android 应用的引导页实现

package com.anzh.viewpager; import java.io.InputStream; import java.util.ArrayList; import java.util.List; import android.app.Activity; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.os.Bundle; import android.support.v4.view.ViewPager; import android.support.v4.view.ViewPager.OnPageChangeListener; import android.view.View; import android.view.View.OnClickListener; import android.widget.ImageView; import android.widget.LinearLayout; import android.widget.Toast; public class MainActivity extends Activity implements OnClickListener, OnPageChangeListener{ private ViewPager vp; private ViewPagerAdapter vpAdapter; private List<View> views; private int lastValue = -1; private Bitmap bitmap; //引导图片资源 private static final int[] pics = { R.drawable.guide1, R.drawable.guide2, R.drawable.guide3, R.drawable.guide4,R.drawable.guide5 }; //底部小店图片 private ImageView[] dots ; //记录当前选中位置 private int currentIndex; /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); views = new ArrayList<View>(); LinearLayout.LayoutParams mParams = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT, LinearLayout.LayoutParams.WRAP_CONTENT); //初始化引导图片列表 for(int i=0; i<pics.length; i++) { ImageView iv = new ImageView(this); iv.setLayoutParams(mParams); iv.setImageBitmap(getBitmap(pics[i])); views.add(iv); } vp = (ViewPager) findViewById(R.id.viewpager); //初始化Adapter vpAdapter = new ViewPagerAdapter(views); vp.setAdapter(vpAdapter); //绑定回调 vp.setOnPageChangeListener(this); //初始化底部小点 initDots(); } /** * 以最小内存获取资源图片 * @param resId * @return */ private Bitmap getBitmap(int resId){ BitmapFactory.Options opt = new BitmapFactory.Options(); opt.inPreferredConfig = Bitmap.Config.RGB_565; opt.inPurgeable = true; opt.inInputShareable = true; InputStream is = this.getResources().openRawResource(resId); bitmap = BitmapFactory.decodeStream(is, null, opt); return bitmap; } private void initDots() { LinearLayout ll = (LinearLayout) findViewById(R.id.ll); dots = new ImageView[pics.length]; //循环取得小点图片 for (int i = 0; i < pics.length; i++) { dots[i] = (ImageView) ll.getChildAt(i); dots[i].setEnabled(true);//都设为灰色 dots[i].setOnClickListener(this); dots[i].setTag(i);//设置位置tag，方便取出与当前位置对应 } currentIndex = 0; dots[currentIndex].setEnabled(false);//设置为白色，即选中状态 } /** *设置当前的引导页 */ private void setCurView(int position) { if (position < 0 || position >= pics.length) { return; } vp.setCurrentItem(position); } /** *这只当前引导小点的选中 */ private void setCurDot(int positon) { if (positon < 0 || positon > pics.length - 1 || currentIndex == positon) { return; } dots[positon].setEnabled(false); dots[currentIndex].setEnabled(true); currentIndex = positon; } //当滑动状态改变时调用 @Override public void onPageScrollStateChanged(int arg0) { if(arg0 == 0){ if(lastValue == pics.length-1){ Toast.makeText(this, "已经是最后一张了", Toast.LENGTH_SHORT).show(); } } } //当当前页面被滑动时调用 @Override public void onPageScrolled(int arg0, float arg1, int arg2) { lastValue = arg0; } //当新的页面被选中时调用 @Override public void onPageSelected(int arg0) { //设置底部小点选中状态 setCurDot(arg0); } @Override public void onClick(View v) { int position = (Integer)v.getTag(); setCurView(position); setCurDot(position); } }