在 Android 中旋转 MapView [英] Rotate MapView in Android

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本文介绍了在 Android 中旋转 MapView的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!

问题描述

我正在编写一个 Android 应用程序,其中一个功能是地图将根据指南针旋转(即,如果手机指向东方,则地图的方向将使得地图的东侧位于顶部).我发现的以前的答案建议在 mapView 中编写 onDraw() 方法,但是,api 将该方法更改为 final,因此它不能被覆盖.因此,我试图像这样覆盖 dispatchDraw() 方法:

I am writing an Android app where one of the features is that the map will rotate according to the compass (i.e. if the phone is pointing east, the map will be oriented so that the east side of the map is on top). Previous answers that I have found suggested over writing the onDraw() method in mapView, however, the api changed the method to final so it cannot be overwritten. As a result I have tried to overwrite the dispatchDraw() method like so:

注意:

-compass 是一个布尔值,如果为真,则旋转视图

-compass is a boolean that if true, rotate the view

-bearing 是一个浮点变量,具有视图应该旋转的度数

-bearing is a float variable that has the degrees that the view should rotate

protected void dispatchDraw(Canvas canvas) {
    canvas.save();
         if (compass) {
             final float w = this.getWidth();
             final float h = this.getHeight();

             final float scaleFactor = (float)(Math.sqrt(h * h + w * w) / Math.min(w, h));

             final float centerX = w / 2.0f;
             final float centerY = h / 2.0f;

             canvas.rotate(bearing, centerX, centerY);
             canvas.scale(scaleFactor, scaleFactor, centerX, centerY);

         }
         super.dispatchDraw(canvas);
         canvas.restore();
}

推荐答案

感谢 pheelicks 和 Nikita Koksharov 的回答,我设法根据指南针打开/关闭地图视图的旋转.

Thanks to pheelicks and Nikita Koksharov answers, I manage to turn on/off the rotation of a mapview according to the compass.

首先,您需要 MapViewCompassDemo.java两个内部 类,位于:Android_SDK_ Toolsadd-onsaddon-google_apis-google-#samplesMapsDemosrccomexampleandroidapisview

First you will need the two inner class of MapViewCompassDemo.java found at: Android_SDK_ Toolsadd-onsaddon-google_apis-google-#samplesMapsDemosrccomexampleandroidapisview

RotateView
SmoothCanvas

将内部类 RotateView 提取到 RotateView.java添加 SmoothCanvas 作为 RotateView.java 的内部类而不是 MapViewCompassDemo.java

Extract the inner class RotateView to RotateView.java and add SmoothCanvas as a inner class of RotateView.java instead of MapViewCompassDemo.java

public class RotateView extends ViewGroup implements SensorListener {
...
   static final class SmoothCanvas extends Canvas {
...
   }//end SmoothCanvas 
}//end RotateView 

maplayout.xml :

maplayout.xml :

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/map_layout_container"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >

<LinearLayout
    android:id="@+id/rotating_view"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >

    <com.google.android.maps.MapView
        android:id="@+id/map_view"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:apiKey="##### YOUR MAP KEY HERE ######"
        android:clickable="true" />
</LinearLayout>

<ToggleButton
    android:id="@+id/button_compass"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentBottom="true"
    android:layout_centerHorizontal="true"
    android:onClick="onClick"
    android:textOff="compass off"
    android:textOn="compass on" />

</RelativeLayout>

地图活动

 /**
 * Example activity on how to display a google map view rotation with compass
 * To make it work you need to add:
 *  - <uses-library android:name="com.google.android.maps" /> in the manifest.xml file
 *  - Your Android Maps API Key from https://developers.google.com/android/maps-api- signup
 *  - Set the project build target to "Google APIs"
 *  - Extract/Add the two inner classes RotateView and SmoothCanvas of MapViewCompassDemo.java found at: 
 * ..AndroidAndroid SDK Toolsadd-onsaddon-google_apis-google-#samplesMapsDemosrccomexampleandroidapisview
 * 
 * @author hsigmond - touchboarder.com - 
 *
 */
public class MapViewRotationWithCompass extends MapActivity {

private MapView mMapView;
private MyLocationOverlay mMyLocationOverlay = null;
private boolean mModeCompass = false;
private SensorManager mSensorManager;
private LinearLayout mRotateViewContainer;
private RotateView mRotateView;


@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    setContentView(R.layout.maplayout);
    mSensorManager = (SensorManager) getSystemService(SENSOR_SERVICE);
    mRotateViewContainer = (LinearLayout) findViewById(R.id.rotating_view);
    mRotateView = new RotateView(this);

    // Sign Up for the Android Maps API at:
    // https://developers.google.com/android/maps-api-signup
    // Add the Android Maps API key to the MapView in the maplayout.xml file 
    mMapView = (MapView) findViewById(R.id.map_view);
    mMyLocationOverlay = new MyLocationOverlay(this, mMapView);     

}

@SuppressWarnings("deprecation")
public void onClick(View v) {

    switch (v.getId()) {

    case R.id.button_compass:
        if (mMyLocationOverlay.isCompassEnabled()) {
            mSensorManager.unregisterListener(mRotateView);
            mRotateView.removeAllViews();
            mRotateViewContainer.removeAllViews();
            mRotateViewContainer.addView(mMapView);
            mMyLocationOverlay.disableCompass();
            mModeCompass = false;
        } else {
            mRotateViewContainer.removeAllViews();
            mRotateView.removeAllViews();
            mRotateView.addView(mMapView);
            mRotateViewContainer.addView(mRotateView);
            mMapView.setClickable(true);
            mSensorManager.registerListener(mRotateView,
                    SensorManager.SENSOR_ORIENTATION,
                    SensorManager.SENSOR_DELAY_UI);
            mMyLocationOverlay.enableCompass();
            mModeCompass = true;
        }
        break;
    }
}

@SuppressWarnings("deprecation")
@Override
public void onResume() {
    super.onResume();
    if (mModeCompass) {
        mMyLocationOverlay.enableCompass();
        mSensorManager.registerListener(mRotateView,
                SensorManager.SENSOR_ORIENTATION,
                SensorManager.SENSOR_DELAY_UI);
    }
}

@Override
public void onPause() {
    super.onPause();
    mMyLocationOverlay.disableCompass();
}

@SuppressWarnings("deprecation")
@Override
protected void onStop() {
    mSensorManager.unregisterListener(mRotateView);
    super.onStop();
}

@Override
protected boolean isRouteDisplayed() {
    return (false);// Don't display a route
}

}

更新:使用指南针旋转 Google MapView 示例项目:https://www.dropbox.com/sh/c1encbc2lr63qd9/6C1C4hsrlT

Update: Rotating Google MapView with Compass Example Project: https://www.dropbox.com/sh/c1encbc2lr63qd9/6C1C4hsrlT

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