我需要实现轮播视图。到目前为止我尝试过的是
此代码工作正常，它还显示图像gallary视图中的封面流程寻呼效果。但是这段代码中的一个问题是当图像显示在封面流程中时，当前图像可以正常显示但下一个图像在当前图像的前面看到。
我该如何解决这个问题。
主要活动
package net.leolink.android.simpleinfinitecarousel;
import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
import android.support.v4.view.ViewPager;
public class MainActivity extends FragmentActivity {
public final static int PAGES = 5;
// You can choose a bigger number for LOOPS, but you know, nobody will fling
// more than 1000 times just in order to test your "infinite" ViewPager :D
public final static int LOOPS = 1000;
public final static int FIRST_PAGE = PAGES * LOOPS / 2;
public final static float BIG_SCALE = 1.0f;
public final static float SMALL_SCALE = 0.7f;
public final static float DIFF_SCALE = BIG_SCALE - SMALL_SCALE;
private int[] musicCover = { R.drawable.cover1, R.drawable.cover2,
R.drawable.cover3, R.drawable.cover4, R.drawable.cover5};
public MyPagerAdapter adapter;
public ViewPager pager;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
pager = (ViewPager) findViewById(R.id.myviewpager);
adapter = new MyPagerAdapter(this, this.getSupportFragmentManager());
pager.setAdapter(adapter);
pager.setOnPageChangeListener(adapter);
// Set current item to the middle page so we can fling to both
// directions left and right
pager.setCurrentItem(FIRST_PAGE);
// Necessary or the pager will only have one extra page to show
// make this at least however many pages you can see
pager.setOffscreenPageLimit(3);
// Set margin for pages as a negative number, so a part of next and
// previous pages will be showed
pager.setPageMargin(-450);
}
}
MyFragment
package net.leolink.android.simpleinfinitecarousel;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.LinearLayout;
import android.widget.TextView;
public class MyFragment extends Fragment {
public static Fragment newInstance(MainActivity context, int pos,
float scale)
{
Bundle b = new Bundle();
b.putInt("pos", pos);
b.putFloat("scale", scale);
return Fragment.instantiate(context, MyFragment.class.getName(), b);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
if (container == null) {
return null;
}
LinearLayout l = (LinearLayout)
inflater.inflate(R.layout.mf, container, false);
int pos = this.getArguments().getInt("pos");
/*TextView tv = (TextView) l.findViewById(R.id.text);
tv.setText("Position = " + pos);*/
MyLinearLayout root = (MyLinearLayout) l.findViewById(R.id.root);
float scale = this.getArguments().getFloat("scale");
root.setScaleBoth(scale);
return l;
}
}
MyLinearLayout
package net.leolink.android.simpleinfinitecarousel;
import android.content.Context;
import android.graphics.Canvas;
import android.util.AttributeSet;
import android.widget.LinearLayout;
public class MyLinearLayout extends LinearLayout {
private float scale = MainActivity.BIG_SCALE;
public MyLinearLayout(Context context, AttributeSet attrs) {
super(context, attrs);
}
public MyLinearLayout(Context context) {
super(context);
}
public void setScaleBoth(float scale)
{
this.scale = scale;
this.invalidate(); // If you want to see the scale every time you set
// scale you need to have this line here,
// invalidate() function will call onDraw(Canvas)
// to redraw the view for you
}
@Override
protected void onDraw(Canvas canvas) {
// The main mechanism to display scale animation, you can customize it
// as your needs
int w = this.getWidth();
int h = this.getHeight();
canvas.scale(scale, scale, w/2, h/2);
super.onDraw(canvas);
}
}
MyPagerAdapter
package net.leolink.android.simpleinfinitecarousel;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;
public class MyPagerAdapter extends FragmentPagerAdapter implements
ViewPager.OnPageChangeListener {
private MyLinearLayout cur = null;
private MyLinearLayout next = null;
private MainActivity context;
private FragmentManager fm;
private float scale;
public MyPagerAdapter(MainActivity context, FragmentManager fm) {
super(fm);
this.fm = fm;
this.context = context;
}
@Override
public Fragment getItem(int position)
{
// make the first pager bigger than others
if (position == MainActivity.FIRST_PAGE)
scale = MainActivity.BIG_SCALE;
else
scale = MainActivity.SMALL_SCALE;
position = position % MainActivity.PAGES;
return MyFragment.newInstance(context, position, scale);
}
@Override
public int getCount()
{
return MainActivity.PAGES * MainActivity.LOOPS;
}
@Override
public void onPageScrolled(int position, float positionOffset,
int positionOffsetPixels)
{
if (positionOffset >= 0f && positionOffset <= 2f)
{
cur = getRootView(position);
next = getRootView(position +1);
cur.setScaleBoth(MainActivity.BIG_SCALE
- MainActivity.DIFF_SCALE * positionOffset);
next.setScaleBoth(MainActivity.SMALL_SCALE
+ MainActivity.DIFF_SCALE * positionOffset);
}
}
@Override
public void onPageSelected(int position) {}
@Override
public void onPageScrollStateChanged(int state) {}
private MyLinearLayout getRootView(int position)
{
return (MyLinearLayout)
fm.findFragmentByTag(this.getFragmentTag(position))
.getView().findViewById(R.id.root);
}
private String getFragmentTag(int position)
{
return "android:switcher:" + context.pager.getId() + ":" + position;
}
}
main.xml中
<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"
android:background="#CCC"
tools:context=".MainActivity" >
<android.support.v4.view.ViewPager
android:id="@+id/myviewpager"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_gravity="center"
android:overScrollMode="never" />
</RelativeLayout>
mf.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:orientation="vertical"
android:gravity="center">
<net.leolink.android.simpleinfinitecarousel.MyLinearLayout
android:id="@+id/root"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:gravity="center"
android:background="@android:color/transparent">
<ImageView
android:id="@+id/content"
android:layout_width="500dp"
android:layout_height="200dp"
android:background="@drawable/cover3"/>
</net.leolink.android.simpleinfinitecarousel.MyLinearLayout>
</LinearLayout>