android ViewPager详解
时间:2014-05-22 07:34:29
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Viewpager 在android界面布局中属于常用类型 ,它可以做导航,页面菜单,进入软件是的欢迎界面 等等。比现在最流行的几款手机软件 ,QQ,微信,微博 等 ,其主界面 都用到了ViewPager,所以学好它,势在必得 ,在这里总结了下,
先用图解 :
这是一个仿微博界面的xml布局 ,他们之间的关系经常搞混淆,怕记不住 ,总结了几句话:ViewPager里面含界面,它的改变控制(title)Imageview的变化,Textview控制页面,并间接控制Title(imageview)。
而要做一个完整的denon,其步骤如下:
1,在xml文件了定义Viewpager,和各种控件。
2,在代码里得到各种控件,并进行相应的浅处理。
3,为Viewpager设置适配器,还有监听器,其他控件也设置相应的监听器。
记录一个小demo:
package com.example.viewpagerdemo; import java.util.ArrayList; import java.util.List; import android.app.Activity; import android.graphics.BitmapFactory; import android.graphics.Matrix; import android.os.Bundle; import android.support.v4.view.PagerAdapter; import android.support.v4.view.ViewPager; import android.support.v4.view.ViewPager.OnPageChangeListener; import android.util.DisplayMetrics; import android.view.LayoutInflater; import android.view.View; import android.view.View.OnClickListener; import android.view.animation.Animation; import android.view.animation.TranslateAnimation; import android.view.ViewGroup; import android.widget.ImageView; import android.widget.TextView; import android.widget.Toast; public class WeiBoActivity extends Activity { private ViewPager viewPager;//页卡内容 private ImageView imageView;// 动画图片 private TextView textView1,textView2,textView3; private List<View> views;// Tab页面列表 private int offset = 0;// 动画图片偏移量 private int currIndex = 0;// 当前页卡编号 private int bmpW;// 动画图片宽度 private View view1,view2,view3;//各个页卡 @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.weibo); InitImageView(); InitTextView(); InitViewPager(); } private void InitViewPager() { viewPager=(ViewPager) findViewById(R.id.vPager); views=new ArrayList<View>(); LayoutInflater inflater=getLayoutInflater(); view1=inflater.inflate(R.layout.lay1, null); view2=inflater.inflate(R.layout.lay2, null); view3=inflater.inflate(R.layout.lay3, null); views.add(view1); views.add(view2); views.add(view3); viewPager.setAdapter(new MyViewPagerAdapter(views)); viewPager.setCurrentItem(0); viewPager.setOnPageChangeListener(new MyOnPageChangeListener()); } /** * 初始化头标 */ private void InitTextView() { textView1 = (TextView) findViewById(R.id.text1); textView2 = (TextView) findViewById(R.id.text2); textView3 = (TextView) findViewById(R.id.text3); textView1.setOnClickListener(new MyOnClickListener(0)); textView2.setOnClickListener(new MyOnClickListener(1)); textView3.setOnClickListener(new MyOnClickListener(2)); } /** 2 * 初始化动画,这个就是页卡滑动时,下面的横线也滑动的效果,在这里需要计算一些数据 3 */ private void InitImageView() { imageView= (ImageView) findViewById(R.id.cursor); bmpW = BitmapFactory.decodeResource(getResources(), R.drawable.a).getWidth();// 获取图片宽度 DisplayMetrics dm = new DisplayMetrics(); getWindowManager().getDefaultDisplay().getMetrics(dm); int screenW = dm.widthPixels;// 获取分辨率宽度 offset = (screenW / 3 - bmpW) / 2;// 计算偏移量 Matrix matrix = new Matrix(); matrix.postTranslate(offset, 0); imageView.setImageMatrix(matrix);// 设置动画初始位置 } <img src="http://img.my.csdn.net/uploads/201211/10/1352554452_1685.jpg" alt=""> /** * * 头标点击监听 3 */ private class MyOnClickListener implements OnClickListener{ private int index=0; public MyOnClickListener(int i){ index=i; } public void onClick(View v) { viewPager.setCurrentItem(index); } } public class MyViewPagerAdapter extends PagerAdapter{ private List<View> mListViews; public MyViewPagerAdapter(List<View> mListViews) { this.mListViews = mListViews; } @Override public void destroyItem(ViewGroup container, int position, Object object) { container.removeView(mListViews.get(position)); } @Override public Object instantiateItem(ViewGroup container, int position) { container.addView(mListViews.get(position), 0); return mListViews.get(position); } @Override public int getCount() { return mListViews.size(); } @Override public boolean isViewFromObject(View arg0, Object arg1) { return arg0==arg1; } } public class MyOnPageChangeListener implements OnPageChangeListener{ int one = offset * 2 + bmpW;// 页卡1 -> 页卡2 偏移量 int two = one * 2;// 页卡1 -> 页卡3 偏移量 public void onPageScrollStateChanged(int arg0) { } public void onPageScrolled(int arg0, float arg1, int arg2) { } public void onPageSelected(int arg0) { /*两种方法,这个是一种,下面还有一种,显然这个比较麻烦 Animation animation = null; switch (arg0) { case 0: if (currIndex == 1) { animation = new TranslateAnimation(one, 0, 0, 0); } else if (currIndex == 2) { animation = new TranslateAnimation(two, 0, 0, 0); } break; case 1: if (currIndex == 0) { animation = new TranslateAnimation(offset, one, 0, 0); } else if (currIndex == 2) { animation = new TranslateAnimation(two, one, 0, 0); } break; case 2: if (currIndex == 0) { animation = new TranslateAnimation(offset, two, 0, 0); } else if (currIndex == 1) { animation = new TranslateAnimation(one, two, 0, 0); } break; } */ Animation animation = new TranslateAnimation(one*currIndex, one*arg0, 0, 0);//显然这个比较简洁,只有一行代码。 currIndex = arg0; animation.setFillAfter(true);// True:图片停在动画结束位置 animation.setDuration(300); imageView.startAnimation(animation); Toast.makeText(WeiBoActivity.this, "您选择了"+ viewPager.getCurrentItem()+"页卡", Toast.LENGTH_SHORT).show(); } } }它的布局文件:
<?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" > <LinearLayout android:id="@+id/linearLayout1" android:layout_width="fill_parent" android:layout_height="40.0dip" android:background="#FFFFFF" > <TextView android:id="@+id/text1" android:layout_width="fill_parent" android:layout_height="fill_parent" android:layout_weight="1.0" android:gravity="center" android:text=" @我" android:textColor="#000000" android:textSize="20.0dip" /> <TextView android:id="@+id/text2" android:layout_width="fill_parent" android:layout_height="fill_parent" android:layout_weight="1.0" android:gravity="center" android:text="评论" android:textColor="#000000" android:textSize="20.0dip" /> <TextView android:id="@+id/text3" android:layout_width="fill_parent" android:layout_height="fill_parent" android:layout_weight="1.0" android:gravity="center" android:text="私信" android:textColor="#000000" android:textSize="20.0dip" /> </LinearLayout> <ImageView android:id="@+id/cursor" android:layout_width="fill_parent" android:layout_height="wrap_content" android:scaleType="matrix" android:src="@drawable/a" /> <android.support.v4.view.ViewPager android:id="@+id/vPager" android:layout_width="wrap_content" android:layout_height="0dp" android:layout_gravity="center" android:layout_weight="1.0" android:background="#000000" android:flipInterval="30" android:persistentDrawingCache="animation" /> </LinearLayout>效果如下:
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