Android-ViewPager的自動滑動
- 在Android-ViewPager循環滑動的基礎上添加了自動滑動
- 添加了一個廣播,用于滑動到下一張圖檔
- 添加了一個服務,用于向廣播發送消息,表示該滑動圖檔了。。。
- 效果圖
Android-ViewPager自動滑動Android-ViewPager的自動滑動我的感受想說的話
添加的服務代碼如下
import android.app.Service;
import android.content.Intent;
import android.os.IBinder;
public class ViewPagerSlideService extends Service{
private Intent intent;
public static boolean isRun = true;
@Override
public void onCreate() {
super.onCreate();
intent = new Intent("com.jz.viewpager.CHANGPAGERRECEIVER");
}
@Override
public IBinder onBind(Intent intent) {
return null;
}
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
new Thread()
{
public void run()
{
while(isRun)
{//每隔三秒向廣播發送消息,滑動到下一張圖檔
try {
Thread.sleep();
} catch (InterruptedException e) {
e.printStackTrace();
}
sendBroadcast(ViewPagerSlideService.this.intent);
}
};
}.start();
return super.onStartCommand(intent, flags, startId);
}
}
改變後的Activity代碼如下
import android.app.Activity;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.Bundle;
import android.support.v4.view.PagerAdapter;
import android.support.v4.view.ViewPager;
import android.support.v4.view.ViewPager.OnPageChangeListener;
import android.view.View;
import android.view.ViewGroup;
import android.view.ViewGroup.LayoutParams;
import android.widget.ImageView;
import android.widget.LinearLayout;
public class MainActivity extends Activity {
private ViewPager viewPager;
private ImageView[] tips;// 小點
private ImageView[] imageViews;//顯示的圖檔
private int[] imgIds;//圖檔的資源id
private Intent intent;//啟動服務的意圖
private ChangePagerReceiver receiver;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ViewGroup group = (ViewGroup) findViewById(R.id.viewGroup);//擷取裝小點的線性布局
viewPager = (ViewPager) findViewById(R.id.viewPager);
// 圖檔資源
imgIds = new int[] { R.drawable.p20, R.drawable.p21, R.drawable.p22};
tips = new ImageView[imgIds.length];
for (int i = ; i < tips.length; i++) {
ImageView img = new ImageView(this);
tips[i] = img;
if (i == ) {
tips[i].setImageResource(R.drawable.yuanquan_up2);
} else {
tips[i].setImageResource(R.drawable.yuanquan_down2);
}
LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(
new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));
params.width = ;//小點寬度
params.height = ;//小點高度
params.leftMargin = ;//小點的左邊margin距離
params.rightMargin = ;//小點的右邊margin距離
group.addView(img, params);//将小點添加到線性布局中
}
//處理了,當圖檔小于等于4張的時候報的錯
imageViews = imgIds.length <= ? new ImageView[imgIds.length * ] : new ImageView[imgIds.length];
for (int i = ; i < imageViews.length; i++) {
imageViews[i] = new ImageView(this);
imageViews[i].setImageResource(imgIds[i % imgIds.length]);
//按比例擴大圖檔的size居中顯示,使得圖檔長(寬)等于或大于View的長(寬)
//ImageView.ScaleType參考:http://blog.csdn.net/larryl2003/article/details/6919513
imageViews[i].setScaleType(ImageView.ScaleType.CENTER_CROP);
}
// 設定Adapter
viewPager.setAdapter(new MyAdapter());
// 設定監聽,主要是設定滑動時點點的圖檔的改變
viewPager.addOnPageChangeListener(new OnPageChangeListener() {
@Override
public void onPageSelected(int arg0) {
setImageBack(arg0 % imgIds.length);
}
@Override
public void onPageScrolled(int arg0, float arg1, int arg2) {
}
@Override
public void onPageScrollStateChanged(int arg0) {
}
});
// 設定ViewPager的預設項, 設定為長度的100倍,這樣子開始就能往左滑動
viewPager.setCurrentItem((imageViews.length) * );
添加的部分:調用這個方法,啟動服務并且添加廣播
startServiceAndBroadcast();//啟動服務來發送廣播讓ViewPager滑動
}
/**
* 啟動服務建立廣播
*/
private void startServiceAndBroadcast()
{
ViewPagerSlideService.isRun = true;//線程可以運作
receiver = new ChangePagerReceiver();//執行個體化廣播接收器
IntentFilter intentFilter = new IntentFilter();
intentFilter.addAction("com.jz.viewpager.CHANGPAGERRECEIVER");
registerReceiver(receiver, intentFilter);//添加廣播的代碼注冊
intent = new Intent(MainActivity.this, ViewPagerSlideService.class);
startService(intent);//啟動服務
}
/**
*
* 設定小點的背景
*
*/
private void setImageBack(int selectItem) {
for (int i = ; i < tips.length; i++) {
if (i == selectItem) {
tips[i].setImageResource(R.drawable.yuanquan_up2);
} else {
tips[i].setImageResource(R.drawable.yuanquan_down2);
}
}
}
/**
*
* ViewPager擴充卡
*
*/
public class MyAdapter extends PagerAdapter {
@Override
public int getCount() {
return Integer.MAX_VALUE;
}
@Override
public boolean isViewFromObject(View arg0, Object arg1) {
return arg0 == arg1;
}
@Override
public void destroyItem(ViewGroup container, int position, Object object) {
container.removeView(imageViews[position % imageViews.length]);
}
@Override
public Object instantiateItem(ViewGroup container, int position) {
container.addView(imageViews[position % imageViews.length], );
return imageViews[position % imageViews.length];
}
}
添加的部分:添加的廣播接收器,用于切換到下一張圖檔
/**
*
* 接收廣播讓ViewPager動态改變
*
*/
public class ChangePagerReceiver extends BroadcastReceiver
{
@Override
public void onReceive(Context context, Intent intent) {
int position = viewPager.getCurrentItem();
viewPager.setCurrentItem(position + , true);
}
}
添加的部分:當頁面被銷毀時
@Override
protected void onDestroy() {
super.onDestroy();
ViewPagerSlideService.isRun = false;
stopService(intent);
unregisterReceiver(receiver);
}
}
我的感受
- 常常有自動滑動的ViewPager,自己就想着添加一個
- 也可以直接在Activity中添加一個線程來控制滑動,這樣來的還挺友善快捷的(@ ̄ー ̄@),感覺我好像想多了給弄麻煩了。。。
想說的話
- 部落格堅持寫,今後學習了新的東西就在這裡記錄一下,以便今後回顧,也希望小小筆記能幫助你們
- 若内容有什麼地方不對、不清楚,還望吐槽,希望大家能一起成長
- 來一個:枯燥無味中尋找成功的快感