android - Android：视图分页器中的标签页指示器

Question

我正在制作一个应用程序，我必须实现“扫描标签”。我已阅读此内容，但找不到任何相关内容。我也试过了ViewPagerIndicator。

下面是我的代码片段：

public class ViewPagerIndicatorActivity extends FragmentActivity {
PagerAdapter mPagerAdapter;
ViewPager  mViewPager;
ViewPagerIndicator mIndicator;
static ArrayList<String> readableDateFormat;
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    // Create our custom adapter to supply pages to the viewpager.
    mPagerAdapter = new PagerAdapter(getSupportFragmentManager());
    mViewPager = (ViewPager)findViewById(R.id.pager);
    mViewPager.setAdapter(mPagerAdapter);

    // Start at a custom position
    mViewPager.setCurrentItem(3);

    // Find the indicator from the layout
    mIndicator = (ViewPagerIndicator)findViewById(R.id.indicator);

    // Set the indicator as the pageChangeListener
    mViewPager.setOnPageChangeListener(mIndicator);

    // Initialize the indicator. We need some information here:
    // * What page do we start on.
    // * How many pages are there in total
    // * A callback to get page titles
    mIndicator.init(5, mPagerAdapter.getCount(), mPagerAdapter);
    Resources res = getResources();
    Drawable prev = res.getDrawable(R.drawable.indicator_prev_arrow);
    Drawable next = res.getDrawable(R.drawable.indicator_next_arrow);
    mIndicator.setFocusedTextColor(new int[]{255, 0, 0});

    // Set images for previous and next arrows.
    mIndicator.setArrows(prev, next);

    mIndicator.setOnClickListener(new OnIndicatorClickListener());
}

class OnIndicatorClickListener implements ViewPagerIndicator.OnClickListener{
    @Override
    public void onCurrentClicked(View v) {
        Toast.makeText(ViewPagerIndicatorActivity.this, "Hello", Toast.LENGTH_SHORT).show();
    }

    @Override
    public void onNextClicked(View v) {
        mViewPager.setCurrentItem(Math.min(mPagerAdapter.getCount() - 1, mIndicator.getCurrentPosition() + 1));
    }

    @Override
    public void onPreviousClicked(View v) {
        mViewPager.setCurrentItem(Math.max(0, mIndicator.getCurrentPosition() - 1));
    }

}

class PagerAdapter extends FragmentPagerAdapter implements ViewPagerIndicator.PageInfoProvider{
    public PagerAdapter(FragmentManager fm) {
        super(fm);
    }

    @Override
    public Fragment getItem(int pos) {

        String list1[]={"Catagories","Latest","Most Downloaded","Top Paid"};

        Calendar cal = Calendar.getInstance();
        cal.add(Calendar.DAY_OF_MONTH, pos - getCount() / 2);
        //return ItemFragment.newInstance(cal.getTime());
        return ItemFragment.newInstance1(list1);
    }

    @Override
    public int getCount() {
        return 4;
    }

    @Override
    public String getTitle(int pos){
        String hello[]={"Catagories","Latest","Most Downloaded","Top Paid"};

        return hello.toString();
    }
}

public static class ItemFragment extends ListFragment{
    Date date;
    String[] hello1;

    static ItemFragment newInstance1(String[] hello) {
        ItemFragment f = new ItemFragment();

        // Supply num input as an argument.
        Bundle args = new Bundle();

        args.putStringArray("date", hello);
        f.setArguments(args);

        return f;
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        try {
            this.hello1=list;
            System.out.println("hello:list -"+hello1);
        } catch (Exception e) {
            e.printStackTrace();

        }
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        View v = inflater.inflate(R.layout.date_fragment, container, false);
        View tv = v.findViewById(R.id.text);

        ((TextView)tv).setText(hello1.toString());

        System.out.println("text view :"+hello1.toString());

        return v;
    }

    @Override
    public void onActivityCreated(Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
        setListAdapter(new ArrayAdapter<String>(getActivity(),
        android.R.layout.simple_list_item_1, list));
    }

