Android 讲义第二版 ViewSwitcher + GestureDetector 练习

浏览数：24 / 时间：2015年06月11日

添加手势监听：

1     GestureDetector detector;// 手势侦听

View Code

1 detector = new GestureDetector(getApplicationContext(),
2                 new myGestureListener());

View Code

手势侦听在 onFling 中指定屏幕滑动效果和展示图像：

 1 class myGestureListener implements OnGestureListener {
 2         // 当触碰事件按下时触发该方法
 3         @Override
 4         public boolean onDown(MotionEvent event) {
 5             return false;
 6         }
 7 
 8         // 用户在触摸屏上拖过时触发该方法
 9         @Override
10         public boolean onFling(MotionEvent event1, MotionEvent event2,
11                 float velocityX, float velocityY) {
12             ((GridView) viewSwitcher.getNextView()).setAdapter(adapter);
13             if (event2.getX() - event1.getX() > FLIP_DISTANCE) {
14                 if (screenNo > 0) {
15                     screenNo--;
16                     // 添加屏幕动画切换效果
17                     viewSwitcher.setInAnimation(animations[0]);
18                     viewSwitcher.setInAnimation(animations[3]);
19                     viewSwitcher.showPrevious();
20                     return true;
21                 } else {
22                     Toast.makeText(getApplicationContext(), "已无更多页面",
23                             Toast.LENGTH_LONG).show();
24                 }
25             } else {
26                 if (screenNo < screenCount - 1) {
27                     screenNo++;
28                     viewSwitcher.setInAnimation(animations[1]);
29                     viewSwitcher.setInAnimation(animations[2]);
30                     viewSwitcher.showNext();
31                     return true;
32                 } else {
33                     Toast.makeText(getApplicationContext(), "已无更多页面",
34                             Toast.LENGTH_LONG).show();
35                 }
36             }
37             return false;
38         }
39 
40         // 用户在屏幕上长按时触发该方法
41         @Override
42         public void onLongPress(MotionEvent event) {
43 
44         }
45 
46         // 用户在屏幕上滚动时触发该方法
47         @Override
48         public boolean onScroll(MotionEvent event1, MotionEvent event2,
49                 float velocityX, float velocityY) {
50             return false;
51         }
52 
53         // 用户在触摸屏上按下，而且还未移动和松开时触发该方法
54         @Override
55         public void onShowPress(MotionEvent arg0) {
56 
57         }
58 
59         // 用户在触屏上的轻击事件将触发该方法
60         @Override
61         public boolean onSingleTapUp(MotionEvent arg0) {
62             return false;
63         }
64 
65     }

View Code

进入的第一个界面展示代码：

 1 public void next(View v) {
 2         if (screenNo == -1) {
 3             screenNo++;
 4             ((GridView) viewSwitcher.getNextView()).setAdapter(adapter);
 5             viewSwitcher.showNext();
 6         } else {
 7             Toast.makeText(getApplicationContext(), "已无更多页面", Toast.LENGTH_LONG)
 8                     .show();
 9         }
10     }

View Code

定义BaseAdapter：

 1 private BaseAdapter adapter = new BaseAdapter() {
 2         @Override
 3         public long getItemId(int position) {
 4             return position;
 5         }
 6 
 7         @Override
 8         public DataItem getItem(int position) {
 9             return total.get(screenNo * Number_Per_Screen + position);
10         }
11 
12         @Override
13         public int getCount() {
14             if (screenNo == screenCount - 1
15                     && total.size() % Number_Per_Screen != 0) {
16                 return total.size() % Number_Per_Screen;
17             }
18             return Number_Per_Screen;
19         }
20 
21         @Override
22         public View getView(int position, View convertView, ViewGroup parent) {
23             View view = convertView;
24             if (convertView == null) {
25                 view = layoutInflater.inflate(R.layout.labelicon, null);
26             }
27             ImageView imageview = (ImageView) view.findViewById(R.id.imageview);
28             imageview.setImageDrawable(getItem(position).drawable);
29             TextView textView = (TextView) view.findViewById(R.id.textview);
30             textView.setText(getItem(position).DataName);
31             return view;
32         }
33     };