Android--手势触控屏幕控制/GestureDetector

实现本实例需要注意几个地方：

1.隐藏状态栏

 /* 隐藏状态栏 */    this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,                              WindowManager.LayoutParams.FLAG_FULLSCREEN);

2.隐藏标题栏

/* 隐藏标题栏 */    requestWindowFeature(Window.FEATURE_NO_TITLE);

这个例子实现的是手势拖动效果展示。

下面给出本实例的截图：

1.初步运行

我们看到这张图片的分辨率很高，我们不能看到这幅图片的全景，这时我们需要实现拖拉效果看到图片的全景，当我们实现了手势之后，运行的效果如下：

下面给出本实例的代码：

package irdc.ex07_19;import android.app.Activity;import android.graphics.Bitmap;import android.graphics.BitmapFactory;import android.os.Bundle;import android.view.GestureDetector;import android.view.MotionEvent;import android.view.Window;import android.view.WindowManager;import android.widget.ImageView;public class EX07_19 extends Activity{  private ImageView image1;  private Bitmap bm;  private int bmWidth=0;  private int bmHeight=0;  private int width=0;  private int height=0;  private int pointX=0;  private int pointY=0;  private GestureDetector detector;  private myGestureListener gListener;    /** Called when the activity is first created. */  @Override  public void onCreate(Bundle savedInstanceState)  {    super.onCreate(savedInstanceState);    /* 隐藏状态栏 */    this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,                              WindowManager.LayoutParams.FLAG_FULLSCREEN);    /* 隐藏标题栏 */    requestWindowFeature(Window.FEATURE_NO_TITLE);    /* 载丈main.xml Layout */    setContentView(R.layout.main);    /* 取得屏幕宽高 */        width=this.getWindowManager().getDefaultDisplay().getWidth();    height=this.getWindowManager().getDefaultDisplay().getHeight();       /* Bitmap设定 */    bm=BitmapFactory.decodeResource(getResources(),R.drawable.photo);    bmWidth=bm.getWidth();    bmHeight=bm.getHeight();    /* ImageView初始化 */    image1=(ImageView)findViewById(R.id.image1);    Bitmap newB=Bitmap.createBitmap(bm,pointX,pointY, width, height);    image1.setImageBitmap(newB);    /* GestureDetector设置 */    gListener = new myGestureListener();    detector = new GestureDetector(EX07_19.this,gListener);  }  /* 当Activity的onTouchEvent()被触发时，   * 触发GestureDetector的onTouchEvent() */  @Override  public boolean onTouchEvent(MotionEvent event)  {    if (detector.onTouchEvent(event))    {      return detector.onTouchEvent(event);    }      else    {      return super.onTouchEvent(event);    }  }    /* 自定义GestureListener类 */  public class myGestureListener implements GestureDetector.OnGestureListener  {    /* 手指在屏幕上拖拉时触发此method */    @Override    public boolean onScroll(MotionEvent e1, MotionEvent e2,                            float distanceX,  float distanceY)    {      /* 计算X轴基准点移动后的吵置 */      if(pointX+distanceX>=0){        if((pointX+distanceX)>(bmWidth-width)){            pointX=bmWidth-width;        }else{          pointX+=distanceX;        }      }else{        pointX=0;      }      /* 计算Y轴基准点移动后的吵置 */      if(pointY+distanceY>=0){          if((pointY+distanceY)>(bmHeight-height)){            pointY=bmHeight-height;        }else{          pointY+=distanceY;        }      }else{        pointY=0;      }      /* 如果有移动，则更新Bitmap设定 */      if(distanceX!=0&&distanceY!=0)      {        Bitmap newB=Bitmap.createBitmap(bm,pointX,pointY,width,height);        image1.setImageBitmap(newB);      }      return false;    }    @Override    public boolean onDown(MotionEvent arg0)    {      return false;    }    @Override    public boolean onFling(MotionEvent e1, MotionEvent e2,        float velocityX, float velocityY)    {      return false;    }    @Override    public void onLongPress(MotionEvent e)    {    }    @Override    public void onShowPress(MotionEvent e)    {    }    @Override    public boolean onSingleTapUp(MotionEvent e)    {      return false;    }  }}