传送门 …翻来覆去
回部古剑
霍青桐一定神，说道：“我性命承公子相救，族中圣物，又蒙公子夺回。不论公子如何待我，都决不怨你。”说到这里，伸手解下腰间短剑，说道：“这短剑是我爹爹所赐，据说剑里藏着一个极大秘密，几百年来辗转相传，始终无人参详得出。今日一别，后会无期，此剑请公子收下。公子慧人，或能解得剑中奥妙。”
今天我们学习如何利用Android平台"回部古剑"ViewFlipper配合点击按钮的操作来实现左右滑动浏览图片的功能，像我们平日里在手机上查看电子相册、浏览电子书时所使用滑动翻页操作，都可以用它来实现。跟上一篇讲到利用ViewFlipper配合手势操作来实现该功能相比，可以说是各有千秋。按钮是有渐变效果的，也就是说点击图片时按钮会立即显示，松开后按钮会慢慢消失。下面给出该情景的案例：
一、案例技术要点
1.创建一个ViewFlipper控件，并且为它增加用于显示图片内容的视图。
2.使用WindowManager窗口管理器及其LayoutParams布局参数来设置导航按钮的布局和参数。改变Window设置需要添加如下权限：
[html]
<uses-permission android:name="android.permission.SYSTEM_ALERT_WINDOW"/>
<uses-permission android:name="android.permission.SYSTEM_ALERT_WINDOW"/>3.创建导航按钮，并且为它们分别设置进出屏幕的动画效果。
4.通过Handler异步消息处理机制来改变导航按钮显示的透明度，从而达到渐变显示的效果。
5.重写当前Activity的触摸事件回调方法onTouchEvent()：当手指按住移动图片或点击图片时显示导航按钮；当手指离开图片时逐渐消失导航按钮。
二、案例代码陈列
工程包目录
[html]
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="cn.lynn.viewflipper"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="15" />
<uses-permission android:name="android.permission.SYSTEM_ALERT_WINDOW"/>
<application
android:icon="@drawable/ic_launcher"
android:label="@string/app_name" >
<activity
android:name=".ViewFlipperMainActivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="cn.lynn.viewflipper"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="15" />
<uses-permission android:name="android.permission.SYSTEM_ALERT_WINDOW"/>
<application
android:icon="@drawable/ic_launcher"
android:label="@string/app_name" >
<activity
android:name=".ViewFlipperMainActivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>strings.xml
[html]
<resources>
<string name="app_name">android图片水平滑动ViewFlipper</string>
</resources>
<resources>
<string name="app_name">android图片水平滑动ViewFlipper</string>
</resources>main.xml
[html]
<?xml version="1.0" encoding="utf-8" ?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<ViewFlipper
android:id="@+id/viewFlipper"
android:layout_width="match_parent"
android:layout_height="match_parent">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center">
<ImageView
android:layout_width="160dp"
android:layout_height="160dp"
android:src="@drawable/item1"/>
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center">
<ImageView
android:layout_width="160dp"
android:layout_height="160dp"
android:src="@drawable/item2"/>
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center">
<ImageView
android:layout_width="160dp"
android:layout_height="160dp"
android:src="@drawable/item3"/>
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center">
<ImageView
android:layout_width="160dp"
android:layout_height="160dp"
android:src="@drawable/item4"/>
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center">
<ImageView
android:layout_width="160dp"
android:layout_height="160dp"
android:src="@drawable/item5"/>
</LinearLayout>
</ViewFlipper>
</LinearLayout>
<?xml version="1.0" encoding="utf-8" ?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<ViewFlipper
android:id="@+id/viewFlipper"
android:layout_width="match_parent"
android:layout_height="match_parent">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center">
<ImageView
android:layout_width="160dp"
android:layout_height="160dp"
android:src="@drawable/item1"/>
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center">
<ImageView
android:layout_width="160dp"
android:layout_height="160dp"
android:src="@drawable/item2"/>
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center">
<ImageView
android:layout_width="160dp"
android:layout_height="160dp"
android:src="@drawable/item3"/>
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center">
<ImageView
android:layout_width="160dp"
android:layout_height="160dp"
android:src="@drawable/item4"/>
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center">
<ImageView
android:layout_width="160dp"
android:layout_height="160dp"
android:src="@drawable/item5"/>
</LinearLayout>
</ViewFlipper>
</LinearLayout>
图片左进动画：left_in.xml[html] view plaincopyprint?
