輪播圖的兩種方法
阿新 • • 發佈：2018-11-17
依賴
implementation ‘com.android.support:design:27.1.1’
implementation ‘com.nostra13.universalimageloader:universal-image-loader:1.9.5’
implementation ‘com.google.code.gson:gson:2.8.5’
implementation project(’:xListView’)
compile ‘com.youth.banner:banner:1.4.10’
activity_banner
<?xml version="1.0" encoding="utf-8"?><android.support.constraint.ConstraintLayout xmlns:android=“ http://schemas.android.com/apk/res/android”
android:layout_width=“match_parent”
android:layout_height=“match_parent”
xmlns:app=“http://schemas.android.com/apk/res-auto”>
<com.youth.banner.Banner android:id="@+id/banner" android:layout_width="0dp" android:layout_height="200dp" app:layout_constraintLeft_toLeftOf="parent" app:layout_constraintRight_toRightOf="parent" app:layout_constraintTop_toTopOf="parent" app:indicator_width="8dp" app:indicator_height="8dp" app:indicator_drawable_selected="@drawable/shape_sel_dot" app:indicator_drawable_unselected="@drawable/shape_normal_dot" />
</android.support.constraint.ConstraintLayout>
activity_main
<?xml version="1.0" encoding="utf-8"?><android.support.constraint.ConstraintLayout
xmlns:android=“http://schemas.android.com/apk/res/android”
xmlns:tools=“http://schemas.android.com/tools”
android:layout_width=“match_parent”
android:layout_height=“match_parent”
xmlns:app=“ http://schemas.android.com/apk/res-auto”
tools:context=".MainActivity">
<android.support.v4.view.ViewPager
android:layout_width="0dp"
android:layout_height="200dp"
android:id="@+id/banner"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
></android.support.v4.view.ViewPager>
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="0dp"
android:orientation="horizontal"
android:padding="8dp"
android:id="@+id/dots"
app:layout_constraintRight_toRightOf="@+id/banner"
app:layout_constraintBottom_toBottomOf="@+id/banner"
></LinearLayout>
<TextView
android:layout_width="0dp"
android:layout_height="wrap_content"
android:id="@+id/desc"
android:ellipsize="end"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintBottom_toBottomOf="@id/banner"
app:layout_constraintRight_toLeftOf="@id/dots"
/>
<me.maxwin.view.XListView
android:id="@+id/xListView"
android:layout_width="0dp"
android:layout_height="0dp"
app:layout_constraintTop_toBottomOf="@+id/banner"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintBottom_toBottomOf="parent"
></me.maxwin.view.XListView>
</android.support.constraint.ConstraintLayout>
activity_second
<?xml version="1.0" encoding="utf-8"?><android.support.constraint.ConstraintLayout xmlns:android=“http://schemas.android.com/apk/res/android”
android:layout_width=“match_parent”
android:layout_height=“150dp”
xmlns:app=“http://schemas.android.com/apk/res-auto”>
<ImageView
android:layout_width="140dp"
android:layout_height="140dp"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintRight_toRightOf="parent"
android:id="@+id/imageurl"
/>
<TextView
android:layout_width="0dp"
android:layout_height="wrap_content"
android:text="text"
app:layout_constraintTop_toTopOf="@+id/imageurl"
app:layout_constraintRight_toLeftOf="@+id/imageurl"
app:layout_constraintLeft_toLeftOf="parent"
android:id="@+id/title"
/>
<TextView
android:layout_width="0dp"
android:layout_height="wrap_content"
android:text="text"
app:layout_constraintBottom_toBottomOf="@+id/imageurl"
app:layout_constraintRight_toLeftOf="@+id/imageurl"
app:layout_constraintLeft_toLeftOf="parent"
android:id="@+id/summary"
/>
</android.support.constraint.ConstraintLayout>
App
public class App extends Application {
@Override
public void onCreate() {
super.onCreate();
ImageLoader.getInstance().init(
new ImageLoaderConfiguration.Builder(this)
.memoryCacheSizePercentage(10)
.diskCacheSize(50*1024*1024)
.defaultDisplayImageOptions(
new DisplayImageOptions.Builder()
.showImageOnFail(R.mipmap.ic_launcher)
.showImageOnLoading(R.mipmap.ic_launcher)
.cacheInMemory(true)
.cacheOnDisk(true)
.build()
)
.build()
);
}
}
NetUtil
public class NetUtil {
//介面
public interface CallBack<T> {
void getdata(T t);
}
//非同步任務
public static void yibu(String lujing, final Class clazz, final CallBack callBack){
new AsyncTask<String, Void, Object>() {
@Override
protected Object doInBackground(String... strings) {
return NetUtil.jiexi(strings[0],clazz);
}
@Override
protected void onPostExecute(Object o) {
callBack.getdata(o);
}
}.execute(lujing);
}
//網路解析
private static <T> T jiexi(String lujing, Class clazz) {
T t = (T) new Gson().fromJson(NetUtil.geturl(lujing),clazz);
return t;
}
//網路請求
public static String geturl(String lujing){
String result="";
try {
//定義地址
URL url=new URL(lujing);
//開啟連線
HttpURLConnection urlConnection= (HttpURLConnection) url.openConnection();
//請求方法
urlConnection.setRequestMethod("GET");
//讀取超時
urlConnection.setReadTimeout(5000);
//連線超時
urlConnection.setConnectTimeout(5000);
if (urlConnection.getResponseCode()==200){
result = NetUtil.zifu(urlConnection.getInputStream());
}
} catch (Exception e) {
e.printStackTrace();
}
return result;
}
private static String zifu(InputStream inputStream) throws IOException {
StringBuilder builder =new StringBuilder();
BufferedReader br = new BufferedReader(new InputStreamReader(inputStream));
