Android新手开发之旅-ViewPager的用法

liu

ViewPager的用法




ViewPager继承自ViewGroup，它的功能是可以使视图滑动，实现多页面的切换

简单举个例子看下用法，几张图片的切换：

首先在主布局中添加ViewPager：
activity_main.xml:

[XML] 纯文本查看 复制代码

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="horizontal">

    <android.support.v4.view.ViewPager
        android:id="@+id/vp"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />
</LinearLayout>

然后加载要显示的页卡，这里是放入了三张图片：

[Java] 纯文本查看 复制代码

 List<View> list = new ArrayList<>();
        int[] imgs = {R.drawable.img1, R.drawable.img2, R.drawable.img3};
        ViewGroup.LayoutParams layoutParams = new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT);
        for (int i = 0; i < imgs.length; i++) {
            // 将图片装载到数组中
            ImageView imageView = new ImageView(this);
            imageView.setBackgroundResource(imgs[i]);
            imageView.setLayoutParams(layoutParams);
            list.add(imageView);
        }

最后设置适配器：

[Java] 纯文本查看 复制代码

package com.company.helloworld.firstapplication;

import android.content.Context;
import android.support.v4.view.PagerAdapter;
import android.support.v4.view.ViewPager;
import android.view.View;
import android.view.ViewGroup;

import java.util.List;

/**
 * Created by Administrator on 2018/12/17.
 */

public class MyAdapter extends PagerAdapter {
    private Context context;
    private List<View> list;

    public MyAdapter(Context context, List<View> list) {
        this.context = context;
        this.list = list;
    }

    //返回的数量
    @Override
    public int getCount() {
        return list.size();
    }

    //删除页卡
    @Override
    public void destroyItem(ViewGroup arg0, int arg1, Object arg2) {
        arg0.removeView(list.get(arg1));
    }

    //添加页卡
    @Override
    public Object instantiateItem(ViewGroup arg0, int arg1) {
        arg0.addView(list.get(arg1), 0);
        return list.get(arg1);
    }

    @Override
    public boolean isViewFromObject(View view, Object object) {
        return (view == object);
    }
}

看下运行效果：


        

liu

MainActivity

[Java] 纯文本查看 复制代码

package com.company.helloworld.firstapplication;

import android.os.Bundle;
import android.support.v4.view.ViewPager;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;

import java.util.ArrayList;
import java.util.List;

public class MainActivity extends AppCompatActivity {
    private List<View> list = new ArrayList<>();
    private int[] imgs = {R.drawable.img1, R.drawable.img2, R.drawable.img3};

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        initView();
    }

    private void initView() {
        ViewGroup.LayoutParams layoutParams = new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT);
        for (int i = 0; i < imgs.length; i++) {
            // 将图片装载到数组中
            ImageView imageView = new ImageView(this);
            imageView.setBackgroundResource(imgs[i]);
            imageView.setLayoutParams(layoutParams);
            list.add(imageView);
        }
        // 初始化Adapter
        MyAdapter adapter = new MyAdapter(this, list);
        ViewPager vp = (ViewPager) findViewById(R.id.vp);
        vp.setAdapter(adapter);
    }


}

竹林风

我只是路过打酱油的。

站长苏飞

我只是路过打酱油的。