如何使用ID引用画布旋转

Question

在kivy语言中，每次滑块将其值更改import android.location.Geocoder; import android.support.v4.app.FragmentActivity; import android.os.Bundle; import android.support.v7.widget.SearchView; import com.google.android.gms.maps.CameraUpdateFactory; import com.google.android.gms.maps.GoogleMap; import com.google.android.gms.maps.OnMapReadyCallback; import com.google.android.gms.maps.SupportMapFragment; import com.google.android.gms.maps.model.LatLng; import com.google.android.gms.maps.model.MarkerOptions; import java.io.IOException; import java.util.List; public class MapsActivity extends FragmentActivity implements OnMapReadyCallback { private GoogleMap mMap; private SearchView searchView; private SupportMapFragment mapFragment; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_maps); mapFragment = (SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map); searchView = findViewById(R.id.location); searchView.setOnQueryTextListener(new SearchView.OnQueryTextListener() { @Override public boolean onQueryTextSubmit(String query) { String location = searchView.getQuery().toString(); List<Address> addressList = null; if (location != null || location != "") { Geocoder geocoder = new Geocoder(MapsActivity.this); try { addressList = geocoder.getFromLocationName(location, 1); } catch (IOException e) { e.printStackTrace(); } Address address = addressList.get(0); LatLng latLng = new LatLng(address.getLatitude(),address.getLongitude()); mMap.addMarker(new MarkerOptions().position(latLng).title(location)); mMap.animateCamera(CameraUpdateFactory.newLatLng(latLng)); } return false; } @Override public boolean onQueryTextChange(String query) { return false; } }); mapFragment.getMapAsync(this); } @Override public void onMapReady(GoogleMap googleMap) { mMap = googleMap; } }``` "I expect that the app would not crash when I again hit enter to submit search in SearchView." 时，我都希望更改画布的角度值。

我试图通过使用“组”为PushMatrix中的“旋转操作”赋予ID

on_touch_move

from kivy.app import App from kivy.uix.boxlayout import BoxLayout from kivy.lang.builder import Builder kv = ''' <Seesaw>: orientation: "horizontal" Widget: id: canvas_widget size_hint_x: 0.85 canvas.before: PushMatrix Rotate: group: 'a' #angle: 0 axis: 0, 0, 1 origin: 300, 300 canvas: Color: rgb: (0, 0, 1) Rectangle: pos: 100,300 size: 400,20 canvas.after: PopMatrix Slider: size_hint_x: 0.15 id: slider1 min: -60 max: 60 orientation: 'vertical' on_touch_move: canvas_widget.a.angle = 45, root.printer() ''' Builder.load_string(kv) class Seesaw(BoxLayout): def printer(self): print('Slider value changed to: ', self.ids.slider1.value) class SimpleApp(App): def build(self): seesaw = Seesaw() return seesaw if __name__ == '__main__': SimpleApp().run()

I can't access the angle of the PushMatrix by using on_touch_move of the Slider in kv-language.

一个ID，以及如何访问Rotation操作？

提前感谢您的时间。

Answer 1

• 向实例化对象angle添加新属性Widget:
• 将新属性分配给角度angle: self.angle
• 将canvas_widget.a.angle = 45替换为canvas_widget.angle = 45

摘要

<Seesaw>:
    orientation: "horizontal"
    Widget:
        id: canvas_widget
        angle: 0    # new attribute
        size_hint_x: 0.85
        canvas.before:                 
            PushMatrix
            Rotate:         
                angle: self.angle    # Assignment             
                axis: 0, 0, 1
                origin: 300, 300
        ...

    Slider:
        ...

        on_touch_move: 
            root.printer()   
            canvas_widget.angle = 45

输出