ViewPager是google SDk中自帶的一個附加包的一個類(在android-compatibility這個檔案夾下),可以用來實作螢幕間的切換。
如可以仿一個workspace的效果。
Actviity:
[java] view plain copy
- import com.viewpagerindicator.CirclePageIndicator;
- import android.os.Bundle;
- import android.support.v4.app.FragmentActivity;
- import android.support.v4.view.ViewPager;
- public class ViewpagerActivity extends FragmentActivity {
- TestFragmentAdapter mAdapter;
- ViewPager mPager;
- @Override
- protected void onCreate(Bundle savedInstanceState) {
- super.onCreate(savedInstanceState);
- //The look of this sample is set via a style in the manifest
- setContentView(R.layout.simple_circles);
- mAdapter = new TestFragmentAdapter(getSupportFragmentManager());
- mPager = (ViewPager)findViewById(R.id.pager);
- mPager.setAdapter(mAdapter);
- CirclePageIndicator indicator = (CirclePageIndicator)findViewById(R.id.indicator);
- indicator.setViewPager(mPager);
- }
- }
simple_circles.xml:
[html] view plain copy
- <?xml version="1.0" encoding="utf-8"?>
- <LinearLayout
- xmlns:android="http://schemas.android.com/apk/res/android"
- android:orientation="vertical"
- android:layout_width="fill_parent"
- android:layout_height="fill_parent">
- <android.support.v4.view.ViewPager
- android:id="@+id/pager"
- android:layout_width="fill_parent"
- android:layout_height="0dp"
- android:layout_weight="1"
- />
- <com.viewpagerindicator.CirclePageIndicator
- android:id="@+id/indicator"
- android:padding="10dip"
- android:layout_height="wrap_content"
- android:layout_width="fill_parent"
- />
- </LinearLayout>
TestFragmentAdapter:
[java] view plain copy
- import android.support.v4.app.Fragment;
- import android.support.v4.app.FragmentManager;
- import android.support.v4.app.FragmentPagerAdapter;
- class TestFragmentAdapter extends FragmentPagerAdapter {
- protected static final String[] CONTENT = new String[] { "第一頁", "第二頁", "第三頁", "第四頁", };
- private int mCount = CONTENT.length;
- public TestFragmentAdapter(FragmentManager fm) {
- super(fm);
- }
- @Override
- public Fragment getItem(int position) {
- return TestFragment.newInstance(CONTENT[position % CONTENT.length]);
- }
- @Override
- public int getCount() {
- return mCount;
- }
- public void setCount(int count) {
- if (count > 0 && count <= 10) {
- mCount = count;
- notifyDataSetChanged();
- }
- }
- }
TestFragment:
[java] view plain copy
- package com.shao.pager;
- import android.os.Bundle;
- import android.support.v4.app.Fragment;
- import android.view.Gravity;
- import android.view.LayoutInflater;
- import android.view.View;
- import android.view.ViewGroup;
- import android.widget.LinearLayout;
- import android.widget.LinearLayout.LayoutParams;
- import android.widget.TextView;
- public final class TestFragment extends Fragment {
- private static final String KEY_CONTENT = "TestFragment:Content";
- public static TestFragment newInstance(String content) {
- TestFragment fragment = new TestFragment();
- fragment.mContent = content;
- return fragment;
- }
- private String mContent = "???";
- @Override
- public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
- if ((savedInstanceState != null) && savedInstanceState.containsKey(KEY_CONTENT)) {
- mContent = savedInstanceState.getString(KEY_CONTENT);
- }
- TextView text = new TextView(getActivity());
- text.setGravity(Gravity.CENTER);
- text.setText(mContent);
- text.setTextSize(20 * getResources().getDisplayMetrics().density);
- text.setPadding(20, 20, 20, 20);
- LinearLayout layout = new LinearLayout(getActivity());
- layout.setLayoutParams(new LayoutParams(LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT));
- layout.setGravity(Gravity.CENTER);
- layout.addView(text);
- return layout;
- }
- @Override
- public void onSaveInstanceState(Bundle outState) {
- super.onSaveInstanceState(outState);
- outState.putString(KEY_CONTENT, mContent);
- }
- }
PageIndicator:
[java] view plain copy