<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android">
<translate android:fromXDelta="100%p" android:toXDelta="0"
android:duration="500" />
<alpha android:fromAlpha="0.1" android:toAlpha="1.0"
android:duration="500" />
</set>
<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android">
<translate android:fromXDelta="100%p" android:toXDelta="0"
android:duration="500" />
<alpha android:fromAlpha="0.1" android:toAlpha="1.0"
android:duration="500" />
</set>图片左出动画：left_out.xml[html] view plaincopyprint?
<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android">
<translate android:fromXDelta="0" android:toXDelta="-100%p"
android:duration="500" />
<alpha android:fromAlpha="1.0" android:toAlpha="0.1"
android:duration="500" />
</set>
<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android">
<translate android:fromXDelta="0" android:toXDelta="-100%p"
android:duration="500" />
<alpha android:fromAlpha="1.0" android:toAlpha="0.1"
android:duration="500" />
</set>图片右进动画：right_in.xml[html] view plaincopyprint?
<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android">
<translate android:fromXDelta="-100%p" android:toXDelta="0"
android:duration="500" />
<alpha android:fromAlpha="0.1" android:toAlpha="1.0"
android:duration="500" />
</set>
<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android">
<translate android:fromXDelta="-100%p" android:toXDelta="0"
android:duration="500" />
<alpha android:fromAlpha="0.1" android:toAlpha="1.0"
android:duration="500" />
</set>图片右出动画：right_out.xml
[html]
<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android">
<translate android:fromXDelta="0" android:toXDelta="100%p"
android:duration="500" />
<alpha android:fromAlpha="1.0" android:toAlpha="0.1"
android:duration="500" />
</set>
<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android">
<translate android:fromXDelta="0" android:toXDelta="100%p"
android:duration="500" />
<alpha android:fromAlpha="1.0" android:toAlpha="0.1"
android:duration="500" />
</set>ViewFlipperMainActivity.java
[java]
package cn.lynn.viewflipper;
import android.app.Activity;
import android.content.Context;
import android.graphics.PixelFormat;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.view.Gravity;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.WindowManager;
import android.view.WindowManager.LayoutParams;
import android.widget.ImageView;
import android.widget.ViewFlipper;
/**
* ViewFlipper实现水平滑动图片，需要点击按钮指引滑动
*
* @author lynnli1229
*/
public class ViewFlipperMainActivity extends Activity {
private static final int SHOW = 0x29;
private static final int HIDE = 0x31;
private ImageView leftBtnView;
private ImageView rightBtnView;
// 设置窗口管理器
private WindowManager winMgr;
// 设置窗口管理器布局参数
private WindowManager.LayoutParams winMgrParams;
// 设置按钮视图alpha的初始值
private int alpha;
// 设置按钮是否隐藏
private boolean isHide;
private ViewFlipper viewFlipper;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
viewFlipper = (ViewFlipper) findViewById(R.id.viewFlipper);
initBtnView();
}
/**
* 初始化按钮视图
*/
private void initBtnView() {
winMgr = (WindowManager) getSystemService(Context.WINDOW_SERVICE);
winMgrParams = new WindowManager.LayoutParams();
winMgrParams.type = LayoutParams.TYPE_PHONE;
// 设置图片背景为透明
winMgrParams.format = PixelFormat.RGBA_8888;
winMgrParams.flags = LayoutParams.FLAG_NOT_TOUCH_MODAL
