自定义banner轮播图

最新推荐文章于 2018-09-28 15:35:01 发布

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最新推荐文章于 2018-09-28 15:35:01 发布

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本文链接：https://blog.youkuaiyun.com/mm_name_zhang/article/details/79435902

版权

float ratio = 1080/1920f;//和后台约定的图片大小

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main2);

ViewPager viewPager = (ViewPager) findViewById(R.id.viewpager);

//代码动态适配，及其常用的应用场景
ViewGroup.LayoutParams layoutParams = viewPager.getLayoutParams();

//像素宽度
layoutParams.width = getResources().getDisplayMetrics().widthPixels;
layoutParams.height = (int) (layoutParams.width/ratio);

viewPager.setLayoutParams(layoutParams);

}

//xml 文件

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
    <android.support.v4.view.ViewPager
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/viewpager"
        ></android.support.v4.view.ViewPager>

  <LinearLayout
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      android:orientation="horizontal"
      android:id="@+id/linao"
      android:paddingBottom="20dp"
      android:gravity="center"
      android:layout_gravity="bottom"
      >

  </LinearLayout>
</FrameLayout>

//在values目录下建attsr.xml文件

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <declare-styleable name="Benner">
        <attr name="size" format="dimension"></attr>
        <attr name="margin" format="dimension"></attr>

    </declare-styleable>

</resources>

、//drawable目录下建dot_selected.xml文件dot_normal.xml文件

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
android:shape="oval">
<solid android:color="@android:color/holo_green_dark"></solid>
<size android:height="10dp" android:width="10dp"/>
</shape>

//dot_normal.xml文件

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
android:shape="oval">
<solid android:color="@android:color/white"></solid>
<size android:height="10dp" android:width="10dp"/>
</shape>

//bannder类

public class Banner extends FrameLayout implements ViewPager.OnPageChangeListener {
private final int DELAY_TIME = 5000;//自动轮播时间
private List<String> mUrls;
private List<ImageView> mViewpagerViews;
private List<ImageView> mDotImageviews;
private Context context;
private int size;//圆点的大小
private int margin;//圆点的间距

private int count;//viewpager中view的数量
private ViewPager mViewPager;
private LinearLayout mDotlayout;//圆点布局
private MyPager mPagerAdapter;

private int currentItem;//当前viewpager索引

private Handler handler = new Handler();

private BannerClicklistener mBannerClicklistener;

public Banner(@NonNull Context context) {
super(context);

init(context, null);
}

public Banner(@NonNull Context context, @Nullable AttributeSet attrs) {
super(context, attrs);
init(context, attrs);
}

public Banner(@NonNull Context context, @Nullable AttributeSet attrs, @AttrRes int defStyleAttr) {
super(context, attrs, defStyleAttr);
init(context, attrs);
}

/**
* 初始化数据
*
* @param context
* @param attrs
*/
private void init(Context context, AttributeSet attrs) {
this.context = context;
mUrls = new ArrayList<>();
mViewpagerViews = new ArrayList<>();
mDotImageviews = new ArrayList<>();
//拿到自定义的属性数组
TypedArray typedArray = context.obtainStyledAttributes(attrs, R.styleable.Banner);
//得到数组里的自定义的size（圆点大小）
size = typedArray.getDimensionPixelSize(R.styleable.Banner_size, 10);
//得到数组里的自定义的margin（圆点间距）
margin = typedArray.getDimensionPixelSize(R.styleable.Banner_margin, 10);

typedArray.recycle();//通知jvm的垃圾回收器，当你回收对象的时候，一定要把我回收了

View view = LayoutInflater.from(context).inflate(R.layout.banner_layout, this, true);
// addView(view);
// View child = LayoutInflater.from(context).inflate(R.layout.banner_layout,null);
// addView(child);
mViewPager = view.findViewById(R.id.viewpager);
mDotlayout = view.findViewById(R.id.layout_dot);

//添加viewpager页面改变监听
mViewPager.addOnPageChangeListener(this);

}

/**
* 绘制自定义view的所有元素
*/
public void display() {
//绘制viewpager
drawViewpager();
//绘制圆点
drawDots();
//设置自动滚动
setAuto();

