ViewPager+RadioGroup 实现网络加载图片的轮播

来源：互联网发布：软件商店开发编辑：程序博客网时间：2024/05/16 18:00

废话不多说先上图实现了轮播和定时播放网络加载图片实现了三级缓存

布局文件（这里实现了radioGroup的动态添加radioButton）

部分核心代码如下：

Timer定时器实现的图片定时播放

timer = new Timer();/* * 1.被关闭过的timer  就不能使用他再次开启 * 2.TimerTask 用过了，就不能再用！ *  */timer.schedule(new TimerTask() {@Overridepublic void run() {// TODO Auto-generated method stubrunOnUiThread(new Runnable() {// 主线程@Overridepublic void run() {// TODO Auto-generated method stubint currentItem = viewPager.getCurrentItem(); // 得到ViewPager当前显示第几页int count = adapter.getCount(); // 总共有多少条// 0123 4if (currentItem == (count - 1)) {// 如果使用第二个参数，单条显示Fragment数据可能无法加载！viewPager.setCurrentItem(0);} else {currentItem++;viewPager.setCurrentItem(currentItem);}}});}}, 2000, 2000);

ViewPager的触摸监听

//触摸监听 viewPager.setOnTouchListener(new OnTouchListener() {/** * 参数1： ViewPager 调用者 * 参数2： 记录触摸的事件  包含： 触摸的xy 触摸的动作： down move up */@Overridepublic boolean onTouch(View v, MotionEvent event) {// TODO Auto-generated method stub// 获取触摸动作int action  = event.getAction();switch (action) {case MotionEvent.ACTION_DOWN://按下 //停止定时器timer.cancel(); //关闭break;case MotionEvent.ACTION_UP://抬起//开启定时器timer = new Timer(); //新创建一个对象timer.schedule(new TimerTask() {@Overridepublic void run() {// TODO Auto-generated method stubrunOnUiThread(new Runnable() {// 主线程@Overridepublic void run() {// TODO Auto-generated method stubint currentItem = viewPager.getCurrentItem(); // 得到ViewPager当前显示第几页int count = adapter.getCount(); // 总共有多少条// 0123 4if (currentItem == (count - 1)) {// 如果使用第二个参数，单条显示Fragment数据可能无法加载！viewPager.setCurrentItem(0);} else {currentItem++;viewPager.setCurrentItem(currentItem);}}});}}, 2000, 2000);break;}return false;}});

ViewPager的状态改变监听

viewPager.setOnPageChangeListener(new OnPageChangeListener() {//改变后是第几页@Overridepublic void onPageSelected(int arg0) {// TODO Auto-generated method stub((RadioButton)rGroup.getChildAt(arg0)).setChecked(true);}//获取拉取偏移量@Overridepublic void onPageScrolled(int position, float arg1, int arg2) {// TODO Auto-generated method stub}//状态改变@Overridepublic void onPageScrollStateChanged(int arg0) {// TODO Auto-generated method stub}});

RadioGroup 的监听事件

//点击RadioButton 把ViewPager切换到当前的页面rGroup.setOnCheckedChangeListener(new OnCheckedChangeListener() {@Overridepublic void onCheckedChanged(RadioGroup group, int checkedId) {// TODO Auto-generated method stub//选中的是第几个RadioButton for (int i = 0; i < group.getChildCount(); i++) {//得到子控件RadioButton button = (RadioButton) group.getChildAt(i);if (button.isChecked()) {//把选中的位置，设置为ViewPager显示的位置viewPager.setCurrentItem(i);break;}}}});

根据添加图片的多少动态添加RadioGroup的RadioButton

for (int i = 0; i < imageurls.length; i++) {//添加点RadioButton  button = new  RadioButton(this);button.setLayoutParams(new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));rGroup.addView(button);  if (i==0) {button.setChecked(true);  //第一个默认选中}}

适配器

@Overridepublic View instantiateItem(ViewGroup container, int position) {// TODO Auto-generated method stubView ret = null;//创建一个视图  ImageView ImageView imageView = new ImageView(context);imageView.setLayoutParams(new LayoutParams(LayoutParams.MATCH_PARENT,LayoutParams.MATCH_PARENT));imageView.setScaleType(ScaleType.FIT_XY);String url = images[position]; //取到网址Bitmap bitmap = utils.getBitmap(url); //看下缓存中是否存在图片if (bitmap == null) {//内存没有需要下载imageView.setImageResource(R.drawable.ic_launcher);new ImageTask(imageView).execute(url);}else{imageView.setImageBitmap(bitmap);}ret = imageView; //添加到容器中container.addView(ret);return ret;}

