Android ViewPager图片滑动
首先展示效果图
Android ViewPager图片滑动代码演示步骤
1.实例化ViewPager
2.通过LayoutInflater加载布局,返回View结果
3.把生成的每一个View对象添加到List集合中
4.实例化适配器,传递View集合
5.在适配器中继承自PagerAdapter,实现内部的四个方法
getCount(); 返回视图的数量
isViewFromObject(); 是否通过对象加载视图 View==object
instantiateltem(); 加载当前页面
(通过container.addView();添加视图)
返回个给用户
destroyItem(); 销毁滑出的视图
(通过container.removerView();销毁视图)
6.实例化每个ImageView
7.点击每个ImageView时,切换不同的页面
(viewPager.setCurrentltem(下标))
8.当页面切换后,还要把当前的导航栏变为绿色
设置文本颜色的
setImageResource(R.drawable.
radio_true
);
9.当你每次点击之前的时候,添加一个方法,清除方法,
(清理之 前的所有导航栏的状态,置为灰色)
10.实现滑动监听需要addOnPagerChangeListener
11.在onPagerSelected方法中,根据position页面的下标判断分别设置对应的底部导航栏状态
一.新建一个项目名为ViewPagerDemo,并引入ViewPager
ViewPager是google SDk中自带的一个附加包的一个类,可以用来实现屏幕间的切换
1.在主布局文件activity_main.xml中引入
android.support.v4.view.
ViewPager包,
添加一个线性布局
在线性布局中添加ImageView用于显示滑动小点
xml version="1.0" encoding="utf-8"?>
<FrameLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context="com.example.cxy.viewpagerdemo.MainActivity">
<android.support.v4.view.ViewPager
android:id="@+id/viewPager"
android:layout_width="match_parent"
android:layout_height="match_parent">
android.support.v4.view.ViewPager>
<LinearLayout
android:layout_gravity="bottom"
android:gravity="center"
android:layout_marginBottom="20dp"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<ImageView
android:id="@+id/imageView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="@drawable/radio_true"
android:layout_gravity="bottom"/>
<ImageView
android:id="@+id/imageView2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="@drawable/radio_false"
android:layout_gravity="bottom"/>
<ImageView
android:id="@+id/imageView3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="@drawable/radio_false"
android:layout_gravity="bottom"/>
<ImageView
android:id="@+id/imageView4"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="@drawable/radio_false"
android:layout_gravity="bottom"/>
<ImageView
android:id="@+id/imageView5"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="@drawable/radio_false"
android:layout_gravity="bottom"/>
<ImageView
android:id="@+id/imageView6"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="@drawable/radio_false"
android:layout_gravity="bottom"/>
LinearLayout>
FrameLayout>
2.ViewPager的加载需要一个适配器pagerAdapter的子类
当继承pagerAdapter生成两个方法,剩下两个方法需要自己补充
package com.example.cxy.viewpagerdemo.adapter;
import android.support.v4.view.PagerAdapter;
import android.view.View;
import android.view.ViewGroup;
import java.util.List;
/**
* date:2017/3/7
* Created:陈箫阳(admin)
*/
public class MyViewPagerAdapter extends PagerAdapter {
private List mList;
public MyViewPagerAdapter(List list) {
mList = list;
}
//返回视图数量
@Override
public int getCount() {
return mList.size();
}
//是否通过对象加载视图
@Override
public boolean isViewFromObject(View view, Object object) {
return view == object;
}
//加载当前页面
@Override
public Object instantiateItem(ViewGroup container, int position) {
container.addView(mList.get(position));
return mList.get(position);
}
//销毁滑出视图
@Override
public void destroyItem(ViewGroup container, int position, Object object) {
container.removeView(mList.get(position));
}
}
3.新建一个fragment包并新建类OneFragment,通过LayoutInflater加载布局,返回View结果,并在布局文件中添加Imageview用于显示滑动所显示的图片,共六个用于显示六张图片,这里只写一个
OneFeagment类
package com.example.cxy.viewpagerdemo.fragment;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import com.example.cxy.viewpagerdemo.R;
/**
* date:2017/3/7
* Created:陈箫阳(admin)
*/
public class OneFragment extends Fragment{
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragmentone, null);
return view;
}
}
fragmentone.xml布局文件
xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent">
<ImageView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@drawable/view1"/>
LinearLayout>
4.编写主类
package com.example.cxy.viewpagerdemo;
import android.support.v4.view.ViewPager;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.ImageView;
