Android 引导页的代码

Posted 2021-02-08 一叶孤城

布局代码

<android.support.v4.view.ViewPager
    android:id="@+id/viewpage"
    android:layout_width="match_parent"
    android:layout_height="match_parent" />
<!--android:background="@drawable/btnselector"-->
<Button
    android:id="@+id/btnty"

    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentBottom="true"
    android:layout_centerHorizontal="true"
    android:layout_marginBottom="100dp"
    android:background="@drawable/btnselector"
    android:paddingLeft="30dp"
    android:paddingRight="30dp"
    android:visibility="gone"
    android:text="立即体验"
    android:textColor="@drawable/textselector"
    android:textSize="20sp" />

<RelativeLayout
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentBottom="true"
    android:layout_centerHorizontal="true"
    android:layout_marginBottom="80dp">

    <LinearLayout
        android:id="@+id/linearpointgroup"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="horizontal" />
    <ImageView
        android:id="@+id/ivredpoint"
        android:background="@drawable/pointred"
        android:layout_width="10dp"
        android:layout_height="10dp" />
    
</RelativeLayout>

后台代码

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.v4.view.PagerAdapter;
import android.support.v4.view.ViewPager;
import android.view.View;
import android.view.ViewGroup;
import android.view.ViewTreeObserver;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.RelativeLayout;

import java.util.ArrayList;
import java.util.List;

public class GuideActivity extends Activity {

List<ImageView> imageViews;
ViewPager vpage;
LinearLayout linearLayout;
ImageView imagepoint;
int leftmax = 0;
Button btnty;

int pointwidth=0;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_guide);
vpage = (ViewPager) findViewById(R.id.viewpage);
linearLayout = (LinearLayout) findViewById(R.id.linearpointgroup);
imagepoint = (ImageView) findViewById(R.id.ivredpoint);
//10为 默认点的 布局宽度
pointwidth=DensityUtil.diptopx(GuideActivity.this,10);
btnty = (Button) findViewById(R.id.btnty);
int[] intimage = new int[]{R.drawable.guide1, R.drawable.guide2, R.drawable.guide3};
imageViews = new ArrayList<>();
for (int ii = 0; ii < intimage.length; ii++) {
ImageView imageView = new ImageView(GuideActivity.this);
imageView.setBackgroundResource(intimage[ii]);
imageViews.add(imageView);
//创建点

        ImageView point = new ImageView(GuideActivity.this);
        point.setBackgroundResource(R.drawable.point);
        //此处单位是像素 需要做大小手机的适配 调用转换成像素的方法
        LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(pointwidth, pointwidth);
        if (ii != 0) {
            params.leftMargin = pointwidth;
        }
        point.setLayoutParams(params);
        linearLayout.addView(point);
    }
    vpage.setAdapter(new pagetadapter());

    Button btn = (Button) findViewById(R.id.btnty);
    btn.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            //设置缓存  进入过主界面
            CacheParam.setkey(GuideActivity.this, "EnterMain", true);
            Intent intent = new Intent(GuideActivity.this, LogInActivity.class);
            startActivity(intent);
            finish();
        }
    });

    imagepoint.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
        @Override
        public void onGlobalLayout() {
            //执行一次即可 所以 先移除
            imagepoint.getViewTreeObserver().removeGlobalOnLayoutListener(this);
            //间距 = 第一个点距离左边的距离-第0个点距离左边的距离
            leftmax = linearLayout.getChildAt(1).getLeft() - linearLayout.getChildAt(0).getLeft();
        }
    });
    vpage.setOnPageChangeListener(new MyPageChange());
}

class MyPageChange implements ViewPager.OnPageChangeListener {
    //当也没滑动的时候调用
    /*
     * 当前滑动页面的位置
     * 页面滑动的百分比
     * 滑动的像素*/
    @Override
    public void onPageScrolled(int position, float positionoffset, int positionoffsetpixels) {

//两点间滑动距离对应的坐标=原来的起始位置+两点间移动的距离
int leftmargin = (int) (position * leftmax + (positionoffset * leftmax));

        RelativeLayout.LayoutParams params = (RelativeLayout.LayoutParams) imagepoint.getLayoutParams();
        params.leftMargin = leftmargin;
        imagepoint.setLayoutParams(params);
    }

    /**
     * 当页面选中的时候调用这个方法
     * 被选中页面的位置
     */
    @Override
    public void onPageSelected(int position) {
        //最后一个页面
        if (position == imageViews.size() - 1) {
            btnty.setVisibility(View.VISIBLE);
        } else//其他页面
        {
            btnty.setVisibility(View.GONE);
        }
    }

    /**
     * 当页面滑动状态变化的时候
     */
    @Override
    public void onPageScrollStateChanged(int i) {

    }
}

class pagetadapter extends PagerAdapter {

    @Override
    public int getCount() {
        return imageViews.size();
    }

    @Override
    public Object instantiateItem(@NonNull ViewGroup container, int position) {
        ImageView imageView = imageViews.get(position);
        container.addView(imageView);
        return imageView;

    }

    @Override
    public boolean isViewFromObject(@NonNull View view, @NonNull Object o) {
        return view == o;
    }


    @Override
    public void destroyItem(@NonNull ViewGroup container, int position, @NonNull Object object) {

// super.destroyItem(container, position, object);
container.removeView((View) object);
}

}

}

import android.content.Context;

public class DensityUtil {
/
根据手机的分辨率 从dip的单位 转为px 像素/
public static int diptopx(Context context,float dpvalue)
{
final float scale=context.getResources().getDisplayMetrics().density;
return (int)(dpvaluescale+0.5f);
}
/
根据手机的分辨率 从px的单位 转为dip
* */
public static int pxtodip(Context context,float pxvalue)
{
final float scale=context.getResources().getDisplayMetrics().density;
return (int)(pxvalue/scale+0.5f);
}

}