以上是主要的核心代码有时间的猿们可以看看如果急需代码一下是所有的代码

MainActivity.java

/* * 带循环轮播的广告，并且底部有RadioGroup *  * ViewPager显示 *  * 定时器  *  * RadioGroup显示联动  *  */public class MainActivity extends Activity {private ViewPager viewPager;private MyAdapter adapter;     private RadioGroup rGroup; @Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);viewPager = (ViewPager) findViewById(R.id.viewPager);rGroup = (RadioGroup) findViewById(R.id.rg);initRadioButton();  //往RadioGroup内部动态添加小点initListener();   //初始化监听事件adapter = new MyAdapter(imageurls, this);viewPager.setAdapter(adapter);timer = new Timer();/* * 1.被关闭过的timer  就不能使用他再次开启 * 2.TimerTask 用过了，就不能再用！ *  */timer.schedule(new TimerTask() {@Overridepublic void run() {// TODO Auto-generated method stubrunOnUiThread(new Runnable() {// 主线程@Overridepublic void run() {// TODO Auto-generated method stubint currentItem = viewPager.getCurrentItem(); // 得到ViewPager当前显示第几页int count = adapter.getCount(); // 总共有多少条// 0123 4if (currentItem == (count - 1)) {// 如果使用第二个参数，单条显示Fragment数据可能无法加载！viewPager.setCurrentItem(0);} else {currentItem++;viewPager.setCurrentItem(currentItem);}}});}}, 2000, 2000);//触摸监听 viewPager.setOnTouchListener(new OnTouchListener() {/** * 参数1： ViewPager 调用者 * 参数2： 记录触摸的事件  包含： 触摸的xy 触摸的动作： down move up */@Overridepublic boolean onTouch(View v, MotionEvent event) {// TODO Auto-generated method stub// 获取触摸动作int action  = event.getAction();switch (action) {case MotionEvent.ACTION_DOWN://按下 //停止定时器timer.cancel(); //关闭break;case MotionEvent.ACTION_UP://抬起//开启定时器timer = new Timer(); //新创建一个对象timer.schedule(new TimerTask() {@Overridepublic void run() {// TODO Auto-generated method stubrunOnUiThread(new Runnable() {// 主线程@Overridepublic void run() {// TODO Auto-generated method stubint currentItem = viewPager.getCurrentItem(); // 得到ViewPager当前显示第几页int count = adapter.getCount(); // 总共有多少条// 0123 4if (currentItem == (count - 1)) {// 如果使用第二个参数，单条显示Fragment数据可能无法加载！viewPager.setCurrentItem(0);} else {currentItem++;viewPager.setCurrentItem(currentItem);}}});}}, 2000, 2000);break;}return false;}});}private void initListener() {// TODO Auto-generated method stubviewPager.setOnPageChangeListener(new OnPageChangeListener() {//改变后是第几页@Overridepublic void onPageSelected(int arg0) {// TODO Auto-generated method stub((RadioButton)rGroup.getChildAt(arg0)).setChecked(true);}//获取拉取偏移量@Overridepublic void onPageScrolled(int position, float arg1, int arg2) {// TODO Auto-generated method stub}//状态改变@Overridepublic void onPageScrollStateChanged(int arg0) {// TODO Auto-generated method stub}});//点击RadioButton 把ViewPager切换到当前的页面rGroup.setOnCheckedChangeListener(new OnCheckedChangeListener() {@Overridepublic void onCheckedChanged(RadioGroup group, int checkedId) {// TODO Auto-generated method stub//选中的是第几个RadioButton for (int i = 0; i < group.getChildCount(); i++) {//得到子控件RadioButton button = (RadioButton) group.getChildAt(i);if (button.isChecked()) {//把选中的位置，设置为ViewPager显示的位置viewPager.setCurrentItem(i);break;}}}});}private void initRadioButton() {// TODO Auto-generated method stubfor (int i = 0; i < imageurls.length; i++) {//添加点RadioButton  button = new  RadioButton(this);button.setLayoutParams(new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));rGroup.addView(button);  if (i==0) {button.setChecked(true);  //第一个默认选中}}}public String imageurls[] = new String[] {"http://img.my.csdn.net/uploads/201407/26/1406383299_1976.jpg","http://img.my.csdn.net/uploads/201407/26/1406383291_6518.jpg","http://img.my.csdn.net/uploads/201407/26/1406383291_8239.jpg","http://img.my.csdn.net/uploads/201407/26/1406383290_9329.jpg","http://img.my.csdn.net/uploads/201407/26/1406383290_1042.jpg","http://img.my.csdn.net/uploads/201407/26/1406383275_3977.jpg","http://img.my.csdn.net/uploads/201407/26/1406383265_8550.jpg","http://img.my.csdn.net/uploads/201407/26/1406383264_3954.jpg","http://img.my.csdn.net/uploads/201407/26/1406383264_4787.jpg" };private Timer timer;}