    @Override
    public void onListItemClick(ListView l, View v, int position, long id) {
        Log.i("FragmentList", "Item clicked: " + id);
    }
}

public static final String[] list = new String[]{"France", "London", "Sweden", "Denmark", "Germany", "Finland", "Thailand", "Taiwan", "USA", "Norway", "Denmark (again)", "Lithuania", "Bosnia", "Russia", "Vietnam", "Australia"};

和其他的是：

public class ViewPagerIndicator extends RelativeLayout implements OnPageChangeListener {
private static final int PADDING = 5;

TextView mPrevious;
TextView mCurrent;
TextView mNext;
int mCurItem;
int mRestoreCurItem = -1;

LinearLayout mPreviousGroup;
LinearLayout mNextGroup;

int mArrowPadding;
int mSize;

ImageView mCurrentIndicator;
ImageView mPrevArrow;
ImageView mNextArrow;

int[] mFocusedTextColor;
int[] mUnfocusedTextColor;

OnClickListener mOnClickHandler;

public interface PageInfoProvider{
    String getTitle(int pos);
}

public interface OnClickListener{
    void onNextClicked(View v);
    void onPreviousClicked(View v);
    void onCurrentClicked(View v);
}

public void setOnClickListener(OnClickListener handler){
    this.mOnClickHandler = handler;
    mPreviousGroup.setOnClickListener(new OnPreviousClickedListener());
    mCurrent.setOnClickListener(new OnCurrentClickedListener());
    mNextGroup.setOnClickListener(new OnNextClickedListener());
}

public int getCurrentPosition(){
    return mCurItem;
}

PageInfoProvider mPageInfoProvider;
public void setPageInfoProvider(PageInfoProvider pageInfoProvider){
    this.mPageInfoProvider = pageInfoProvider;
}

public void setFocusedTextColor(int[] col){
    System.arraycopy(col, 0, mFocusedTextColor, 0, 3);
    updateColor(0);
}

public void setUnfocusedTextColor(int[] col){
    System.arraycopy(col, 0, mUnfocusedTextColor, 0, 3);
    mNext.setTextColor(Color.argb(255, col[0], col[1], col[2]));
    mPrevious.setTextColor(Color.argb(255, col[0], col[1], col[2]));
    updateColor(0);
}

@Override
protected Parcelable onSaveInstanceState() {
    Parcelable state = super.onSaveInstanceState();
    Bundle b = new Bundle();
    b.putInt("current", this.mCurItem);
    b.putParcelable("viewstate", state);
    return b;
}

@Override
protected void onRestoreInstanceState(Parcelable state) {
    super.onRestoreInstanceState(((Bundle)state).getParcelable("viewstate"));
    mCurItem = ((Bundle)state).getInt("current", mCurItem);
    this.setText(mCurItem - 1);
    this.updateArrows(mCurItem);
    this.invalidate();
}

/**
 * Initialization
 * 
 * @param startPos The initially selected element in the ViewPager
 * @param size Total amount of elements in the ViewPager
 * @param pageInfoProvider Interface that returns page titles
 */
public void init(int startPos, int size, PageInfoProvider pageInfoProvider){
    setPageInfoProvider(pageInfoProvider);
    this.mSize = size;
    setText(startPos - 1);
    mCurItem = startPos;
}

public ViewPagerIndicator(Context context, AttributeSet attrs) {
    super(context, attrs);
    addContent();
}

public ViewPagerIndicator(Context context, AttributeSet attrs, int defStyle){
    super(context, attrs, defStyle);
    addContent();
}

public ViewPagerIndicator(Context context) {
    super(context);
    addContent();
}

/**
 * Add drawables for arrows
 * 
 * @param prev Left pointing arrow
 * @param next Right pointing arrow
 */
public void setArrows(Drawable prev, Drawable next){
    this.mPrevArrow = new ImageView(getContext());
    this.mPrevArrow.setImageDrawable(prev);

    this.mNextArrow = new ImageView(getContext());
    this.mNextArrow.setImageDrawable(next);