| LayoutParams.FLAG_NOT_FOCUSABLE;
winMgrParams.x = 0;
winMgrParams.y = 0;
winMgrParams.width = 48;
winMgrParams.height = 48;
createLeftBtnView();
createRightBtnView();
}
/**
* 创建向左（前）按钮
*/
private void createLeftBtnView() {
leftBtnView = new ImageView(this);
leftBtnView.setImageResource(R.drawable.left);
leftBtnView.setAlpha(0);
leftBtnView.setOnClickListener(new OnClickListener() {
public void onClick(View view) {
// 上一个图像
viewFlipper.setInAnimation(ViewFlipperMainActivity.this,
R.anim.left_in);
viewFlipper.setOutAnimation(ViewFlipperMainActivity.this,
R.anim.left_out);
viewFlipper.showPrevious();
}
});
// 调整窗口
winMgrParams.gravity = Gravity.LEFT | Gravity.CENTER_VERTICAL;
// 显示图像
winMgr.addView(leftBtnView, winMgrParams);
}
/**
* 创建向右（后）按钮
*/
private void createRightBtnView() {
rightBtnView = new ImageView(this);
rightBtnView.setImageResource(R.drawable.right);
rightBtnView.setAlpha(0);
rightBtnView.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View view) {
// 下一个图像
viewFlipper.setInAnimation(ViewFlipperMainActivity.this,
R.anim.right_in);
viewFlipper.setOutAnimation(ViewFlipperMainActivity.this,
R.anim.right_out);
viewFlipper.showNext();
}
});
// 调整窗口
winMgrParams.gravity = Gravity.RIGHT | Gravity.CENTER_VERTICAL;
// 显示图像
winMgr.addView(rightBtnView, winMgrParams);
}
/**
* 设置按钮渐变显示效果
*/
private final Handler handler = new Handler() {
@Override
public void handleMessage(Message msg) {
if (msg.what == SHOW && alpha < 255) {
// 增加按钮的不透明度
alpha += 50;
// 溢出则重置
if (alpha > 255) {
alpha = 255;
}
leftBtnView.setAlpha(alpha);
leftBtnView.invalidate(); // 在主线程中刷新视图
rightBtnView.setAlpha(alpha);
rightBtnView.invalidate();
if (!isHide && alpha < 255)
handler.sendEmptyMessageDelayed(SHOW, 100);
} else if (msg.what == HIDE && alpha > 0) {
// 增加按钮的透明度
alpha -= 25;
// 溢出则重置
if (alpha < 0) {
alpha = 0;
}
leftBtnView.setAlpha(alpha);
leftBtnView.invalidate();
rightBtnView.setAlpha(alpha);
rightBtnView.invalidate();
if (isHide && alpha > 0)
handler.sendEmptyMessageDelayed(HIDE, 500);
}
}
};
private void showBtnView() {
isHide = false;
handler.sendEmptyMessage(SHOW);
}
private void hideBtnView() {
new Thread() {
public void run() {
try {
Thread.sleep(1000); // 休眠1秒，为了达到更好的演示效果
isHide = true;
handler.sendEmptyMessage(HIDE);
} catch (Exception e) {
}
}
}.start();
}
@Override
public boolean onTouchEvent(MotionEvent event) {
switch (event.getAction()) {
case MotionEvent.ACTION_MOVE: // 手指按住移动图片
case MotionEvent.ACTION_DOWN: // 手指点击图片
showBtnView();
break;
case MotionEvent.ACTION_UP:
hideBtnView();
break;
}
return true;
}
@Override
public void onDestroy() {
super.onDestroy();
// 销毁导航按钮视图
winMgr.removeView(leftBtnView);
winMgr.removeView(rightBtnView);
}
}
package cn.lynn.viewflipper;
import android.app.Activity;
import android.content.Context;
import android.graphics.PixelFormat;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.view.Gravity;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.WindowManager;
import android.view.WindowManager.LayoutParams;
import android.widget.ImageView;
import android.widget.ViewFlipper;
/**
* ViewFlipper实现水平滑动图片，需要点击按钮指引滑动
*
* @author lynnli1229
*/
public class ViewFlipperMainActivity extends Activity {
private static final int SHOW = 0x29;
private static final int HIDE = 0x31;
private ImageView leftBtnView;
private ImageView rightBtnView;
// 设置窗口管理器