- package com.viewpagerindicator;
- import android.support.v4.view.ViewPager;
- public interface PageIndicator extends ViewPager.OnPageChangeListener {
- public void setViewPager(ViewPager view);
- public void setViewPager(ViewPager view, int initialPosition);
- public void setCurrentItem(int item);
- public void setOnPageChangeListener(ViewPager.OnPageChangeListener listener);
- }
CliclePageIndicator:
[java] view plain copy
- package com.viewpagerindicator;
- import android.content.Context;
- import android.content.res.Resources;
- import android.content.res.TypedArray;
- import android.graphics.Canvas;
- import android.graphics.Paint;
- import android.graphics.Paint.Style;
- import android.os.Parcel;
- import android.os.Parcelable;
- import android.support.v4.view.ViewPager;
- import android.util.AttributeSet;
- import android.view.MotionEvent;
- import android.view.View;
- import com.shao.pager.R;
- public class CirclePageIndicator extends View implements PageIndicator {
- public static final int HORIZONTAL = 0;
- public static final int VERTICAL = 1;
- private float mRadius;
- private final Paint mPaintStroke;
- private final Paint mPaintFill;
- private ViewPager mViewPager;
- private ViewPager.OnPageChangeListener mListener;
- private int mCurrentPage;
- private int mSnapPage;
- private int mCurrentOffset;
- private int mScrollState;
- private int mPageSize;
- private int mOrientation;
- private boolean mCentered;
- private boolean mSnap;
- public CirclePageIndicator(Context context) {
- this(context, null);
- }
- public CirclePageIndicator(Context context, AttributeSet attrs) {
- this(context, attrs, R.attr.circlePageIndicatorStyle);
- }
- public CirclePageIndicator(Context context, AttributeSet attrs, int defStyle) {
- super(context, attrs, defStyle);
- //Load defaults from resources
- final Resources res = getResources();
- final int defaultFillColor = res.getColor(R.color.default_circle_indicator_fill_color);
- final int defaultOrientation = res.getInteger(R.integer.default_circle_indicator_orientation);
- final int defaultStrokeColor = res.getColor(R.color.default_circle_indicator_stroke_color);
- final float defaultStrokeWidth = res.getDimension(R.dimen.default_circle_indicator_stroke_width);
- final float defaultRadius = res.getDimension(R.dimen.default_circle_indicator_radius);
- final boolean defaultCentered = res.getBoolean(R.bool.default_circle_indicator_centered);
- final boolean defaultSnap = res.getBoolean(R.bool.default_circle_indicator_snap);
- //Retrieve styles attributes
- TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.CirclePageIndicator, defStyle, R.style.Widget_CirclePageIndicator);
- mCentered = a.getBoolean(R.styleable.CirclePageIndicator_centered, defaultCentered);
- mOrientation = a.getInt(R.styleable.CirclePageIndicator_orientation, defaultOrientation);
- mPaintStroke = new Paint(Paint.ANTI_ALIAS_FLAG);
- mPaintStroke.setStyle(Style.STROKE);
- mPaintStroke.setColor(a.getColor(R.styleable.CirclePageIndicator_strokeColor, defaultStrokeColor));
- mPaintStroke.setStrokeWidth(a.getDimension(R.styleable.CirclePageIndicator_strokeWidth, defaultStrokeWidth));
- mPaintFill = new Paint(Paint.ANTI_ALIAS_FLAG);
- mPaintFill.setStyle(Style.FILL);
- mPaintFill.setColor(a.getColor(R.styleable.CirclePageIndicator_fillColor, defaultFillColor));
- mRadius = a.getDimension(R.styleable.CirclePageIndicator_radius, defaultRadius);
- mSnap = a.getBoolean(R.styleable.CirclePageIndicator_snap, defaultSnap);
- a.recycle();
- }
- public void setCentered(boolean centered) {
- mCentered = centered;
- invalidate();
- }
- public boolean isCentered() {
- return mCentered;
- }
- public void setFillColor(int fillColor) {
- mPaintFill.setColor(fillColor);
- invalidate();
- }
- public int getFillColor() {
- return mPaintFill.getColor();
- }
- public void setOrientation(int orientation) {
