Android大图轮播-学习笔记

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