private WindowManager winMgr;
// 设置窗口管理器布局参数
private WindowManager.LayoutParams winMgrParams;
// 设置按钮视图alpha的初始值
private int alpha;
// 设置按钮是否隐藏
private boolean isHide;
private ViewFlipper viewFlipper;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
viewFlipper = (ViewFlipper) findViewById(R.id.viewFlipper);
initBtnView();
}
/**
* 初始化按钮视图
*/
private void initBtnView() {
winMgr = (WindowManager) getSystemService(Context.WINDOW_SERVICE);
winMgrParams = new WindowManager.LayoutParams();
winMgrParams.type = LayoutParams.TYPE_PHONE;
// 设置图片背景为透明
winMgrParams.format = PixelFormat.RGBA_8888;
winMgrParams.flags = LayoutParams.FLAG_NOT_TOUCH_MODAL
| LayoutParams.FLAG_NOT_FOCUSABLE;
winMgrParams.x = 0;
winMgrParams.y = 0;
winMgrParams.width = 48;
winMgrParams.height = 48;
createLeftBtnView();
createRightBtnView();
}
/**
* 创建向左（前）按钮
*/
private void createLeftBtnView() {
leftBtnView = new ImageView(this);
leftBtnView.setImageResource(R.drawable.left);
leftBtnView.setAlpha(0);
leftBtnView.setOnClickListener(new OnClickListener() {
public void onClick(View view) {
// 上一个图像
viewFlipper.setInAnimation(ViewFlipperMainActivity.this,
R.anim.left_in);
viewFlipper.setOutAnimation(ViewFlipperMainActivity.this,
R.anim.left_out);
viewFlipper.showPrevious();
}
});
// 调整窗口
winMgrParams.gravity = Gravity.LEFT | Gravity.CENTER_VERTICAL;
// 显示图像
winMgr.addView(leftBtnView, winMgrParams);
}
/**
* 创建向右（后）按钮
*/
private void createRightBtnView() {
rightBtnView = new ImageView(this);
rightBtnView.setImageResource(R.drawable.right);
rightBtnView.setAlpha(0);
rightBtnView.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View view) {
// 下一个图像
viewFlipper.setInAnimation(ViewFlipperMainActivity.this,
R.anim.right_in);
viewFlipper.setOutAnimation(ViewFlipperMainActivity.this,
R.anim.right_out);
viewFlipper.showNext();
}
});
// 调整窗口
winMgrParams.gravity = Gravity.RIGHT | Gravity.CENTER_VERTICAL;
// 显示图像
winMgr.addView(rightBtnView, winMgrParams);
}
/**
* 设置按钮渐变显示效果
*/
private final Handler handler = new Handler() {
@Override
public void handleMessage(Message msg) {
if (msg.what == SHOW && alpha < 255) {
// 增加按钮的不透明度
alpha += 50;
// 溢出则重置
if (alpha > 255) {
alpha = 255;
}
leftBtnView.setAlpha(alpha);
leftBtnView.invalidate(); // 在主线程中刷新视图
rightBtnView.setAlpha(alpha);
rightBtnView.invalidate();
if (!isHide && alpha < 255)
handler.sendEmptyMessageDelayed(SHOW, 100);
} else if (msg.what == HIDE && alpha > 0) {
// 增加按钮的透明度
alpha -= 25;
// 溢出则重置
if (alpha < 0) {
alpha = 0;
}
leftBtnView.setAlpha(alpha);
leftBtnView.invalidate();
rightBtnView.setAlpha(alpha);
rightBtnView.invalidate();
if (isHide && alpha > 0)
handler.sendEmptyMessageDelayed(HIDE, 500);
}
}
};
private void showBtnView() {
isHide = false;
handler.sendEmptyMessage(SHOW);
}
private void hideBtnView() {
new Thread() {
public void run() {
try {
Thread.sleep(1000); // 休眠1秒，为了达到更好的演示效果
isHide = true;
handler.sendEmptyMessage(HIDE);
} catch (Exception e) {
}
}
}.start();
}
@Override
public boolean onTouchEvent(MotionEvent event) {
switch (event.getAction()) {
case MotionEvent.ACTION_MOVE: // 手指按住移动图片
case MotionEvent.ACTION_DOWN: // 手指点击图片
showBtnView();
break;
case MotionEvent.ACTION_UP:
hideBtnView();
break;
}
return true;
}
@Override
public void onDestroy() {
super.onDestroy();
// 销毁导航按钮视图
winMgr.removeView(leftBtnView);
winMgr.removeView(rightBtnView);
}
}
三、案例效果展示
