自定义View的第二个学习案例，使用ViewPage实现广告轮播，通过组合现有的View实现效果如下：
有关ViewPage使用可以学习谷歌官方API,和训练案例：
1.使用ViewPage实现屏幕滑动：https://developer.android.com/training/animation/screen-slide.html
2.API:https://developer.android.com/reference/android/support/v4/view/ViewPager.html
viewPage试用范围较广 比如tab切换，和引导页面等。学习过程中遇到一个问题，使用setCurrentItem(posetion)实现页面定位时会报错误，需要重新设定Adapter
viewPage.setAdapter(new MyViewPageAdapter());viewPage.setCurrentItem(posetion, true);
Monition分下如下，性能方面应该不存在bug
1：布局和资源文件如下是：
主页面布局文件：
<?xml version="1.0" encoding="utf-8"?>
<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="com.demo.cyq.MainActivity">
<android.support.v7.widget.Toolbar
android:id="@+id/toobar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="@color/colorPrimary">
</android.support.v7.widget.Toolbar>
<android.support.v4.view.ViewPager
android:id="@+id/viewPage"
android:layout_width="match_parent"
android:layout_height="200dp"
android:layout_below="@+id/toobar">
</android.support.v4.view.ViewPager>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignBottom="@id/viewPage"
android:background="#44000000"
android:gravity="center_horizontal"
android:orientation="vertical">
<TextView
android:id="@+id/imgDescription"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:padding="10dp"
android:text=""
android:textColor="#FFFFFF"
android:textSize="20sp" />
<LinearLayout
android:id="@+id/ll_point_group"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="center_horizontal"
android:orientation="horizontal">
</LinearLayout>
</LinearLayout>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerInParent="true"
android:text="viePage实现轮播"
android:textSize="26sp" />
</RelativeLayout>
下标圆点：
<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:drawable="@drawable/point_press" android:state_enabled="false" />
<item android:drawable="@drawable/point_normal" android:state_enabled="true"/>
</selector>
<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
android:shape="oval">
<size android:width="8dp"
android:height="8dp"/>
<solid android:color="#ff0000"/>
</shape>
<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
android:shape="oval">
<size android:width="8dp"
android:height="8dp"/>
<solid android:color="#FFFFFF"/>
</shape>
MainActivity.class类
package com.demo.cyq;
import android.os.Handler;
import android.os.Message;
import android.support.v4.view.PagerAdapter;
import android.support.v4.view.ViewPager;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.Toolbar;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.TextView;
import android.widget.Toast;
import java.util.ArrayList;
public class MainActivity extends AppCompatActivity {
private Toolbar toolbar;
private ViewPager viewPage;
private TextView imgDescription;
private ArrayList images;
private LinearLayout ll_point_group;
private int[] imgesId = {R.mipmap.banner1, R.mipmap.banner2, R.mipmap.banner3, R.mipmap.banner4};
private String[] imgDescriptions = {"Facebooks Audience Network", "新一代Mac Pro发布", "全国大学生珠三角论坛", "Maple 2016"};
private int presentPostion = 0;
private final int OPTION_TYPE_AUTO = 1, OPTION_TYPE_POINT = 2;
private static int pointClickPosition = 0; //point点击的位置
private boolean isDraging = false;
private Handler handler = new Handler() {
@Override
public void handleMessage(Message msg) {
int option = msg.what;
switch (option) {
case OPTION_TYPE_AUTO: //option==1执行viewPage跳转到下一个
int currentPostion = viewPage.getCurrentItem();//获得当前的ViewPage位置
viewPage.setCurrentItem(++currentPostion, true);
handler.sendEmptyMessageDelayed(OPTION_TYPE_AUTO, 3000);//回调handler 实现自动轮播
break;
case OPTION_TYPE_POINT:
//重新设置Adapter 这个地方不设置就会报如下错误 很诡异：
// The specified child already has a parent. You must call removeView() on the child‘s parent first
int currentPostion2 = viewPage.getCurrentItem();//获得当前的ViewPage位置
viewPage.setAdapter(new MyViewPageAdapter());
viewPage.setCurrentItem(currentPostion2 - currentPostion2 % images.size() + pointClickPosition, true);
handler.sendEmptyMessageDelayed(OPTION_TYPE_AUTO, 3000);//回调handler 实现自动轮播
break;
}
}
};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
toolbar = (Toolbar) findViewById(R.id.toobar);
toolbar.setTitle("ViewPage实现图片轮播");
setSupportActionBar(toolbar);
viewPage = (ViewPager) findViewById(R.id.viewPage);
ll_point_group = (LinearLayout) findViewById(R.id.ll_point_group);
imgDescription = (TextView) findViewById(R.id.imgDescription);
