我正在尝试实现一个简单的图像库，其中我有一个图像要在设备屏幕上一次显示。当我们从左向右滑动屏幕时，它应该会显示下一张图片。
为此，我实现了一个视图翻转器并向其添加了图像视图。
但我不知道如何捕捉该滑动事件。
谁能告诉我一个例子？
【问题讨论】：
标签： android
我的应用需要同样的东西，并使用了ViewPager：
http://blog.sqisland.com/2012/09/android-swipe-image-viewer-with-viewpager.html
之前我使用了ImageSwitcher 和GestureDetector：http://blog.sqisland.com/2012/07/android-swipe-image-viewer.html
ViewPager 的代码更简单，体验也更好，因为手指在屏幕上滑动时图像会滑动。我直接创建ImageView，不需要碎片。
【讨论】：
您可以为您的 ViewPager 创建一个自定义 Pager Adapter：
public class ImageAdapter extends PagerAdapter {
private Context context;
private int[] GalImages = new int[]{
R.drawable.cap8, R.drawable.cap2, R.drawable.cap3, R.drawable.cap1, R.drawable.cap5,
R.drawable.cap6, R.drawable.cap7, R.drawable.cap9, R.drawable.cap4,
R.drawable.cap10
};
ImageAdapter(Context context) {
this.context = context;
}
@Override
public int getCount() {
return GalImages.length;
}
@Override
public boolean isViewFromObject(View view, Object object) {
return view == object;
}
@Override
public Object instantiateItem(ViewGroup container, int position) {
ImageView imageView = new ImageView(context);
int padding = context.getResources().getDimensionPixelSize(R.dimen.activity_horizontal_margin);
imageView.setPadding(padding, padding, padding, padding);
imageView.setScaleType(ImageView.ScaleType.FIT_CENTER);
imageView.setImageResource(GalImages[position]);
container.addView(imageView, 0);
return imageView;
}
@Override
public void destroyItem(ViewGroup container, int position, Object object) {
container.removeView((ImageView) object);
}
}
在布局中使用 ViewPager 并注册适配器：
<android.support.v4.view.ViewPager
android:id="@+id/mvieww"
android:layout_width="match_parent"
android:layout_height="match_parent" />
【讨论】：
你也可以这样做，不使用视图翻转器
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<ImageView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_gravity="center"
android:gravity="center"
android:layout_margin="10dip"
android:id="@+id/image_place_holder"
/>
</RelativeLayout>
活动类
public class MainActivity extends Activity {
private Integer[] mImageIds = { R.drawable.img1, R.drawable.img2,R.drawable.img3 };
private static final String DEBUG_TAG = "MainActivity ";
ImageView imageView;
float startXValue = 1;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.gallery);
imageView = (ImageView) findViewById(R.id.image_place_holder);
imageView.setImageResource(mImageIds[num]);
}
@Override
public boolean onTouchEvent(MotionEvent event) {
float endXValue = 0;
float x1 = event.getAxisValue(MotionEvent.AXIS_X);
int action = MotionEventCompat.getActionMasked(event);
switch (action) {
case (MotionEvent.ACTION_DOWN):
startXValue = event.getAxisValue(MotionEvent.AXIS_X);
return true;
case (MotionEvent.ACTION_UP):
endXValue = event.getAxisValue(MotionEvent.AXIS_X);
if (endXValue > startXValue) {
if (endXValue - startXValue > 100) {
System.out.println("Left-Right");
imageView.setImageResource(mImageIds[2]);
}
}else {
if (startXValue -endXValue> 100) {
System.out.println("Right-Left");
imageView.setImageResource(mImageIds[0]);
}
}
return true;
default:
return super.onTouchEvent(event);
}
}
}
【讨论】：
您想使用Android Support Jar 中的ViewPager。这是一个教程：http://thepseudocoder.wordpress.com/2011/10/05/android-page-swiping-using-viewpager/
您不想使用 Gallery，因为有些人建议它没有被弃用。但是从documentation 他们建议ViewPager 和HorizantleScrollView 相对容易地解决这个问题：
This class is deprecated.
This widget is no longer supported. Other horizontally scrolling widgets include
HorizontalScrollView and ViewPager from the support library.
