android使用ViewPager实现图片自动切换

本文实现viewpager图片轮播的功能、左右滑动的时候能够流畅的切换图片、并且没有边界限制

1、activity_main.xml布局

<RelativeLayout xmlns:android='http://schemas.android.com/apk/res/android' xmlns:tools='http://schemas.android.com/tools' android:layout_width='match_parent' android:layout_height='match_parent' > <RelativeLayout android: android:layout_width='match_parent' android:layout_height='match_parent'/> </RelativeLayout>

因为我的ViewPager是继承RelativeLayout

2、layout_recommend_item.xml中的布局

<?xml version='1.0' encoding='utf-8'?><LinearLayout xmlns:android='http://schemas.android.com/apk/res/android' android:orientation='vertical' android:layout_width='match_parent' android:layout_height='match_parent'> <ImageView android: android:layout_width='match_parent' android:layout_height='match_parent' android:src='https://www.haobala.com/bcjs/@mipmap/ic_launcher' android:layout_weight='1'/> <TextView android: android:text='123' android:layout_width='match_parent' android:layout_height='wrap_content' /> </LinearLayout>

ImageView是显示图片 TextView用来显示每一个pager的标题

3、MyViewPager类，因为图个方便，把能够实现这个功能否合成一个类、这样用起来比较方便

import android.content.Context;import android.graphics.Canvas;import android.graphics.Color;import android.graphics.Paint;import android.os.Handler;import android.os.Message;import android.support.v4.view.PagerAdapter;import android.support.v4.view.ViewPager;import android.util.DisplayMetrics;import android.util.Log;import android.util.TypedValue;import android.view.View;import android.view.ViewGroup;import android.widget.ImageView;import android.widget.RelativeLayout;import android.widget.TextView; import java.util.ArrayList;import java.util.List; public class MyViewPager extends RelativeLayout { private static final int START_SCROLL = 1; private static final int SCROLL_NEXT = 2; private static final int SHOW_TIME = 5000;//显示时间 private List<String> mDatas = new ArrayList<>();//viewpager每一页对应的标题 private ViewPager mPager; private Context mContext; private int mWidth, mHeight; //viewpager的宽高 private int mTitleHeight; //标题高度 private TipView mTipView; //标题对应的view //在主ui中更新viewpager，也就是切换图片 private static Handler sHandler = new Handler() { @Override public void handleMessage(Message msg) { int w = msg.what; ViewPager pager = (ViewPager) msg.obj; switch (w) { case START_SCROLL: pager.setCurrentItem(msg.arg1, true); break; case SCROLL_NEXT: pager.setCurrentItem(msg.arg1, true); break; } } }; /** * 构造函数 * @param context content * @param w 要显示的viewpager的宽 * @param h 要显示的viewpager的高 */ public MyViewPager(Context context, int w, int h) { super(context); mContext = context; mWidth = w; mHeight = h; initView(); //取得数据 左边随便取的 只是为了看起来有效果// 对viewpager滑动进行监听 mPager.setOnPageChangeListener(new MOnPagerChangeListener()); init(); DisplayMetrics dm = mContext.getResources().getDisplayMetrics(); mTitleHeight = cm_DptoPx(48, dm); } /** * 对viewpager控件进行绘制宽高 */ @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { ViewGroup.LayoutParams vp = getLayoutParams(); if (vp != null) { vp.width = mWidth; vp.height = mHeight; } super.onMeasure(widthMeasureSpec, heightMeasureSpec); } /** * 把dp转化成px */ public static int cm_DptoPx(int dp,DisplayMetrics dis){ return (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, dp, dis); } private void init() { getData(); } private void initView() { mPager = new ViewPager(mContext); RelativeLayout.LayoutParams rp = new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.MATCH_PARENT, RelativeLayout.LayoutParams.MATCH_PARENT); addView(mPager, rp); } public void getData() { for (int i = 0; i < 4 ; i++){ mDatas.add(i,'viewpager'+i); } sHandler.postDelayed(new Runnable() { @Override public void run() { stopAnimation(); initTipView(); mPager.setAdapter(new RecommendAdapter()); mPager.setCurrentItem(10000 * mDatas.size()); } }, 2000); } /** * 删除队列中的消息 */ public void stopAnimation() { sHandler.removeMessages(START_SCROLL); sHandler.removeMessages(SCROLL_NEXT); } public void startAnimation() { if (mDatas.size() == 0) { return; } Message msg = sHandler.obtainMessage(START_SCROLL); msg.obj = mPager; msg.arg1 = (mPager.getCurrentItem() + 1);//取得后一张图片 sHandler.sendMessageDelayed(msg, SHOW_TIME);//5秒后发送给ui线程 } /** * 对标题view移动的光标初始化 */ private void initTipView() { if (mTipView == null) { RelativeLayout.LayoutParams rp = new RelativeLayout.LayoutParams(10, 10); rp.addRule(RelativeLayout.ALIGN_PARENT_BOTTOM); rp.bottomMargin = mTitleHeight; mTipView = new TipView(mContext, mDatas.size()); addView(mTipView, rp); } else { mTipView.setCount(mDatas.size()); } } private class MOnPagerChangeListener implements ViewPager.OnPageChangeListener { private int curState; @Override public void onPageScrolled(int i, float v, int i1) { } @Override public void onPageSelected(int i) { //滑动结束 sHandler.removeMessages(SCROLL_NEXT); sHandler.removeMessages(START_SCROLL); if(curState == ViewPager.SCROLL_STATE_DRAGGING){ return; } Message msg = sHandler.obtainMessage(SCROLL_NEXT); msg.arg1 = i + 1; msg.obj = mPager; sHandler.sendMessageDelayed(msg, SHOW_TIME); mTipView.setCurPostion(i % mDatas.size()); } @Override public void onPageScrollStateChanged(int i) { //正在滑动时 curState = i; if(i == ViewPager.SCROLL_STATE_DRAGGING){ //SCROLL_STATE_DRAGGING正在滑动 SCROLL_STATE_IDLE什么都没有做 //SCROLL_STATE_SETTLING 滑动完毕 stopAnimation(); }else { if(!(sHandler.hasMessages(START_SCROLL)&&sHandler.hasMessages(SCROLL_NEXT))){ startAnimation(); } } } } private class RecommendAdapter extends PagerAdapter { @Override public Object instantiateItem(ViewGroup container, int position) { Log.i('MyViewPager','instantiateItem '); int curPos = position % mDatas.size(); View view = View.inflate(mContext, R.layout.layout_recommend_item, null); ViewGroup.LayoutParams vp = new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT); ImageView iv = (ImageView) view.findViewById(R.id.iv_pic); TextView tv = (TextView) view.findViewById(R.id.tv_desc); tv.setText(mDatas.get(curPos)); container.addView(view, vp); view.setTag(curPos); view.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { } }); return view; } @Override public int getCount() { return Integer.MAX_VALUE; } @Override public boolean isViewFromObject(View view, Object o) { return view == o; } @Override public void destroyItem(ViewGroup container, int position, Object object) { container.removeView((View) object); } } private class TipView extends View { private int mPadding; private int mCount; private int mCurPos; private Paint mNorPaint; private Paint mSelPaint; private int mHeight; public TipView(Context context, int count) { super(context); mNorPaint = new Paint(); mNorPaint.setAntiAlias(true); DisplayMetrics dm = context.getResources().getDisplayMetrics(); int selHeight = cm_DptoPx(2, dm); int norHeight = cm_DptoPx(1, dm); mHeight = cm_DptoPx(2, dm); mNorPaint.setStrokeWidth(norHeight); mNorPaint.setColor(Color.argb(80, 255, 255, 255)); mSelPaint = new Paint(); mSelPaint.setAntiAlias(true); mSelPaint.setStrokeWidth(selHeight); mSelPaint.setColor(Color.WHITE); mCount = count; mPadding = cm_DptoPx(0, dm); } @Override protected void onDraw(Canvas canvas) { super.onDraw(canvas); int ow = (getWidth()-2*mPadding)/ mCount; int y = getHeight() / 2; canvas.drawLine(mPadding, y, mCurPos * ow + mPadding, y, mNorPaint); canvas.drawLine(mCurPos * ow + mPadding, y, (mCurPos + 1) * ow + mPadding, y, mSelPaint); canvas.drawLine((mCurPos + 1) * ow + mPadding, y, getWidth() - mPadding, y, mNorPaint); } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { ViewGroup.LayoutParams vp = getLayoutParams(); vp.width = ViewGroup.LayoutParams.MATCH_PARENT; vp.height = mHeight; super.onMeasure(widthMeasureSpec, heightMeasureSpec); } public void setCurPostion(int pos) { mCurPos = pos; invalidate(); } public void setCount(int count) { mCount = count; } }}

4、还有MainActivity中的实现

import android.app.Activity;import android.os.Bundle;import android.util.DisplayMetrics;import android.widget.RelativeLayout; public class MainActivity extends Activity { private RelativeLayout mViewPager; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); DisplayMetrics dm = getResources().getDisplayMetrics(); mViewPager = (RelativeLayout) findViewById(R.id.my_viewpager); mViewPager.addView(new MyViewPager(getApplicationContext(),dm.widthPixels ,(dm.widthPixels)/2)); }}

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持好吧啦网。