- switch (orientation) {
- case HORIZONTAL:
- case VERTICAL:
- mOrientation = orientation;
- updatePageSize();
- requestLayout();
- break;
- default:
- throw new IllegalArgumentException("Orientation must be either HORIZONTAL or VERTICAL.");
- }
- }
- public int getOrientation() {
- return mOrientation;
- }
- public void setStrokeColor(int strokeColor) {
- mPaintStroke.setColor(strokeColor);
- invalidate();
- }
- public int getStrokeColor() {
- return mPaintStroke.getColor();
- }
- public void setStrokeWidth(float strokeWidth) {
- mPaintStroke.setStrokeWidth(strokeWidth);
- invalidate();
- }
- public float getStrokeWidth() {
- return mPaintStroke.getStrokeWidth();
- }
- public void setRadius(float radius) {
- mRadius = radius;
- invalidate();
- }
- public float getRadius() {
- return mRadius;
- }
- public void setSnap(boolean snap) {
- mSnap = snap;
- invalidate();
- }
- public boolean isSnap() {
- return mSnap;
- }
- @Override
- protected void onDraw(Canvas canvas) {
- super.onDraw(canvas);
- int longSize;
- int longPaddingBefore;
- int longPaddingAfter;
- int shortPaddingBefore;
- if (mOrientation == HORIZONTAL) {
- longSize = getWidth();
- longPaddingBefore = getPaddingLeft();
- longPaddingAfter = getPaddingRight();
- shortPaddingBefore = getPaddingTop();
- } else {
- longSize = getHeight();
- longPaddingBefore = getPaddingTop();
- longPaddingAfter = getPaddingBottom();
- shortPaddingBefore = getPaddingLeft();
- }
- final int count = mViewPager.getAdapter().getCount();
- final float threeRadius = mRadius * 3;
- final float shortOffset = shortPaddingBefore + mRadius;
- float longOffset = longPaddingBefore + mRadius;
- if (mCentered) {
- longOffset += ((longSize - longPaddingBefore - longPaddingAfter) / 2.0f) - ((count * threeRadius) / 2.0f);
- }
- float dX;
- float dY;
- //Draw stroked circles
- for (int iLoop = 0; iLoop < count; iLoop++) {
- float drawLong = longOffset + (iLoop * threeRadius);
- if (mOrientation == HORIZONTAL) {
- dX = drawLong;
- dY = shortOffset;
- } else {
- dX = shortOffset;
- dY = drawLong;
- }
- canvas.drawCircle(dX, dY, mRadius, mPaintStroke);
- }
- //Draw the filled circle according to the current scroll
- float cx = (mSnap ? mSnapPage : mCurrentPage) * threeRadius;
- if (!mSnap && (mPageSize != 0)) {
- cx += (mCurrentOffset * 1.0f / mPageSize) * threeRadius;
- }
- if (mOrientation == HORIZONTAL) {
- dX = longOffset + cx;
- dY = shortOffset;
- } else {
- dX = shortOffset;
- dY = longOffset + cx;
- }
- canvas.drawCircle(dX, dY, mRadius, mPaintFill);
- }
- @Override
- public boolean onTouchEvent(MotionEvent event) {
- if (event.getAction() == MotionEvent.ACTION_DOWN) {
- final int count = mViewPager.getAdapter().getCount();
- final int longSize = (mOrientation == HORIZONTAL) ? getWidth() : getHeight();
- final float halfLongSize = longSize / 2;
- final float halfCircleLongSize = (count * 3 * mRadius) / 2;
- final float pointerValue = (mOrientation == HORIZONTAL) ? event.getX() : event.getY();
- if ((mCurrentPage > 0) && (pointerValue < halfLongSize - halfCircleLongSize)) {
- setCurrentItem(mCurrentPage - 1);
- return true;
- } else if ((mCurrentPage < count - 1) && (pointerValue > halfLongSize + halfCircleLongSize)) {
- setCurrentItem(mCurrentPage + 1);
- return true;
- }
- }
- return super.onTouchEvent(event);
- }
- @Override
- public void setViewPager(ViewPager view) {
- if (view.getAdapter() == null) {
- throw new IllegalStateException("ViewPager does not have adapter instance.");
- }
- mViewPager = view;
- mViewPager.setOnPageChangeListener(this);
- updatePageSize();
- invalidate();
- }
- private void updatePageSize() {
- if (mViewPager != null) {
- mPageSize = (mOrientation == HORIZONTAL) ? mViewPager.getWidth() : mViewPager.getHeight();
- }
- }
- @Override
- public void setViewPager(ViewPager view, int initialPosition) {
- setViewPager(view);
