Android开发经验之在图片上随意点击移动文字

只要在图片范围之内，文字可随意点击移动。

package xiaosi.GetTextImage;      import android.content.Context;  import android.content.res.Resources;  import android.graphics.Bitmap;  import android.graphics.BitmapFactory;  import android.graphics.Canvas;  import android.graphics.Paint;  import android.util.DisplayMetrics;  import android.view.MotionEvent;  import android.view.View;  import android.view.WindowManager;    public class GetTextImage extends View  {   private float x = 20, y = 40;   private static float windowWidth;   private static float windowHeight;   private static float left = 0;      //图片在屏幕中位置X坐标   private static float top = 0;       //图片在屏幕中位置Y坐标   private String str = "我爱你";   private DisplayMetrics dm = new DisplayMetrics();  //用于获取屏幕的高度和宽度   private WindowManager windowManager;   private Bitmap newbitmap;     public GetTextImage(Context context)   {    super(context);    windowManager = (WindowManager) context      .getSystemService(Context.WINDOW_SERVICE);    //屏幕的宽度    windowWidth = windowManager.getDefaultDisplay().getWidth();    //屏幕的高度    windowHeight = windowManager.getDefaultDisplay().getHeight();   }     public void onDraw(Canvas canvas)   {    Resources res = getResources();    Bitmap bmp = BitmapFactory.decodeResource(res, R.drawable.b);    newbitmap = getTextImage(bmp, str, x, y);    canvas.drawBitmap(newbitmap, 0, 0, null);   }   /**    * 返回值: Bitmap 参数：原图片,文字 功能: 根据给定的文字生成相应图片    *     * @param originalMap     * @param text  文字    * @param x  点击的X坐标    * @param y  点击的Y坐标    * @return    */   public static Bitmap getTextImage(Bitmap originalMap, String text, float x,     float y)   {    float bitmapWidth = originalMap.getWidth();    float bitmapHeight = originalMap.getHeight();    // 定义画布       Canvas canvas = new Canvas(originalMap);       // 定义画笔    Paint paint = new Paint();    //获得文本的长度（像素）    float textWidth = paint.measureText(text);     canvas.drawBitmap(originalMap, 0, 0, null);        // 如果图片宽度小于屏幕宽度    if (left + bitmapWidth < windowWidth)    {     // 右边界     if (x >= left + bitmapWidth - textWidth)     {      x = left + bitmapWidth - textWidth;     }     // 左边界     else if (x <= left)     {      x = left;     }    }    else    {     // 右边界     if (x >= windowWidth - textWidth)     {      x = windowWidth - textWidth;     }     // 左边界     else if (x <= 0)     {      x = 0;     }    }    // 如果图片高度小于屏幕高度    if (top + bitmapHeight < windowHeight)    {     // 下     if (y >= top + bitmapHeight)     {      y = top + bitmapHeight;     }     // 上     else if (y <= top + 10)     {      y = top + 10;     }    }    else    {     if (y >= windowHeight)     {      y = windowHeight;     }     else if (y <= 0)     {      y = 0;     }    }        // 添加字       canvas.drawText(text, x, y, paint);    return originalMap;   }   @Override   public boolean onTouchEvent(MotionEvent event)   {    if (event.getAction() == MotionEvent.ACTION_DOWN)    {     x = event.getX();     y = event.getY();     // 重绘     invalidate();    }    return true;   }  }

package xiaosi.GetTextImage;    import android.app.Activity;  import android.os.Bundle;    public class GetTextImageActivity extends Activity {      /** Called when the activity is first created. */   private GetTextImage get;      @Override      public void onCreate(Bundle savedInstanceState) {          super.onCreate(savedInstanceState);          get = new GetTextImage(this);          setContentView(get);      }  }