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我是Android新手，我正在尝试创建一个页面，可以从左到右，从右到左滑动以前往和后续页面。我花了很多时间查找和尝试不同的事情。出于某种原因，当我滑动（不管朝哪个方向）时，它只会显示下一张照片。当我从右向左滑动时，它应该向我显示前一张照片。任何帮助将不胜感激！非常感谢您的时间:)Android：从左到右从左到右滑动
public class MyGestureDetector extends SimpleOnGestureListener
{
private static final int SWIPE_MIN_DISTANCE = 120;
private static final int SWIPE_MAX_OFF_PATH = 250;
private static final int SWIPE_THRESHOLD_VELOCITY = 200;
public boolean isRightToLeft = false;
@Override
public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY)
{
try {
if (Math.abs(e1.getY() - e2.getY()) > SWIPE_MAX_OFF_PATH)
return false;
// right to left swipe
// right to left swipe
if(e1.getX() - e2.getX() > SWIPE_MIN_DISTANCE && Math.abs(velocityX) > SWIPE_THRESHOLD_VELOCITY) {
isRightToLeft = true;
return true;
}
// left to right swipe
else if (e2.getX() - e1.getX() > SWIPE_MIN_DISTANCE && Math.abs(velocityX) > SWIPE_THRESHOLD_VELOCITY) {
isRightToLeft = false;
return true;
}
} catch (Exception e) {
// nothing
}
return false;
}
}
public class Pictures extends Activity
{
private int pictureCounter = 1;
private Context myContext = this;
private GestureDetector gestureDetector;
View.OnTouchListener gestureListener;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.pictures);
getPicture(pictureCounter);
final MyGestureDetector myGestureDetector = new MyGestureDetector();
// Gesture detection
gestureDetector = new GestureDetector(myGestureDetector);
gestureListener = new View.OnTouchListener() {
public boolean onTouch(View v, MotionEvent event) {
if (gestureDetector.onTouchEvent(event)) {
if (myGestureDetector.isRightToLeft)
{
previousPicture();
}
else if (!myGestureDetector.isRightToLeft)
{
nextPicture();
}
return true;
}
return false;
}
};
//iv.setOnTouchListener(gestureListener);
((ImageView)findViewById(R.id.title_pictures)).setOnTouchListener(gestureListener);
ImageView iv = (ImageView) findViewById(R.id.flag_pic);
iv.setOnClickListener(new OnClickListener()
{
public void onClick(View arg0)
{
// TODO Auto-generated method stub
nextPicture();
}
});
}
public void getPicture(int picCounter)
{
DatabaseHelper myDbHelper = new DatabaseHelper(this);
try
{
myDbHelper.createDatabase();
}
catch (IOException ioe)
{
throw new Error("Unable to create databse");
}
try
{
myDbHelper.openDatabase();
}
catch(SQLException sqle)
{
throw sqle;
}
String query = "select Before_Picture, After_Picture from picture_mapping where _id = " + picCounter;
SQLiteDatabase db = myDbHelper.getReadableDatabase();
Cursor cursor = db.rawQuery(query, null);
cursor.moveToFirst();
String beforePicture = cursor.getString(0);
String afterPicture = cursor.getString(1);
cursor.close();
db.close();
ImageView before_pic = (ImageView) findViewById(R.id.imgView_before_pic);
int resId = myContext.getResources().getIdentifier(beforePicture,"drawable", "com.ash.android.pictures");
before_pic.setBackgroundResource(resId);
TextView after_pic = (TextView) findViewById(R.id.txtView_after_picture);
after_pic.setText(afterPicture);
//Toast toast=Toast.makeText(this, beforePicture+ ":" + afterPicture, Toast.LENGTH_LONG);
//toast.show();
}
public void nextPicture()
{
if (pictureCounter < 36)
{
pictureCounter += 1;
getPicture(pictureCounter);
}
else
{
//do nothing
}
}
public void previousPicture()
{
if (pictureCounter > 1)
{
pictureCounter -= 1;
getPicture(pictureCounter);
}
else
{
//do nothing
}
}
}
在此先感谢！