4.13

所花时间（包括上课）：1

打码量(行)：130

博客量(篇)：1

了解到知识点：学习ViewPager实现启动引导页

 

package com.example.myapp;

 

import android.os.Bundle;

 

import androidx.appcompat.app.AppCompatActivity;

import androidx.viewpager.widget.ViewPager;

 

public class MainActivity extends AppCompatActivity {

 

    private ViewPager viewPager;

    private ViewPagerAdapter adapter;

 

    private int[] layouts = {

            R.layout.slide1,

            R.layout.slide2,

            R.layout.slide3

    };

 

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

 

        viewPager = findViewById(R.id.viewPager);

        adapter = new ViewPagerAdapter(layouts, this);

        viewPager.setAdapter(adapter);

    }

}

package com.example.myapp;

 

import android.content.Context;

import android.view.LayoutInflater;

import android.view.View;

import android.view.ViewGroup;

 

import androidx.annotation.NonNull;

import androidx.viewpager.widget.PagerAdapter;

 

public class ViewPagerAdapter extends PagerAdapter {

 

    private int[] layouts;

    private Context context;

 

    public ViewPagerAdapter(int[] layouts, Context context) {

        this.layouts = layouts;

        this.context = context;

    }

 

    @NonNull

    @Override

    public Object instantiateItem(@NonNull ViewGroup container, int position) {

        LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);

        View view = inflater.inflate(layouts[position], container, false);

        container.addView(view);

        return view;

    }

 

    @Override

    public int getCount() {

        return layouts.length;

    }

 

    @Override

    public boolean isViewFromObject(@NonNull View view, @NonNull Object object) {

        return view == object;

    }

 

    @Override

    public void destroyItem(@NonNull ViewGroup container, int position, @NonNull Object object) {

        View view = (View) object;

        container.removeView(view);

    }

}