images = new ArrayList<ImageView>();
for (int i = 0; i < imgesId.length; i++) {
ImageView image = new ImageView(this);
image.setBackgroundResource(imgesId[i]);
images.add(image);
ImageView point = new ImageView(this);
point.setBackgroundResource(R.drawable.point_selecte);
//为Point设置布局参数 应为point的父节点是LinerLayout，所以需要使用LinearLayout.LayoutParams
LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(20, 20);
params.bottomMargin = 20;
if (i == 0)
point.setEnabled(false);
else {
point.setEnabled(true);
params.leftMargin = 20;
}
point.setLayoutParams(params);
ll_point_group.addView(point);
}
viewPage.setAdapter(new MyViewPageAdapter());
//初始化显示imgDescription
imgDescription.setText(imgDescriptions[presentPostion]);
//设置初始启动imageView的位置为1000的中间，避免初始为0时不能向左滑动
viewPage.setCurrentItem(1000 / 2 - 1000 / 2 % images.size(), true);
//设置ViewPage页面切换的监听事件
viewPage.addOnPageChangeListener(new MyPageChangeListener());
//延迟发送handler消息 用于启动ViewPage自动轮播
handler.sendEmptyMessageDelayed(OPTION_TYPE_AUTO, 2000);
for (int i = 0; i < ll_point_group.getChildCount(); i++) {
final View point = ll_point_group.getChildAt(i);
final int finalI = i;
point.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
pointClickPosition = finalI;
handler.removeCallbacksAndMessages(null);
handler.sendEmptyMessageDelayed(OPTION_TYPE_POINT, 50);
for (int j = 0; j < ll_point_group.getChildCount(); j++) {
ll_point_group.getChildAt(j).setEnabled(true);
}
point.setEnabled(false);
}
});
}
}
/**
* viewPage切换监听
*/
class MyPageChangeListener implements ViewPager.OnPageChangeListener {
/**
* 当页滑动的时候 回调该方法
*
* @param position 当前滑动页面的位置
* @param positionOffset 当前页面滑动的百分比
* @param positionOffsetPixels 当前页面滑动的像素
*/
@Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
/**
* 页面被选中后已完全显示时调用改方法
*
* @param position 被选中的页面的位置
*/
@Override
public void onPageSelected(int position) {
imgDescription.setText(imgDescriptions[position % imgDescriptions.length]);
ll_point_group.getChildAt(presentPostion % images.size()).setEnabled(true);
ll_point_group.getChildAt(position % imgDescriptions.length).setEnabled(false);
presentPostion = position;
}
/**
* 页面滑动的状态
* 静止-滑动
* 滑动-静止
* 静止-拖拽
*
* @param state
*/
@Override
public void onPageScrollStateChanged(int state) {
if (state == viewPage.SCROLL_STATE_DRAGGING) { //拖拽状态
isDraging = true;
//如果处于拖拽状态 就移除handler 避免拖拽过程中自动轮播、
handler.removeCallbacksAndMessages(null);
} else if (state == viewPage.SCROLL_STATE_SETTLING) {//滑动状态
} else if (state == viewPage.SCROLL_STATE_IDLE) {//休闲状态
isDraging = false;
//拖拽结束后调用改方法 先移除handler 然后重新发送handler 启动自动 轮播
handler.removeCallbacksAndMessages(null);
handler.sendEmptyMessageDelayed(OPTION_TYPE_AUTO, 3000);
}
}
}
/**
* pageAdaapter适配器
*/
class MyViewPageAdapter extends PagerAdapter {
/**
* 返回ViewPage总数
*
* @return
*/
@Override
public int getCount() {
return 1000;
}
/**
* 返回ViewPage中的position位置处的ImageView
*
* @param container 代表ViewPage
* @param position 位置
* @return 返回ViewPage
*/
@Override
public Object instantiateItem(ViewGroup container, final int position) {
ImageView imageView = (ImageView) images.get(position % images.size());
container.addView(imageView);
//监听Touch事件 长按图片时禁止viewpage滚动
viewPage.setOnTouchListener(new View.OnTouchListener() {
@Override
public boolean onTouch(View view, MotionEvent motionEvent) {
switch (motionEvent.getAction()) {
case MotionEvent.ACTION_DOWN:
//鼠标按下的时候移除handler
handler.removeCallbacksAndMessages(null);
break;
case MotionEvent.ACTION_MOVE:
break;
case MotionEvent.ACTION_UP:
//鼠标抬起的时候移除handler 并且重新发送handler
handler.removeCallbacksAndMessages(null);
handler.sendEmptyMessageDelayed(OPTION_TYPE_AUTO, 3000);
break;
}
return false; //返回false 表示不消费触摸操作 任然可以触发其他操作
}
});
//为当前imageView设置点击监听
imageView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Toast.makeText(MainActivity.this, imgDescriptions[position % imgDescriptions.length], Toast.LENGTH_SHORT).show();
}
});
return imageView;
}
/**
* 工系统调用 判断instantiateItem方法返回的View是否和object相同
*
* @param view instantiateItem方法返回的ImageView
* @param object
* @return
*/
@Override
public boolean isViewFromObject(View view, Object object) {
return view == object;
}
/**
* 供系统调用 用于销毁ViewPage中的object
*
* @param container
* @param position
* @param object
*/
@Override
public void destroyItem(ViewGroup container, int position, Object object) {
container.removeView((View) object);
}
}
}
时间： 2024-08-07 07:46:47