Android——自定义view实现轮播图
1.添加依赖
implementation ‘com.squareup.okio:okio:1.5.0’
implementation ‘com.squareup.okhttp3:okhttp:3.2.0’
implementation ‘com.github.bumptech.glide:glide:4.9.0’
implementation ‘com.squareup.okhttp3:logging-interceptor:3.4.1’
添加权限
2.封装单例OkHttp
public class OkHttpUtils {
//私有的静态的成员变量，只声明不创建
private static OkHttpUtils okHttpUtils = null;
//私有的构造方法
private OkHttpUtils() {
}
//返回公共静态的实例方法
public static OkHttpUtils getInstance() {
if (okHttpUtils == null) {
synchronized (OkHttpUtils.class) {
if (okHttpUtils == null) {
okHttpUtils = new OkHttpUtils();
}
}
}
return okHttpUtils;
}
private static OkHttpClient okHttpClient = null;
//返回ok
public synchronized static OkHttpClient getOkHttpClient() {
if (okHttpClient == null) {
//创建日志拦截器
HttpLoggingInterceptor loggingInterceptor = new HttpLoggingInterceptor(new HttpLoggingInterceptor.Logger() {
@Override
public void log(String message) {
Log.i("xxx", message);
}
});
//设置日志拦截器模式
loggingInterceptor.setLevel(HttpLoggingInterceptor.Level.BODY);
//创建okHttpClient
okHttpClient = new OkHttpClient.Builder().addInterceptor(loggingInterceptor).build();
}
return okHttpClient;
}
//get请求
public void doGet(String url, Callback callback) {
//创建OkHttpClient
OkHttpClient okHttpClient = getOkHttpClient();
//创建Request
Request request = new Request.Builder().url(url).build();
Call call = okHttpClient.newCall(request);
//执行异步
call.enqueue(callback);
}
//post请求
public void doPost(String url, Map parmars, Callback callback) {
//创建OkHttpClient
OkHttpClient okHttpClient = getOkHttpClient();
//创建builder
FormBody.Builder builder = new FormBody.Builder();
//遍历集合
for (String key : parmars.keySet()) {
builder.add(key,parmars.get(key));
}
//构建FormBody
FormBody formBody = builder.build();
//创建Request
Request request = new Request.Builder().url(url).post(formBody).build();
Call call = okHttpClient.newCall(request);
//执行异步
call.enqueue(callback);
}
}
3.创建自定义view实现轮播
布局
public class CustomViewGroup extends RelativeLayout {
private ViewPager vp;
private LinearLayout ll_point;
private List imageViews=new ArrayList<>();
@SuppressLint("HandlerLeak")
private Handler handler=new Handler(){
@Override
public void handleMessage(Message msg) {
super.handleMessage(msg);
switch (msg.what){
case 0:
String json= (String) msg.obj;
try {
JSONObject jsonObject=new JSONObject(json);
JSONArray result = jsonObject.getJSONArray("result");
for (int i = 0; i < result.length(); i++){
JSONObject jo = result.getJSONObject(i);
String imageUrl = jo.getString("imageUrl");
ImageView imageView=new ImageView(getContext());
Glide.with(getContext()).load(imageUrl).into(imageView);
imageViews.add(imageView);
}
MyViewPagerAdapter adapter=new MyViewPagerAdapter();
vp.setAdapter(adapter);
initPoint(imageViews);
} catch (JSONException e) {
e.printStackTrace();
}
break;
}
}
};
public CustomViewGroup(Context context) {
super(context);
}
public CustomViewGroup(Context context, AttributeSet attrs) {
super(context, attrs);
initView(context);
}
public CustomViewGroup(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
}
private void initView(Context context) {
View view = LayoutInflater.from(context).inflate(R.layout.custom_viewpager, null, false);
addView(view);
vp = view.findViewById(R.id.vp);
ll_point = view.findViewById(R.id.ll_point);
getBannerData();
vp.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {
@Override
public void onPageScrolled(int i, float v, int i1) {
}
@Override
public void onPageSelected(int position) {
position %= imageViews.size();
//获取小圆点个数
int count = ll_point.getChildCount();
for (int i = 0; i < count; i++) {
View view = ll_point.getChildAt(i);
//设置选中状态
view.setEnabled(i == position ? false : true);
}
}
@Override
public void onPageScrollStateChanged(int i) {
}
});
}
private void getBannerData() {
OkHttpUtils.getInstance().doGet("http://172.17.8.100/small/commodity/v1/bannerShow", new Callback() {
@Override
public void onFailure(Call call, IOException e) {
}
@Override
public void onResponse(Call call, Response response) throws IOException {
String json = response.body().string();
Message message=new Message();
message.what=0;
message.obj=json;
handler.sendMessage(message);
}
});
}
//轮播适配器
private class MyViewPagerAdapter extends PagerAdapter {
//返回Integer长度 不断循环
@Override
public int getCount() {
return Integer.MAX_VALUE;
}
@Override
public boolean isViewFromObject(@NonNull View view, @NonNull Object o) {
return view == o;
}
@NonNull
@Override
public Object instantiateItem(@NonNull ViewGroup container, int position) {
position %= imageViews.size();
ImageView imageView = imageViews.get(position);
container.addView(imageView);
return imageView;
}
@Override
public void destroyItem(@NonNull ViewGroup container, int position, @NonNull Object object) {
container.removeView((View) object);
}
}
//添加小圆点
private void initPoint(List imageViews) {
for (int i = 0; i < imageViews.size(); i++) {
//创建小圆点
View view = new View(getContext());
view.setBackgroundResource(R.drawable.point_bg_selector);
//自定义大小
LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(20, 20);
params.rightMargin = 20;
//把小圆点动态添加到布局中
ll_point.addView(view, params);
}
View view = ll_point.getChildAt(0);
//默认第一个选中的
view.setEnabled(false);
}
//开始轮播
public void startBanner() {
handler.postDelayed(new Runnable() {
@Override
public void run() {
int currentItem = vp.getCurrentItem();
currentItem++;
vp.setCurrentItem(currentItem);
handler.postDelayed(this, 2000);
}
}, 2000);
}
//停止轮播
public void stopBanner() {
handler.removeCallbacksAndMessages(null);
}
//测量
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
}
//摆放
@Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
super.onLayout(changed, l, t, r, b);
}
}
4.主页面调用
public class MainActivity extends AppCompatActivity {
private CustomViewGroup customViewGroup;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
customViewGroup = findViewById(R.id.cvg);
}
@Override
protected void onResume() {
super.onResume();
customViewGroup.startBanner();
}
@Override
protected void onPause() {
super.onPause();
customViewGroup.stopBanner();
}
}