Android滾動背景

Question

this is my background. just click here...

我正在構建一個遊戲。我的問題是在後臺。我不能在循環中連續滾動它。請給我一些建議。

Answer 1

試試這個，

public class ScenarioView extends ImageView { 
    Bitmap city1; 
    Bitmap city2; 
    Bitmap city3; 

    Bitmap mCloud1; 
    Bitmap mCloud2; 
    Bitmap mCloud3; 

    private class CloudPosition{ 
     int BitmapId; 
     int mCloudX; 
     int mCloudY; 
    } 

    CloudPosition[] clouds; 

    private static final int MAX_CLOUDS = 6; 

    private int FRAME_RATE = 30; 
    private Handler mHandler; 
    private mSpeed1 = 5; 
    private mSpeed2 = mSpeed1/2; 

    public ScenarioView(Context context, AttributeSet attrs){ 
     super(context, attrs); 
     setBackgroundResource(R.drawable.animation_sky); 
     mHandler = new Handler(); 
     clouds = new CloudPosition[MAX_CLOUDS]; 
    } 

    private Runnable r = new Runnable() { 

     @Override 
     public void run() { 
      invalidate();   
     } 
    }; 

    public void setCity1Bitmap(Bitmap city){ 
     city1 = city; 
    } 

    public void setCity2Bitmap(Bitmap city){ 
     city2 = city; 
    } 

    public void setCity3Bitmap(Bitmap city){ 
     city3 = city; 
    } 

    private void generateCloudPositions() { 
     int rowSeparator = getHeight()/2; 
     Random r = new Random(System.currentTimeMillis()); 
     int minY = 0; 
     int maxY = rowSeparator; 
     int minX = 0; 
     int maxX = getWidth(); 

     // Generate 1st row 
     int y = r.nextInt(maxY - minY + 1) + minY; 
     int x = r.nextInt(maxX - minX + 1) + minX; 
     int cloudId = r.nextInt(3); 
     setupCloud(0, x, y, cloudId); 

     y = r.nextInt(maxY - minY + 1) + minY; 
     x = r.nextInt(maxX - minX + 1) + minX; 
     cloudId = r.nextInt(3); 
     setupCloud(1, x, y, cloudId); 

     y = r.nextInt(maxY - minY + 1) + minY; 
     x = r.nextInt(maxX - minX + 1) + minX; 
     cloudId = r.nextInt(3); 
     setupCloud(2, x, y, cloudId); 

     minY = rowSeparator; 
     maxY = getHeight(); 
     // Generate 2nd row 
     y = r.nextInt(maxY - minY + 1) + minY; 
     x = r.nextInt(maxX - minX + 1) + minX; 
     cloudId = r.nextInt(3); 
     setupCloud(3, x, y, cloudId); 

     y = r.nextInt(maxY - minY + 1) + minY; 
     x = r.nextInt(maxX - minX + 1) + minX; 
     cloudId = r.nextInt(3); 
     setupCloud(4, x, y, cloudId); 

     y = r.nextInt(maxY - minY + 1) + minY; 
     x = r.nextInt(maxX - minX + 1) + minX; 
     cloudId = r.nextInt(3); 
     setupCloud(5, x, y, cloudId); 
    } 

    public void setCloudsBitmaps(Bitmap cloud1, Bitmap cloud2, Bitmap cloud3){ 
     mCloud1 = cloud1; 
     mCloud2 = cloud2; 
     mCloud3 = cloud3; 
     generateCloudPositions(); 
    } 

    private void setupCloud(int cloudNum, int x, int y, int cloudId){ 
     CloudPosition cp = new CloudPosition(); 
     cp.mCloudX = x; 
     cp.mCloudY = y; 
     cp.BitmapId = cloudId; 
     clouds[cloudNum] = cp; 
    } 

    @Override 
    protected void onDraw(Canvas canvas) { 
     super.onDraw(canvas); 
     mSpeed1 = mCallbacks.getSpeed(); 
     mSpeed2 = mSpeed1/2; 
     mBGFarMoveX = mBGFarMoveX - mSpeed1; 
     // decrement the near background 
     mBGNearMoveX = mBGNearMoveX - mSpeed1; 

     if(city1 != null && city2 != null && city3 != null){ 
      if(mCloud1 != null && mCloud2 != null && mCloud3 != null){ 
       drawClouds(canvas); 
      } 
      drawLandscape(canvas); 
     } 

