輪播圖地址
概述
- 寫一個佈局,其中有ViewPager,TextView,LinearLayout.
- ViewPager:用來承載圖片
- TextView:用來展示文字描述
- LinearLayout:用來展示指示器
- 自定義ConstraintLayout, 在該控件中處理頁面切換邏輯等.
分析
- 獲取自定義屬性以及設置一些屬性
public BannerY(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
initView(context);
initXmlParams(context, attrs, defStyleAttr);
fixParams();
initListener();
initLists();
initImageLoader();
}
private void initImageLoader() {
ImageLoader.getInstance().init(ImageLoaderConfiguration.createDefault(mContext));
}
private void initView(Context context) {
mContext = context;
LayoutInflater.from(context).inflate(R.layout.layout_banner, this);
mVp = (ViewPager) findViewById(R.id.vp);
mTvDesc = (TextView) findViewById(R.id.tv_desc);
mLLPoint = (LinearLayout) findViewById(R.id.ll_point);
}
private void initXmlParams(Context context, AttributeSet attrs, int defStyleAttr) {
TypedArray typedArray = context.obtainStyledAttributes(attrs, R.styleable.BannerY, defStyleAttr, 0);
mPointSize = typedArray.getDimensionPixelSize(R.styleable.BannerY_point_size, 8);
mPointBG = typedArray.getResourceId(R.styleable.BannerY_point_bg, R.drawable.point_selector);
mInterval = typedArray.getInteger(R.styleable.BannerY_banner_interval, 2000);
mTvBottomMargin = typedArray.getDimensionPixelSize(R.styleable.BannerY_desc_bottom_margin, 8);
mPointBottomMargin = typedArray.getDimensionPixelSize(R.styleable.BannerY_point_bottom_margin, 8);
mDescColor = typedArray.getColor(R.styleable.BannerY_desc_color, Color.BLACK);
mDescSize = typedArray.getDimensionPixelSize(R.styleable.BannerY_desc_size, 14);
mScaleType = typedArray.getInt(R.styleable.BannerY_banner_scaletype, -1);
typedArray.recycle();
}
private void fixParams() {
LayoutParams mTvDescLayoutParams = (LayoutParams) mTvDesc.getLayoutParams();
mTvDescLayoutParams.bottomMargin = (int) mTvBottomMargin;
mTvDesc.setLayoutParams(mTvDescLayoutParams);
mTvDesc.setTextColor(mDescColor);
mTvDesc.getPaint().setTextSize(mDescSize);
LayoutParams mLLPointLayoutParams = (LayoutParams) mLLPoint.getLayoutParams();
mLLPointLayoutParams.bottomMargin = (int) mPointBottomMargin;
mLLPoint.setLayoutParams(mLLPointLayoutParams);
}
@SuppressLint("HandlerLeak")
private void initLists() {
mImageViewList = new ArrayList<>();
mDescList = new ArrayList<>();
mHandler = new Handler(Looper.getMainLooper()) {
@Override
public void handleMessage(@NonNull Message msg) {
super.handleMessage(msg);
int currentItem = mVp.getCurrentItem();
mVp.setCurrentItem(currentItem + 1);
mHandler.sendEmptyMessageDelayed(1, mInterval);
}
};
}
private void initListener() {
mVp.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
@Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
@Override
public void onPageSelected(int position) {
int realPosition = position % mImageViewList.size();
if (mDescList.size() == mImageViewList.size()) {
String desc = mDescList.get(realPosition);
mTvDesc.setText(desc);
} else {
if (BuildConfig.DEBUG) {
Log.d(TAG, "文字集合和圖片集合長度不相等");
}
}
mLLPoint.getChildAt(prePosition).setEnabled(false);
mLLPoint.getChildAt(realPosition).setEnabled(true);
prePosition = realPosition;
}
@Override
public void onPageScrollStateChanged(int state) {
if (state == ViewPager.SCROLL_STATE_DRAGGING) {
isDragging = true;
mHandler.removeCallbacksAndMessages(null);
}
if (state == ViewPager.SCROLL_STATE_IDLE && isDragging) {
