Android大图轮播-学习笔记
16lz
2021-01-24
Android大图轮播-学习笔记
图片轮播组合控件如：
图片可以轮播，现在我们可以一点一点开发
ViewPager框架
首先明确大框架是ViewPager然后整个布局是RelativeLayout，其中ViewPager布满整个布局，之下是一个线性布局线性布局中有文字和小点两种View，CiewPager是V4包下的，布局文件如下：
<?xml version="1.0" encoding="utf-8"?><RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="160dp" tools:context="com.hty.ad.MainActivity"> <android.support.v4.view.ViewPager android:id="@+id/view_pager" android:layout_width="match_parent" android:layout_height="match_parent"/> <LinearLayout android:layout_width="match_parent" android:layout_height="wrap_content" android:orientation="vertical" android:layout_alignParentBottom="true" android:background="#25000000"> <TextView android:paddingBottom="5dp" android:id="@+id/text_view" android:text="调试完毕" android:gravity="center" android:textSize="20sp" android:textColor="#ffffff" android:layout_width="match_parent" android:layout_height="wrap_content"/> <LinearLayout android:id="@+id/dot_layout" android:layout_width="match_parent" android:orientation="horizontal" android:layout_height="20dp" android:gravity="center"> </LinearLayout> </LinearLayout></RelativeLayout>定义Adapter填充ViewPager
定义一个MyAdapter继承PagerAdapter然后实现getcount（）方法和isviewFromObject（）方法
代码如下：
class MyAdapter extends PagerAdapter { @Override public int getCount() { return Integer.MAX_VALUE; }/** * true: 表示不去创建，使用缓存 false:去重新创建 * view： 当前滑动的view * object：将要进入的新创建的view，由instantiateItem方法创建 */ @Override public boolean isViewFromObject(View view, Object object) { return view == object; }封装javaBean填充MyAdapter
package com.hty.ad;/** * 作者：司马啸尘 * 创建日期：2016/4/12 * 描述： */public class Ad { private int icon; private String into; public Ad(int icon, String into) { this.icon = icon; this.into = into; } public int getIcon() { return icon; } public void setIcon(int icon) { this.icon = icon; } public String getInto() { return into; } public void setInto(String into) { this.into = into; }}对bean赋值并且在MyAdapter中初始化视图
private void initData() { mAds = new ArrayList<Ad>(); mAds.add(new Ad(R.drawable.c, "哈哈哈哈h")); mAds.add(new Ad(R.drawable.c, "ddddddh")); mAds.add(new Ad(R.drawable.c, "vvvvvv哈h")); mViewPager.setAdapter(new MyAdapter()); Log.d("setAdapter", "------------"); }在MyAdapter中重写instantianteItem方法
public Object instantiateItem(ViewGroup container, int position) { View view = View.inflate(MainActivity.this, R.layout.dapter_ad, null); ImageView imageView = (ImageView) view.findViewById(R.id.iv_body); imageView.setImageResource(mAds.get(position % mAds.size()).getIcon()); container.addView(view); return view; }现在就可以实现滑动但是在边界不能滑动，而且小点和文字不同步
同步小点和文字
对mViewAdapter设置监听，api变化成addOnPagerChangeLiatener，初始化监听器
private void initListener() { mViewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() { @Override public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) { } @Override public void onPageSelected(int position) { update(); } @Override public void onPageScrollStateChanged(int state) { } }); }设置事件同步
private void update() { int currentPosition = mViewPager.getCurrentItem(); mTextView.setText(mAds.get(currentPosition % mAds.size()).getInto()); for (int i = 0; i < mLinearLayout.getChildCount(); i++) { mLinearLayout.getChildAt(i).setEnabled(i == currentPosition % mAds.size()); } }解决到边界的问题
就是把所有位置变成position % mAds.size()而不是position
然后再添加周期改变：
android.os.Handler mHandler = new android.os.Handler() { @Override public void handleMessage(Message msg) { mViewPager.setCurrentItem(mViewPager.getCurrentItem() + 1); mHandler.sendEmptyMessageDelayed(0, 1000); } };完整java代码
package com.hty.ad;import android.os.Bundle;import android.os.Message;import android.support.v4.view.PagerAdapter;import android.support.v4.view.ViewPager;import android.support.v7.app.AppCompatActivity;import android.util.Log;import android.view.View;import android.view.ViewGroup;import android.widget.ImageView;import android.widget.LinearLayout;import android.widget.TextView;import java.util.ArrayList;public class MainActivity extends AppCompatActivity { private ViewPager mViewPager; private ArrayList<Ad> mAds; private TextView mTextView; private LinearLayout mLinearLayout; android.os.Handler mHandler = new android.os.Handler() { @Override public void handleMessage(Message msg) { mViewPager.setCurrentItem(mViewPager.getCurrentItem() + 1); mHandler.sendEmptyMessageDelayed(0, 1000); } }; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); initView(); initData(); initListener(); } private void initListener() { mViewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() { @Override public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) { } @Override public void onPageSelected(int position) { update(); } @Override public void onPageScrollStateChanged(int state) { } }); } private void update() { int currentPosition = mViewPager.getCurrentItem(); mTextView.setText(mAds.get(currentPosition % mAds.size()).getInto()); for (int i = 0; i < mLinearLayout.getChildCount(); i++) { mLinearLayout.getChildAt(i).setEnabled(i == currentPosition % mAds.size()); } } private void initView() { setContentView(R.layout.activity_main); mViewPager = (ViewPager) findViewById(R.id.view_pager); mTextView = (TextView) findViewById(R.id.text_view); mLinearLayout = (LinearLayout) findViewById(R.id.dot_layout); } private void initData() { mAds = new ArrayList<Ad>(); mAds.add(new Ad(R.drawable.c, "哈哈哈哈h")); mAds.add(new Ad(R.drawable.c, "ddddddh")); mAds.add(new Ad(R.drawable.c, "vvvvvv哈h")); mViewPager.setAdapter(new MyAdapter()); Log.d("setAdapter", "------------"); int center = Integer.MAX_VALUE / 2; mViewPager.setCurrentItem(center); initDot(); mHandler.sendEmptyMessageDelayed(0, 1000); update(); } private void initDot() { for (int i = 0; i < mAds.size(); i++) { View view = new View(MainActivity.this); view.setBackgroundResource(R.drawable.selector); LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(20, 20); layoutParams.setMargins(10, 0, 0, 0); view.setLayoutParams(layoutParams); mLinearLayout.addView(view); } } class MyAdapter extends PagerAdapter { @Override public int getCount() { return Integer.MAX_VALUE; } @Override public boolean isViewFromObject(View view, Object object) { return view == object; } @Override public void destroyItem(ViewGroup container, int position, Object object) {// super.destroyItem(container, position, object); container.removeView((View) object); } @Override public Object instantiateItem(ViewGroup container, int position) { View view = View.inflate(MainActivity.this, R.layout.dapter_ad, null); ImageView imageView = (ImageView) view.findViewById(R.id.iv_body); imageView.setImageResource(mAds.get(position % mAds.size()).getIcon()); container.addView(view); return view; } }}PS：有几天没有更新博客了，四月好美加油
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