onSpringUpdate.
float value = (float) spring.getCurrentValue();
float scale = .5f - (value * 0.1f);
img.setScaleX(scale);
img.setScaleY(scale);
}
});
// spring.setEndValue(1);
img.setOnTouchListener(new View.OnTouchListener() {
@Override
public boolean onTouch(View v, MotionEvent event) {
LayoutParams layoutParams = (LayoutParams) img
.getLayoutParams();
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
dx = event.getRawX() - 10;
dy = event.getRawY() - 10;
if (velocity == null) {
// Retrieve a new VelocityTracker object to watch the
// velocity of a motion.
velocity = VelocityTracker.obtain();
} else {
// Reset the velocity tracker back to its initial state.
velocity.clear();
}
break;
case MotionEvent.ACTION_MOVE:
dx = event.getRawX() - 10;
dy = event.getRawY() - 10;
velocity.addMovement(event);
spring.setVelocity(velocity.getYVelocity());
spring.setCurrentValue(dy);
spring.setEndValue(dy);
layoutParams.leftMargin = (int) dx - 10;
layoutParams.topMargin = (int) dy - 10;
img.setLayoutParams(layoutParams);
break;
case MotionEvent.ACTION_CANCEL:
break;
case MotionEvent.ACTION_UP:
velocity.addMovement(event);
spring.setVelocity(velocity.getYVelocity());
spring.setCurrentValue(event.getRawY() - 10);
spring.setEndValue(0);
break;
default:
break;
}
return true;
}
});
}
@Override
public void onResume() {
super.onResume();
}
@Override
public void onPause() {
super.onPause();
}
}
推荐答案
关于这个:
class V extends View implements SpringListener {
private static final int NUM_ELEMS = 4;
private Spring[] mXSprings = new Spring[NUM_ELEMS];
private Spring[] mYSprings = new Spring[NUM_ELEMS];
private Paint mPaint = new Paint();
private Bitmap mBitmap = BitmapFactory.decodeResource(getResources(), R.drawable.ic_launcher);
public V(Context context) {
super(context);
SpringSystem ss = SpringSystem.create();
Spring s;
for (int i = 0; i < NUM_ELEMS; i++) {
s = ss.createSpring();
s.setSpringConfig(new MySpringConfig(200, i == 0? 8 : 15 + i * 2, i, true));
s.addListener(this);
mXSprings[i] = s;
s = ss.createSpring();
s.setSpringConfig(new MySpringConfig(200, i == 0? 8 : 15 + i * 2, i, false));
s.addListener(this);
mYSprings[i] = s;
}
}
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
mXSprings[0].setCurrentValue(w / 2);
mYSprings[0].setCurrentValue(0);
mXSprings[0].setEndValue(w / 2);
mYSprings[0].setEndValue(h / 2);
}
@Override
public void onSpringActivate(Spring s) {
}
@Override
public void onSpringAtRest(Spring s) {
}
@Override
public void onSpringEndStateChange(Spring s) {
}
@Override
public void onSpringUpdate(Spring s) {
MySpringConfig cfg = (MySpringConfig) s.getSpringConfig();
if (cfg.index < NUM_ELEMS - 1) {
Spring[] springs = cfg.horizontal? mXSprings : mYSprings;
springs[cfg.index + 1].setEndValue(s.getCurrentValue());
}
if (cfg.index == 0) {
invalidate();
}
}
@Override
public boolean onTouchEvent(MotionEvent event) {
mXSprings[0].setEndValue(event.getX());
mYSprings[0].setEndValue(event.getY());
return true;
}
@Override
protected void onDraw(Canvas canvas) {
for (int i = NUM_ELEMS - 1; i >= 0; i--) {
mPaint.setAlpha(i == 0? 255 : 192 - i * 128 / NUM_ELEMS);
canvas.drawBitmap(mBitmap,
(float) mXSprings[i].getCurrentValue() - mBitmap.getWidth() / 2,
(float) mYSprings[i].getCurrentValue() - mBitmap.getHeight() / 2,
mPaint);
}
}
class MySpringConfig extends SpringConfig {
int index;
boolean horizontal;
public MySpringConfig(double tension, double friction, int index, boolean horizontal) {
super(tension, friction);
this.index = index;
this.horizontal = horizontal;
}
}
}
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