MyAdapter.java 代码适配器

/** *  * ViewPager  *  *    pagerAdapter *    FragmentPagerAdapter *    FragmentStateAdapter *  * @author Administrator * */public class MyAdapter extends PagerAdapter{     private String [] images;private Context context;private LruCacheUtils utils;public MyAdapter(String[] images, Context context) {this.images = images;this.context = context;utils = LruCacheUtils.getInstance(); //得到缓存工具类}@Overridepublic int getCount() {// TODO Auto-generated method stubreturn images != null?images.length:0;}   /*    * 1.修改返回值    *     *     */@Overridepublic View instantiateItem(ViewGroup container, int position) {// TODO Auto-generated method stubView ret = null;//创建一个视图  ImageView ImageView imageView = new ImageView(context);imageView.setLayoutParams(new LayoutParams(LayoutParams.MATCH_PARENT,LayoutParams.MATCH_PARENT));imageView.setScaleType(ScaleType.FIT_XY);String url = images[position]; //取到网址Bitmap bitmap = utils.getBitmap(url); //看下缓存中是否存在图片if (bitmap == null) {//内存没有需要下载imageView.setImageResource(R.drawable.ic_launcher);new ImageTask(imageView).execute(url);}else{imageView.setImageBitmap(bitmap);}ret = imageView; //添加到容器中container.addView(ret);return ret;}@Overridepublic boolean isViewFromObject(View arg0, Object arg1) {// TODO Auto-generated method stubreturn arg0 == arg1;}/** * 1.去掉 super * 2. *  */@Overridepublic void destroyItem(ViewGroup container, int position, Object object) {    if (object instanceof View) {View view = (View) object;container.removeView(view); //移除}}

网络请求记载图片这是使用的是异步任务加载

 //异步任务  class ImageTask extends AsyncTask<String, Void, Bitmap>{private ImageView imageView;public ImageTask(ImageView imageView) {this.imageView = imageView;}@Overrideprotected Bitmap doInBackground(String... params) {// TODO Auto-generated method stubtry {URL url = new URL(params[0]);HttpURLConnection connection = (HttpURLConnection) url.openConnection();if (connection.getResponseCode() == 200) {InputStream inputStream = connection.getInputStream();Bitmap bitmap = BitmapFactory.decodeStream(inputStream);//保存一份utils.putBitmap(params[0], bitmap);return bitmap;}} catch (MalformedURLException e) {// TODO Auto-generated catch blocke.printStackTrace();} catch (IOException e) {// TODO Auto-generated catch blocke.printStackTrace();}return null;}   @Overrideprotected void onPostExecute(Bitmap result) {// TODO Auto-generated method stubsuper.onPostExecute(result);     if (result != null) {imageView.setImageBitmap(result);}}}

图片显示的不是很全，这里使用了LruCache进行图片的缓存处理，使图片加载的更加顺溜《这是使用了三级缓存》

/** *  * ViewPager  *  *    pagerAdapter *    FragmentPagerAdapter *    FragmentStateAdapter *  * @author Administrator * */public class MyAdapter extends PagerAdapter{     private String [] images;private Context context;private LruCacheUtils utils;public MyAdapter(String[] images, Context context) {this.images = images;this.context = context;utils = LruCacheUtils.getInstance(); //得到缓存工具类}@Overridepublic int getCount() {// TODO Auto-generated method stubreturn images != null?images.length:0;}   /*    * 1.修改返回值    *     *     */@Overridepublic View instantiateItem(ViewGroup container, int position) {// TODO Auto-generated method stubView ret = null;//创建一个视图  ImageView ImageView imageView = new ImageView(context);imageView.setLayoutParams(new LayoutParams(LayoutParams.MATCH_PARENT,LayoutParams.MATCH_PARENT));imageView.setScaleType(ScaleType.FIT_XY);String url = images[position]; //取到网址Bitmap bitmap = utils.getBitmap(url); //看下缓存中是否存在图片if (bitmap == null) {//内存没有需要下载imageView.setImageResource(R.drawable.ic_launcher);new ImageTask(imageView).execute(url);}else{imageView.setImageBitmap(bitmap);}ret = imageView; //添加到容器中container.addView(ret);return ret;}@Overridepublic boolean isViewFromObject(View arg0, Object arg1) {// TODO Auto-generated method stubreturn arg0 == arg1;}/** * 1.去掉 super * 2. *  */@Overridepublic void destroyItem(ViewGroup container, int position, Object object) {    if (object instanceof View) {View view = (View) object;container.removeView(view); //移除}}      //异步任务  class ImageTask extends AsyncTask<String, Void, Bitmap>{private ImageView imageView;public ImageTask(ImageView imageView) {this.imageView = imageView;}@Overrideprotected Bitmap doInBackground(String... params) {// TODO Auto-generated method stubtry {URL url = new URL(params[0]);HttpURLConnection connection = (HttpURLConnection) url.openConnection();if (connection.getResponseCode() == 200) {InputStream inputStream = connection.getInputStream();Bitmap bitmap = BitmapFactory.decodeStream(inputStream);//保存一份utils.putBitmap(params[0], bitmap);return bitmap;}} catch (MalformedURLException e) {// TODO Auto-generated catch blocke.printStackTrace();} catch (IOException e) {// TODO Auto-generated catch blocke.printStackTrace();}return null;}   @Overrideprotected void onPostExecute(Bitmap result) {// TODO Auto-generated method stubsuper.onPostExecute(result);     if (result != null) {imageView.setImageBitmap(result);}}}

以上就是全部代码希望能帮助到大家，一起学习
希望在技术的道路上能于君共勉越走越远

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