    LinearLayout.LayoutParams arrowLayoutParams = new LinearLayout.LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
    arrowLayoutParams.gravity = Gravity.CENTER;

    mPreviousGroup.removeAllViews();
    mPreviousGroup.addView(mPrevArrow, arrowLayoutParams);
    mPreviousGroup.addView(mPrevious, arrowLayoutParams);

    mPrevious.setPadding(PADDING, 0, 0, 0);
    mNext.setPadding(0, 0, PADDING, 0);

    mArrowPadding = PADDING + prev.getIntrinsicWidth();

    mNextGroup.addView(mNextArrow, arrowLayoutParams);
    updateArrows(mCurItem);
}

/**
 * Create all views, build the layout
 */
private void addContent(){
    mFocusedTextColor = new int[]{0, 0, 0};
    mUnfocusedTextColor = new int[]{190, 190, 190};

    // Text views
    mPrevious = new TextView(getContext());
    mCurrent = new TextView(getContext());
    mNext = new TextView(getContext());

    RelativeLayout.LayoutParams previousParams = new RelativeLayout.LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
    previousParams.addRule(RelativeLayout.ALIGN_LEFT);

    RelativeLayout.LayoutParams currentParams = new RelativeLayout.LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
    currentParams.addRule(RelativeLayout.CENTER_HORIZONTAL);

    RelativeLayout.LayoutParams nextParams = new RelativeLayout.LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
    nextParams.addRule(RelativeLayout.ALIGN_PARENT_RIGHT);

    // Groups holding text and arrows
    mPreviousGroup = new LinearLayout(getContext());
    mPreviousGroup.setOrientation(LinearLayout.HORIZONTAL);
    mNextGroup = new LinearLayout(getContext());
    mNextGroup.setOrientation(LinearLayout.HORIZONTAL);

    mPreviousGroup.addView(mPrevious, new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));
    mNextGroup.addView(mNext, new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));

    addView(mPreviousGroup, previousParams);
    addView(mCurrent, currentParams);
    addView(mNextGroup, nextParams);

    mPrevious.setSingleLine();
    mCurrent.setSingleLine();
    mNext.setSingleLine();

    mPrevious.setText("previous");
    mCurrent.setText("current");
    mNext.setText("next");

    mPrevious.setClickable(false);
    mNext.setClickable(false);
    mCurrent.setClickable(true);
    mPreviousGroup.setClickable(true);
    mNextGroup.setClickable(true);

    // Set colors
    mNext.setTextColor(Color.argb(255, mUnfocusedTextColor[0], mUnfocusedTextColor[1], mUnfocusedTextColor[2]));
    mPrevious.setTextColor(Color.argb(255, mUnfocusedTextColor[0], mUnfocusedTextColor[1], mUnfocusedTextColor[2]));
    updateColor(0);
}

@Override
public void onPageScrollStateChanged(int state) {

}

@Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
    positionOffsetPixels = adjustOffset(positionOffsetPixels);
    position = updatePosition(position, positionOffsetPixels);
    setText(position - 1);
    updateColor(positionOffsetPixels);
    updateArrows(position);
    updatePositions(positionOffsetPixels);
    mCurItem = position;
}

void updatePositions(int positionOffsetPixels){
    int textWidth = mCurrent.getWidth() - mCurrent.getPaddingLeft() - mCurrent.getPaddingRight();
    int maxOffset = this.getWidth() / 2 - textWidth / 2 - mArrowPadding;
    if(positionOffsetPixels > 0){
        maxOffset -= this.getPaddingLeft();
        int offset = Math.min(positionOffsetPixels, maxOffset - 1);
        mCurrent.setPadding(0, 0, 2 * offset, 0);

        // Move previous text out of the way. Slightly buggy.
        /*
        int overlapLeft = mPreviousGroup.getRight() - mCurrent.getLeft() + mArrowPadding;
        mPreviousGroup.setPadding(0, 0, Math.max(0, overlapLeft), 0);
        mNextGroup.setPadding(0, 0, 0, 0);
        */
    }else{
        maxOffset -= this.getPaddingRight();
        int offset = Math.max(positionOffsetPixels, -maxOffset);
        mCurrent.setPadding(-2 * offset, 0, 0, 0);

        // Move next text out of the way. Slightly buggy.
        /*
        int overlapRight = mCurrent.getRight() - mNextGroup.getLeft() + mArrowPadding;
        mNextGroup.setPadding(Math.max(0, overlapRight), 0, 0, 0);
        mPreviousGroup.setPadding(0, 0, 0, 0);
        */
    }
}

