安卓之引导页

  当APP安装的时候，一般都需要引导页。

  首先当然是写XML

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >


    <android.support.v4.view.ViewPager
        android:id="@+id/vp_guide"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />


    <Button
        android:id="@+id/btn_start"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_centerHorizontal="true"
        android:layout_marginBottom="30dp"
        android:background="@drawable/btn_bg"
        android:text="开始体验"
        android:visibility="invisible"
        android:textColor="#FFFFCC" />


    <RelativeLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_centerHorizontal="true"
        android:layout_marginBottom="10dp" >


        <LinearLayout
            android:id="@+id/ll_point_group"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:orientation="horizontal" >
        </LinearLayout>


        <View
            android:id="@+id/view_red_point"
            android:layout_width="8dp"
            android:layout_height="8dp"
            android:background="@drawable/shape_point_red" />
    </RelativeLayout>


</RelativeLayout>

然后写你的引导页的业务逻辑，里面有一些位置的计算

public class GuideActivity extends Activity {
private static final int[] mImagIds = new int[] { R.drawable.guide_1,
R.drawable.guide_2, R.drawable.guide_3 };
private ViewPager vp_Guide;
private ArrayList<ImageView> mImageViewList;
private Button btn_start;
private LinearLayout ll_point_group;
private int width;
private View viewRedPoint;


@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_guide);
vp_Guide = (ViewPager) findViewById(R.id.vp_guide);
btn_start = (Button) findViewById(R.id.btn_start);
ll_point_group = (LinearLayout) findViewById(R.id.ll_point_group);
viewRedPoint = findViewById(R.id.view_red_point);
SharedPreferences sp = getSharedPreferences("updated_at", MODE_PRIVATE);
sp.edit().putString("updated_at", "暂未更新过！").commit();
initViews();
init();
vp_Guide.setAdapter(new GuideAdapter());


vp_Guide.setOnPageChangeListener(new GuidePageListener());
}


protected void init() {
btn_start.setOnClickListener(new OnClickListener() {


public void onClick(View v) {
SharedPreferences sp = getSharedPreferences("config",
MODE_PRIVATE);
sp.edit().putBoolean("is_user_guide_showed", true).commit();
Intent intent = getIntent();
String token = intent.getStringExtra("Token");
GuideActivity.this.startActivity(new Intent(GuideActivity.this,
MainActivity.class).putExtra("Token", token));
GuideActivity.this.finish();
}
});
}


/**
* 初始化数据
*/
public void initViews() {
mImageViewList = new ArrayList<ImageView>();
// 初始化引导页的页面
for (int i = 0; i < mImagIds.length; i++) {
ImageView image = new ImageView(this);
image.setBackgroundResource(mImagIds[i]);
mImageViewList.add(image);
}
// 初始化小圆点
for (int i = 0; i < mImagIds.length; i++) {
View point = new View(this);
point.setBackgroundResource(R.drawable.shape_point_gray);
LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(
10, 10);
if (i > 0) {
params.leftMargin = 10;
}
point.setLayoutParams(params);
ll_point_group.addView(point); // 讲圆点添加进去


}
// 获取视图树
ll_point_group.getViewTreeObserver().addOnGlobalLayoutListener(
new OnGlobalLayoutListener() {

@Override
public void onGlobalLayout() {
ll_point_group.getViewTreeObserver()
.removeGlobalOnLayoutListener(this);
width = ll_point_group.getChildAt(1).getLeft()
- ll_point_group.getChildAt(0).getLeft();
System.out.println(width + "圆点距离");
}
});
}
    
class GuideAdapter extends PagerAdapter {


public int getCount() {
return mImagIds.length;
}


public boolean isViewFromObject(View arg0, Object arg1) {
return arg0 == arg1;
}


public Object instantiateItem(ViewGroup container, int


position) {
container.addView(mImageViewList.get(position));
return mImageViewList.get(position);
}


public void destroyItem(ViewGroup container, int position,


Object object) {
container.removeView((View) object);
}
}

class GuidePageListener implements OnPageChangeListener {


@Override
public void onPageScrollStateChanged(int arg0) {
}


@Override
public void onPageScrolled(int arg0, float arg1, int arg2) {
System.out.println("当前位置" + arg0 + "百分比" + arg1 + "移动距离" + arg2);
int len = (int) (width * arg1) + arg0 * width;
RelativeLayout.LayoutParams params = (RelativeLayout.LayoutParams) viewRedPoint
.getLayoutParams();
params.leftMargin = len;
viewRedPoint.setLayoutParams(params);
}


@Override
public void onPageSelected(int arg0) {
if (arg0 == mImagIds.length - 1) {
btn_start.setVisibility(View.VISIBLE);
} else {
btn_start.setVisibility(View.INVISIBLE);
}
}
 
}
}