import com.example.cxy.viewpagerdemo.adapter.MyViewPagerAdapter;
import java.util.ArrayList;
import java.util.List;
public class MainActivity extends AppCompatActivity implements View.OnClickListener, ViewPager.OnPageChangeListener {
private ViewPager mViewPager;
private List mList;
private ImageView mImageView1, mImageView2, mImageView3, mImageView4, mImageView5, mImageView6;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//初始化所有控件
initView();
}
private void initView() {
//实例化ViewPager
mViewPager = (ViewPager) findViewById(R.id.viewPager);
//实例化ImageView
mImageView1 = (ImageView) findViewById(R.id.imageView1);
mImageView2 = (ImageView) findViewById(R.id.imageView2);
mImageView3 = (ImageView) findViewById(R.id.imageView3);
mImageView4 = (ImageView) findViewById(R.id.imageView4);
mImageView5 = (ImageView) findViewById(R.id.imageView5);
mImageView6 = (ImageView) findViewById(R.id.imageView6);
//给ImageView添加监听点击事件
mImageView1.setOnClickListener(this);
mImageView2.setOnClickListener(this);
mImageView3.setOnClickListener(this);
mImageView4.setOnClickListener(this);
mImageView5.setOnClickListener(this);
mImageView6.setOnClickListener(this);
//实例化Lise数组
mList = new ArrayList<>();
View view1 = LayoutInflater.from(this).inflate(R.layout.fragmentone, null);
View view2 = LayoutInflater.from(this).inflate(R.layout.fragmenttwo, null);
View view3 = LayoutInflater.from(this).inflate(R.layout.fragmentthree, null);
View view4 = LayoutInflater.from(this).inflate(R.layout.fragmentfour, null);
View view5 = LayoutInflater.from(this).inflate(R.layout.fragmentfive, null);
View view6 = LayoutInflater.from(this).inflate(R.layout.fragmentsix, null);
//把生成的每一个View对象添加到List集合中
mList.add(view1);
mList.add(view2);
mList.add(view3);
mList.add(view4);
mList.add(view5);
mList.add(view6);
//实例化适配器
MyViewPagerAdapter adapter = new MyViewPagerAdapter(mList);
//给ViewPager添加适配器
mViewPager.setAdapter(adapter);
//给ViewPager添加监听
mViewPager.addOnPageChangeListener(this);
}
@Override
public void onClick(View v) {
//清理所有导航栏的状态
clearState();
switch (v.getId()) {
case R.id.imageView1:
//给ViewPager设置当前布局
mViewPager.setCurrentItem(0);
//给ImageView设置文本颜色
mImageView1.setImageResource(R.drawable.radio_true);
break;
case R.id.imageView2:
mViewPager.setCurrentItem(1);
mImageView2.setImageResource(R.drawable.radio_true);
break;
case R.id.imageView3:
mViewPager.setCurrentItem(2);
mImageView3.setImageResource(R.drawable.radio_true);
break;
case R.id.imageView4:
mViewPager.setCurrentItem(3);
mImageView4.setImageResource(R.drawable.radio_true);
break;
case R.id.imageView5:
mViewPager.setCurrentItem(4);
mImageView5.setImageResource(R.drawable.radio_true);
break;
case R.id.imageView6:
mViewPager.setCurrentItem(5);
mImageView6.setImageResource(R.drawable.radio_true);
break;
}
}
//将底部导航栏小点初始化
private void clearState() {
mImageView1.setImageResource(R.drawable.radio_false);
mImageView2.setImageResource(R.drawable.radio_false);
mImageView3.setImageResource(R.drawable.radio_false);
mImageView4.setImageResource(R.drawable.radio_false);
mImageView5.setImageResource(R.drawable.radio_false);
mImageView6.setImageResource(R.drawable.radio_false);
}
//滑动过程中的动作
@Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
//选择某个页面松手后会被调用
@Override
public void onPageSelected(int position) {
//清理所有导航栏的状态
clearState();
//使用Switch拿到下标定义当滑动到相应位置小点显示颜色
switch (position) {
case 0:
mImageView1.setImageResource(R.drawable.radio_true);
break;
case 1:
mImageView2.setImageResource(R.drawable.radio_true);
break;
case 2:
mImageView3.setImageResource(R.drawable.radio_true);
break;
case 3:
mImageView4.setImageResource(R.drawable.radio_true);
break;
case 4:
mImageView5.setImageResource(R.drawable.radio_true);
break;
case 5:
mImageView6.setImageResource(R.drawable.radio_true);
break;
}
}
//手指放上去,松开,拖动都会被调用
@Override
public void onPageScrollStateChanged(int state) {
}
}