     if(mCar != null){ 
      canvas.drawBitmap(mCar, mCarX, mCarY, null); 
     } 

     if(mWheel != null){ 
      drawWheels(canvas); 
     } 

     if(mBridge != null){ 
      drawBridge(canvas); 
     } 

     mHandler.postDelayed(r, FRAME_RATE); 
    } 

    private void drawLandscape(Canvas canvas) { 
     // calculate the wrap factor for matching image draw 
     int newFarX = city1.getWidth() + mBGFarMoveX; 
     // if we have scrolled all the way, reset to start 
     int bgY = getHeight() - city1.getHeight(); 

     if(mSpeed1 > 0 && newFarX <= 0){ 
      mBGFarMoveX = 0;  
      increseLandscape(); 
     } 

     if(mSpeed1 < 0 && mBGFarMoveX >= getWidth()){ 
      mBGFarMoveX = (mBGFarMoveX - city1.getWidth()); 
      decreseLandscape(); 
     } 

     if(newFarX >= 0 && newFarX <= getWidth()){ 
      switch (currCity) { 
      case 0: 
       canvas.drawBitmap(city1, mBGFarMoveX, bgY, null); 
       canvas.drawBitmap(city2, newFarX, bgY, null); 
       break; 
      case 1: 
       canvas.drawBitmap(city2, mBGFarMoveX, bgY, null); 
       canvas.drawBitmap(city3, newFarX, bgY, null); 
       break; 
      case 2: 
       canvas.drawBitmap(city3, mBGFarMoveX, bgY, null); 
       canvas.drawBitmap(city1, newFarX, bgY, null); 
       break; 
      } 
     } 
     if(mBGFarMoveX >= 0 && mBGFarMoveX <= getWidth()){ 
      switch (currCity) { 
      case 0: 
       canvas.drawBitmap(city3, mBGFarMoveX - city3.getWidth(), bgY, null);  
       canvas.drawBitmap(city1, mBGFarMoveX, bgY, null);     
       break; 
      case 1: 
       canvas.drawBitmap(city1, mBGFarMoveX - city1.getWidth(), bgY, null);  
       canvas.drawBitmap(city2, mBGFarMoveX, bgY, null); 
       break; 
      case 2: 
       canvas.drawBitmap(city2, mBGFarMoveX - city2.getWidth(), bgY, null); 
       canvas.drawBitmap(city3, mBGFarMoveX, bgY, null); 
       break; 
      } 
     } 
     if(mBGFarMoveX <= 0 && newFarX >= getWidth()){ 
      switch (currCity) { 
      case 0: 
       canvas.drawBitmap(city1, mBGFarMoveX, bgY, null); 
       break; 
      case 1: 
       canvas.drawBitmap(city2, mBGFarMoveX, bgY, null); 
       break; 
      case 2: 
       canvas.drawBitmap(city3, mBGFarMoveX, bgY, null); 
       break; 
      } 
     } 
    } 

    private void drawClouds(Canvas canvas) { 
     int width = getWidth(); 
     for(int i = 0; i < MAX_CLOUDS; i++){ 
      Bitmap cloud; 
      clouds[i].mCloudX = clouds[i].mCloudX - mSpeed2; 
      switch (clouds[i].BitmapId) { 
      case 0: 
       cloud = mCloud1; 
       break; 
      case 1: 
       cloud = mCloud2; 
       break; 
      case 2: 
       cloud = mCloud3; 
       break; 
      default: 
       cloud = mCloud1; 
       break; 
      } 
      int cloudX1 = clouds[i].mCloudX; 
      int cloudX2 = cloudX1 + cloud.getWidth(); 

      if (cloudX2 <= 0 && mSpeed2 > 0) { 
      clouds[i].mCloudX = clouds[i].mCloudX + (5 * cloud.getWidth()); 
      cloudX1 = clouds[i].mCloudX; 
      cloudX2 = cloudX1 + cloud.getWidth(); 
     } 
     if (cloudX1 >= width && mSpeed2 < 0) { 
       clouds[i].mCloudX = clouds[i].mCloudX - (5 * cloud.getWidth()); 
       cloudX1 = clouds[i].mCloudX; 
       cloudX2 = cloudX1 + cloud.getWidth(); 
      } 
      if(cloudX1 < width && cloudX2 > 0){ 
       canvas.drawBitmap(cloud, clouds[i].mCloudX, clouds[i].mCloudY, null); 
      } 
     } 

    } 
} 

在XML中，我用這樣的

<FrameLayout 
    xmlns:android="http://schemas.android.com/apk/res/android" 
    xmlns:tools="http://schemas.android.com/tools" 
    android:id="@+id/container" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent"> 

    <com.animation.ScenarioView 
     android:id="@+id/bg_view" 
     android:layout_width="match_parent" 
     android:layout_height="match_parent" 
     android:baselineAlignBottom="true"> 

    </com.animation.ScenarioView> 

</FrameLayout>