for(String tmp = br.readLine(); tmp != null ; tmp = br.readLine() ){
builder.append(tmp);
}
return builder.toString();
}
}
BannerAdapter
public class BannerAdapter extends PagerAdapter {
private List<BannerResponse.Banner> mDatas;
private Context context;
public BannerAdapter(Context context) {
this.context = context;
mDatas = new ArrayList<>();
}
@Override
public int getCount() {
return mDatas.size() > 0 ? 5000 : 0;
}
public BannerResponse.Banner getItem(int position) {
return mDatas.get(position % mDatas.size());
}
public void setmDatas(List <BannerResponse.Banner> datas) {
mDatas.clear();
if(datas != null) {
mDatas.addAll(datas);
}
notifyDataSetChanged();
}
@Override
public boolean isViewFromObject(@NonNull View view, @NonNull Object object) {
return view == object;
}
@NonNull
@Override
public Object instantiateItem(@NonNull ViewGroup container, int position) {
ImageView imageView = new ImageView(context);
imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);
container.addView(imageView);
ImageLoader.getInstance().displayImage(getItem(position).getPicUrl(),imageView);
return imageView;
}
@Override
public void destroyItem(@NonNull ViewGroup container, int position, @NonNull Object object) {
container.removeView((View) object);
}
}
BannerActivity
public class BannerActivity extends AppCompatActivity {
private Banner banner;
@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_banner);
banner = findViewById(R.id.banner);
//設定banner樣式
banner.setBannerStyle(BannerConfig.CIRCLE_INDICATOR_TITLE_INSIDE);
//設定圖片載入器
banner.setImageLoader(new ImageLoaderInterface<ImageView>() {
@Override
public void displayImage(Context context, Object path, ImageView imageView) {
BannerResponse.Banner banner = (BannerResponse.Banner) path;
com.nostra13.universalimageloader.core.ImageLoader.getInstance()
.displayImage(banner.getPicUrl(), imageView);
}
@Override
public ImageView createImageView(Context context) {
ImageView imageView = new ImageView(context);
imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);
return imageView;
}
});
initData();
}
private void initData() {
NetUtil.yibu("https://api.tianapi.com/wxnew/?key=c4aa776e0a51d57d6750511e2baa46b6&num=6&page=1", BannerResponse.class, new NetUtil.CallBack<BannerResponse>() {
@Override
public void getdata(BannerResponse o) {
//設定圖片集合
banner.setImages(o.getNewslist());
banner.setBannerTitles(getTitles(o));
//banner設定方法全部呼叫完畢時最後呼叫
banner.start();
}
});
}
private List<String> getTitles(BannerResponse bannerResponse) {
List<String> result = new ArrayList<>();
for (BannerResponse.Banner banner: bannerResponse.getNewslist()) {
result.add(banner.getTitle());
}
return result;
}
}
MainActivity
public class MainActivity extends AppCompatActivity {
private ViewPager banner;
private TextView desc;
private LinearLayout dots;
private BannerAdapter adapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
banner = findViewById(R.id.banner);
desc = findViewById(R.id.desc);
dots = findViewById(R.id.dots);
adapter = new BannerAdapter(this);
banner.setAdapter(adapter);
banner.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
//快取的點
private int cacheIndex = -1;
//頁面滾動
@Override
public void onPageScrolled(int i, float v, int i1) {
}
//頁面選擇
@Override
public void onPageSelected(int i) {
//改變檔案
desc.setText(adapter.getItem(i).getTitle());
//改變當前點
dots.getChildAt(i % dots.getChildCount()).setSelected(true);
//還原原來的點
if (cacheIndex >= 0) {
dots.getChildAt(cacheIndex % dots.getChildCount()).setSelected(false);
}
cacheIndex = i;
}
@Override
public void onPageScrollStateChanged(int i) {
}
});
initData();
}
private void initData() {
NetUtil.yibu("https://api.tianapi.com/wxnew/?key=c4aa776e0a51d57d6750511e2baa46b6&num=6&page=1"
, BannerResponse.class, new NetUtil.CallBack<BannerResponse>() {
@Override
public void getdata(BannerResponse bannerResponse) {
if (bannerResponse == null || !bannerResponse.isSuccess()) {
Toast.makeText(MainActivity.this, "請求錯誤", Toast.LENGTH_SHORT).show();
return;
}
adapter. setmDatas(bannerResponse.getNewslist());
initDot(bannerResponse.getNewslist().size());
//切換到中間
int center = adapter.getCount() / 2;
center = center - center % bannerResponse.getNewslist().size();
banner.setCurrentItem(center);
//開啟輪播
startlooper();
}
});
}
private Handler mHandler = new Handler() {
@Override
public void handleMessage(Message msg) {
banner.setCurrentItem(banner.getCurrentItem() + 1);
mHandler.sendEmptyMessageDelayed(0, 2000);
}
};
private void startlooper() {
mHandler.removeMessages(0);
mHandler.sendEmptyMessageDelayed(0, 2000);
}
//初始化小圓點
private void initDot(int size) {
dots.removeAllViews();
for (int i = 0; i < size; i++) {
ImageView imageView = new ImageView(this);
imageView.setBackgroundResource(R.drawable.selector_dot);
//佈局引數: 寬高包裹 左右8dp
LinearLayout.LayoutParams params =
new LinearLayout.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT,
ViewGroup.LayoutParams.WRAP_CONTENT);
int margin = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 2, getResources().getDisplayMetrics());
params.leftMargin = margin;
params.rightMargin = margin;
dots.addView(imageView, params);
}
}
}