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我正在開發一個操縱桿按鈕。在圓周上移動時一切都可以，但是當我想將它向上或向下移動時，它只會從右側繞過圓圈。所以，我想要有兩種選擇（像真正的操縱桿一樣向上或向下移動）。這是我的代碼示例。感謝您的幫助ImageView onTouch不能上下移動，只能繞着圓圈運行
public class JoystickView extends FrameLayout implements View.OnTouchListener {
private Context context;
private ImageView backgroundImageView;
private ImageView buttonImageView;
private RelativeLayout relativeLayout;
private View rootView;
float xx = 0;
float yy = 0;
public JoystickView(Context context) {
super(context);
this.context = context;
setLayout(this);
buttonImageView.setOnTouchListener(this);
this.setClipChildren(false);
}
public void setLayout(ViewGroup view) {
FrameLayout.LayoutParams layoutParams = new FrameLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT);
View v = inflateControlerLayout();
view.addView(v, layoutParams);
}
protected View inflateControlerLayout() {
initSlider();
rootView = relativeLayout;
return rootView;
}
public void initSlider() {
if (relativeLayout == null) {
relativeLayout = new RelativeLayout(context);
RelativeLayout.LayoutParams layoutParams = new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.MATCH_PARENT, RelativeLayout.LayoutParams.MATCH_PARENT);
relativeLayout.setLayoutParams(layoutParams);
relativeLayout.setClipChildren(false);
}
if (backgroundImageView == null) {
backgroundImageView = new ImageView(context);
LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.MATCH_PARENT, LinearLayout.LayoutParams.MATCH_PARENT);
backgroundImageView.setLayoutParams(layoutParams);
// load image
try {
// get input stream
InputStream ims = getContext().getAssets().open("joystick_background.png");
// load image as Drawable
Drawable d = Drawable.createFromStream(ims, null);
// set image to ImageView
backgroundImageView.setImageDrawable(d);
} catch (IOException ex) {
return;
}
}
if (buttonImageView == null) {
buttonImageView = new ImageView(context);
LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.MATCH_PARENT, LinearLayout.LayoutParams.MATCH_PARENT, Gravity.CENTER);
buttonImageView.setLayoutParams(layoutParams);
// load image
try {
// get input stream
InputStream ims2 = getContext().getAssets().open("jostick_button.png");
// load image as Drawable
Drawable d2 = Drawable.createFromStream(ims2, null);
// set image to ImageView
buttonImageView.setImageDrawable(d2);
buttonImageView.bringToFront();
} catch (IOException ex) {
return;
}
}
if (relativeLayout != null) {
relativeLayout.addView(backgroundImageView);
relativeLayout.addView(buttonImageView);
}
}
@Override
public boolean onTouch(View view, MotionEvent motionEvent) {
switch (motionEvent.getAction() & MotionEvent.ACTION_MASK) {
case MotionEvent.ACTION_DOWN:
break;
case MotionEvent.ACTION_UP:
view.setX(xx);
view.setY(yy);
break;
case MotionEvent.ACTION_POINTER_DOWN:
break;
case MotionEvent.ACTION_POINTER_UP:
break;
case MotionEvent.ACTION_MOVE:
float cx = view.getWidth()/2.f;
float cy = view.getHeight()/2.f;
float x = motionEvent.getRawX();
float y = motionEvent.getRawY();
float w = buttonImageView.getWidth();
float h = buttonImageView.getHeight();
double r = Math.min(cx, cy)/2.;
double dx = x - cx;
double dy = y - cy;
double hypot = Math.hypot(dx, dy);
double cos = dx/hypot;
double sin = dy/hypot;
double rdx = hypot < 1. ? 0. : r * cos;
double rdy = hypot < 1. ? 0. : r * sin;
buttonImageView.setTranslationX((float) (cx + rdx - w/2.));
buttonImageView.setTranslationY((float) (cy + rdy - h/2.));
break;
}
return true;
}
}
嗨克里斯，謝謝你快速回答，它的作品！現在，這讓我更加明白什麼是問題。但現在我正在處理另一件事。我想聽聽你的想法：它工作正常，我現在可以移動按鈕，上下左右等等。但現在當我用手指觸摸它的中心並嘗試移動它時，它從右下方開始（按鈕向右移動），手指中心尖端位於按鈕的左上角。我希望你明白我的意思......無論如何，謝謝你的解決方案！ –
我確實注意到了這種行爲。我認爲你必須從一個代碼片段開始，該代碼片段用於旋轉撥號盤或其他東西，因爲代碼適用於將視圖移動一圈。爲了得到你想要的行爲，你可以保存指針向下事件的初始x/y座標，然後在指針移動事件中派生相對運動。嘗試自己做出這些更改;如果您遇到困難，請爲社區發佈另一個問題。 –
Thanx kris求助！我找到了一個解決方案。 –