我正在做一个项目。我想用页面指示器显示滑动图像。
幻灯片显示和页面指示符都出现在我的应用程序中，当我滚动图像时，图像成功更改并且可以正常工作。但我的页面指示器没有改变。当我在eclipse中运行代码时，这让我感到困惑，它可以正常工作，但在android studio中却不能。这是我的PageIndicator：
public class PageIndicator extends ImageView{
private Paint fillPaint;
private Paint strokePaint;
private int count;
private int indicatorWidth;
private static final int CIRCLE_RADIUS = 8;
private static final int CIRCLE_SPACE = 10;
private static final int CIRCLE_STROKE_COLOR = Color.GRAY;
private static final int CIRCLE_FILL_COLOR = Color.LTGRAY;
private int screenWidth;
private float offsetX;
private int currentPageIndex;
private float percent;
public PageIndicator(Context context) {
super(context);
initialize();
}
public PageIndicator(Context context, AttributeSet attrs) {
super(context, attrs);
initialize();
}
public PageIndicator(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
initialize();
}
private void initialize() {
fillPaint = new Paint();
fillPaint.setStyle(Style.FILL);
fillPaint.setColor(CIRCLE_FILL_COLOR);
fillPaint.setAntiAlias(true);
strokePaint = new Paint();
strokePaint.setStyle(Style.STROKE);
strokePaint.setColor(CIRCLE_STROKE_COLOR);
strokePaint.setAntiAlias(true);
screenWidth = G.appContext.getResources().getDisplayMetrics().widthPixels;
}
public void setIndicatorsCount(int value) {
count = value;
computeIndicatorWidth();
}
public void setCurrentPage(int value) {
currentPageIndex = value;
}
public void setPercent(float percent) {
this.percent = percent;
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
for (int i = 0; i < count; i++) {
Paint paint = strokePaint;
float radius = CIRCLE_RADIUS;
boolean canDrawFill = false;
if (i == currentPageIndex) {
fillPaint.setAlpha((int) ((1.0f - percent) * 255));
//radius *= 2;
canDrawFill = true;
}
if (percent > 0) {
if (i == currentPageIndex + 1) {
fillPaint.setAlpha((int) (percent * 255));
canDrawFill = true;
}
}
canvas.drawCircle(offsetX + i * (CIRCLE_RADIUS + CIRCLE_SPACE), 10, radius / 2.0f, strokePaint);
if (canDrawFill) {
canvas.drawCircle(offsetX + i * (CIRCLE_RADIUS + CIRCLE_SPACE), 10, radius / 2.0f, fillPaint);
}
}
}
private void computeIndicatorWidth() {
indicatorWidth = count * (CIRCLE_RADIUS + CIRCLE_SPACE);
offsetX = (screenWidth - indicatorWidth) / 2;
}
}
和我的ImagePageAdapter
public class ImagePagerAdapter extends PagerAdapter {
public ArrayList<Integer> imageIds;
public ArrayList<String> imageTitles;
public ImagePagerAdapter(ArrayList<Integer> imageIds , ArrayList<String> imageTitles){
this.imageIds = imageIds;
this.imageTitles = imageTitles;
}
@Override
public int getCount() {
// TODO Auto-generated method stub
return imageIds.size();
}
@Override
public boolean isViewFromObject(View view, Object object) {
// TODO Auto-generated method stub
return view.equals(object);
}
@Override
public Object instantiateItem(ViewGroup container, final int position) {
// TODO Auto-generated method stub
View view = G.inflater.inflate(R.layout.sliding, null);
ImageView image = (ImageView) view.findViewById(R.id.image_sliding);
TextView title = (TextView) view.findViewById(R.id.title_sliding);
image.setImageResource(imageIds.get(position));
title.setText(imageTitles.get(position));
container.addView(view);
return view;
}
@Override
public void destroyItem(ViewGroup container, int position, Object object) {
// TODO Auto-generated method stub
container.removeView((View)object );
}
}
和我的活动：
public class HomeActivity extends AppCompatActivity {
ViewPager pager;
PageIndicator indicator;
ArrayList<Integer> imageIds = new ArrayList<>();
ArrayList<String> imageTitles = new ArrayList<>();
@TargetApi(12)
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.home_activity);
pager = (ViewPager)findViewById(R.id.Pager);
indicator = (PageIndicator)findViewById(R.id.Indicator);
indicator.setIndicatorsCount(3);
addImageSliding("ofogh_mehr","به افق مهر خوش آمدید");
addImageSliding("sliding_1","تصویر 2");
addImageSliding("sliding_2","تصویر 3");
pager.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {
public void onPageSelected(int arg0) {
// TODO Auto-generated method stub
}
public void onPageScrolled(int startIndex, float percent, int pixel) {
// TODO Auto-generated method stub
indicator.setPercent(percent);
indicator.setCurrentPage(startIndex);
Log.i("Scroll", percent+ " " + startIndex );
}
public void onPageScrollStateChanged(int arg0) {
// TODO Auto-generated method stub
}
});
ImagePagerAdapter adapter = new ImagePagerAdapter(imageIds, imageTitles);
pager.setAdapter(adapter);
}
@Override
protected void onResume() {
super.onResume();
G.currentActivity = this;
}
private void addImageSliding(String name, String title){
int imageID = getApplicationContext().
getResources().
getIdentifier(name,
"drawable", getApplicationContext().getPackageName());
imageIds.add(imageID);
imageTitles.add(title);
}
}
最佳答案
为什么要重新发明轮子？
您可以使用TabLayout轻松创建页面指示器。不需要自定义类，也不需要与活动中的页面指示器进行交互，只需少量xml magic即可解决问题。
为了清楚起见，我们正在转换此代码：
像这样：
在您的活动中：
TabLayout dots = (TabLayout)findViewById(R.id.dots);
dots.setupWithViewPager(viewPager, true); // <-- magic here!
布局：
<LinearLayout
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingBottom="@dimen/activity_horizontal_margin">
<android.support.v4.view.ViewPager
android:id="@+id/viewpager"
android:layout_width="match_parent"
android:layout_height="250dp"
android:layout_marginBottom="5dp"/>
<android.support.design.widget.TabLayout
android:id="@+id/dots"
android:layout_width="match_parent"
android:layout_height="26dp"
local:tabBackground="@drawable/dot_selector"
local:tabGravity="center"
local:tabIndicatorHeight="0dp"
local:tabPaddingStart="7dp"
local:tabPaddingEnd="7dp"/>
</LinearLayout>
tabPaddingStart和tabPaddingEnd将定义点之间的分隔。为了简洁起见，我在这里使用了LinearLayout，但是您可以使用所需的任何布局。真的没关系。
dot_selector.xml：<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:drawable="@drawable/selected_dot" android:state_selected="true"/>
<item android:drawable="@drawable/default_dot"/>
</selector>
selected_dot.xml：<?xml version="1.0" encoding="utf-8" ?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
<item>
<shape
android:innerRadius="0dp"
android:shape="ring"
android:thickness="4dp"
android:useLevel="false">
<solid android:color="@color/page_indicator_selected_color"/>
</shape>
</item>
</layer-list>
default_dot.xml：与selected_dot.xml完全相同，但更改颜色。您可能会猜到，
android:thickness是点的大小。做完了！