- setCurrentItem(initialPosition);
- }
- @Override
- public void setCurrentItem(int item) {
- if (mViewPager == null) {
- throw new IllegalStateException("ViewPager has not been bound.");
- }
- mViewPager.setCurrentItem(item);
- mCurrentPage = item;
- invalidate();
- }
- @Override
- public void onPageScrollStateChanged(int state) {
- mScrollState = state;
- if (mListener != null) {
- mListener.onPageScrollStateChanged(state);
- }
- }
- @Override
- public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
- mCurrentPage = position;
- mCurrentOffset = positionOffsetPixels;
- updatePageSize();
- invalidate();
- if (mListener != null) {
- mListener.onPageScrolled(position, positionOffset, positionOffsetPixels);
- }
- }
- @Override
- public void onPageSelected(int position) {
- if (mSnap || mScrollState == ViewPager.SCROLL_STATE_IDLE) {
- mCurrentPage = position;
- mSnapPage = position;
- invalidate();
- }
- if (mListener != null) {
- mListener.onPageSelected(position);
- }
- }
- @Override
- public void setOnPageChangeListener(ViewPager.OnPageChangeListener listener) {
- mListener = listener;
- }
- @Override
- protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
- if (mOrientation == HORIZONTAL) {
- setMeasuredDimension(measureLong(widthMeasureSpec), measureShort(heightMeasureSpec));
- } else {
- setMeasuredDimension(measureShort(widthMeasureSpec), measureLong(heightMeasureSpec));
- }
- }
- private int measureLong(int measureSpec) {
- int result = 0;
- int specMode = MeasureSpec.getMode(measureSpec);
- int specSize = MeasureSpec.getSize(measureSpec);
- if (specMode == MeasureSpec.EXACTLY) {
- //We were told how big to be
- result = specSize;
- } else {
- //Calculate the width according the views count
- final int count = mViewPager.getAdapter().getCount();
- result = (int)(getPaddingLeft() + getPaddingRight()
- + (count * 2 * mRadius) + (count - 1) * mRadius + 1);
- //Respect AT_MOST value if that was what is called for by measureSpec
- if (specMode == MeasureSpec.AT_MOST) {
- result = Math.min(result, specSize);
- }
- }
- return result;
- }
- private int measureShort(int measureSpec) {
- int result = 0;
- int specMode = MeasureSpec.getMode(measureSpec);
- int specSize = MeasureSpec.getSize(measureSpec);
- if (specMode == MeasureSpec.EXACTLY) {
- //We were told how big to be
- result = specSize;
- } else {
- //Measure the height
- result = (int)(2 * mRadius + getPaddingTop() + getPaddingBottom() + 1);
- //Respect AT_MOST value if that was what is called for by measureSpec
- if (specMode == MeasureSpec.AT_MOST) {
- result = Math.min(result, specSize);
- }
- }
- return result;
- }
- @Override
- public void onRestoreInstanceState(Parcelable state) {
- SavedState savedState = (SavedState)state;
- super.onRestoreInstanceState(savedState.getSuperState());
- mCurrentPage = savedState.currentPage;
- mSnapPage = savedState.currentPage;
- requestLayout();
- }
- @Override
- public Parcelable onSaveInstanceState() {
- Parcelable superState = super.onSaveInstanceState();
- SavedState savedState = new SavedState(superState);
- savedState.currentPage = mCurrentPage;
- return savedState;
- }
- static class SavedState extends BaseSavedState {
- int currentPage;
- public SavedState(Parcelable superState) {
- super(superState);
- }
- private SavedState(Parcel in) {
- super(in);
- currentPage = in.readInt();
- }
- @Override
- public void writeToParcel(Parcel dest, int flags) {
- super.writeToParcel(dest, flags);
- dest.writeInt(currentPage);
- }
- public static final Parcelable.Creator<SavedState> CREATOR = new Parcelable.Creator<SavedState>() {
- @Override
- public SavedState createFromParcel(Parcel in) {
- return new SavedState(in);
- }
- @Override
- public SavedState[] newArray(int size) {
- return new SavedState[size];
- }
- };
- }
- }
代碼下載下傳http://download.csdn.net/detail/shaojie519/4256481