闪屏界面的实现分析

实现的效果：

主要代码及分析：

1.引导界面整体布局，在布局文件中首先加入ViewPager 这个组件，然后加入四个ImageView 组件，代码如下：

<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"
tools:context=".GuideActivit<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"
tools:context=".GuideActivity" >
<android.support.v4.view.ViewPager
android:id="@+id/vpGuide"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
>
</android.support.v4.view.ViewPager>
<LinearLayout
android:id="@+id/linearLayout1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_centerHorizontal="true"
android:layout_marginTop="40dp" >
<ImageView
android:id="@+id/guide_dot1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="@drawable/bg_point_selected"
/>
<ImageView
android:id="@+id/guide_2"
android:layout_marginLeft="10dp"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="@drawable/bg_point"

/>
<ImageView
android:id="@+id/guide_3"
android:layout_marginLeft="10dp"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="@drawable/bg_point"
/>
<ImageView
android:id="@+id/guide_4"
android:layout_marginLeft="10dp"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="@drawable/bg_point"
/>
</LinearLayout>
</RelativeLayout>y" >
<android.support.v4.view.ViewPager
android:id="@+id/vpGuide"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
>
</android.support.v4.view.ViewPager>
<LinearLayout
android:id="@+id/linearLayout1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_centerHorizontal="true"
android:layout_marginTop="40dp" >
<ImageView
android:id="@+id/guide_dot1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="@drawable/bg_point_selected"
/>
<ImageView
android:id="@+id/guide_2"
android:layout_marginLeft="10dp"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="@drawable/bg_point"
/>
<ImageView
android:id="@+id/guide_3"
android:layout_marginLeft="10dp"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="@drawable/bg_point"
/>
<ImageView
android:id="@+id/guide_4"
android:layout_marginLeft="10dp"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="@drawable/bg_point"
/>
</LinearLayout>
</RelativeLayout>

其中bg_point_selected的代码：

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android" android:shape="oval" >

<solid android:color="#427AB7" />
<size
android:height="8dp"
android:width="8dp" />
</shape>

bg_point文件如下：

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android" android:shape="oval">
<!-- 未被选中 -->
<solid android:color="@android:color/black" />
<size
android:height="8dp"
android:width="8dp" />

</shape>

2.切换布局文件：

view1_of_pager.xml:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@drawable/guide_2"
android:orientation="vertical" >
</LinearLayout>

view2_of_pager.xml文件、view3_of_pager.xml文件与上的代码相同，只是图片不同。

view4_of_pager.xml文件：

<?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:background="@drawable/guide_1"
android:orientation="vertical" >
<TextView
android:id="@+id/tvGO"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_alignParentRight="true"
android:layout_marginBottom="16dp"
android:layout_marginRight="19dp"
android:background="@drawable/start_select"
android:gravity="center"
android:text="GO"
android:textColor="#ffffff"
android:textSize="30sp"
/>
</RelativeLayout>

3.编写GuideAdapter类：

package com.example.cl;
import java.util.List;

import android.support.v4.view.PagerAdapter;
import android.util.Log;
import android.view.View;
import android.view.ViewGroup;
public class GuideAdapter extends PagerAdapter {
private List<View> views;
public GuideAdapter(List<View> views) {
this.views = views;
}
@Override
public int getCount() {
return  views.size();

}
@Override
public boolean isViewFromObject(View view, Object object) {
return view==object;
}
@Override
public void destroyItem(ViewGroup container, int position, Object object) {
View view=views.get(position);
container.removeView(view);
}
@Override
public Object instantiateItem(ViewGroup container, int position) {
container.addView(views.get(position));
return views.get(position);
}

}

<span style="color:#ff0000;">
</span>

这里特别讲一下PageAdapter——PageView的适配器：

适配器想必大家都不莫生，在ListView中也有适配器，listView通过重写GetView（）函数来获取当前要加载的Item。而PageAdapter不太相同，毕竟PageAdapter是单个VIew的合集。

PageAdapter 必须重写的四个函数：

boolean isViewFromObject(View arg0, Object arg1)
int getCount() 
void destroyItem(ViewGroup container, int position,Object object)
Object instantiateItem(ViewGroup container, int position)
先看看各个函数，我们上面都做了什么吧：

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

}

getCount():返回要滑动的VIew的个数

@Override
public void destroyItem(ViewGroup container, int position, Object object) {
View view=views.get(position);
container.removeView(view);
}

destroyItem（）：从当前container中删除指定位置（position）的View;

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

这样重写

ad70
4.修改GuideActivity：

public class GuideActivity extends Activity {
private List<View> guideViews;
private ViewPager vpGuide;
private int[]guide_dots={R.id.guide_dot1,R.id.guide_2,R.id.guide_3,R.id.guide_4};
private ImageView[] dots;
private TextView tvGO;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_guide);
initGuideViews();
initDots();
setListeners();
}

private void setListeners() {

vpGuide.setOnPageChangeListener(new OnPageChangeListener() {

@Override
public void onPageSelected(int position) {

for(int i=0;i<guide_dots.length;i++){
if(position==i){
dots[i].setImageResource(R.drawable.bg_point_selected);

}else{

dots[i].setImageResource(R.drawable.bg_point);
}
}
}

@Override
public void onPageScrolled(int arg0, float arg1, int arg2) {
// TODO Auto-generated method stub

}

@Override
public void onPageScrollStateChanged(int arg0) {

}
});
tvGO.setOnClickListener(new OnClickListener() {

@Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
Intent intent=new Intent(GuideActivity.this,LoginActivity.class);
startActivity(intent);
}
});
}

private void initDots() {

dots=new ImageView[4];
for(int i=0;i<dots.length;i++){
dots[i]=(ImageView) findViewById(guide_dots[i]);

}

}

private void initGuideViews() {
vpGuide=(ViewPager) findViewById(R.id.vpGuide);
//准备好切换的view
guideViews=new ArrayList<View>();
LayoutInflater layoutInfalter=LayoutInflater.from(this);
guideViews.add(layoutInfalter.inflate(R.layout.view1_of_pager, null));
guideViews.add(layoutInfalter.inflate(R.layout.view2_of_pager, null));
guideViews.add(layoutInfalter.inflate(R.layout.view3_of_pager, null));
<strong><span style="color:#ff0000;">View view4=layoutInfalter.inflate(R.layout.view4_of_pager, null);
guideViews.add(view4);
tvGO=(TextView) view4.findViewById(R.id.tvGO);</span></strong>

GuideAdapter guideAdapter=new GuideAdapter(guideViews);
vpGuide.setAdapter(guideAdapter);
}

}

以上为实现闪屏界面的主要代码，还不完善，继续加油！！！！