【讨论】：
你可以这样做，它在没有任何视图的情况下正常工作
public class Swipe extends Activity implements OnClickListener {
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;
final GestureDetector gdt = new GestureDetector(new GestureListener());
private GestureDetector gestureDetector;
ImageView img;
View.OnTouchListener gestureListener;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.swipe);
img = (ImageView)findViewById(R.id.imageView1swipe);
img.setOnTouchListener(new OnTouchListener() {
public boolean onTouch(final View view, final MotionEvent event) {
// TODO Auto-generated method stub
gdt.onTouchEvent(event);
//Log.i("Hello my Log 1","How dfgfd are you");
return true;
}
});
并在您的 .java 中声明此方法
private class GestureListener extends SimpleOnGestureListener {
@Override
public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX,
float velocityY) {
Log.i("Hello my Log 2","How dfgfd are you");
if (e1.getX() - e2.getX() > SWIPE_MIN_DISTANCE
&& Math.abs(velocityX) > SWIPE_THRESHOLD_VELOCITY) {
Log.i("dfsd", "Right to left");
return false; // Right to left
} else if (e2.getX() - e1.getX() > SWIPE_MIN_DISTANCE
&& Math.abs(velocityX) > SWIPE_THRESHOLD_VELOCITY) {
return false; // Left to right
}
if (e1.getY() - e2.getY() > SWIPE_MIN_DISTANCE
&& Math.abs(velocityY) > SWIPE_THRESHOLD_VELOCITY) {
return false; // Bottom to top
} else if (e2.getY() - e1.getY() > SWIPE_MIN_DISTANCE
&& Math.abs(velocityY) > SWIPE_THRESHOLD_VELOCITY) {
return false; // Top to bottom
}
return false;
}'
可能是this 将帮助您安排所有的图像滑动
【讨论】：
我是这样实现的：
package com.demoimageslider;
import java.util.List;
import java.util.Vector;
import com.nineoldandroids.view.ViewHelper;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
public class MainActivity extends FragmentActivity {
private PagerAdapter mPagerAdapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
this.initialisePaging();
}
private void initialisePaging() {
List<Fragment> fragments = new Vector<Fragment>();
fragments.add(Fragment.instantiate(this, Tab1Fragment.class.getName()));
fragments.add(Fragment.instantiate(this, Tab2Fragment.class.getName()));
fragments.add(Fragment.instantiate(this, Tab3Fragment.class.getName()));
this.mPagerAdapter = new PagerAdapter(
super.getSupportFragmentManager(), fragments);
ViewPager pager = (ViewPager) super.findViewById(R.id.pager);
pager.setAdapter(this.mPagerAdapter);
pager.setPageTransformer(true, new ZoomOutPageTransformer());
}
public static class Tab1Fragment extends Fragment {
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
if (container == null) {
return null;
}
return (ImageView) inflater.inflate(R.layout.tab_frag1_layout,
container, false);
}
}
public static class Tab2Fragment extends Fragment {
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
if (container == null) {
return null;
}
return (ImageView) inflater.inflate(R.layout.tab_frag2_layout,
container, false);
}
}
public static class Tab3Fragment extends Fragment {
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
if (container == null) {
return null;
}
return (ImageView) inflater.inflate(R.layout.tab_frag3_layout,
container, false);
}
}
public static class PagerAdapter extends FragmentPagerAdapter {
private List<Fragment> fragments;
public PagerAdapter(FragmentManager fm, List<Fragment> fragments) {
super(fm);
this.fragments = fragments;
}
@Override
public Fragment getItem(int position) {
return this.fragments.get(position);
}
@Override
public int getCount() {
return this.fragments.size();
}
}
public static class ZoomOutPageTransformer implements
ViewPager.PageTransformer {
private static final float MIN_SCALE = 0.85f;
private static final float MIN_ALPHA = 0.5f;
public void transformPage(View view, float position) {
int pageWidth = view.getWidth();
int pageHeight = view.getHeight();
if (position < -1) { // [-Infinity,-1)
// This page is way off-screen to the left.
// view.setAlpha(0);
ViewHelper.setAlpha(view, 0);
} else if (position <= 1) { // [-1,1]
// Modify the default slide transition to shrink the page as
// well
float scaleFactor = Math.max(MIN_SCALE, 1 - Math.abs(position));
float vertMargin = pageHeight * (1 - scaleFactor) / 2;
float horzMargin = pageWidth * (1 - scaleFactor) / 2;
if (position < 0) {
// view.setTranslationX(horzMargin - vertMargin / 2);
ViewHelper.setTranslationX(view, horzMargin - vertMargin
/ 2);
} else {
// view.setTranslationX(-horzMargin + vertMargin / 2);
ViewHelper.setTranslationX(view, -horzMargin + vertMargin
/ 2);
}
// Scale the page down (between MIN_SCALE and 1)
// view.setScaleX(scaleFactor);
// view.setScaleY(scaleFactor);
ViewHelper.setScaleX(view, scaleFactor);
ViewHelper.setScaleY(view, scaleFactor);
// Fade the page relative to its size.
// view.setAlpha(MIN_ALPHA +
// (scaleFactor - MIN_SCALE) /
// (1 - MIN_SCALE) * (1 - MIN_ALPHA));
ViewHelper.setAlpha(view, MIN_ALPHA + (scaleFactor - MIN_SCALE)
/ (1 - MIN_SCALE) * (1 - MIN_ALPHA));
} else { // (1,+Infinity]
// This page is way off-screen to the right.
// view.setAlpha(0);
ViewHelper.setAlpha(view, 0);
}
}
}
}
我使用 Nineoldroids 库来支持旧 android 版本的效果。
【讨论】：
你为什么不使用画廊小部件来实现它？
【讨论】：