我有两个独立的 (x, y) 点,我想用它们对 View 应用旋转。
第一个点是固定的,我很容易找到它的值(例如 200,200)。我的第二点是存在 TOUCH 的地方,因此我也可以轻松捕获 RawX 和 RawY 点。我将这两点输入到我在另一个堆栈溢出问题中找到的这个方法中。
private float findRotation(int firstPointX, int firstPointY, int secondPointX, int secondPointY) {
double delta_x = (firstPointX - secondPointX);
double delta_y = (firstPointY - secondPointY);
double radians = Math.atan2(delta_y, delta_x);
return (float) Math.toDegrees(radians);
}
我使用它的返回来设置 View 的旋转。就像这样myView.setRotation(...)
。当我在屏幕上移动光标/手指时,结果最终是一个疯狂旋转的 View 。有任何想法吗?
我捕获的两点似乎是正确的,让我猜测也许 findRotation 方法是不正确的。
我的 Activity :
public class MainActivity extends Activity {
ImageView imageView;
ImageView dragHandle;
RelativeLayout layout;
int rememberAngle;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
imageView = (ImageView) findViewById(R.id.imageView1);
dragHandle = (ImageView) findViewById(R.id.imageView2);
layout = (RelativeLayout) findViewById(R.id.relativeLayout2);
resize(dragHandle);
}
public void resize(ImageView resizeButton) {
resizeButton.setOnTouchListener(new View.OnTouchListener() {
public boolean onTouch(View v, MotionEvent motionEvent) {
if (motionEvent.getAction() == MotionEvent.ACTION_DOWN) {
int[] locationOfLayout = new int[2];
int[] locationOfDrag = new int[2];
layout.getLocationOnScreen(locationOfLayout);
dragHandle.getLocationOnScreen(locationOfDrag);
int firstPointX = locationOfLayout[0];
int firstPointY = locationOfLayout[1];
int secondPointX = dragHandle.getWidth() / 2 + locationOfDrag[0];
int secondPointY = dragHandle.getHeight() / 2 + locationOfDrag[1];
rememberAngle = (int) findRotation(firstPointX, firstPointY, secondPointX, secondPointY) + layout.getRotation();
} else if (motionEvent.getAction() == MotionEvent.ACTION_MOVE) {
int[] locationOfLayout = new int[2];
int[] locationOfDrag = new int[2];
layout.getLocationOnScreen(locationOfLayout);
dragHandle.getLocationOnScreen(locationOfDrag);
int centerXOnLayout = layout.getWidth() / 2 + locationOfLayout[0];
int centerYOnLayout = layout.getHeight() / 2 + locationOfLayout[1];
int centerXOnDrag = dragHandle.getWidth() / 2 + locationOfDrag[0];
int centerYOnDrag = dragHandle.getHeight() / 2 + locationOfDrag[1];
layout.setRotation(findRotation(centerXOnLayout, centerYOnLayout, centerXOnDrag, centerYOnDrag) - rememberAngle);
} else if (motionEvent.getAction() == MotionEvent.ACTION_UP) {
}
return true;
}
});
}
private float findRotation(int firstPointX, int firstPointY, int secondPointX, int secondPointY) {
double delta_x = (secondPointX - firstPointX);
double delta_y = (secondPointY - firstPointY);
double radians = Math.atan2(delta_y, delta_x);
return (float) Math.toDegrees(radians);
}
}
我的 XML:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<RelativeLayout
android:id="@+id/relativeLayout2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerInParent="true" >
<ImageView
android:id="@+id/imageView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:layout_centerVertical="true"
android:src="@drawable/ic_launcher" />
<ImageView
android:id="@+id/imageView2"
android:layout_width="48dp"
android:layout_height="48dp"
android:layout_below="@+id/imageView1"
android:layout_toRightOf="@+id/imageView1"
android:src="@drawable/meanicons" />
</RelativeLayout>
</RelativeLayout>
最佳答案
public void resize(ImageView resizeButton) {
resizeButton.setOnTouchListener(new View.OnTouchListener() {
float startAngle;
float zeroAngle;
int firstPointX;
int firstPointY;
public boolean onTouch(View v, MotionEvent motionEvent) {
if (motionEvent.getAction() == MotionEvent.ACTION_DOWN) {
int[] locationOfLayout = new int[2];
int[] locationOfDrag = new int[2];
layout.getLocationOnScreen(locationOfLayout);
dragHandle.getLocationOnScreen(locationOfDrag);
firstPointX = locationOfLayout[0];
firstPointY = locationOfLayout[1];
int secondPointX = motionEvent.getRawX();
int secondPointY = motionEvent.getRawY();
zeroAngle = findRotation(firstPointX, firstPointY, secondPointX, secondPointY) // remember "zero" angle
startAngle = layout.getRotation(); // remember angle at which layout is rotated at the start
} else if (motionEvent.getAction() == MotionEvent.ACTION_MOVE) {
layout.setRotation(findRotation(firstPointX, firstPointY, motionEvent.getRawX(), motionEvent.getRawY()) - zeroAngle + startAngle); // rotate relative to start and zero angle
} else if (motionEvent.getAction() == MotionEvent.ACTION_UP) {
}
return true;
}
});
}
private float findRotation(int firstPointX, int firstPointY, int secondPointX, int secondPointY) {
double delta_x = (secondPointX - firstPointX);
double delta_y = (secondPointY - firstPointY);
double radians = Math.atan2(delta_y, delta_x);
return (float) Math.toDegrees(radians);
}
关于java - 在android中绕两点旋转不起作用,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/23000012/