mHandler.removeCallbacksAndMessages(null);
mHandler.sendEmptyMessageDelayed(1, mInterval);
}
}
});
}
- 設置圖片源集合
public <T> void setImagesRes(ArrayList<T> imagesRes) {
if (judgeLenght(imagesRes)) {
mImageViewList.clear();
initImageList(imagesRes);
mBannerAdapter = new BannerAdapter(mImageViewList);
mVp.setAdapter(mBannerAdapter);
int position = Integer.MAX_VALUE / 2 - Integer.MAX_VALUE / 2 % mImageViewList.size();
mVp.setCurrentItem(position);
mHandler.sendEmptyMessageDelayed(1, mInterval);
if (mDescList.size() == mImageViewList.size()) {
mTvDesc.setText(mDescList.get(prePosition));
}
}
}
private void initImageList(ArrayList imagesRes) {
Class<?> imageResClass = imagesRes.get(0).getClass();
for (int i = 0; i < imagesRes.size(); i++) {
ImageView imageView = createImageView(imagesRes, i, imageResClass);
setImageViewListener(imageView);
mImageViewList.add(imageView);
addPoint(i);
}
}
private ImageView createImageView(ArrayList imagesRes, int i, Class<?> imageResClass) {
ImageView imageView = new ImageView(mContext);
ViewGroup.LayoutParams layoutParams = new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT);
imageView.setLayoutParams(layoutParams);
ImageView.ScaleType scaleType = sScaleTypeArray[mScaleType];
imageView.setScaleType(scaleType);
if (imageResClass.equals(String.class)) {
String url = (String) imagesRes.get(i);
ImageLoader.getInstance().displayImage(url, imageView);
} else if (imageResClass.equals(Integer.class)) {
Integer resId = (Integer) imagesRes.get(i);
imageView.setImageResource(resId);
}
return imageView;
}
@SuppressLint("ClickableViewAccessibility")
private void setImageViewListener(ImageView imageView) {
imageView.setOnTouchListener(new View.OnTouchListener() {
@Override
public boolean onTouch(View v, MotionEvent event) {
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
mHandler.removeCallbacksAndMessages(null);
break;
case MotionEvent.ACTION_UP:
mHandler.removeCallbacksAndMessages(null);
mHandler.sendEmptyMessageDelayed(1, mInterval);
break;
}
return false;
}
});
imageView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (mIClickBanner != null) {
int positon = (int) v.getTag();
int i = positon % mImageViewList.size();
mIClickBanner.click(i);
} else {
if (BuildConfig.DEBUG) {
Log.e(TAG, "圖片回調方法爲不存在");
}
}
}
});
}
- BannerY的Adapter
public class BannerAdapter<T> extends PagerAdapter {
private final static String TAG = BannerAdapter.class.getName();
ArrayList<ImageView> mImageViewList;
public BannerAdapter(ArrayList<ImageView> mImageViewList) {
this.mImageViewList = mImageViewList;
}
@Override
public int getCount() {
return Integer.MAX_VALUE;
}
@SuppressLint("ClickableViewAccessibility")
@NonNull
@Override
public Object instantiateItem(@NonNull ViewGroup container, final int position) {
final int realPosition = position % mImageViewList.size();
ImageView imageView = mImageViewList.get(realPosition);
imageView.setTag(position);
ViewParent viewParent = imageView.getParent();
if (viewParent != null) {
((ViewGroup) viewParent).removeView(imageView);
}
container.addView(imageView);
return imageView;
}
@Override
public boolean isViewFromObject(@NonNull View view, @NonNull Object object) {
return view == object;
}
@Override
public void destroyItem(@NonNull ViewGroup container, int position, @NonNull Object object) {
}
}