Android 左右滑动小圆点(ViewPager)布局有两种方法

Posted 2021-12-07 彬sir哥

第一种方法：
一、测试如下，直接设置小圆点不是图标

二、准备工作
1.在drawable创建dot.xml,设置小圆点，比较方便

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:state_selected="true">
        <shape android:shape="oval">
            <solid android:color="@color/black" />
            <corners android:radius="8dp" />
        </shape>
    </item>
    <item android:state_selected="false">
        <shape android:shape="oval">
            <solid android:color="@color/white" />
            <corners android:radius="8dp" />
        </shape>
    </item>
</selector>

2.布局小圆点的状态可以被左右滑动dotview.xml

<!--?xml version="1.0" encoding="utf-8"?-->
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:padding="5dp">

    <ImageView
        android:id="@+id/v_dot"
        android:layout_width="10dp"
        android:layout_height="10dp"
        android:src="@drawable/dot"/>
</LinearLayout>

3.分页适配器自定义ViewPagerAdapter.java

public class ViewPagerAdapter extends PagerAdapter {
    private List<View> mViewList;

    public ViewPagerAdapter(List<View> mViewList) {
        this.mViewList = mViewList;
    }

    @Override
    public void destroyItem(ViewGroup container, int position, Object object) {
        container.removeView(mViewList.get(position));
    }

    @Override
    public Object instantiateItem(ViewGroup container, int position) {
        container.addView(mViewList.get(position));
        return (mViewList.get(position));
    }

    @Override
    public int getCount() {
        if (mViewList == null)
            return 0;
        return mViewList.size();
    }

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

三、使用工作：
1.activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:background="#D4D3D3">

    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="100dp"
        android:background="#FFFFFF"
        android:orientation="vertical">

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

        <LinearLayout
            android:id="@+id/ll_dots"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_alignParentBottom="true"
            android:gravity="center"
            android:orientation="horizontal" />
    </RelativeLayout>
</LinearLayout>

分析下布局结构：
(1)首先是一个ViewPager,用于结合GridView实现左右滑动菜单
(2)下面是一个LinearLayout，有多少个ViewPager的页面就会inflate出多少个小圆点，并且在ViewPager翻页时，也就是说在左右滑动时，下面小圆点的状态也要相应地做出改变
2.MainActivity.java

public class MainActivity extends AppCompatActivity {
    private ViewPager mPager;
    private LinearLayout mLlDots;
    private LayoutInflater inflater;
    private List<View> mPagerList;
    private int pageCount = 3;//默认三个小点
    /**
     * 当前显示的是第几页
     */
    private int curIndex = 0;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mPager = (ViewPager) findViewById(R.id.viewpager);
        mLlDots = (LinearLayout) findViewById(R.id.ll_dots);
        inflater = LayoutInflater.from(this);
        mPagerList = new ArrayList<View>();
        //#FF9800：黄，#4CAF50：绿，#2196F3：蓝
        String[] colors = {"#FF9800", "#4CAF50", "#2196F3"};
        for (int i = 0; i < pageCount; i++) {
            LinearLayout mLL = (LinearLayout) inflater.inflate(R.layout.linearlayout, mPager, false);
            mLL.setBackgroundColor(Color.parseColor(colors[i]));
            mPagerList.add(mLL);
        }
        //设置适配器
        mPager.setAdapter(new ViewPagerAdapter(mPagerList));
        //设置圆点
        setDotLayout();
    }

    /**
     * 设置圆点
     */
    public void setDotLayout() {
        for (int i = 0; i < pageCount; i++) {
            mLlDots.addView(inflater.inflate(R.layout.dotview, null));
        }
        // 默认显示第一页
        mLlDots.getChildAt(0).setSelected(true);
        mPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
            @Override
            public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {

            }

            @Override
            public void onPageSelected(int position) {
                // 取消原点选中
                mLlDots.getChildAt(curIndex).setSelected(false);
                // 原点选中
                mLlDots.getChildAt(position).setSelected(true);
                curIndex = position;
            }

            @Override
            public void onPageScrollStateChanged(int state) {

            }
        });
    }
}

这代码中一句，布局LinearLayout随着左右滑动小圆点翻页

LinearLayout mLL = (LinearLayout) inflater.inflate(R.layout.linearlayout, mPager, false);

布局linearlayout.xml

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

第二种方法：
1.测试如下，小圆点图标

2.dotview.xml

......
<ImageView
        android:id="@+id/v_dot"
        android:layout_width="10dp"
        android:layout_height="10dp"/>
......

3.设置二个小圆点图标(黑白)，点击链接：二个小圆点图标.zip

        // 默认显示第一页
        mLlDots.getChildAt(0).findViewById(R.id.v_dot)
                .setBackgroundResource(R.drawable.dot_normal);

        mLlDots.getChildAt(1).findViewById(R.id.v_dot)
                .setBackgroundResource(R.drawable.dot_selected);

        mLlDots.getChildAt(2).findViewById(R.id.v_dot)
                .setBackgroundResource(R.drawable.dot_selected);

        mPager.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {
            public void onPageSelected(int position) {
                // 取消圆点选中
                mLlDots.getChildAt(curIndex)
                        .findViewById(R.id.v_dot)
                        .setBackgroundResource(R.drawable.dot_selected);
                // 圆点选中
                mLlDots.getChildAt(position)
                        .findViewById(R.id.v_dot)
                        .setBackgroundResource(R.drawable.dot_normal);
                curIndex = position;
            }

            public void onPageScrolled(int arg0, float arg1, int arg2) {
            }

            public void onPageScrollStateChanged(int arg0) {
            }
        });