android - 如何通过手指滑动自定义自动滑动图像
问题描述
我已经实现了一个带点的图像滑块。工作完美。滑块仅通过从手指向左或向右滑动而不是自动按时间间隔 3 秒进行手动工作。
查看代码并建议我一些自动工作滑块的方法。.xml 布局文件中的 ViewPager
<androidx.viewpager.widget.ViewPager
android:id="@+id/view_pager"
android:layout_width="match_parent"
android:layout_height="160dp"
android:layout_alignParentTop="true" />
<LinearLayout
android:paddingTop="8dp"
android:id="@+id/slider_dots"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:gravity="center_horizontal|center_vertical"
android:layout_below="@id/view_pager"></LinearLayout>
</RelativeLayout>
这是 ViewPageAdapter java 类
public class ViewPagerAdapter extends PagerAdapter {
Context context;
LayoutInflater layoutInflater;
int images[] = {R.mipmap.banner, R.mipmap.banner1, R.mipmap.banner2, R.mipmap.banner3, R.mipmap.banner4, R.mipmap.banner5};
public ViewPagerAdapter(Context context) {
this.context = context;
}
@Override
public int getCount() {
return images.length;
}
@Override
public boolean isViewFromObject(View view, Object object) {
return view == object;
}
@Override
public Object instantiateItem(ViewGroup container, int position) {
layoutInflater = (LayoutInflater) context.getSystemService(LAYOUT_INFLATER_SERVICE);
View view = layoutInflater.inflate(R.layout.slider_banner_layout, null);
ImageView imageView = view.findViewById(R.id.image_view_banner_image);
imageView.setImageResource(images[position]);
ViewPager viewPager = (ViewPager) container;
viewPager.addView(view, 0);
return view;
}
@Override
public void destroyItem(ViewGroup container, int position, Object object) {
ViewPager viewPager = (ViewPager) container;
View view = (View) object;
viewPager.removeView(view);
}
}
MainActivity.java
public class HomeActivity extends AppCompatActivity {
ViewPager viewPager;
LinearLayout sliderDotsPanel;
ImageView[] dots;
private int dotCount;
ViewPagerAdapter viewPagerAdapter;
private Toolbar toolbar;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_home);
toolbar = findViewById(R.id.app_bar);
toolbar.setTitle("");
toolbar.setLogo(R.mipmap.toolbar_logo);
setSupportActionBar(toolbar);
viewPager = findViewById(R.id.view_pager);
viewPagerAdapter= new ViewPagerAdapter(this);
viewPager.setAdapter(viewPagerAdapter);
sliderDotsPanel=findViewById(R.id.slider_dots);
initializeDots();
}
private void initializeDots() {
dotCount = viewPagerAdapter.getCount();
dots = new ImageView[dotCount];
for (int i = 0; i < dotCount; i++) {
dots[i] = new ImageView(this);
dots[i].setImageDrawable(ContextCompat.getDrawable(getApplicationContext(), R.drawable.non_active_dot));
LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT, LinearLayout.LayoutParams.WRAP_CONTENT);
params.setMargins(8, 0, 8, 0);
sliderDotsPanel.addView(dots[i], params);
}
dots[0].setImageDrawable(ContextCompat.getDrawable(getApplicationContext(), R.drawable.active_dot));
viewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
@Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
@Override
public void onPageSelected(int position) {
for (int i = 0; i < dotCount; i++) {
dots[i].setImageDrawable(ContextCompat.getDrawable(getApplicationContext(), R.drawable.non_active_dot));
}
dots[position].setImageDrawable(ContextCompat.getDrawable(getApplicationContext(), R.drawable.active_dot));
}
@Override
public void onPageScrollStateChanged(int state) {
}
});
}
}
解决方案
我将向您展示如何使其滑动,一页接一页然后停止:
private void slideAutomatically(final long milliSeconds){
new Thread(new Runnable(){
@Override
public void run(){
for(int i = 0 ; i<6 ; i++){
//sleep
try{
Thread.sleep(milliSeconds);
}catch(InterruptedException e){
}
//change position
runOnUiThread(new Runnable(){
@Override
public void run(){
viewPager.setCurrentItem(i);}
});
}
}
}).start();
}
每当您希望页面自动滑动时调用此方法:
//lets say I want the pages to change every 3 seconds
slideAutomatically(3000);
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