/**
 * Hide arrows if we can't scroll further
 * 
 * @param position
 */
void updateArrows(int position){
    if(mPrevArrow != null){
        mPrevArrow.setVisibility(position == 0 ? View.INVISIBLE : View.VISIBLE);
        mNextArrow.setVisibility(position == mSize - 1 ? View.INVISIBLE : View.VISIBLE);
    }
}

/**
 * Adjust position to be the view that is showing the most.
 * 
 * @param givenPosition
 * @param offset
 * @return
 */
int updatePosition(int givenPosition, int offset){
    int pos;
    if(offset < 0){
        pos = givenPosition + 1;
    }else{
        pos = givenPosition;
    }
    return pos; 
}

/**
 * Fade "currently showing" color depending on it's position
 * 
 * @param offset
 */
void updateColor(int offset){
    offset = Math.abs(offset);
    // Initial condition: offset is always 0, this.getWidth is also 0! 0/0 = NaN
    int width = this.getWidth();
    float fraction = width == 0 ? 0 : offset / ((float)width / 4.0f);
    fraction = Math.min(1, fraction);
    int r = (int)(mUnfocusedTextColor[0] * fraction + mFocusedTextColor[0] * (1 - fraction));
    int g = (int)(mUnfocusedTextColor[1] * fraction + mFocusedTextColor[1] * (1 - fraction));
    int b = (int)(mUnfocusedTextColor[2] * fraction + mFocusedTextColor[2] * (1 - fraction));
    mCurrent.setTextColor(Color.argb(255, r, g, b));
}

/**
 * Update text depending on it's position
 * 
 * @param prevPos
 */
void setText(int prevPos){
    if(prevPos < 0){
        mPrevious.setText("");
    }else{
        mPrevious.setText(mPageInfoProvider.getTitle(prevPos));
    }
    mCurrent.setText(mPageInfoProvider.getTitle(prevPos + 1));
    String hellolo= ("current"+mPageInfoProvider.getTitle(prevPos + 1));
    if(prevPos + 2 == this.mSize){
        mNext.setText("");
    }else{
        mNext.setText(mPageInfoProvider.getTitle(prevPos + 2));
    }
}

// Original:
// 244, 245, 0, 1, 2
// New:
// -2, -1, 0, 1, 2
int adjustOffset(int positionOffsetPixels){
    // Move offset half width
    positionOffsetPixels += this.getWidth() / 2;
    // Clamp to width
    positionOffsetPixels %= this.getWidth();
    // Center around zero
    positionOffsetPixels -= this.getWidth() / 2;
    return positionOffsetPixels;
}

@Override
public void onPageSelected(int position) {
    // Reset padding when the page is finally selected (May not be necessary)
    mCurrent.setPadding(0, 0, 0, 0);
}

class OnPreviousClickedListener implements android.view.View.OnClickListener{
    @Override
    public void onClick(View v) {
        if(mOnClickHandler != null){
            mOnClickHandler.onPreviousClicked(ViewPagerIndicator.this);
        }
    }
}
class OnCurrentClickedListener implements android.view.View.OnClickListener{
    @Override
    public void onClick(View v) {
        if(mOnClickHandler != null){
            mOnClickHandler.onCurrentClicked(ViewPagerIndicator.this);
        }
    }
}
class OnNextClickedListener implements android.view.View.OnClickListener{
    @Override
    public void onClick(View v) {
        if(mOnClickHandler != null){
            mOnClickHandler.onNextClicked(ViewPagerIndicator.this);
        }
    }
}

，而不是名称我得到 Ljava.lang.String@44daf8

任何有关这方面的帮助都会有所帮助。

Answer 1

您所指的“扫描标签”实际上只是ViewPager每个页面都有相应的标题标签。默认情况下，这不包含在 Android SDK 中，但您可以使用 Jake WhartonViewPagerIndicator为您的ViewPager.

Jake Wharton 在 GitHub 上提供了一堆示例代码，你应该看看。如果您已经实现了您的ViewPager，那么更改您的代码以便它使用TabPagerIndicator（将为您的选项卡添加标题的类）根本不会太困难。您还可以参考Jake Wharton 网站上的使用部分。

我觉得这足以确保您ViewPager正确实施，但如果出现问题，请随时提出任何问题。