}

/**
* 设置自动滚动
*/
private void setAuto() {
handler.postDelayed(mTask, DELAY_TIME);
}

/**
* 定时任务
*/
Runnable mTask = new Runnable() {
@Override
public void run() {
currentItem++;
if (currentItem >= count) {
currentItem = 0;
}
mViewPager.setCurrentItem(currentItem);
handler.postDelayed(this, DELAY_TIME);
}
};

/**
* 传urls
*
* @param urls
*/
public Banner loadData(List<String> urls) {
this.mUrls = urls;
this.count = urls.size();
return this;
}

/**
* 绘制圆点
*/
private void drawDots() {

for (int i = 0; i < count; i++) {

ImageView iv = new ImageView(context);

LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(size, size);
params.leftMargin = margin;
params.rightMargin = margin;
iv.setLayoutParams(params);

mDotImageviews.add(iv);

if (i == 0) {

iv.setImageResource(R.drawable.dot_selected);
} else {
iv.setImageResource(R.drawable.dot_normal);
}

mDotlayout.addView(iv);
}

}

private void drawViewpager() {
for (int i = 0; i < count; i++) {
ImageView iv = new ImageView(context);
iv.setScaleType(ImageView.ScaleType.CENTER_CROP);
mViewpagerViews.add(iv);
}
if (mViewpagerViews != null) {
mPagerAdapter = new MyPager();
mViewPager.setAdapter(mPagerAdapter);
}
}

@Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {

}

/**
* 切换页面的监听
* @param position
*/
@Override
public void onPageSelected(int position) {

for (int i = 0; i < count; i++) {
if (i == position) {
mDotImageviews.get(i).setImageResource(R.drawable.dot_selected);
} else {
mDotImageviews.get(i).setImageResource(R.drawable.dot_normal);
}

}

}

@Override
public void onPageScrollStateChanged(int state) {

}

class MyPager extends PagerAdapter {

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

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

@Override
public Object instantiateItem(ViewGroup container, final int position) {

ImageView view = mViewpagerViews.get(position);
container.addView(view);

view.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View view) {

//实现点击逻辑

mBannerClicklistener.onClickListener(position);
}
});

System.out.println("urls:"+mUrls.get(position));

ImageLoader.getInstance().displayImage(mUrls.get(position), view);

return view;
}

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

/**
* 处理自动轮播和手动滑动的冲突
*
* @param ev
* @return
*/
@Override
public boolean dispatchTouchEvent(MotionEvent ev) {
int action = ev.getAction();
if (action == MotionEvent.ACTION_DOWN || action == MotionEvent.ACTION_MOVE) {
stopAuto();
} else if (action == MotionEvent.ACTION_UP) {
setAuto();
}
return super.dispatchTouchEvent(ev);
}

/**
* 取消自动轮播任务
*/
private void stopAuto() {
handler.removeCallbacks(mTask);//取消任务
}

/**
* 供外部调用者调用的接口类
*/
public interface BannerClicklistener {
void onClickListener(int pos);
}

/**
* 供外部调用者初始化接口对象
*/
public void setBannerClicklistener(BannerClicklistener bannerClicklistener) {
this.mBannerClicklistener = bannerClicklistener;
}

//取消轮播任务
public void cancel(){
handler.removeCallbacks(mTask);
}
}

//MainActivity类

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
getSupportActionBar().hide();
banner = (Banner) findViewById(R.id.banner);

urls = new ArrayList<>();
urls.add("https://www.zhaoapi.cn/images/quarter/ad1.png");
urls.add("https://www.zhaoapi.cn/images/quarter/ad2.png");
urls.add("https://www.zhaoapi.cn/images/quarter/ad3.png");
urls.add("https://www.zhaoapi.cn/images/quarter/ad4.png");

//解耦
banner.loadData(urls).display();//构建者模式返回对象本身
// banner.display();

banner.setBannerClicklistener(new Banner.BannerClicklistener() {
@Override
public void onClickListener(int pos) {

Toast.makeText(MainActivity.this, "pos====" + pos, Toast.LENGTH_SHORT).show();
}
});

}

@Override
protected void onDestroy() {
super.onDestroy();
if (banner != null) {
banner.cancel();
banner = null;

}
}
}