Android 轮播图片的实现

最新推荐文章于 2024-10-03 15:07:30 发布

try_zp_catch

最新推荐文章于 2024-10-03 15:07:30 发布

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分类专栏： Android

本文链接：https://blog.youkuaiyun.com/try_zp_catch/article/details/78532058

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本文介绍了一款基于Android的广告轮播实现方案，通过使用ViewPager进行页面切换，并结合自定义适配器和线程定时任务实现自动化轮播效果。

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主布局： activity_main

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.example.ms.myapplication.MainActivity">

    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="160dp">

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

        </android.support.v4.view.ViewPager>

        <LinearLayout
            android:id="@+id/ll_dot"
            android:layout_width="match_parent"
            android:layout_height="20dp"
            android:layout_alignParentBottom="true"
            android:layout_margin="10dp"
            android:gravity="center"
            android:orientation="horizontal">

        </LinearLayout>
    </RelativeLayout>

</RelativeLayout>

主程序：MainActivity

public class MainActivity extends AppCompatActivity implements ViewPager.OnPageChangeListener {

    private LinearLayout ll_dot;
    private ViewPager viewPager;
    private ViewPagerAdapter mAdapter;
    private List<Fragment> mData;
    private List<String> links;
    private List<String> images;
    private MyThread myThread;
    private Handler handler;
    private int MSG_HANDLER = 0;
    int thisposition;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mData = new ArrayList<>();
        images = new ArrayList<>();
        links = new ArrayList<>();
        ll_dot = (LinearLayout) findViewById(R.id.ll_dot);
        viewPager = (ViewPager) findViewById(R.id.viewpager);
        mAdapter = new ViewPagerAdapter(getSupportFragmentManager(), mData);
        viewPager.setAdapter(mAdapter);
        viewPager.addOnPageChangeListener(this);
        handler = new Handler() {
            @Override
            public void handleMessage(Message msg) {
                if (msg.what == MSG_HANDLER) {
                    if (thisposition == (mData.size() - 1)) {
                        thisposition = 0;
                        viewPager.setCurrentItem(thisposition);
                    } else {
                        viewPager.setCurrentItem(thisposition + 1);
                    }
                }
            }
        };
        myThread = new MyThread();
        myThread.start();
        loadData();
    }

    private void loadData() {
        String url = "";
        RequestParams params = new RequestParams(url);
        x.http().get(params, new Callback.CommonCallback<String>() {
            @Override
            public void onSuccess(String result) {
                try {
                    JSONObject jsonObject = new JSONObject(result);
                    String code = jsonObject.getString("code");
                    if (code.equals("0000")) {
                        JSONArray jsonArray = jsonObject.getJSONArray("data");
                        for (int i = 0; i < jsonArray.length(); i++) {
                            JSONObject json = jsonArray.getJSONObject(i);
                            String image = json.getString("image");
                            images.add(image);
                            String link = json.getString("linkUrl");
                            links.add(link);
                        }
                    }
                } catch (JSONException e) {
                    e.printStackTrace();
                }
            }

            @Override
            public void onError(Throwable ex, boolean isOnCallback) {

            }

            @Override
            public void onCancelled(CancelledException cex) {

            }

            @Override
            public void onFinished() {
                for (int i = 0; i < images.size(); i++) {
                    ImageView view = new ImageView(MainActivity.this);
                    view.setImageResource(R.drawable.bg_dot_selector);
                    view.setPadding(0, 18, 0, 18);
                    ll_dot.addView(view);
                }
                for (int i = 0; i < images.size() * 100; i++) {
                    NewFragment newFragment = new NewFragment();
                    Bundle bundle = new Bundle();
                    bundle.putString("images", images.get(i % images.size()));
                    bundle.putString("links", links.get(i % images.size()));
                    newFragment.setArguments(bundle);
                    mData.add(newFragment);
                }
                mAdapter.notifyDataSetChanged();
                viewPager.setCurrentItem(images.size() * 50,false);
            }
        });
    }

    @Override
    public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
        if (position == mData.size()) {
            thisposition = 0;
        }
        for (int i = 0; i < images.size(); i++) {
            if (i == position % images.size()) {
                ll_dot.getChildAt(i).setSelected(true);
            } else {
                ll_dot.getChildAt(i).setSelected(false);
            }
        }
    }

    @Override
    public void onPageSelected(int position) {
        thisposition = position;
    }

    @Override
    public void onPageScrollStateChanged(int state) {

    }

    private class MyThread extends Thread {
        @Override
        public void run() {
            super.run();
            while (true) {
                try {
                    Thread.sleep(2000);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                handler.sendEmptyMessage(MSG_HANDLER);
            }
        }
    }
}

适配器：ViewPagerAdapter

public class ViewPagerAdapter extends FragmentPagerAdapter{
    private List<Fragment> mData;

    public ViewPagerAdapter(FragmentManager fm, List<Fragment> mData) {
        super(fm);
        this.mData = mData;
    }

    @Override
    public Fragment getItem(int position) {
        return mData.get(position);
    }

    @Override
    public int getCount() {
        return mData.size();
    }
}

点的选择器：bg_dot_selector

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:drawable="@drawable/bg_dot_press" android:state_selected="true"/>
    <item android:drawable="@drawable/bg_dot_normal" android:state_selected="false"/>
</selector>

bg_dot_press

<layer-list xmlns:android="http://schemas.android.com/apk/res-auto"
    xmlns:Android="http://schemas.android.com/apk/res/android">
    <item>
        <shape xmlns:android="http://schemas.android.com/apk/res/android">
            <size
                android:height="20dp"
                android:width="20dp"/>
            <solid android:color="@color/tvGray"/>
            <corners android:radius="100dp"/>
        </shape>
    </item>
</layer-list>