Android大圖輪播-學習筆記

Android大圖輪播-學習筆記

圖片輪播組合控件如：

圖片可以輪播，現在我們可以一點一點開發

ViewPager框架

首先明確大框架是ViewPager然後整個佈局是RelativeLayout，其中ViewPager佈滿整個佈局，之下是一個線性佈局線性佈局中有文字和小點兩種View，CiewPager是V4包下的，佈局文件如下：

<?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="調試完畢"
            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>

定義Adapter填充ViewPager

定義一個MyAdapter繼承PagerAdapter然後實現getcount（）方法和isviewFromObject（）方法

代碼如下：

   class MyAdapter extends PagerAdapter {

        @Override
        public int getCount() {
            return Integer.MAX_VALUE;
        }
/**
         * true: 表示不去創建，使用緩存  false:去重新創建
         * view： 當前滑動的view
         * object：將要進入的新創建的view，由instantiateItem方法創建
         */
        @Override
        public boolean isViewFromObject(View view, Object object) {
            return view == object;
        }

封裝javaBean填充MyAdapter

package com.hty.ad;

/**
 * 作者：司馬嘯塵
 * 創建日期：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;
    }
}

對bean賦值並且在MyAdapter中初始化視圖

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中重寫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;
        }

現在就可以實現滑動但是在邊界不能滑動，而且小點和文字不同步

同步小點和文字

對mViewAdapter設置監聽，api變化成addOnPagerChangeLiatener，初始化監聽器

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) {

            }
        });
    }

設置事件同步

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());
        }

    }

解決到邊界的問題

就是把所有位置變成position % mAds.size()而不是position
然後再添加週期改變：

 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代碼

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：有幾天沒有更新博客了，四月好美加油