android ViewPager具体解释

Viewpager 在android界面布局中属于经常使用类型 ,它能够做导航,页面菜单,进入软件是的欢迎界面 等等。比方今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 :

android ViewPager具体解释

这是一个仿微博界面的xml布局 ,他们之间的关系常常搞混淆,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,其过程例如以下:

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,并进行对应的浅处理。

3,为Viewpager设置适配器,还有监听器,其它控件也设置对应的监听器。

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;// 动绘图片
private TextView textView1,textView2,textView3;
private List<View> views;// Tab页面列表
private int offset = 0;// 动绘图片偏移量
private int currIndex = 0;// 当前页卡编号
private int bmpW;// 动绘图片宽度
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,以下的横线也滑动的效果,在这里须要计算一些数据
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,以下另一种,显然这个比較麻烦
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);//显然这个比較简洁,仅仅有一行代码。
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>

效果例如以下:

android ViewPager具体解释

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