Android 中的通过 ViewPager 实现左右滑屏
fmms
14年前
先看效果，就是左右滑屏的效果
具体实现详解
android compatibility package, revision 3在7月份发布后，其中有个ViewPager引起了我的注意
官方的描述：
请参考：http://developer.android.com/sdk/compatibility-library.html#Notes
ViewPager的下载与安装
首先通过SDK Manager更新最新版android compatibility package, revision 3
更新后，在eclipse中工程上点击右键，选择android tools -> add compatibility library即可完成安装
实际上就是一个jar包，手工导到工程中也可
jar包所在位置是\android-sdk\extras\android\compatibility\v4\android-support-v4.jar
至此准备环境已经ok
下边还是通过代码进行说话吧
准备布局文件
准备布局文件
viewpager_layout.xml
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="fill_parent" android:orientation="vertical"> <!-- 此处需要给出全路径 --> <android.support.v4.view.ViewPager android:id="@+id/viewpagerLayout" android:layout_height="fill_parent" android:layout_width="fill_parent"/> </LinearLayout>layout1.xml
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="fill_parent" android:orientation="vertical"> <TextView android:textAppearance="?android:attr/textAppearanceLarge" android:layout_height="wrap_content" android:id="@+id/textView1" android:layout_width="fill_parent" android:text="第一页"></TextView> <EditText android:layout_width="match_parent" android:layout_height="wrap_content" android:id="@+id/editText1"> <requestFocus></requestFocus> </EditText> </LinearLayout>layout2.xml
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="fill_parent" android:orientation="vertical"> <TextView android:textAppearance="?android:attr/textAppearanceLarge" android:layout_height="wrap_content" android:id="@+id/textView1" android:layout_width="fill_parent" android:text="第二页"></TextView> <EditText android:layout_width="match_parent" android:layout_height="wrap_content" android:id="@+id/editText1"> <requestFocus></requestFocus> </EditText> </LinearLayout>layout3.xml
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="fill_parent" android:orientation="vertical"> <TextView android:textAppearance="?android:attr/textAppearanceLarge" android:layout_height="wrap_content" android:id="@+id/textView1" android:layout_width="fill_parent" android:text="第三页"></TextView> <EditText android:layout_width="match_parent" android:layout_height="wrap_content" android:id="@+id/editText1"> <requestFocus></requestFocus> </EditText> </LinearLayout>主程序
package a.b; import java.util.ArrayList; import java.util.List; import android.app.Activity; import android.os.Bundle; import android.os.Parcelable; import android.support.v4.view.PagerAdapter; import android.support.v4.view.ViewPager; import android.support.v4.view.ViewPager.OnPageChangeListener; import android.util.Log; import android.view.LayoutInflater; import android.view.View; import android.widget.EditText; public class TestViewPager extends Activity { private ViewPager myViewPager; private MyPagerAdapter myAdapter; private LayoutInflater mInflater; private List<View> mListViews; private View layout1 = null; private View layout2 = null; private View layout3 = null; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.viewpager_layout); myAdapter = new MyPagerAdapter(); myViewPager = (ViewPager) findViewById(R.id.viewpagerLayout); myViewPager.setAdapter(myAdapter); mListViews = new ArrayList<View>(); mInflater = getLayoutInflater(); layout1 = mInflater.inflate(R.layout.layout1, null); layout2 = mInflater.inflate(R.layout.layout2, null); layout3 = mInflater.inflate(R.layout.layout3, null); mListViews.add(layout1); mListViews.add(layout2); mListViews.add(layout3); //初始化当前显示的view myViewPager.setCurrentItem(1); //初始化第二个view的信息 EditText v2EditText = (EditText)layout2.findViewById(R.id.editText1); v2EditText.setText("动态设置第二个view的值"); myViewPager.setOnPageChangeListener(new OnPageChangeListener() { @Override public void onPageSelected(int arg0) { Log.d("k", "onPageSelected - " + arg0); //activity从1到2滑动，2被加载后掉用此方法 View v = mListViews.get(arg0); EditText editText = (EditText)v.findViewById(R.id.editText1); editText.setText("动态设置#"+arg0+"edittext控件的值"); } @Override public void onPageScrolled(int arg0, float arg1, int arg2) { Log.d("k", "onPageScrolled - " + arg0); //从1到2滑动，在1滑动前调用 } @Override public void onPageScrollStateChanged(int arg0) { Log.d("k", "onPageScrollStateChanged - " + arg0); //状态有三个0空闲，1是增在滑行中，2目标加载完毕 /** * Indicates that the pager is in an idle, settled state. The current page * is fully in view and no animation is in progress. */ //public static final int SCROLL_STATE_IDLE = 0; /** * Indicates that the pager is currently being dragged by the user. */ //public static final int SCROLL_STATE_DRAGGING = 1; /** * Indicates that the pager is in the process of settling to a final position. */ //public static final int SCROLL_STATE_SETTLING = 2; } }); } private class MyPagerAdapter extends PagerAdapter{ @Override public void destroyItem(View arg0, int arg1, Object arg2) { Log.d("k", "destroyItem"); ((ViewPager) arg0).removeView(mListViews.get(arg1)); } @Override public void finishUpdate(View arg0) { Log.d("k", "finishUpdate"); } @Override public int getCount() { Log.d("k", "getCount"); return mListViews.size(); } @Override public Object instantiateItem(View arg0, int arg1) { Log.d("k", "instantiateItem"); ((ViewPager) arg0).addView(mListViews.get(arg1),0); return mListViews.get(arg1); } @Override public boolean isViewFromObject(View arg0, Object arg1) { Log.d("k", "isViewFromObject"); return arg0==(arg1); } @Override public void restoreState(Parcelable arg0, ClassLoader arg1) { Log.d("k", "restoreState"); } @Override public Parcelable saveState() { Log.d("k", "saveState"); return null; } @Override public void startUpdate(View arg0) { Log.d("k", "startUpdate"); } } }在实机上测试后，非常流畅，这也就是说官方版的左右滑屏控件已经实现 目前，关于viewpager的文章非常少，本文是通过阅读viewpager源代码分析出的写法
当然此文章仅是抛砖引玉，而且属于框架式程序，目的就是让读者了解API的基本用法
希望这篇原创文章对大家有帮助
欢迎感兴趣的朋友一起讨论
共同学习，共同进步
另外，ViewPager的注释上有这么一段话，大体意思是该控件目前属于早期实现，后续会有修改
/** * Layout manager that allows the user to flip left and right * through pages of data. You supply an implementation of a * {@link PagerAdapter} to generate the pages that the view shows. * * <p>Note this class is currently under early design and * development. The API will likely change in later updates of * the compatibility library, requiring changes to the source code * of apps when they are compiled against the newer version.</p> */