在 Android 中旋轉 MapView

Question

我正在編寫一個 Android 應用程序，其中一個功能是地圖將根據指南針旋轉（即，如果手機指向東方，則地圖的方向將使得地圖的東側位於頂部）。 我發現的以前的答案建議在 mapView 中編寫 onDraw() 方法，但是，api 將該方法更改為 final，因此它不能被覆蓋。 因此，我試圖像這樣覆蓋dispatchDraw()方法：

筆記：

-compass 是一個布爾值，如果為真，則旋轉視圖

-bearing 是一個浮點變量，具有視圖應該旋轉的度數

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();
}

Answer 1

感謝 pheelicks 和 Nikita Koksharov 的回答，我設法根據指南針打開/關閉地圖視圖的旋轉。

首先，您需要在以下位置找到MapViewCompassDemo.java的兩個內部類： Android_SDK_ Tools\\add-ons\\addon-google_apis-google-#\\samples\\MapsDemo\\src\\com\\example\\android\\apis\\view\\

RotateView
SmoothCanvas

將內部類 RotateView 提取到RotateView.java並添加SmoothCanvas 作為 RotateView.java 的內部類而不是 MapViewCompassDemo.java

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

地圖布局.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>

地圖活動

 /**
 * 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: 
 * ..\Android\Android SDK Tools\add-ons\addon-google_apis-google-#\samples\MapsDemo\src\com\example\android\apis\view\
 * 
 * @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：使用羅盤示例項目旋轉 Google MapView： https : //www.dropbox.com/sh/c1encbc2lr63qd9/6C1C4hsrlT

Answer 2

從文檔：

protected void dispatchDraw (Canvas 畫布)

由 draw 調用以繪制子視圖。 這可能會被派生類覆蓋，以在繪制其子類之前（但在繪制其自己的視圖之后）獲得控制權。

所以覆蓋 dispatchDraw 是不好的，因為主地圖視圖已經被繪制

一種解決方案可能是將 MapView 添加為另一個 CustomView（ViewGroup 的子類）的子類，然后使用 CustomView 的 dispatchDraw 方法繪制旋轉的 MapView（現在是子類）。 所以在 xml 你會做這樣的事情：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:orientation="vertical"
  android:layout_width="fill_parent"
  android:layout_height="fill_parent" >

  <com.example.CustomView
    android:layout_width="fill_parent"
    android:layout_height="fill_parent">

    <com.google.android.maps.MapView
      android:id="@+id/mapview"
      android:layout_width="fill_parent"
      android:layout_height="fill_parent"
      android:apiKey="XXXXXXXXXXXXXXXXX"/>

  </com.example.CustomView>
</RelativeLayout>

Answer 3

此答案適用於Google Maps api v2 。 可以通過使用 Sensor Listener for Orientation 注冊您的應用程序並獲取相對於onSensorChanged內的真北的角度並相應地更新相機。 角度可用於軸承。 可以使用以下代碼：

而不是使用Sensor.TYPE_ORIENTATION嘗試使用 getOrinetation api。 Sensor.TYPE_ORIENTATION已被棄用。

@Override
protected void onResume() {
    // TODO Auto-generated method stub
    super.onResume();
    if (sensorManager != null)
        sensorManager.registerListener(this,
                sensorManager.getDefaultSensor(Sensor.TYPE_ORIENTATION),
                SensorManager.SENSOR_DELAY_GAME);
}

public void onSensorChanged(SensorEvent event) {

    float degree = Math.round(event.values[0]);

    Log.d(TAG, "Degree ---------- " + degree);

    updateCamera(degree);

}

private void updateCamera(float bearing) {
    CameraPosition oldPos = googleMap.getCameraPosition();

    CameraPosition pos = CameraPosition.builder(oldPos).bearing(bearing)
            .build();

    googleMap.moveCamera(CameraUpdateFactory.newCameraPosition(pos));

}

Answer 4

它應該是這樣的：

@Override
protected void dispatchDraw(Canvas canvas) {
    canvas.save(Canvas.MATRIX_SAVE_FLAG);
    if (compass) {
        // rotate the canvas with the pivot on the center of the screen
        canvas.rotate(-azimuth, getWidth() * 0.5f, getHeight() * 0.5f);
        super.dispatchDraw(canvas);
        canvas.restore();
    }
}

Answer 5

查看ANDROID_SDK\\add-ons\\addon-google_apis-google_inc_-7\\samples\\MapsDemo 。 它有旋轉地圖演示。